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Liao, Shuyu, Mengxue Sun, Jinxiu Zhan, Min Xu i Li Yao. "Advances in the Biological Application of Force-Induced Remnant Magnetization Spectroscopy". Molecules 27, nr 7 (23.03.2022): 2072. http://dx.doi.org/10.3390/molecules27072072.
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Biomolecules participate in various physiological and pathological processes through intermolecular interactions generally driven by non-covalent forces. In the present review, the force-induced remnant magnetization spectroscopy (FIRMS) is described and illustrated as a novel method to measure non-covalent forces. During the FIRMS measurement, the molecular magnetic probes are magnetized to produce an overall magnetization signal. The dissociation under the interference of external force yields a decrease in the magnetic signal, which is recorded and collected by atomic magnetometer in a spectrum to study the biological interactions. Furthermore, the recent FIRMS development with various external mechanical forces and magnetic probes is summarized.
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Valotteau, Claire, Fidan Sumbul i Felix Rico. "High-speed force spectroscopy: microsecond force measurements using ultrashort cantilevers". Biophysical Reviews 11, nr 5 (październik 2019): 689–99. http://dx.doi.org/10.1007/s12551-019-00585-4.
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Abstract Complete understanding of the role of mechanical forces in biological processes requires knowledge of the mechanical properties of individual proteins and living cells. Moreover, the dynamic response of biological systems at the nano- and microscales span over several orders of magnitude in time, from sub-microseconds to several minutes. Thus, access to force measurements over a wide range of length and time scales is required. High-speed atomic force microscopy (HS-AFM) using ultrashort cantilevers has emerged as a tool to study the dynamics of biomolecules and cells at video rates. The adaptation of HS-AFM to perform high-speed force spectroscopy (HS-FS) allows probing protein unfolding and receptor/ligand unbinding up to the velocity of molecular dynamics (MD) simulations with sub-microsecond time resolution. Moreover, application of HS-FS on living cells allows probing the viscoelastic response at short time scales providing deep understanding of cytoskeleton dynamics. In this mini-review, we assess the principles and recent developments and applications of HS-FS using ultrashort cantilevers to probe molecular and cellular mechanics.
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LI, Hongying, Ningyu GU i Jilin TANG. "Application of Atomic Force Microscopy Based Single Molecule Force Spectroscopy in Biological Research". Acta Agronomica Sinica 29, nr 12 (2012): 1356. http://dx.doi.org/10.3724/sp.j.1095.2013.20210.
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Carvalho, Filomena A., i Nuno C. Santos. "Atomic force microscopy-based force spectroscopy - biological and biomedical applications". IUBMB Life 64, nr 6 (2.05.2012): 465–72. http://dx.doi.org/10.1002/iub.1037.
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Wang, Yuchen, Jenny V. Le, Kyle Crocker, Michael A. Darcy, Patrick D. Halley, Dengke Zhao, Nick Andrioff i in. "A nanoscale DNA force spectrometer capable of applying tension and compression on biomolecules". Nucleic Acids Research 49, nr 15 (6.08.2021): 8987–99. http://dx.doi.org/10.1093/nar/gkab656.
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Abstract Single molecule force spectroscopy is a powerful approach to probe the structure, conformational changes, and kinetic properties of biological and synthetic macromolecules. However, common approaches to apply forces to biomolecules require expensive and cumbersome equipment and relatively large probes such as beads or cantilevers, which limits their use for many environments and makes integrating with other methods challenging. Furthermore, existing methods have key limitations such as an inability to apply compressive forces on single molecules. We report a nanoscale DNA force spectrometer (nDFS), which is based on a DNA origami hinge with tunable mechanical and dynamic properties. The angular free energy landscape of the nDFS can be engineered across a wide range through substitution of less than 5% of the strand components. We further incorporate a removable strut that enables reversible toggling of the nDFS between open and closed states to allow for actuated application of tensile and compressive forces. We demonstrate the ability to apply compressive forces by inducing a large bend in a 249bp DNA molecule, and tensile forces by inducing DNA unwrapping of a nucleosome sample. These results establish a versatile tool for force spectroscopy and robust methods for designing nanoscale mechanical devices with tunable force application.
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Gabas, Fabio, Riccardo Conte i Michele Ceotto. "Semiclassical Vibrational Spectroscopy of Biological Molecules Using Force Fields". Journal of Chemical Theory and Computation 16, nr 6 (6.05.2020): 3476–85. http://dx.doi.org/10.1021/acs.jctc.0c00127.
