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1
Bilaniuk, Nykolai. "Optical microphone transduction techniques." Applied Acoustics 50, no. 1 (January 1997): 35–63. http://dx.doi.org/10.1016/s0003-682x(96)00034-5.
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Yesilkoy, Filiz. "Optical Interrogation Techniques for Nanophotonic Biochemical Sensors." Sensors 19, no. 19 (October 3, 2019): 4287. http://dx.doi.org/10.3390/s19194287.
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The manipulation of light via nanoengineered surfaces has excited the optical community in the past few decades. Among the many applications enabled by nanophotonic devices, sensing has stood out due to their capability of identifying miniscule refractive index changes. In particular, when free-space propagating light effectively couples into subwavelength volumes created by nanostructures, the strongly-localized near-fields can enhance light’s interaction with matter at the nanoscale. As a result, nanophotonic sensors can non-destructively detect chemical species in real-time without the need of exogenous labels. The impact of such nanophotonic devices on biochemical sensor development became evident as the ever-growing research efforts in the field started addressing many critical needs in biomedical sciences, such as low-cost analytical platforms, simple quantitative bioassays, time-resolved sensing, rapid and multiplexed detection, single-molecule analytics, among others. In this review, the optical transduction methods used to interrogate optical resonances of nanophotonic sensors will be highlighted. Specifically, the optical methodologies used thus far will be evaluated based on their capability of addressing key requirements of the future sensor technologies, including miniaturization, multiplexing, spatial and temporal resolution, cost and sensitivity.
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Bracamonte, Angel Guillermo. "Current Advances in Nanotechnology for the Next Generation of Sequencing (NGS)." Biosensors 13, no. 2 (February 12, 2023): 260. http://dx.doi.org/10.3390/bios13020260.
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This communication aims at discussing strategies based on developments from nanotechnology focused on the next generation of sequencing (NGS). In this regard, it should be noted that even in the advanced current situation of many techniques and methods accompanied with developments of technology, there are still existing challenges and needs focused on real samples and low concentrations of genomic materials. The approaches discussed/described adopt spectroscopical techniques and new optical setups. PCR bases are introduced to understand the role of non-covalent interactions by discussing about Nobel prizes related to genomic material detection. The review also discusses colorimetric methods, polymeric transducers, fluorescence detection methods, enhanced plasmonic techniques such as metal-enhanced fluorescence (MEF), semiconductors, and developments in metamaterials. In addition, nano-optics, challenges linked to signal transductions, and how the limitations reported in each technique could be overcome are considered in real samples. Accordingly, this study shows developments where optical active nanoplatforms generate signal detection and transduction with enhanced performances and, in many cases, enhanced signaling from single double-stranded deoxyribonucleic acid (DNA) interactions. Future perspectives on miniaturized instrumentation, chips, and devices aimed at detecting genomic material are analyzed. However, the main concept in this report derives from gained insights into nanochemistry and nano-optics. Such concepts could be incorporated into other higher-sized substrates and experimental and optical setups.
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Hira, Steven M., Khaled Aledealat, Kan-Sheng Chen, Mark Field, Gerard J. Sullivan, P. Bryant Chase, Peng Xiong, Stephan von Molnár, and Geoffrey F. Strouse. "Detection of Target ssDNA Using a Microfabricated Hall Magnetometer with Correlated Optical Readout." Journal of Biomedicine and Biotechnology 2012 (2012): 1–10. http://dx.doi.org/10.1155/2012/492730.
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Sensing biological agents at the genomic level, while enhancing the response time for biodetection over commonly used, optics-based techniques such as nucleic acid microarrays or enzyme-linked immunosorbent assays (ELISAs), is an important criterion for new biosensors. Here, we describe the successful detection of a 35-base, single-strand nucleic acid target by Hall-based magnetic transduction as a mimic for pathogenic DNA target detection. The detection platform has low background, large signal amplification following target binding and can discriminate a single, 350 nm superparamagnetic bead labeled with DNA. Detection of the target sequence was demonstrated at 364 pM (<2 target DNA strands per bead) target DNA in the presence of 36 μM nontarget (noncomplementary) DNA (<10 ppm target DNA) using optical microscopy detection on a GaAs Hall mimic. The use of Hall magnetometers as magnetic transduction biosensors holds promise for multiplexing applications that can greatly improve point-of-care (POC) diagnostics and subsequent medical care.
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MacDougall, Matthew, Samuel U. Nummela, Shanna Coop, Anita Disney, Jude F. Mitchell, and Cory T. Miller. "Optogenetic manipulation of neural circuits in awake marmosets." Journal of Neurophysiology 116, no. 3 (September 1, 2016): 1286–94. http://dx.doi.org/10.1152/jn.00197.2016.
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Optogenetics has revolutionized the study of functional neuronal circuitry (Boyden ES, Zhang F, Bamberg E, Nagel G, Deisseroth K. Nat Neurosci 8: 1263–1268, 2005; Deisseroth K. Nat Methods 8: 26–29, 2011). Although these techniques have been most successfully implemented in rodent models, they have the potential to be similarly impactful in studies of nonhuman primate brains. Common marmosets ( Callithrix jacchus) have recently emerged as a candidate primate model for gene editing, providing a potentially powerful model for studies of neural circuitry and disease in primates. The application of viral transduction methods in marmosets for identifying and manipulating neuronal circuitry is a crucial step in developing this species for neuroscience research. In the present study we developed a novel, chronic method to successfully induce rapid photostimulation in individual cortical neurons transduced by adeno-associated virus to express channelrhodopsin (ChR2) in awake marmosets. We found that large proportions of neurons could be effectively photoactivated following viral transduction and that this procedure could be repeated for several months. These data suggest that techniques for viral transduction and optical manipulation of neuronal populations are suitable for marmosets and can be combined with existing behavioral preparations in the species to elucidate the functional neural circuitry underlying perceptual and cognitive processes.
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Rittersma, Z. M. "Recent achievements in miniaturised humidity sensors—a review of transduction techniques." Sensors and Actuators A: Physical 96, no. 2-3 (February 2002): 196–210. http://dx.doi.org/10.1016/s0924-4247(01)00788-9.
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Tsien, R. Y. "Intracellular signal transduction in four dimensions: from molecular design to physiology." American Journal of Physiology-Cell Physiology 263, no. 4 (October 1, 1992): C723—C728. http://dx.doi.org/10.1152/ajpcell.1992.263.4.c723.
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Designed fluorescent indicators are the basis for a major new technique in cell physiology, the quantitative measurement and dynamic imaging of intracellular concentrations of important ions and messengers such as Ca2+, Na+, H+, and adenosine 3',5'-cyclic monophosphate. Molecular engineering has now produced indicators with quite good selectivity and sensitivity for these analytes. In many cases, these probes can be introduced into large populations of cells by means of membrane-permeant chemical derivatives, so that the plasma membrane need never be disrupted or physically breached at any point. Like many other optical microscopic techniques, fluorescent indicators are readily applied to study living cells and tissues, with an unparalleled combination of spatial and temporal resolution. They offer one of the few methods for continuous nondestructive monitoring of dynamic intracellular biochemistry and signal transduction in single cells or subregions of cells.
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Tang, Jiukai, Guangyu Qiu, and Jing Wang. "Recent Development of Optofluidics for Imaging and Sensing Applications." Chemosensors 10, no. 1 (January 1, 2022): 15. http://dx.doi.org/10.3390/chemosensors10010015.
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Optofluidics represents the interaction of light and fluids on a chip that integrates microfluidics and optics, which provides a promising optical platform for manipulating and analyzing fluid samples. Recent years have witnessed a substantial growth in optofluidic devices, including the integration of optical and fluidic control units, the incorporation of diverse photonic nanostructures, and new applications. All these advancements have enabled the implementation of optofluidics with improved performance. In this review, the recent advances of fabrication techniques and cutting-edge applications of optofluidic devices are presented, with a special focus on the developments of imaging and sensing. Specifically, the optofluidic based imaging techniques and applications are summarized, including the high-throughput cytometry, biochemical analysis, and optofluidic nanoparticle manipulation. The optofluidic sensing section is categorized according to the modulation approaches and the transduction mechanisms, represented by absorption, reflection/refraction, scattering, and plasmonics. Perspectives on future developments and promising avenues in the fields of optofluidics are also provided.
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Li, Xinrui, and Dandan Li. "Study of Wireless Sensor Network Based on Optical Communication: Research Challenges and Current Results." Modern Electronic Technology 6, no. 1 (June 23, 2022): 33. http://dx.doi.org/10.26549/met.v6i1.11372.
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With the rapid developments of commercial demands, a majority of advanced researches have been investigated for the applications of underwater wireless sensor (WSN) networks. Recently optical communication has been considered for underwater wireless sensor network. An experimental set-up for testing optical communication underwater has been provided and designed in present papers to maximize the energy coupled from these displacements to the transduction mechanism that converts the mechanical energy into electrical. The true case has been considered by measuring diffuse attenuation coefficients in different seas. One stand out potential optical communication method, Visible Light Communication (VLC) has been talked and several communication methods are compared from many points of view, for example attenuation in salt water. The evaluation of modulation techniques for underwater wireless optical communications has been displayed, and further how the data collection and storage with an underwater WSN is introduced. In this paper current researches for an (UWSN) based on optical communication are studied, in particular the potential VLC method and comparisons of VLC with other optical communication approaches. Underwater challenges would be analyzed by comparing a sort of communication methods, applied in underwater. Future work will be developed at last.
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Bonini, Andrea, Angela Gilda Carota, Noemi Poma, Federico Maria Vivaldi, Denise Biagini, Daria Bottai, Alessio Lenzi, Arianna Tavanti, Fabio Di Francesco, and Tommaso Lomonaco. "Emerging Biosensing Technologies towards Early Sepsis Diagnosis and Management." Biosensors 12, no. 10 (October 18, 2022): 894. http://dx.doi.org/10.3390/bios12100894.
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Sepsis is defined as a systemic inflammatory dysfunction strictly associated with infectious diseases, which represents an important health issue whose incidence is continuously increasing worldwide. Nowadays, sepsis is considered as one of the main causes of death that mainly affects critically ill patients in clinical settings, with a higher prevalence in low-income countries. Currently, sepsis management still represents an important challenge, since the use of traditional techniques for the diagnosis does not provide a rapid response, which is crucial for an effective infection management. Biosensing systems represent a valid alternative due to their characteristics such as low cost, portability, low response time, ease of use and suitability for point of care/need applications. This review provides an overview of the infectious agents associated with the development of sepsis and the host biomarkers suitable for diagnosis and prognosis. Special focus is given to the new emerging biosensing technologies using electrochemical and optical transduction techniques for sepsis diagnosis and management.
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Aziz, Ilaria Abdel, and Maria Rosa Antognazza. "Wireless nanotechnologies light up the next frontier in cell Calcium signalling." MRS Advances 5, no. 64 (2020): 3473–89. http://dx.doi.org/10.1557/adv.2020.348.
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AbstractCalcium ions impact nearly every aspect of cellular life, playing crucial roles as secondary messengers in regulation of neurotransmission, cell proliferation, migration and differentiation processes, intracellular homeostasis, long-distance signal propagation and stimuli physiological response. Despite its key-role, available techniques to study and selectively regulate Ca2+ signalling largely rely on chemical and electrical approaches, which often cannot ensure the necessary spatial and temporal resolution, specificity, modulation and reversal capability. In this context, Ca2+ modulation based on physical stimuli, such as magnetic, mechanical and optical tools, are emerging ass promising innovative solutions. Here, we focus our attention on a subclass of these approaches, namely wireless-activated techniques, and on functional materials able to act as non-invasive transduction elements. We present an overview of most recent outcomes in the field, and we critically evaluate their advantages and drawbacks. This work is mainly directed to the material science community, but hopefully it will provide a useful perspective also to the broader readership of biotechnologists, physiologists and clinicians.
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Moore, Steven Ian, Michael G. Ruppert, and Yuen Kuan Yong. "Multimodal cantilevers with novel piezoelectric layer topology for sensitivity enhancement." Beilstein Journal of Nanotechnology 8 (February 6, 2017): 358–71. http://dx.doi.org/10.3762/bjnano.8.38.
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Self-sensing techniques for atomic force microscope (AFM) cantilevers have several advantageous characteristics compared to the optical beam deflection method. The possibility of down scaling, parallelization of cantilever arrays and the absence of optical interference associated imaging artifacts have led to an increased research interest in these methods. However, for multifrequency AFM, the optimization of the transducer layout on the cantilever for higher order modes has not been addressed. To fully utilize an integrated piezoelectric transducer, this work alters the layout of the piezoelectric layer to maximize both the deflection of the cantilever and measured piezoelectric charge response for a given mode with respect to the spatial distribution of the strain. On a prototype cantilever design, significant increases in actuator and sensor sensitivities were achieved for the first four modes without any substantial increase in sensor noise. The transduction mechanism is specifically targeted at multifrequency AFM and has the potential to provide higher resolution imaging on higher order modes.
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El Kazzy, Marielle, Jonathan S. Weerakkody, Charlotte Hurot, Raphaël Mathey, Arnaud Buhot, Natale Scaramozzino, and Yanxia Hou. "An Overview of Artificial Olfaction Systems with a Focus on Surface Plasmon Resonance for the Analysis of Volatile Organic Compounds." Biosensors 11, no. 8 (July 23, 2021): 244. http://dx.doi.org/10.3390/bios11080244.
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The last three decades have witnessed an increasing demand for novel analytical tools for the analysis of gases including odorants and volatile organic compounds (VOCs) in various domains. Traditional techniques such as gas chromatography coupled with mass spectrometry, although very efficient, present several drawbacks. Such a context has incited the research and industrial communities to work on the development of alternative technologies such as artificial olfaction systems, including gas sensors, olfactory biosensors and electronic noses (eNs). A wide variety of these systems have been designed using chemiresistive, electrochemical, acoustic or optical transducers. Among optical transduction systems, surface plasmon resonance (SPR) has been extensively studied thanks to its attractive features (high sensitivity, label free, real-time measurements). In this paper, we present an overview of the advances in the development of artificial olfaction systems with a focus on their development based on propagating SPR with different coupling configurations, including prism coupler, wave guide, and grating.
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Magazzù, Alessandro, and Carlos Marcuello. "Investigation of Soft Matter Nanomechanics by Atomic Force Microscopy and Optical Tweezers: A Comprehensive Review." Nanomaterials 13, no. 6 (March 7, 2023): 963. http://dx.doi.org/10.3390/nano13060963.
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Soft matter exhibits a multitude of intrinsic physico-chemical attributes. Their mechanical properties are crucial characteristics to define their performance. In this context, the rigidity of these systems under exerted load forces is covered by the field of biomechanics. Moreover, cellular transduction processes which are involved in health and disease conditions are significantly affected by exogenous biomechanical actions. In this framework, atomic force microscopy (AFM) and optical tweezers (OT) can play an important role to determine the biomechanical parameters of the investigated systems at the single-molecule level. This review aims to fully comprehend the interplay between mechanical forces and soft matter systems. In particular, we outline the capabilities of AFM and OT compared to other classical bulk techniques to determine nanomechanical parameters such as Young’s modulus. We also provide some recent examples of nanomechanical measurements performed using AFM and OT in hydrogels, biopolymers and cellular systems, among others. We expect the present manuscript will aid potential readers and stakeholders to fully understand the potential applications of AFM and OT to soft matter systems.
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Awang, Mohd Syafiq, Yazmin Bustami, Hairul Hisham Hamzah, Nor Syafirah Zambry, Mohamad Ahmad Najib, Muhammad Fazli Khalid, Ismail Aziah, and Asrulnizam Abd Manaf. "Advancement in Salmonella Detection Methods: From Conventional to Electrochemical-Based Sensing Detection." Biosensors 11, no. 9 (September 18, 2021): 346. http://dx.doi.org/10.3390/bios11090346.
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Large-scale food-borne outbreaks caused by Salmonella are rarely seen nowadays, thanks to the advanced nature of the medical system. However, small, localised outbreaks in certain regions still exist and could possess a huge threat to the public health if eradication measure is not initiated. This review discusses the progress of Salmonella detection approaches covering their basic principles, characteristics, applications, and performances. Conventional Salmonella detection is usually performed using a culture-based method, which is time-consuming, labour intensive, and unsuitable for on-site testing and high-throughput analysis. To date, there are many detection methods with a unique detection system available for Salmonella detection utilising immunological-based techniques, molecular-based techniques, mass spectrometry, spectroscopy, optical phenotyping, and biosensor methods. The electrochemical biosensor has growing interest in Salmonella detection mainly due to its excellent sensitivity, rapidity, and portability. The use of a highly specific bioreceptor, such as aptamers, and the application of nanomaterials are contributing factors to these excellent characteristics. Furthermore, insight on the types of biorecognition elements, the principles of electrochemical transduction elements, and the miniaturisation potential of electrochemical biosensors are discussed.
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Cinelli, Angel R., Dalton Wang, Ping Chen, Weimin Liu, and Mimi Halpern. "Calcium Transients in the Garter Snake Vomeronasal Organ." Journal of Neurophysiology 87, no. 3 (March 1, 2002): 1449–72. http://dx.doi.org/10.1152/jn.00651.2001.
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The signaling cascade involved in chemosensory transduction in the VN organ is incompletely understood. In snakes, the response to nonvolatile prey chemicals is mediated by the vomeronasal (VN) system. Using optical techniques and fluorescent Ca2+ indicators, we found that prey-derived chemoattractants produce initially a transient cytosolic accumulation of [Ca2+]i in the dendritic regions of VN neurons via two pathways: Ca2+release from IP3-sensitive intracellular stores and, to a lesser extent, Ca2+ influx through the plasma membrane. Both components seem to be dependent on IP3 production. Chemoattractants evoke a short-latency Ca2+ elevation even in the absence of extracellular Ca2+, suggesting that in snake VN neurons, Ca2+ release from intracellular stores is independent of a preceding Ca2+ influx, and both components are activated in parallel during early stages of chemosensory transduction. Once the response develops in apical dendritic segments, other mechanisms can also contribute to the amplification and modulation of these chemoattractant-mediated cytosolic Ca2+ transients. In regions close to the cell bodies of the VN neurons, the activation of voltage-sensitive Ca2+ channels and a Ca2+-induced Ca2+ release from intracellular ryanodine-sensitive stores secondarily boost initial cytosolic Ca2+ elevations increasing their magnitude and durations. Return of intracellular Ca2+ to prestimulation levels appears to involve a Ca2+ extrusion mediated by a Na+/Ca2+ exchanger mechanism that probably plays an important role in limiting the magnitude and duration of the stimulation-induced Ca2+ transients.