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Lee, Gil U., Linda Chrisey i Richard J. Colton. "Measuring forces between biological macromolecules with the Atomic Force Microscope: characterization and applications". Proceedings, annual meeting, Electron Microscopy Society of America 53 (13.08.1995): 718–19. http://dx.doi.org/10.1017/s0424820100139962.
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Structure and function in biological macromolecular systems such as proteins and polynucleotides are based on intermolecular interactions that are short ranged and chemically specific. Our knowledge of these molecular interactions results from indirect physical and thermodynamic measurements such as x-ray crystallography, light scattering and nuclear magnetic resonance spectroscopy. Direct measurement of molecular interaction forces requires that the state of a system be monitored with near atomic resolution while an independent force is applied to the system of 10−12 to 10−9 Newton magnitude. The atomic force microscope (AFM) has recently been applied to the study of single molecular interactions. The microfabricated cantilever of the AFM, a force transducer of small yet variable stiffness and high resonance frequency, produces a transducer of 10−15 N/Hz1/2 force sensitivities and 0.01 nm position accuracy.This presentation describes the AFM measurement of the molecular interaction forces in the model ligand-receptor system streptavidin-biotin and between complementary strands of DNA.
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Proksch, Roger, i Sergei Kalinin. "Piezoresponse Force Microscopy". Microscopy Today 17, nr 6 (listopad 2009): 10–15. http://dx.doi.org/10.1017/s1551929509990988.
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Coupling between electrical and mechanical phenomena is an important feature of functional inorganic materials and biological systems alike. The applications of electromechanically active materials include sonar, ultrasonic and medical imaging, sensors, actuators, and energy-harvesting technologies, as well as non-volatile computer memories. Electromechanical coupling in electromotor proteins and cellular membranes is the universal basis for biological functionalities from hearing to cardiac activity. The future will undoubtedly see the emergence of broad arrays of piezoelectric, biological, and molecular-based electromechanical systems to allow mankind the capability not only to “think” but also “act” on the nanoscale. The need for probing electromechanical functionalities has led to the development of Piezoresponse Force Microscopy (PFM) as a tool for local nanoscale imaging (Figures 1 and 2), spectroscopy, and manipulation of piezoelectric and ferroelectric materials.
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Fisette, Olivier, Patrick Lagüe, Stéphane Gagné i Sébastien Morin. "Synergistic Applications of MD and NMR for the Study of Biological Systems". Journal of Biomedicine and Biotechnology 2012 (2012): 1–12. http://dx.doi.org/10.1155/2012/254208.
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Modern biological sciences are becoming more and more multidisciplinary. At the same time, theoretical and computational approaches gain in reliability and their field of application widens. In this short paper, we discuss recent advances in the areas of solution nuclear magnetic resonance (NMR) spectroscopy and molecular dynamics (MD) simulations that were made possible by the combination of both methods, that is, through their synergistic use. We present the main NMR observables and parameters that can be computed from simulations, and how they are used in a variety of complementary applications, including dynamics studies, model-free analysis, force field validation, and structural studies.
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Nandi, Tathagata, i Sri Rama Koti Ainavarapu. "Applications of atomic force microscopy in modern biology". Emerging Topics in Life Sciences 5, nr 1 (12.02.2021): 103–11. http://dx.doi.org/10.1042/etls20200255.
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Single-molecule force spectroscopy (SMFS) is an emerging tool to investigate mechanical properties of biomolecules and their responses to mechanical forces, and one of the most-used techniques for mechanical manipulation is the atomic force microscope (AFM). AFM was invented as an imaging tool which can be used to image biomolecules in sub-molecular resolution in physiological conditions. It can also be used as a molecular force probe for applying mechanical forces on biomolecules. In this brief review, we will provide exciting examples from recent literature which show how the advances in AFM have enabled us to gain deep insights into mechanical properties and mechanobiology of biomolecules. AFM has been applied to study mechanical properties of cells, tissues, microorganisms, viruses as well as biological macromolecules such as proteins. It has found applications in biomedical fields like cancer biology, where it has been used both in the diagnostic phases as well as drug discovery. AFM has been able to answer questions pertaining to mechanosensing by neurons, and mechanical changes in viruses during infection by the viral particles as well as the fundamental processes such as cell division. Fundamental questions related to protein folding have also been answered by SMFS like determination of energy landscape properties of variety of proteins and their correlation with their biological functions. A multipronged approach is needed to diversify the research, as a combination with optical spectroscopy and computer-based steered molecular dynamic simulations along with SMFS can help us gain further insights into the field of biophysics and modern biology.