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Banakar, Morteza, Masoud Hamidi, Zohaib Khurshid, Muhammad Sohail Zafar, Janak Sapkota, Reza Azizian, and Dinesh Rokaya. "Electrochemical Biosensors for Pathogen Detection: An Updated Review." Biosensors 12, no. 11 (October 26, 2022): 927. http://dx.doi.org/10.3390/bios12110927.
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Electrochemical biosensors are a family of biosensors that use an electrochemical transducer to perform their functions. In recent decades, many electrochemical biosensors have been created for pathogen detection. These biosensors for detecting infections have been comprehensively studied in terms of transduction elements, biorecognition components, and electrochemical methods. This review discusses the biorecognition components that may be used to identify pathogens. These include antibodies and aptamers. The integration of transducers and electrode changes in biosensor design is a major discussion topic. Pathogen detection methods can be categorized by sample preparation and secondary binding processes. Diagnostics in medicine, environmental monitoring, and biothreat detection can benefit from electrochemical biosensors to ensure food and water safety. Disposable and reusable biosensors for process monitoring, as well as multiplexed and conformal pathogen detection, are all included in this review. It is now possible to identify a wide range of diseases using biosensors that may be applied to food, bodily fluids, and even objects’ surfaces. The sensitivity of optical techniques may be superior to electrochemical approaches, but optical methods are prohibitively expensive and challenging for most end users to utilize. On the other hand, electrochemical approaches are simpler to use, but their efficacy in identifying infections is still far from satisfactory.
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Wong, Elicia L. S., Khuong Q. Vuong, and Edith Chow. "Nanozymes for Environmental Pollutant Monitoring and Remediation." Sensors 21, no. 2 (January 8, 2021): 408. http://dx.doi.org/10.3390/s21020408.
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Nanozymes are advanced nanomaterials which mimic natural enzymes by exhibiting enzyme-like properties. As nanozymes offer better structural stability over their respective natural enzymes, they are ideal candidates for real-time and/or remote environmental pollutant monitoring and remediation. In this review, we classify nanozymes into four types depending on their enzyme-mimicking behaviour (active metal centre mimic, functional mimic, nanocomposite or 3D structural mimic) and offer mechanistic insights into the nature of their catalytic activity. Following this, we discuss the current environmental translation of nanozymes into a powerful sensing or remediation tool through inventive nano-architectural design of nanozymes and their transduction methodologies. Here, we focus on recent developments in nanozymes for the detection of heavy metal ions, pesticides and other organic pollutants, emphasising optical methods and a few electrochemical techniques. Strategies to remediate persistent organic pollutants such as pesticides, phenols, antibiotics and textile dyes are included. We conclude with a discussion on the practical deployment of these nanozymes in terms of their effectiveness, reusability, real-time in-field application, commercial production and regulatory considerations.
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Wong, Elicia L. S., Khuong Q. Vuong, and Edith Chow. "Nanozymes for Environmental Pollutant Monitoring and Remediation." Sensors 21, no. 2 (January 8, 2021): 408. http://dx.doi.org/10.3390/s21020408.
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Nanozymes are advanced nanomaterials which mimic natural enzymes by exhibiting enzyme-like properties. As nanozymes offer better structural stability over their respective natural enzymes, they are ideal candidates for real-time and/or remote environmental pollutant monitoring and remediation. In this review, we classify nanozymes into four types depending on their enzyme-mimicking behaviour (active metal centre mimic, functional mimic, nanocomposite or 3D structural mimic) and offer mechanistic insights into the nature of their catalytic activity. Following this, we discuss the current environmental translation of nanozymes into a powerful sensing or remediation tool through inventive nano-architectural design of nanozymes and their transduction methodologies. Here, we focus on recent developments in nanozymes for the detection of heavy metal ions, pesticides and other organic pollutants, emphasising optical methods and a few electrochemical techniques. Strategies to remediate persistent organic pollutants such as pesticides, phenols, antibiotics and textile dyes are included. We conclude with a discussion on the practical deployment of these nanozymes in terms of their effectiveness, reusability, real-time in-field application, commercial production and regulatory considerations.
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Gharib, Ghazaleh, İsmail Bütün, Zülâl Muganlı, Gül Kozalak, İlayda Namlı, Seyedali Seyedmirzaei Sarraf, Vahid Ebrahimpour Ahmadi, Erçil Toyran, Andre J. van Wijnen, and Ali Koşar. "Biomedical Applications of Microfluidic Devices: A Review." Biosensors 12, no. 11 (November 16, 2022): 1023. http://dx.doi.org/10.3390/bios12111023.
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Both passive and active microfluidic chips are used in many biomedical and chemical applications to support fluid mixing, particle manipulations, and signal detection. Passive microfluidic devices are geometry-dependent, and their uses are rather limited. Active microfluidic devices include sensors or detectors that transduce chemical, biological, and physical changes into electrical or optical signals. Also, they are transduction devices that detect biological and chemical changes in biomedical applications, and they are highly versatile microfluidic tools for disease diagnosis and organ modeling. This review provides a comprehensive overview of the significant advances that have been made in the development of microfluidics devices. We will discuss the function of microfluidic devices as micromixers or as sorters of cells and substances (e.g., microfiltration, flow or displacement, and trapping). Microfluidic devices are fabricated using a range of techniques, including molding, etching, three-dimensional printing, and nanofabrication. Their broad utility lies in the detection of diagnostic biomarkers and organ-on-chip approaches that permit disease modeling in cancer, as well as uses in neurological, cardiovascular, hepatic, and pulmonary diseases. Biosensor applications allow for point-of-care testing, using assays based on enzymes, nanozymes, antibodies, or nucleic acids (DNA or RNA). An anticipated development in the field includes the optimization of techniques for the fabrication of microfluidic devices using biocompatible materials. These developments will increase biomedical versatility, reduce diagnostic costs, and accelerate diagnosis time of microfluidics technology.
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Aydin, Elif Burcu, Muhammet Aydin, and Mustafa Kemal Sezginturk. "Biosensors in Drug Discovery and Drug Analysis." Current Analytical Chemistry 15, no. 4 (July 3, 2019): 467–84. http://dx.doi.org/10.2174/1573411014666180912131811.
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Background: The determination of drugs in pharmaceutical formulations and human biologic fluids is important for pharmaceutical and medical sciences. Successful analysis requires low sensitivity, high selectivity and minimum interference effects. Current analytical methods can detect drugs at very low levels but these methods require long sample preparation steps, extraction prior to analysis, highly trained technical staff and high-cost instruments. Biosensors offer several advantages such as short analysis time, high sensitivity, real-time analysis, low-cost instruments, and short pretreatment steps over traditional techniques. Biosensors allow quantification not only of the active component in pharmaceutical formulations, but also the degradation products and metabolites in biological fluids. The present review gives comprehensive information on the application of biosensors for drug discovery and analysis. Moreover, this review focuses on the fabrication of these biosensors. Methods: Biosensors can be classified as the utilized bioreceptor and the signal transduction mechanism. The classification based on signal transductions includes electrochemical optical, thermal or acoustic. Electrochemical and optic transducers are mostly utilized transducers used for drug analysis. There are many biological recognition elements, such as enzymes, antibodies, cells that have been used in fabricating of biosensors. Aptamers and antibodies are the most widely used recognition elements for the screening of the drugs. Electrochemical sensors and biosensors have several advantages such as low detection limits, a wide linear response range, good stability and reproducibility. Optical biosensors have several advantages such as direct, real-time and label-free detection of many biological and chemical substances, high specificity, sensitivity, small size and low cost. Modified electrodes enhance sensitivity of the electrodes to develop a new biosensor with desired features. Chemically modified electrodes have gained attention in drug analysis owing to low background current, wide potential window range, simple surface renewal, low detection limit and low cost. Modified electrodes produced by modifying of a solid surface electrode via different materials (carbonaceous materials, metal nanoparticles, polymer, biomolecules) immobilization. Recent advances in nanotechnology offer opportunities to design and construct biosensors. Unique features of nanomaterials provide many advantages in the fabrication of biosensors. Nanomaterials have controllable chemical structures, large surface to volume ratios, functional groups on their surface. To develop proteininorganic hybrid nanomaterials, four preparation methods have been used. These methods are immobilization, conjugation, crosslinking and self-assembly. In the present manuscript, applications of different biosensors, fabricated by using several materials, for drug analysis are reviewed. The biosensing strategies are investigated and discussed in detail. Results: Several analytical techniques such as chromatography, spectroscopy, radiometry, immunoassays and electrochemistry have been used for drug analysis and quantification. Methods based on chromatography require timeconsuming procedure, long sample-preparation steps, expensive instruments and trained staff. Compared to chromatographic methods, immunoassays have simple protocols and lower cost. Electrochemical measurements have many advantages over traditional chemical analyses and give information about drug quantity, metabolic fate of drugs, and pharmacological activity. Moreover, the electroanalytical methods are useful to determine drugs sensitively and selectivity. Additionally, these methods decrease analysis cost and require low-cost instruments and simple sample pretreatment steps. Conclusion: In recent years, drug analyses are performed using traditional techniques. These techniques have a good detection limit, but they have some limitations such as long analysis time, expensive device and experienced personnel requirement. Increased demand for practical and low-cost analytical techniques biosensor has gained interest for drug determinations in medical sciences. Biosensors are unique and successful devices when compared to traditional techniques. For drug determination, different electrode modification materials and different biorecognition elements are used for biosensor construction. Several biosensor construction strategies have been developed to enhance the biosensor performance. With the considerable progress in electrode surface modification, promotes the selectivity of the biosensor, decreases the production cost and provides miniaturization. In the next years, advances in technology will provide low cost, sensitive, selective biosensors for drug analysis in drug formulations and biological samples.
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Manciu, Felicia S., John D. Ciubuc, Karla Parra, Marian Manciu, Kevin E. Bennet, Paloma Valenzuela, Emma M. Sundin, William G. Durrer, Luis Reza, and Giulio Francia. "Label-Free Raman Imaging to Monitor Breast Tumor Signatures." Technology in Cancer Research & Treatment 16, no. 4 (July 4, 2016): 461–69. http://dx.doi.org/10.1177/1533034616655953.
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Although not yet ready for clinical application, methods based on Raman spectroscopy have shown significant potential in identifying, characterizing, and discriminating between noncancerous and cancerous specimens. Real-time and accurate medical diagnosis achievable through this vibrational optical method largely benefits from improvements in current technological and software capabilities. Not only is the acquisition of spectral information now possible in milliseconds and analysis of hundreds of thousands of data points achieved in minutes, but Raman spectroscopy also allows simultaneous detection and monitoring of several biological components. Besides demonstrating a significant Raman signature distinction between nontumorigenic (MCF-10A) and tumorigenic (MCF-7) breast epithelial cells, our study demonstrates that Raman can be used as a label-free method to evaluate epidermal growth factor activity in tumor cells. Comparative Raman profiles and images of specimens in the presence or absence of epidermal growth factor show important differences in regions attributed to lipid, protein, and nucleic acid vibrations. The occurrence, which is dependent on the presence of epidermal growth factor, of new Raman features associated with the appearance of phosphothreonine and phosphoserine residues reflects a signal transduction from the membrane to the nucleus, with concomitant modification of DNA/RNA structural characteristics. Parallel Western blotting analysis reveals an epidermal growth factor induction of phosphorylated Akt protein, corroborating the Raman results. The analysis presented in this work is an important step toward Raman-based evaluation of biological activity of epidermal growth factor receptors on the surfaces of breast cancer cells. With the ultimate future goal of clinically implementing Raman-guided techniques for the diagnosis of breast tumors (e.g., with regard to specific receptor activity), the current results just lay the foundation for further label-free optical tools to diagnose the disease.
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Gargiulo, Valentina, Michela Alfè, Laura Giordano, and Stefano Lettieri. "Materials for Chemical Sensing: A Comprehensive Review on the Recent Advances and Outlook Using Ionic Liquids, Metal–Organic Frameworks (MOFs), and MOF-Based Composites." Chemosensors 10, no. 8 (July 22, 2022): 290. http://dx.doi.org/10.3390/chemosensors10080290.
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The ability to measure and monitor the concentration of specific chemical and/or gaseous species (i.e., “analytes”) is the main requirement in many fields, including industrial processes, medical applications, and workplace safety management. As a consequence, several kinds of sensors have been developed in the modern era according to some practical guidelines that regard the characteristics of the active (sensing) materials on which the sensor devices are based. These characteristics include the cost-effectiveness of the materials’ manufacturing, the sensitivity to analytes, the material stability, and the possibility of exploiting them for low-cost and portable devices. Consequently, many gas sensors employ well-defined transduction methods, the most popular being the oxidation (or reduction) of the analyte in an electrochemical reactor, optical techniques, and chemiresistive responses to gas adsorption. In recent years, many of the efforts devoted to improving these methods have been directed towards the use of certain classes of specific materials. In particular, ionic liquids have been employed as electrolytes of exceptional properties for the preparation of amperometric gas sensors, while metal–organic frameworks (MOFs) are used as highly porous and reactive materials which can be employed, in pure form or as a component of MOF-based functional composites, as active materials of chemiresistive or optical sensors. Here, we report on the most recent developments relative to the use of these classes of materials in chemical sensing. We discuss the main features of these materials and the reasons why they are considered interesting in the field of chemical sensors. Subsequently, we review some of the technological and scientific results published in the span of the last six years that we consider among the most interesting and useful ones for expanding the awareness on future trends in chemical sensing. Finally, we discuss the prospects for the use of these materials and the factors involved in their possible use for new generations of sensor devices.
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Skorobogatiy, Maksim. "Microstructured and Photonic Bandgap Fibers for Applications in the Resonant Bio- and Chemical Sensors." Journal of Sensors 2009 (2009): 1–20. http://dx.doi.org/10.1155/2009/524237.
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We review application of microstructured and photonic bandgap fibers for designing resonant optical sensors of changes in the value of analyte refractive index. This research subject has recently invoked much attention due to development of novel fiber types, as well as due to development of techniques for the activation of fiber microstructure with functional materials. Particularly, we consider two sensors types. The first sensor type employs hollow core photonic bandgap fibers where core guided mode is confined in the analyte filled core through resonant effect in the surrounding periodic reflector. The second sensor type employs metalized microstructured or photonic bandgap waveguides and fibers, where core guided mode is phase matched with a plasmon propagating at the fiber/analyte interface. In resonant sensors one typically employs fibers with strongly nonuniform spectral transmission characteristics that are sensitive to changes in the real part of the analyte refractive index. Moreover, if narrow absorption lines are present in the analyte transmission spectrum, due to Kramers-Kronig relation this will also result in strong variation in the real part of the refractive index in the vicinity of an absorption line. Therefore, resonant sensors allow detection of minute changes both in the real part of the analyte refractive index (10−6–10−4 RIU), as well as in the imaginary part of the analyte refractive index in the vicinity of absorption lines. In the following we detail various resonant sensor implementations, modes of operation, as well as analysis of sensitivities for some of the common transduction mechanisms for bio- and chemical sensing applications. Sensor designs considered in this review span spectral operation regions from the visible to terahertz.
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Helbig, Klaus. "Fifty years of amplitude control." GEOPHYSICS 63, no. 2 (March 1998): 750–62. http://dx.doi.org/10.1190/1.1444375.
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The amplitudes of seismic waves have always been a foremost concern of the seismologist to which considerable ingenuity was devoted. In the 1920s the problem was to magnify the ground motion sufficiently for detection. This was done at first by simple levers that moved mechanical pens. But at the start of exploration seismology, this had already been superseded by optical levers, photographic recording, and (soon after) electromechanical transduction followed by amplification. From the 1930s to about the early ’60s, devices of increasing complexity were introduced to compress the large amplitude difference between the first arrivals and the weakest reflections of interest to the limited dynamic range of the recording medium: first the paper record, then magnetic storage media, and finally the digital magnetic tape. This period can be identified with techniques known as automatic gain control (AGC). Soon after the introduction of digital recording techniques, the emphasis shifted: with intermediate digital storage, the limit to the dynamic range was no longer controlled by the properties of the storage medium. Now everything that passed through the acquisition unit could, in principle, be stored on magnetic disk or tape. At that time the aim became to record the ground motion as faithfully as possible. There were several technical developments on the way to achieve “true amplitudes” that, in turn, made exploration concepts like bright spots, seismic stratigraphy, and amplitude‐versus‐offset evaluation possible. However, the most significant innovation was what became known as floating‐point amplifier. It dominated seismic acquisition for about 25 years. Floating‐point representation of seismic signals allowed storage of the entire dynamic range in relatively economic words of about 18 bits. During the last decade, the quest for ever‐greater resolution—and the availability of mass‐produced components for hi‐fi audio equipment—led to the introduction of the sigma‐delta (Σ-δ) converter. With this device, the full range of the seismic signal (or rather the geophone output) is recorded in binary fixed‐point formats with 24 bits. With this development, the full seismic signal can be stored without distortion or loss of resolution.
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Song, Sang Ok, Anirikh Chakrabarti, and Jeffrey D. Varner. "Ensembles of signal transduction models using Pareto Optimal Ensemble Techniques (POETs)." Biotechnology Journal 5, no. 7 (July 2010): 768–80. http://dx.doi.org/10.1002/biot.201000059.
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Chappanda, Karumbaiah N., Mohamed R. Tchalala, Osama Shekhah, Sandeep G. Surya, Mohamed Eddaoudi, and Khaled N. Salama. "A Comparative Study of Interdigitated Electrode and Quartz Crystal Microbalance Transduction Techniques for Metal–Organic Framework-Based Acetone Sensors." Sensors 18, no. 11 (November 12, 2018): 3898. http://dx.doi.org/10.3390/s18113898.