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Casuso, Ignacio, Lorena Redondo-Morata i Felix Rico. "Biological physics by high-speed atomic force microscopy". Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 378, nr 2186 (26.10.2020): 20190604. http://dx.doi.org/10.1098/rsta.2019.0604.
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While many fields have contributed to biological physics, nanotechnology offers a new scale of observation. High-speed atomic force microscopy (HS-AFM) provides nanometre structural information and dynamics with subsecond resolution of biological systems. Moreover, HS-AFM allows us to measure piconewton forces within microseconds giving access to unexplored, fast biophysical processes. Thus, HS-AFM provides a tool to nourish biological physics through the observation of emergent physical phenomena in biological systems. In this review, we present an overview of the contribution of HS-AFM, both in imaging and force spectroscopy modes, to the field of biological physics. We focus on examples in which HS-AFM observations on membrane remodelling, molecular motors or the unfolding of proteins have stimulated the development of novel theories or the emergence of new concepts. We finally provide expected applications and developments of HS-AFM that we believe will continue contributing to our understanding of nature, by serving to the dialogue between biology and physics. This article is part of a discussion meeting issue ‘Dynamic in situ microscopy relating structure and function’.
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Bizzarri, Anna Rita, i Salvatore Cannistraro. "The application of atomic force spectroscopy to the study of biological complexes undergoing a biorecognition process". Chem. Soc. Rev. 39, nr 2 (2010): 734–49. http://dx.doi.org/10.1039/b811426a.
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Cheng, Yuanlei, Yashuo Zhang i Huijuan You. "Characterization of G-Quadruplexes Folding/Unfolding Dynamics and Interactions with Proteins from Single-Molecule Force Spectroscopy". Biomolecules 11, nr 11 (25.10.2021): 1579. http://dx.doi.org/10.3390/biom11111579.
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G-quadruplexes (G4s) are stable secondary nucleic acid structures that play crucial roles in many fundamental biological processes. The folding/unfolding dynamics of G4 structures are associated with the replication and transcription regulation functions of G4s. However, many DNA G4 sequences can adopt a variety of topologies and have complex folding/unfolding dynamics. Determining the dynamics of G4s and their regulation by proteins remains challenging due to the coexistence of multiple structures in a heterogeneous sample. Here, in this mini-review, we introduce the application of single-molecule force-spectroscopy methods, such as magnetic tweezers, optical tweezers, and atomic force microscopy, to characterize the polymorphism and folding/unfolding dynamics of G4s. We also briefly introduce recent studies using single-molecule force spectroscopy to study the molecular mechanisms of G4-interacting proteins.
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McCraw, Marshall, Berkin Uluutku i Santiago Solares. "Linear Viscoelasticity: Review of Theory and Applications in Atomic Force Microscopy". Reports in Mechanical Engineering 2, nr 1 (22.07.2021): 156–79. http://dx.doi.org/10.31181/rme200102156m.
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Recently, much research has been performed involving the mechanical analysis of biological and polymeric samples with the use of Atomic Force Microscopy (AFM). Such materials require careful treatments which consider the rate-dependence of their viscoelastic response. Here, we review the fundamental theories of linear viscoelasticity, as well as their application to the analysis of AFM spectroscopy data. An outline of general viscoelastic mechanical phenomena is initially given, followed by a brief outline of AFM techniques. Then, an extensive outline of linear viscoelastic material models, as well as contact mechanics descriptions of AFM systems, are presented.
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Xia, Fangzhou, i Kamal Youcef-Toumi. "Review: Advanced Atomic Force Microscopy Modes for Biomedical Research". Biosensors 12, nr 12 (2.12.2022): 1116. http://dx.doi.org/10.3390/bios12121116.
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Visualization of biomedical samples in their native environments at the microscopic scale is crucial for studying fundamental principles and discovering biomedical systems with complex interaction. The study of dynamic biological processes requires a microscope system with multiple modalities, high spatial/temporal resolution, large imaging ranges, versatile imaging environments and ideally in-situ manipulation capabilities. Recent development of new Atomic Force Microscopy (AFM) capabilities has made it such a powerful tool for biological and biomedical research. This review introduces novel AFM functionalities including high-speed imaging for dynamic process visualization, mechanobiology with force spectroscopy, molecular species characterization, and AFM nano-manipulation. These capabilities enable many new possibilities for novel scientific research and allow scientists to observe and explore processes at the nanoscale like never before. Selected application examples from recent studies are provided to demonstrate the effectiveness of these AFM techniques.