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We present a comparative study of two types of sensor with different transduction techniques but coated with the same sensing material to determine the effect of the transduction mechanism on the sensing performance of sensing a target analyte. For this purpose, interdigitated electrode (IDE)-based capacitors and quartz crystal microbalance (QCM)-based resonators were coated with a zeolitic–imidazolate framework (ZIF-8) metal–organic framework thin films as the sensing material and applied to the sensing of the volatile organic compound acetone. Cyclic immersion in methanolic precursor solutions technique was used for depositing the ZIF-8 thin films. The sensors were exposed to various acetone concentrations ranging from 5.3 to 26.5 vol % in N2 and characterized/compared for their sensitivity, hysteresis, long-term and short-term stability, selectivity, detection limit, and effect of temperature. Furthermore, the IDE substrates were used for resistive transduction and compared using capacitive transduction.
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Djohan, Risal S., Heron E. Rodriguez, Mark M. Connolly, Sara Jean Childers, Berton Braverman, and Francis J. Podbielski. "Intraoperative Monitoring of Recurrent Laryngeal Nerve Function." American Surgeon 66, no. 6 (June 2000): 595–97. http://dx.doi.org/10.1177/000313480006600614.
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Intraoperative recurrent laryngeal nerve identification is sometimes difficult in reoperative cervical dissection or operation for inflammatory thyroid disorders. Three modalities have been described to intraoperatively assess nerve function: vocal cord visualization with fiberoptic bronchoscopy or direct laryngoscopy, electromyelographic surveillance of arytenoid muscle function, and cord function assessment with an electromyelogram-electrode endotracheal tube. Our study focused on patients requiring cervical dissection for thyroid or parathyroid disease in which intraoperative recurrent laryngeal nerve function was monitored by nerve stimulation with a concentric bipolar probe. Impulses were tracked via a specialized electrode-bearing endotracheal tube with signal transduction to a recording monitor. No operative nerve injuries occurred in the patients of our study group. This surveillance technique's several advantages include use of standard intubation techniques with no increase in operative time, nerve stimulation tracings that are quantifiable and reproducible with production of a permanent record, and less subjectivity due to observer variability. We believe these factors make the electromyelogram-electrode endotracheal tube approach to intraoperative recurrent laryngeal nerve assessment the optimal technique.
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Martinez, Emily M., Samuel D. Klebanoff, Stephanie Secrest, Gabrielle Romain, Samuel T. Haile, Peter C. R. Emtage, and Amy E. Gilbert. "High-Throughput Flow Cytometric Method for the Simultaneous Measurement of CAR-T Cell Characterization and Cytotoxicity against Solid Tumor Cell Lines." SLAS DISCOVERY: Advancing the Science of Drug Discovery 23, no. 7 (April 10, 2018): 603–12. http://dx.doi.org/10.1177/2472555218768745.
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High-throughput flow cytometry is an attractive platform for the analysis of adoptive cellular therapies such as chimeric antigen receptor T cell therapy (CAR-T) because it allows for the concurrent measurement of T cell–dependent cellular cytotoxicity (TDCC) and the functional characterization of engineered T cells with respect to percentage of CAR transduction, T cell phenotype, and measurement of T cell function such as activation in a single assay. The use of adherent tumor cell lines can be challenging in these flow-based assays. Here, we present the development of a high-throughput flow-based assay to measure TDCC for a CAR-T construct co-cultured with multiple adherent tumor cell lines. We describe optimal assay conditions (such as adherent cell dissociation techniques to minimize impact on cell viability) that result in robust cytotoxicity assays. In addition, we report on the concurrent use of T cell transduction and activation antibody panels (CD25) that provide further dissection of engineered T cell function. In conclusion, we present the development of a high-throughput flow cytometry method allowing for in vitro interrogation of solid tumor, targeting CAR-T cell–mediated cytotoxicity, CAR transduction, and engineered T cell characterization in a single assay.
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Olsen, Zakai J., and Kwang J. Kim. "Characterizing the transduction behavior of ionic polymer-metal composite actuators and sensors via dimensional analysis." Smart Materials and Structures 31, no. 2 (December 24, 2021): 025014. http://dx.doi.org/10.1088/1361-665x/ac411e.
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Abstract Ionic polymer-metal composites (IPMCs) are functional smart materials that exhibit both electromechanical and mechanoelectrical transduction properties, and the physical phenomenon underlying the transduction mechanisms have been studied across the literature extensively. Here we use a new modeling framework to conduct the most comprehensive dimensional analysis of IPMC transduction phenomena, characterizing the IPMC actuator displacement, actuator blocking force, short-circuit sensing current, and open-circuit sensing voltage under static and dynamic loading. The information obtained in this analysis is used to construct nonlinear regression models for the transduction response as univariant and multivariant functions. Automatic differentiation techniques are leveraged to linearize the nonlinear regression models in the vicinity of a typical IPMC description and derive the sensitivity of the transduction response with respect to the driving independent variables. Further, the multiphysics model is validated using experimental data collected for the dynamic IPMC actuator and voltage sensor. With data collected from physical samples of IPMC materials in-lab, the regression models developed under the new computational framework are verified.
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El-Sharoud, Walid M. "Two-Component Signal Transduction Systems as Key Players in Stress responses of Lactic Acid Bacteria." Science Progress 88, no. 4 (November 2005): 203–28. http://dx.doi.org/10.3184/003685005783238381.
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Lactic acid bacteria (LAB) continue as an important group of gram-positive bacteria that have been extensively exploited in food industries and various biotechnological applications. Some LAB species are, however, opportunistic pathogens and were reported to be associated with overwhelming number of human infections. During the use of LAB in industry or over the course of human infection, these bacteria are exposed to environmental stress. While LAB display adaptive mechanisms to cope with adverse conditions, the regulation of these mechanisms remains to be elucidated. Recent completion of genome sequencing of various LAB strains combined with the development of advanced molecular techniques have enabled the identification of a number of putative two-component signal transduction systems, also known as two-component regulatory systems (2CRS), in LAB. Examining the effect of deleting genes specifying putative 2CRS proteins in these organisms has revealed the involvement of 2CRS in the responses of LAB to different stresses. There are lines of evidence indicating that certain 2CRS may mediate a general stress response in Enterococcus faecalis and Streptococcus pyogenes. This review highlights the influence of 2CRS on the physiology of LAB during optimal growth and survival/growth on exposure to environmental stress.
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Niu, Ting, Amer M. Najjar, Simon N. Robinson, Hong Yang, William K. Decker, John D. McMannis, Jingjing Ng, et al. "Retroviral Gene Transfer with Triple Genetic Reporter Genes into Human Cord Blood CD133+ Cells." Blood 104, no. 11 (November 16, 2004): 5260. http://dx.doi.org/10.1182/blood.v104.11.5260.5260.
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Abstract Umbilical cord blood (CB) is used increasingly as a source of hematopoietic support in bone marrow transplant patients lacking family or unrelated donors. Little is known about human CB with respect to in vivo migration, homing, long-term viability, the organ-specific checkpoints and its differentiation. In order to study CB migration and homing, the gibbon ape leukemia virus (GALV)-pseudotyped retroviral gene transfer technique was developed to genetically modify CB CD133+ cells with triple reporter genes which encode enhanced green fluorescent protein (eGFP), luciferase, and herpes simplex virus type one thymidine kinase (HSV1-tk). The novelty of this approach is that it allows multimodal repetitive non-invasive imaging using fluorescence, bioluminescence (BLI), and nuclear imaging techniques, respectively. CD133+ cell fractions were isolated from human CB using the MidiMACS device (Miltenyi). To facilitate transduction, CB CD133+ cells were stimulated with 100ng/ml each of stem cell factor (SCF), granulocyte colony-stimulating factor (G-CSF) and thrombopoietin (TPO) in alpha-MEM medium supplemented with 20% fetal bovine serum. After 3, 5, 7 or 14 days of stimulation, CB cells were transduced by RetroNectin (TaKaRa)-assisted gene transfer. RetroNectin, recombinant human fibronectin fragment CH-296, can provide colocalization of retroviral particles and target cells. Specifically, 6-well plates were coated with 5ug/cm2 RetroNectin for 2 hours at room temperature, followed by preloading with fresh virus-containing medium (VCM) for 4 hours at 37°C. VCM was then removed and the CB cells were added in medium containing cytokines for 2 or 3 days. This approach resulted in > 90% transduction of control U87 human glioma cells and up to 36% transduction of CD133+ CB cells. Preliminary experiments suggested that optimal transduction appeared to be at day 7 of CB stimulation. When compared to non-RetroNectin coated plates, this approach showed a 5- to 11- fold increase in eGFP+ cells as determined by flow cytometry, increasing the transduction efficiency from < 5% to a maximal 36%. The addition of polybrene, a cationic polymer, to this process did not improve transduction efficiency. Studies are underway to visualize retrovirally-transduced CB CD133+ cells in NOD/SCID mice in vivo. The ability to trace the fate of CD133+ cells following transplantation may allow a better understanding of the mechanisms of migration, homing and long-term viability.
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dos Santos, Andreia, Elvira Fortunato, Rodrigo Martins, Hugo Águas, and Rui Igreja. "Transduction Mechanisms, Micro-Structuring Techniques, and Applications of Electronic Skin Pressure Sensors: A Review of Recent Advances." Sensors 20, no. 16 (August 7, 2020): 4407. http://dx.doi.org/10.3390/s20164407.
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Electronic skin (e-skin), which is an electronic surrogate of human skin, aims to recreate the multifunctionality of skin by using sensing units to detect multiple stimuli, while keeping key features of skin such as low thickness, stretchability, flexibility, and conformability. One of the most important stimuli to be detected is pressure due to its relevance in a plethora of applications, from health monitoring to functional prosthesis, robotics, and human-machine-interfaces (HMI). The performance of these e-skin pressure sensors is tailored, typically through micro-structuring techniques (such as photolithography, unconventional molds, incorporation of naturally micro-structured materials, laser engraving, amongst others) to achieve high sensitivities (commonly above 1 kPa−1), which is mostly relevant for health monitoring applications, or to extend the linearity of the behavior over a larger pressure range (from few Pa to 100 kPa), an important feature for functional prosthesis. Hence, this review intends to give a generalized view over the most relevant highlights in the development and micro-structuring of e-skin pressure sensors, while contributing to update the field with the most recent research. A special emphasis is devoted to the most employed pressure transduction mechanisms, namely capacitance, piezoelectricity, piezoresistivity, and triboelectricity, as well as to materials and novel techniques more recently explored to innovate the field and bring it a step closer to general adoption by society.
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Cerimovic, Samir, Albert Treytl, Thomas Glatzl, Roman Beigelbeck, Franz Keplinger, and Thilo Sauter. "Development and Characterization of Thermal Flow Sensors for Non-Invasive Measurements in HVAC Systems." Sensors 19, no. 6 (March 21, 2019): 1397. http://dx.doi.org/10.3390/s19061397.
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We investigated non-invasive flow rate measurements in heating, ventilation, and air conditioning (HVAC) systems utilizing thermal transduction instead of commonly used ultrasonic techniques. The proposed thermal flow transduction comprises two temperature sensors and a heater, all mounted non-invasively on the outer surface of metal-pipes and, therefore, not disturbing the fluid flow inside. One temperature sensor measures the heater temperature, whereas the other one, mounted upstream of the heater, follows the fluid temperature for reference. The temperature difference (i.e., the heater excess temperature) depends on the fluid flow velocity and can be used to derive the mean volume flow inside the pipe. Experimental characterizations were conducted using two sensor prototypes. Beside output characteristics, other main issues such as dynamic behavior and noise density were investigated in detail. Special attention was paid to error compensation allowing measurements within a large range of fluid temperatures. Measurement results confirm the feasibility of this approach, however with some constraints regarding response time.
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Rocca, Andrea, and Boris N. Kholodenko. "Can Systems Biology Advance Clinical Precision Oncology?" Cancers 13, no. 24 (December 16, 2021): 6312. http://dx.doi.org/10.3390/cancers13246312.
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Precision oncology is perceived as a way forward to treat individual cancer patients. However, knowing particular cancer mutations is not enough for optimal therapeutic treatment, because cancer genotype-phenotype relationships are nonlinear and dynamic. Systems biology studies the biological processes at the systems’ level, using an array of techniques, ranging from statistical methods to network reconstruction and analysis, to mathematical modeling. Its goal is to reconstruct the complex and often counterintuitive dynamic behavior of biological systems and quantitatively predict their responses to environmental perturbations. In this paper, we review the impact of systems biology on precision oncology. We show examples of how the analysis of signal transduction networks allows to dissect resistance to targeted therapies and inform the choice of combinations of targeted drugs based on tumor molecular alterations. Patient-specific biomarkers based on dynamical models of signaling networks can have a greater prognostic value than conventional biomarkers. These examples support systems biology models as valuable tools to advance clinical and translational oncological research.
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Niu, Ting, Amer M. Najjar, Simon N. Robinson, Hong Yang, William K. Decker, John D. McMannis, Jingjing Ng, et al. "High Efficiency Transduction of Human Mesenchymal Stem Cells Using Retroviral Gene Transfer with Triple Reporter Genes." Blood 104, no. 11 (November 16, 2004): 4258. http://dx.doi.org/10.1182/blood.v104.11.4258.4258.
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Abstract Cotransplantation of ex vivo-expanded mesenchymal stem cells (MSC) together with hematopoietic stem cells hastens hematopoietic recovery in animal models and potentially humans. The in vivo mechanisms of migration, homing and long-term viability of MSC following implantation are not well understood. Reporter gene labeling would permit the tracking of transplanted MSC in vivo through noninvasive imaging techniques, namely fluorescence, bioluminescence, and nuclear imaging. Accordingly, a gibbon ape leukemia virus (GALV)-pseudotyped retrovirus was utilized to transfer a triple fusion gene reporter system, expressing enhanced green fluorescent protein (eGFP), luciferase, and herpes simplex virus type one thymidine kinase (HSV1-tk) into MSC. Human MSC were isolated and propagated from normal bone marrow aspirates by culturing ficoll-separated fractions in alpha-MEM medium supplemented with 20% fetal bovine serum. FACS analysis confirmed the MSC phenotype, with cells expressing HLA-Class I, CD105, CD73, CD90 and CD166 antigens and not expressing HLA-Class II, CD80, CD31, CD34 and CD45 antigens. No significant phenotypic changes were observed in early and late passage numbers of MSC. MSC were transduced during their exponential growth phase (as determined by growth curve measurements), with virus-containing medium (VCM) from the PG13 packaging cells (targeting Pit-1 receptors) for 24 hours in the presence of different concentrations of the cationic polymer, polybrene, ranging from 2 μg/ml to 12μg/ml. The 2μg/ml concentration appeared to be optimal for transduction of MSC. VCM was harvested following a 24-hour incubation of the PG13 packaging cells at 32°C or 37°C. These initial experiments suggested that incubation at 32°C appeared to be optimal for virus production. Repeated VCM exposure at 24-hour intervals for 2 or 3 days did not increase the percentage of transduced cells as determined by flow cytometry (eGFP-positive). VCM harvested at 32°C added to MSC in the presence of 2μg/ml polybrene, yielded a 62% transduction efficiency following one round of exposure. U87 human glioma cells were used throughout as a positive control to verify retrovirus efficacy and demonstrated >90% transduction efficiency. MSC clones highly expressing triple reporter genes are being selected and propagated in our laboratory to image transduced cells in NOD/SCID mice, thereby providing a better understanding of the potential role of these cells in transplantation processes.
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Weihs, Felix, Alisha Anderson, Stephen Trowell, and Karine Caron. "Resonance Energy Transfer-Based Biosensors for Point-of-Need Diagnosis—Progress and Perspectives." Sensors 21, no. 2 (January 19, 2021): 660. http://dx.doi.org/10.3390/s21020660.
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The demand for point-of-need (PON) diagnostics for clinical and other applications is continuing to grow. Much of this demand is currently serviced by biosensors, which combine a bioanalytical sensing element with a transducing device that reports results to the user. Ideally, such devices are easy to use and do not require special skills of the end user. Application-dependent, PON devices may need to be capable of measuring low levels of analytes very rapidly, and it is often helpful if they are also portable. To date, only two transduction modalities, colorimetric lateral flow immunoassays (LFIs) and electrochemical assays, fully meet these requirements and have been widely adopted at the point-of-need. These modalities are either non-quantitative (LFIs) or highly analyte-specific (electrochemical glucose meters), therefore requiring considerable modification if they are to be co-opted for measuring other biomarkers. Förster Resonance Energy Transfer (RET)-based biosensors incorporate a quantitative and highly versatile transduction modality that has been extensively used in biomedical research laboratories. RET-biosensors have not yet been applied at the point-of-need despite its advantages over other established techniques. In this review, we explore and discuss recent developments in the translation of RET-biosensors for PON diagnoses, including their potential benefits and drawbacks.
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Pesavento, Maria, Simone Marchetti, Letizia De Maria, Luigi Zeni, and Nunzio Cennamo. "Sensing by Molecularly Imprinted Polymer: Evaluation of the Binding Properties with Different Techniques." Sensors 19, no. 6 (March 18, 2019): 1344. http://dx.doi.org/10.3390/s19061344.
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The possibility of investigating the binding properties of the same molecularly imprinted polymer (MIP), most probably heterogeneous, at various concentration levels by different methods such as batch equilibration and sensing, is examined, considering two kinds of sensors, based respectively on electrochemical and surface plasmon resonance (SPR) transduction. As a proof of principle, the considered MIP was obtained by non-covalent molecular imprinting of 2-furaldehyde (2-FAL). It has been found that different concentration ranges of 2-FAL in aqueous matrices can be measured by the two sensing methods. The SPR sensor responds in a concentration range from 1 × 10−4 M down to about 1 × 10−7 M, while the electrochemical sensor from about 5 × 10−6 M up to about 9 × 10−3 M. The binding isotherms have been fit to the Langmuir adsorption model, in order to evaluate the association constant. Three kinds of sites with different affinity for 2-FAL have been detected. The sites at low affinity are similar to the interaction sites of the corresponding NIP since they have a similar association constant. This is near to the affinity evaluated by batch equilibration too. The same association constant has been evaluated in the same concentration range. The sensing methods have been demonstrated to be very convenient for the characterization of the binding properties of MIP in comparison to the batch equilibration, in terms of reproducibility and low amount of material required for the investigation.
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Szlaszynski, Filip, Michael J. S. Lowe, and Peter Huthwaite. "Short Range Pipe Guided Wave Testing Using SH0 Plane Wave Imaging for Improved Quantification Accuracy." Sensors 22, no. 8 (April 13, 2022): 2973. http://dx.doi.org/10.3390/s22082973.