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Bonnell, D. A., S. V. Kalinin, A. L. Kholkin i A. Gruverman. "Piezoresponse Force Microscopy: A Window into Electromechanical Behavior at the Nanoscale". MRS Bulletin 34, nr 9 (wrzesień 2009): 648–57. http://dx.doi.org/10.1557/mrs2009.176.
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AbstractPiezoresponse force microscopy (PFM) is a powerful method widely used for nanoscale studies of the electromechanical coupling effect in various materials systems. Here, we review recent progress in this field that demonstrates great potential of PFM for the investigation of static and dynamic properties of ferroelectric domains, nanofabrication and lithography, local functional control, and structural imaging in a variety of inorganic and organic materials, including piezoelectrics, semiconductors, polymers, biomolecules, and biological systems. Future pathways for PFM application in high-density data storage, nanofabrication, and spectroscopy are discussed.
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Irmukhametova, G. S., E. M. Shaikhutdinov, R. K. Rakhmetullayeva, B. B. Yermukhambetova, A. K. Ishanova, G. Temirkhanova i G. A. Mun. "Nanostructured Hydrogel Dressings on Base of Crosslinked Polyvinylpyrrolidone for Biomedical Application". Advanced Materials Research 875-877 (luty 2014): 1467–71. http://dx.doi.org/10.4028/www.scientific.net/amr.875-877.1467.
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Hydrogel dressings for biomedical application were obtained by γ-irradiation of poly-N-vinipirrolidon (PVP), agar-agar, polyethylene glycol and silver nitrate solution. Influence of irradiation doses (range from 25 kGy to 75 kGy), silver nitrate concentration and PVP concentration in initial monomer mixture on properties of obtained material were investigated. Presence and distribution of silver nanoparticles in obtained bandages is confirmed by optical microscopy and atomic force spectroscopy. Antimicrobial activity study in vitro showed antimicrobial activity, flexibility, high sorption capacity to water and biological fluids.
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Arthisree, D., Girish M. Joshi i Annamalai Senthil Kumar. "Morphology and Admittance Spectroscopy of Cellulose Acetate/Graphene Quantum Dots Nanocomposites". International Journal of Nanoscience 17, nr 01n02 (12.10.2017): 1760006. http://dx.doi.org/10.1142/s0219581x17600067.
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Graphene quantum dots (GQDs) are considered as fascinating materials feasible for biological, optoelectronic devices, energy and environmental applications. Casting nanocomposite films for technological application is a challenging research interest. Cellulose acetate (CA) is one of the most abundant, economic, environmental friendly and biodegradable biomaterials. It has been found that CA is a preferred composite matrix to prepare recasting films, due to its efficient antifouling feature. In the present investigation, we exhibited preparation of CA/GQD nanocomposite by solution blending as a function of GQD loading 0.1–0.5[Formula: see text]wt.%. Morphology and electrical properties were examined as a function of GQD loading. The nanocomposite was characterized by impedance spectroscopy, and the measured admittance ([Formula: see text]) was plotted against temperature across broadband frequency. The magnitude of [Formula: see text] exhibits direct relation under the varying temperature. The morphology of the nanocomposites was observed by atomic force microscope technique in contact mode. Collective observation from our results is that it can be revealed that CA/GQD nanocomposites are suitable for thermal sensing applications.
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Dulińska-Molak, Ida. "AFM force spectroscopy as a powerful tool to address material design for biomedical applications. A review". Biomedical Spectroscopy and Imaging 9, nr 3-4 (28.12.2020): 141–64. http://dx.doi.org/10.3233/bsi-200205.
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Force Spectroscopy (FS), which is one of the operating modes of Atomic Force Microscope (AFM) technique proven to be useful in many biological and medical applications, such as cancer cells recognition. Currently, many scientific institutions carry on research on the Young’s modulus of individual cancer cells in order to detect the disease at an early stage of its development. As a result of the growing interest in the use of force spectroscopy to study cells’ mechanic, this review summarizes new applications of this method to study changes in the physical and chemical properties of cells under the influence of external stimuli of different origins. The work is divided into four research areas, in which the use of AFM force spectroscopy was used to explain phenomena occurring at the early stages of intracellular organization changes. Research areas presented in this manuscript focuses on detailed description of the effect of manifold external stimuli on cells, such as: (i) cell aging, (ii) active ingredients used in the cosmetics industry to improve skin condition, (iii) nanoparticles used in biomedicine, and (iv) micro- and nano-structures of topography on the surface of substrates used for cell cultures. This review is based on a critical analysis of the latest literature reports (seven of which were created with Author’s contribution) describing the use of force spectroscopy as an effective tool to study the mechanical properties of living cells.