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Detection and criticality assessment of defects appearing in inaccessible locations in pipelines pose a great challenge for many industries. Inspection methods which allow for remote defect detection and accurate characterisation are needed. Guided wave testing (GWT) is capable of screening large lengths of pipes from a single device position, however it provides very limited individual feature characterisation. This paper adapts Plane Wave Imaging (PWI) to pipe GWT to improve defect characterization for inspection in nearby locations such as a few metres from the transducers. PWI performance is evaluated using finite element (FE) and experimental studies, and it is compared to other popular synthetic focusing imaging techniques. The study is concerned with part-circumferential part-depth planar cracks. It is shown that PWI achieves superior resolution compared to the common source method (CSM) and comparable resolution to the total focusing method (TFM). The techniques involving plane wave acquisition (PWI and CSM) are found to substantially outperform methods based on full matrix capture (FMC) in terms of signal-to-noise ratio (SNR). Therefore, it is concluded that PWI which achieves good resolution and high SNR is a more attractive choice for pipe GWT, compared to other considered techniques. Subsequently, a novel PWI transduction setup is proposed, and it is shown to suppresses the transmission of unwanted S0 mode, which further improves SNR of PWI.
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Pandey, Padmaker, Anamika Pandey, Shruti Singh, and Nikhil Kant Shukla. "Self Assembled Monolayers and Carbon Nanotubes: A Significant Tool’s for Modification of Electrode Surface." Sensor Letters 18, no. 9 (September 1, 2020): 669–85. http://dx.doi.org/10.1166/sl.2020.4280.
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A compromising and well-organized model system is needed for investigating the molecular behaviour of biomolecules as many transduction processes and biological recognition occur at biological surfaces. The application of techniques in interfacial surfaces like one molecule thick films has made a feasible and significant tool for modern scientific studies. Self Assembling Monolayers (SAMs) technology is a very useful means for producing monomolecular films of various biological molecules on different substrates. Carbon Nanotubes (CNTs) have length-to-diameter aspect ratio property which provides a large surface-to-volume ratio, making it an intensely capable material for biomolecular attachments. The incorporation of Carbon Nanotubes (CNTs) with biological systems forming functional assemblies has shown an explored area of research. Organo-sulfur mainly alkanethiol (CnH2n+1–SH) molecules get adsorbed onto CNTs. This phenomenon has grabbed a lot of attention because Self Assembling Monolayers (SAMs) of organo-sulfur compound acts as an example system for understanding important chemical, physical or biological processes.
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Choi, Seung-Ho, Joon-Seok Lee, Won-Jun Choi, Jae-Woo Seo, and Seon-Jin Choi. "Nanomaterials for IoT Sensing Platforms and Point-of-Care Applications in South Korea." Sensors 22, no. 2 (January 13, 2022): 610. http://dx.doi.org/10.3390/s22020610.
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Herein, state-of-the-art research advances in South Korea regarding the development of chemical sensing materials and fully integrated Internet of Things (IoT) sensing platforms were comprehensively reviewed for verifying the applicability of such sensing systems in point-of-care testing (POCT). Various organic/inorganic nanomaterials were synthesized and characterized to understand their fundamental chemical sensing mechanisms upon exposure to target analytes. Moreover, the applicability of nanomaterials integrated with IoT-based signal transducers for the real-time and on-site analysis of chemical species was verified. In this review, we focused on the development of noble nanostructures and signal transduction techniques for use in IoT sensing platforms, and based on their applications, such systems were classified into gas sensors, ion sensors, and biosensors. A future perspective for the development of chemical sensors was discussed for application to next-generation POCT systems that facilitate rapid and multiplexed screening of various analytes.
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Yu, Yu, Yating Zhang, Lufan Jin, Zhiliang Chen, Yifan Li, Qingyan Li, Mingxuan Cao, Yongli Che, Junbo Yang, and Jianquan Yao. "A Fast Response−Recovery 3D Graphene Foam Humidity Sensor for User Interaction." Sensors 18, no. 12 (December 8, 2018): 4337. http://dx.doi.org/10.3390/s18124337.
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Humidity sensors allow electronic devices to convert the water content in the environment into electronical signals by utilizing material properties and transduction techniques. Three-dimensional graphene foam (3DGF) can be exploited in humidity sensors due to its convenient features including low-mass density, large specific surface area, and excellent electrical. In this paper, 3DGF with super permeability to water enables humidity sensors to exhibit a broad relative humidities (RH) range, from 0% to 85.9%, with a fast response speed (response time: ~89 ms, recovery time: ~189 ms). To interpret the physical mechanism behind this, we constructed a 3DGF model decorated with water to calculate the energy structure and we carried out the CASTEP as implemented in Materials Studio 8.0. This can be ascribed to the donor effect, namely, the electronic donation of chemically adsorbed water molecules to the 3DGF surface. Furthermore, this device can be used for user interaction (UI) with unprecedented performance. These high performances support 3DGF as a promising material for humidity sensitive material.
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Purnama, Yugi Hari Chandra, Gondo Mastutik, and Suhartono Taat Putra. "Increased Activity Of Mature Osteoblast from Rat Bone Marrow-Mesenchymal Stem Cells tn Osteogenic Medium Exposed to Melatonin." Folia Medica Indonesiana 54, no. 4 (December 11, 2018): 282. http://dx.doi.org/10.20473/fmi.v54i4.10714.
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Exposure to melatonin in the cultures of Bone Marrow Mesenchymal Stem Cells (BM-MSCs) in osteogenic medium is able to induce mesenchymal stem cells and preosteoblasts into active osteoblasts via several transduction signals such as ERK 1/2. Previous studies used a single dose of 50 nM and a physiological dose of 20-200 pg/ml. The objective of the study was to obtain an optimal dose of melatonin that enhances osteoblast activity by increasing the expression of ERK1/2 and ALP levels in the culture of Rat Bone Marrow Mesenchymal Stem Cells (BM-MSCs) in osteogenic medium. This study was an in vitro experimental laboratory study using BM-MSCs from rat femoral bone grown on osteogenic medium without or with exposure to melatonin in doses of 0, 50, 100, 150 nM for 21 days. BM-MSCs were characterized by immunocytochemical techniques (CD45- and CD 105+) and ERK 1/2 expression was checked 24 hours after exposure to melatonin, while ALP levels were examined on day 21 using ELISA technique. ERK 1/2 expression on BM-MScs exposed to melatonin in doses 0, 50, 100, and 150 nM were respectively 0.087, 0.095, 0.081, and 0.079. Mean ERK 1/2 expression in various groups showed a decrease along with increasing doses of melatonin. Among the four treatment groups, the administration of melatonin in a dose of 50 nM resulted in highest mean ERK 1/2 expression. ALP levels in BM-MSCs exposed to melatonin doses of 0, 50, 100, and 150 nM were 0.128; 0.130; 0.117, and 0.111 ng/ml respectively. Data showed that decreasing mean ALP levels occurred along with the addition of melatonin dose. In conclusion, the administration of melatonin 50 nM is the optimal dose to increase the differentiation of cultured rat BM-MSCs into active osteoblasts.
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Verma, Akash, Ruben Goos, Jurre De Weerdt, Patrick Pelgrims, and Eleonora Ferraris. "Design, Fabrication, and Testing of a Fully 3D-Printed Pressure Sensor Using a Hybrid Printing Approach." Sensors 22, no. 19 (October 4, 2022): 7531. http://dx.doi.org/10.3390/s22197531.
Full textAbstract:
Pressure sensing is not a new concept and can be applied by using different transduction mechanisms and manufacturing techniques, including printed electronics approaches. However, very limited efforts have been taken to realise pressure sensors fully using additive manufacturing techniques, especially for personalised guide prosthetics in biomedical applications. In this work, we present a novel, fully printed piezoresistive pressure sensor, which was realised by using Aerosol Jet® Printing (AJP) and Screen Printing. AJ®P was specifically chosen to print silver interconnects on a selective laser sintered (SLS) polyamide board as a customised substrate, while piezoresistive electrodes were manually screen-printed on the top of the interconnects as the sensing layer. The sensor was electromechanically tested, and its response was registered upon the application of given signals, in terms of sensitivity, hysteresis, reproducibility, and time drift. When applying a ramping pressure, the sensor showed two different sensitive regions: (i) a highly sensitive region in the range of 0 to 0.12 MPa with an average sensitivity of 106 Ω/MPa and a low sensitive zone within 0.12 to 1.25 MPa with an average sensitivity of 7.6 Ω/MPa with some indeterminate overlapping regions. Hysteresis was negligible and an electrical resistance deviation of about 14% was observed in time drift experiments. Such performances will satisfy the demands of our application in the biomedical field as a smart prosthetics guide.
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Minamiki, Tsukuru, Yuki Ichikawa, and Ryoji Kurita. "The Power of Assemblies at Interfaces: Nanosensor Platforms Based on Synthetic Receptor Membranes." Sensors 20, no. 8 (April 15, 2020): 2228. http://dx.doi.org/10.3390/s20082228.