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JIANG, Bo, XiaoYan TANG, Yu SONG i WenKe* ZHANG. "The application of AFM-based single molecule force spectroscopy in real material and biological systems—The challenges and opportunities". Scientia Sinica Chimica 43, nr 12 (2013): 1780. http://dx.doi.org/10.1360/032013-250.
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Cheung, Eugene, Yan Xia, Marc A. Caporini i Jamie L. Gilmore. "Tools shaping drug discovery and development". Biophysics Reviews 3, nr 3 (wrzesień 2022): 031301. http://dx.doi.org/10.1063/5.0087583.
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Spectroscopic, scattering, and imaging methods play an important role in advancing the study of pharmaceutical and biopharmaceutical therapies. The tools more familiar to scientists within industry and beyond, such as nuclear magnetic resonance and fluorescence spectroscopy, serve two functions: as simple high-throughput techniques for identification and purity analysis, and as potential tools for measuring dynamics and structures of complex biological systems, from proteins and nucleic acids to membranes and nanoparticle delivery systems. With the expansion of commercial small-angle x-ray scattering instruments into the laboratory setting and the accessibility of industrial researchers to small-angle neutron scattering facilities, scattering methods are now used more frequently in the industrial research setting, and probe-less time-resolved small-angle scattering experiments are now able to be conducted to truly probe the mechanism of reactions and the location of individual components in complex model or biological systems. The availability of atomic force microscopes in the past several decades enables measurements that are, in some ways, complementary to the spectroscopic techniques, and wholly orthogonal in others, such as those related to nanomechanics. As therapies have advanced from small molecules to protein biologics and now messenger RNA vaccines, the depth of biophysical knowledge must continue to serve in drug discovery and development to ensure quality of the drug, and the characterization toolbox must be opened up to adapt traditional spectroscopic methods and adopt new techniques for unraveling the complexities of the new modalities. The overview of the biophysical methods in this review is meant to showcase the uses of multiple techniques for different modalities and present recent applications for tackling particularly challenging situations in drug development that can be solved with the aid of fluorescence spectroscopy, nuclear magnetic resonance spectroscopy, atomic force microscopy, and small-angle scattering.
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Andolfi, Laura, Alice Battistella, Michele Zanetti, Marco Lazzarino, Lorella Pascolo, Federico Romano i Giuseppe Ricci. "Scanning Probe Microscopies: Imaging and Biomechanics in Reproductive Medicine Research". International Journal of Molecular Sciences 22, nr 8 (7.04.2021): 3823. http://dx.doi.org/10.3390/ijms22083823.
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Basic and translational research in reproductive medicine can provide new insights with the application of scanning probe microscopies, such as atomic force microscopy (AFM) and scanning near-field optical microscopy (SNOM). These microscopies, which provide images with spatial resolution well beyond the optical resolution limit, enable users to achieve detailed descriptions of cell topography, inner cellular structure organization, and arrangements of single or cluster membrane proteins. A peculiar characteristic of AFM operating in force spectroscopy mode is its inherent ability to measure the interaction forces between single proteins or cells, and to quantify the mechanical properties (i.e., elasticity, viscoelasticity, and viscosity) of cells and tissues. The knowledge of the cell ultrastructure, the macromolecule organization, the protein dynamics, the investigation of biological interaction forces, and the quantification of biomechanical features can be essential clues for identifying the molecular mechanisms that govern responses in living cells. This review highlights the main findings achieved by the use of AFM and SNOM in assisted reproductive research, such as the description of gamete morphology; the quantification of mechanical properties of gametes; the role of forces in embryo development; the significance of investigating single-molecule interaction forces; the characterization of disorders of the reproductive system; and the visualization of molecular organization. New perspectives of analysis opened up by applying these techniques and the translational impacts on reproductive medicine are discussed.
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Mozaffari, Abolfazl, Mazeyar Parvinzadeh Gashti, Mohammad Mirjalili i Masoud Parsania. "Argon and Argon–Oxygen Plasma Surface Modification of Gelatin Nanofibers for Tissue Engineering Applications". Membranes 11, nr 1 (2.01.2021): 31. http://dx.doi.org/10.3390/membranes11010031.