Full textAbstract:
Synthetic sensing materials (artificial receptors) are some of the most attractive components of chemical/biosensors because of their long-term stability and low cost of production. However, the strategy for the practical design of these materials toward specific molecular recognition in water is not established yet. For the construction of artificial material-based chemical/biosensors, the bottom-up assembly of these materials is one of the effective methods. This is because the driving forces of molecular recognition on the receptors could be enhanced by the integration of such kinds of materials at the ‘interfaces’, such as the boundary portion between the liquid and solid phases. Additionally, the molecular assembly of such self-assembled monolayers (SAMs) can easily be installed in transducer devices. Thus, we believe that nanosensor platforms that consist of synthetic receptor membranes on the transducer surfaces can be applied to powerful tools for high-throughput analyses of the required targets. In this review, we briefly summarize a comprehensive overview that includes the preparation techniques for molecular assemblies, the characterization methods of the interfaces, and a few examples of receptor assembly-based chemical/biosensing platforms on each transduction mechanism.
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Karachaliou, Chrysoula-Evangelia, and Evangelia Livaniou. "Immunosensors for Autoimmune-Disease-Related Biomarkers: A Literature Review." Sensors 23, no. 15 (July 28, 2023): 6770. http://dx.doi.org/10.3390/s23156770.
Full textAbstract:
Immunosensors are a special class of biosensors that employ specific antibodies for biorecognition of the target analyte. Immunosensors that target disease biomarkers may be exploited as tools for disease diagnosis and/or follow-up, offering several advantages over conventional analytical techniques, such as rapid and easy analysis of patients’ samples at the point-of-care. Autoimmune diseases have been increasingly prevalent worldwide in recent years, while the COVID-19 pandemic has also been associated with autoimmunity. Consequently, demand for tools enabling the early and reliable diagnosis of autoimmune diseases is expected to increase in the near future. To this end, interest in immunosensors targeting autoimmune disease biomarkers, mainly, various autoantibodies and specific pro-inflammatory proteins (e.g., specific cytokines), has been rekindled. This review article presents most of the immunosensors proposed to date as potential tools for the diagnosis of various autoimmune diseases, such as type 1 diabetes, rheumatoid arthritis, and multiple sclerosis. The signal transduction and the immunoassay principles of each immunosensor have been suitably classified and are briefly presented along with certain sensor elements, e.g., special nano-sized materials used in the construction of the immunosensing surface. The main concluding remarks are presented and future perspectives of the field are also briefly discussed.
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Wang, Binglin, Yi Wang, Xiaofan Sun, Guoliang Deng, Wei Huang, Xingxin Wu, Yanghong Gu, et al. "CXCR6 is required for antitumor efficacy of intratumoral CD8+ T cell." Journal for ImmunoTherapy of Cancer 9, no. 8 (August 2021): e003100. http://dx.doi.org/10.1136/jitc-2021-003100.
Full textAbstract:
BackgroundIncreasing infiltration of CD8+ T cells within tumor tissue predicts a better prognosis and is essential for response to checkpoint blocking therapy. Furthermore, current clinical protocols use unfractioned T cell populations as the starting point for transduction of chimeric antigen receptors (CARs)-modified T cells, but the optimal T cell subtype of CAR-modified T cells remains unclear. Thus, accurately identifying a group of cytotoxic T lymphocytes with high antitumor efficacy is imperative. Inspired by the theory of yin and yang, we explored a subset of CD8+ T cell in cancer with the same phenotypic characteristics as highly activated inflammatory T cells in autoimmune diseases.MethodsCombination of single-cell RNA sequencing, general transcriptome sequencing data and multiparametric cytometric techniques allowed us to map CXCR6 expression on specific cell type and tissue. We applied Cxcr6−/− mice, immune checkpoint therapies and bone marrow chimeras to identify the function of CXCR6+CD8+ T cells. Transgenic Cxcr6−/− OT-I mice were employed to explore the functional role of CXCR6 in antigen-specific antitumor response.ResultsWe identified that CXCR6 was exclusively expressed on intratumoral CD8+ T cell. CXCR6+CD8+ T cells were more immunocompetent, and chimeras with specific deficiency on CD8+ T cells showed weaker antitumor activity. In addition, Cxcr6−/− mice could not respond to anti-PD-1 treatment effectively. High tumor expression of CXCR6 was not mainly caused by ligand-receptor chemotaxis of CXCL16/CXCR6 but induced by tumor tissue self. Induced CXCR6+CD8+ T cells possessed tumor antigen specificity and could enhance the effect of anti-PD-1 blockade to retard tumor progression.ConclusionsThis study may contribute to the rational design of combined immunotherapy. Alternatively, CXCR6 may be used as a biomarker for effective CD8+ T cell state before adoptive cell therapy, providing a basis for tumor immunotherapy.
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Olisa, Samuel Chukwuemeka, Muhammad A. Khan, and Andrew Starr. "Review of Current Guided Wave Ultrasonic Testing (GWUT) Limitations and Future Directions." Sensors 21, no. 3 (January 26, 2021): 811. http://dx.doi.org/10.3390/s21030811.
Full textAbstract:
Damage is an inevitable occurrence in metallic structures and when unchecked could result in a catastrophic breakdown of structural assets. Non-destructive evaluation (NDE) is adopted in industries for assessment and health inspection of structural assets. Prominent among the NDE techniques is guided wave ultrasonic testing (GWUT). This method is cost-effective and possesses an enormous capability for long-range inspection of corroded structures, detection of sundries of crack and other metallic damage structures at low frequency and energy attenuation. However, the parametric features of the GWUT are affected by structural and environmental operating conditions and result in masking damage signal. Most studies focused on identifying individual damage under varying conditions while combined damage phenomena can coexist in structure and hasten its deterioration. Hence, it is an impending task to study the effect of combined damage on a structure under varying conditions and correlate it with GWUT parametric features. In this respect, this work reviewed the literature on UGWs, damage inspection, severity, temperature influence on the guided wave and parametric characteristics of the inspecting wave. The review is limited to the piezoelectric transduction unit. It was keenly observed that no significant work had been done to correlate the parametric feature of GWUT with combined damage effect under varying conditions. It is therefore proposed to investigate this impending task.
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Alam, Arif Ul, Dennis Clyne, and M. Jamal Deen. "A Low-Cost Multi-Parameter Water Quality Monitoring System." Sensors 21, no. 11 (May 29, 2021): 3775. http://dx.doi.org/10.3390/s21113775.
Full textAbstract:
Multi-parameter water quality monitoring is crucial in resource-limited areas to provide persistent water safety. Conventional water monitoring techniques are time-consuming, require skilled personnel, are not user-friendly and are incompatible with operating on-site. Here, we develop a multi-parameter water quality monitoring system (MWQMS) that includes an array of low-cost, easy-to-use, high-sensitivity electrochemical sensors, as well as custom-designed sensor readout circuitry and smartphone application with wireless connectivity. The system overcomes the need of costly laboratory-based testing methods and the requirement of skilled workers. The proposed MWQMS system can simultaneously monitor pH, free chlorine, and temperature with sensitivities of 57.5 mV/pH, 186 nA/ppm and 16.9 mV/°C, respectively, as well as sensing of BPA with <10 nM limit of detection. The system also provides seamless interconnection between transduction of the sensors’ signal, signal processing, wireless data transfer and smartphone app-based operation. This interconnection was accomplished by fabricating nanomaterial and carbon nanotube-based sensors on a common substrate, integrating these sensors to a readout circuit and transmitting the sensor data to an Android application. The MWQMS system provides a general platform technology where an array of other water monitoring sensors can also be easily integrated and programmed. Such a system can offer tremendous opportunity for a broad range of environmental monitoring applications.
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Sharafeldin, Mohamed, Karteek Kadimisetty, Ketki S. Bhalerao, Tianqi Chen, and James F. Rusling. "3D-Printed Immunosensor Arrays for Cancer Diagnostics." Sensors 20, no. 16 (August 12, 2020): 4514. http://dx.doi.org/10.3390/s20164514.
Full textAbstract:
Detecting cancer at an early stage of disease progression promises better treatment outcomes and longer lifespans for cancer survivors. Research has been directed towards the development of accessible and highly sensitive cancer diagnostic tools, many of which rely on protein biomarkers and biomarker panels which are overexpressed in body fluids and associated with different types of cancer. Protein biomarker detection for point-of-care (POC) use requires the development of sensitive, noninvasive liquid biopsy cancer diagnostics that overcome the limitations and low sensitivities associated with current dependence upon imaging and invasive biopsies. Among many endeavors to produce user-friendly, semi-automated, and sensitive protein biomarker sensors, 3D printing is rapidly becoming an important contemporary tool for achieving these goals. Supported by the widely available selection of affordable desktop 3D printers and diverse printing options, 3D printing is becoming a standard tool for developing low-cost immunosensors that can also be used to make final commercial products. In the last few years, 3D printing platforms have been used to produce complex sensor devices with high resolution, tailored towards researchers’ and clinicians’ needs and limited only by their imagination. Unlike traditional subtractive manufacturing, 3D printing, also known as additive manufacturing, has drastically reduced the time of sensor and sensor array development while offering excellent sensitivity at a fraction of the cost of conventional technologies such as photolithography. In this review, we offer a comprehensive description of 3D printing techniques commonly used to develop immunosensors, arrays, and microfluidic arrays. In addition, recent applications utilizing 3D printing in immunosensors integrated with different signal transduction strategies are described. These applications include electrochemical, chemiluminescent (CL), and electrochemiluminescent (ECL) 3D-printed immunosensors. Finally, we discuss current challenges and limitations associated with available 3D printing technology and future directions of this field.