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In the present study, we developed a novel approach for functionalization of gelatin nanofibers using the plasma method for tissue engineering applications. For this purpose, tannic acid-crosslinked gelatin nanofibers were fabricated with electrospinning, followed by treatment with argon and argon–oxygen plasmas in a vacuum chamber. Samples were evaluated by using scanning electron microscopy (SEM), atomic force microscopy (AFM), attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy, contact angle (CA) and X-ray diffraction (XRD). The biological activity of plasma treated gelatin nanofibers were further investigated by using fibroblasts as cell models. SEM studies showed that the average diameter and the surface morphology of nanofibers did not change after plasma treatment. However, the mean surface roughness (RMS) of samples were increased due to plasma activation. ATR-FTIR spectroscopy demonstrated several new bands on plasma treated fibers related to the plasma ionization of nanofibers. The CA test results stated that the surface of nanofibers became completely hydrophilic after argon–oxygen plasma treatment. Finally, increasing the polarity of crosslinked gelatin after plasma treatment resulted in an increase of the number of fibroblast cells. Overall, results expressed that our developed method could open new insights into the application of the plasma process for functionalization of biomedical scaffolds. Moreover, the cooperative interplay between gelatin biomaterials and argon/argon–oxygen plasmas discovered a key composition showing promising biocompatibility towards biological cells. Therefore, we strongly recommend plasma surface modification of nanofiber scaffolds as a pretreatment process for tissue engineering applications.
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Rajeshkumar, Shanmugam, Royapuram Parthasarathy Parameswari, Dayalan Sandhiya, Khalid A. Al-Ghanim, Marcello Nicoletti i Marimuthu Govindarajan. "Green Synthesis, Characterization and Bioactivity of Mangifera indica Seed-Wrapped Zinc Oxide Nanoparticles". Molecules 28, nr 6 (21.03.2023): 2818. http://dx.doi.org/10.3390/molecules28062818.
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In the realm of nanoparticles, metal-based nanoparticles have traditionally been regarded as the pioneering category. Compared to other nanoparticles, zinc oxide nanoparticles have several advantages, including optical and biological properties, which provide them a significant competitive advantage in clinical and biological applications. In the current investigation, we used an aqueous Mangifera indica seed extract to synthesize nanoparticles of zinc oxide (ZnO NPs). UV-Vis spectroscopy, Fourier transform infrared spectroscopy analysis, atomic force spectroscopy, X-ray diffraction, scanning electron microscopy, and transmission electron microscopy were used to characterize the synthesized ZnO NPs. The nanoparticles were assessed for their potential to inhibit bacterial growth and protect cells from free radical damage. According to the current study’s findings, zinc oxide nanoparticles that had been modified with the aid of mango seeds were very efficient in preventing the development of the tested bacteria and were also powerful antioxidants.
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Gajaria, Tejal K., Himadri Bhatt, Ankit Khandelwal, Vihas T. Vasu, CRK Reddy i D. Shanthana Lakshmi. "A facile chemical cross-linking approach toward the fabrication of a sustainable porous ulvan scaffold". Journal of Bioactive and Compatible Polymers 35, nr 4-5 (lipiec 2020): 301–13. http://dx.doi.org/10.1177/0883911520939986.
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Ulvans represent one of the most abundant marine-derived macromolecular sulfated polysaccharides accounting for numerous biological applications including in one of the fastest growing field of biomedical sciences. Tissue engineering based on biologically inspired and naturally derived polymers has been one of the prime focuses of regenerative medicine. The present investigation is intended to explore an ionic cross-linking approach at higher pH lead by the calcium ions for casting cell growth promoting scaffolds out of the raw ulvan. The characterization studies using attenuated total reflectance infrared spectroscopy represent specific absorptions at 2950, 980, and 600 cm−1, whereas the x-ray diffraction showed a total absence of major crystalline peaks presenting significant shift to an amorphous state. The 1H nuclear magnetic resonance study revealed functional group modifications in the backbone that might be potentially derived from calcium interactions with glucurorhamnose 3-sulfate and iduronorhamnose 3-sulfate. The atomic force microscopy together with field emission scanning electron microscopy and energy dispersive x-ray spectroscopy mapping revealed the resultant surface changes, whereas confocal microscopy z-stacking showed the cell proliferative activity as evident by the attainment of complete morphology. The combined chemical and biological response of the scaffold makes it a well suitable support for its cell culture and tissue engineering applications.
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Collins, Liam, Stephen Jesse, Jason I. Kilpatrick, Alexander Tselev, M. Baris Okatan, Sergei V. Kalinin i Brian J. Rodriguez. "Kelvin probe force microscopy in liquid using electrochemical force microscopy". Beilstein Journal of Nanotechnology 6 (19.01.2015): 201–14. http://dx.doi.org/10.3762/bjnano.6.19.
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Conventional closed loop-Kelvin probe force microscopy (KPFM) has emerged as a powerful technique for probing electric and transport phenomena at the solid–gas interface. The extension of KPFM capabilities to probe electrostatic and electrochemical phenomena at the solid–liquid interface is of interest for a broad range of applications from energy storage to biological systems. However, the operation of KPFM implicitly relies on the presence of a linear lossless dielectric in the probe–sample gap, a condition which is violated for ionically-active liquids (e.g., when diffuse charge dynamics are present). Here, electrostatic and electrochemical measurements are demonstrated in ionically-active (polar isopropanol, milli-Q water and aqueous NaCl) and ionically-inactive (non-polar decane) liquids by electrochemical force microscopy (EcFM), a multidimensional (i.e., bias- and time-resolved) spectroscopy method. In the absence of mobile charges (ambient and non-polar liquids), KPFM and EcFM are both feasible, yielding comparable contact potential difference (CPD) values. In ionically-active liquids, KPFM is not possible and EcFM can be used to measure the dynamic CPD and a rich spectrum of information pertaining to charge screening, ion diffusion, and electrochemical processes (e.g., Faradaic reactions). EcFM measurements conducted in isopropanol and milli-Q water over Au and highly ordered pyrolytic graphite electrodes demonstrate both sample- and solvent-dependent features. Finally, the feasibility of using EcFM as a local force-based mapping technique of material-dependent electrostatic and electrochemical response is investigated. The resultant high dimensional dataset is visualized using a purely statistical approach that does not require a priori physical models, allowing for qualitative mapping of electrostatic and electrochemical material properties at the solid–liquid interface.
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Shtansky, Dmitry V., Andrei T. Matveev, Elizaveta S. Permyakova, Denis V. Leybo, Anton S. Konopatsky i Pavel B. Sorokin. "Recent Progress in Fabrication and Application of BN Nanostructures and BN-Based Nanohybrids". Nanomaterials 12, nr 16 (16.08.2022): 2810. http://dx.doi.org/10.3390/nano12162810.
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Due to its unique physical, chemical, and mechanical properties, such as a low specific density, large specific surface area, excellent thermal stability, oxidation resistance, low friction, good dispersion stability, enhanced adsorbing capacity, large interlayer shear force, and wide bandgap, hexagonal boron nitride (h-BN) nanostructures are of great interest in many fields. These include, but are not limited to, (i) heterogeneous catalysts, (ii) promising nanocarriers for targeted drug delivery to tumor cells and nanoparticles containing therapeutic agents to fight bacterial and fungal infections, (iii) reinforcing phases in metal, ceramics, and polymer matrix composites, (iv) additives to liquid lubricants, (v) substrates for surface enhanced Raman spectroscopy, (vi) agents for boron neutron capture therapy, (vii) water purifiers, (viii) gas and biological sensors, and (ix) quantum dots, single photon emitters, and heterostructures for electronic, plasmonic, optical, optoelectronic, semiconductor, and magnetic devices. All of these areas are developing rapidly. Thus, the goal of this review is to analyze the critical mass of knowledge and the current state-of-the-art in the field of BN-based nanomaterial fabrication and application based on their amazing properties.
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Amarie, Sergiu, Paul Zaslansky, Yusuke Kajihara, Erika Griesshaber, Wolfgang W. Schmahl i Fritz Keilmann. "Nano-FTIR chemical mapping of minerals in biological materials". Beilstein Journal of Nanotechnology 3 (5.04.2012): 312–23. http://dx.doi.org/10.3762/bjnano.3.35.
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Methods for imaging of nanocomposites based on X-ray, electron, tunneling or force microscopy provide information about the shapes of nanoparticles; however, all of these methods fail on chemical recognition. Neither do they allow local identification of mineral type. We demonstrate that infrared near-field microscopy solves these requirements at 20 nm spatial resolution, highlighting, in its first application to natural nanostructures, the mineral particles in shell and bone. "Nano-FTIR" spectral images result from Fourier-transform infrared (FTIR) spectroscopy combined with scattering scanning near-field optical microscopy (s-SNOM). On polished sections of Mytilus edulis shells we observe a reproducible vibrational (phonon) resonance within all biocalcite microcrystals, and distinctly different spectra on bioaragonite. Surprisingly, we discover sparse, previously unknown, 20 nm thin nanoparticles with distinctly different spectra that are characteristic of crystalline phosphate. Multicomponent phosphate bands are observed on human tooth sections. These spectra vary characteristically near tubuli in dentin, proving a chemical or structural variation of the apatite nanocrystals. The infrared band strength correlates with the mineral density determined by electron microscopy. Since nano-FTIR sensitively responds to structural disorder it is well suited for the study of biomineral formation and aging. Generally, nano-FTIR is suitable for the analysis and identification of composite materials in any discipline, from testing during nanofabrication to even the clinical investigation of osteopathies.
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Kulkarni, Prateek, Charitha B. Ponnappa, Partha Doshi, Padmalatha Rao i Seetharaman Balaji. "Lignin from termite frass: a sustainable source for anticorrosive applications". Journal of Applied Electrochemistry 51, nr 10 (13.07.2021): 1491–500. http://dx.doi.org/10.1007/s10800-021-01592-8.
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AbstractThe present study reports a sustainable source of lignin, from termite frass. Lignin was extracted using Klason’s method and subjected to polarization studies to check the inhibition efficiency and measured the electrochemical performance of the coated sample on the carbon steel using electrochemical impedance spectroscopy. The anticorrosive property was determined in a simulated corrosive environment (0.1 M NaOH and 0.5 M NaOH). The morphological analysis of the surface of both bare metal and the lignin-coated ones, before and after exposure to the corrosive environment, was recorded using atomic force microscopy (AFM), scanning electron microscopy (SEM), and energy-dispersive X-Ray spectroscopy (EDX). The lignin showed maximum inhibition efficiency at 600 ppm in 0.5 M NaOH solution. Moreover, the lignin coated on carbon steel exhibited about 70% corrosion inhibition efficiency as recorded by potentiodynamic polarization studies and electrochemical impedance spectroscopy. The AFM and SEM analyses further corroborated the protection of the metal surface from corrosion when coated with lignin. Hence, the study suggests lignin from termite frass as a sustainable biological source suitable for anticorrosive applications. Graphic abstract
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SUN, HANWEN, JIAHUI YU, PEIJUN GONG, DONGMEI XU, JUN HONG, CHUNFU ZHANG i SIDE YAO. "NOVEL CORE–SHELL MAGNETIC NANOGELS SYNTHESIZED IN AN EMULSION-FREE AQUEOUS SYSTEM UNDER UV IRRADIATION FOR POTENTIAL TARGETED RADIOPHARMACEUTICAL APPLICATIONS". International Journal of Nanoscience 05, nr 02n03 (kwiecień 2006): 253–58. http://dx.doi.org/10.1142/s0219581x06004322.
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Novel core–shell poly(acrylamide) magnetic nanogels with controllable particle size produced via photochemical method in emulsion-free aqueous system at room temperature have been developed for the first time. After Hoffmann elimination of carbonyl, the nanogels with amino groups, or poly(acrylamide-vinyl amine) magnetic nanogels, were also obtained. Particle size, size distributions and zeta potential of the magnetic nanogels before and after Hoffmann elimination were measured by photo correlation spectroscopy (PCS). Structure and morphology of the magnetic nanogels were characterized by Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM) and atomic force microscopy (AFM). The higher dispersibility and stability of the magnetic nanogels suggest promising potential applications in targeted radiopharmaceuticals carrier for cancer therapy, and in biological and medical studies as well.
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Pryjmaková, Jana, Mariia Hryhoruk, Martin Veselý, Petr Slepička, Václav Švorčík i Jakub Siegel. "Engineered Cu-PEN Composites at the Nanoscale: Preparation and Characterisation". Nanomaterials 12, nr 7 (5.04.2022): 1220. http://dx.doi.org/10.3390/nano12071220.
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As polymeric materials are already used in many industries, the range of their applications is constantly expanding. Therefore, their preparation procedures and the resulting properties require considerable attention. In this work, we designed the surface of polyethylene naphthalate (PEN) introducing copper nanowires. The surface of PEN was transformed into coherent ripple patterns by treatment with a KrF excimer laser. Then, Cu deposition onto nanostructured surfaces by a vacuum evaporation technique was accomplished, giving rise to nanowires. The morphology of the prepared structures was investigated by atomic force microscopy and scanning electron microscopy. Energy dispersive spectroscopy and X-ray photoelectron spectroscopy revealed the distribution of Cu in the nanowires and their gradual oxidation. The optical properties of the Cu nanowires were measured by UV-Vis spectroscopy. The sessile drop method revealed the hydrophobic character of the Cu/PEN surface, which is important for further studies of biological responses. Our study suggests that a combination of laser surface texturing and vacuum evaporation can be an effective and simple method for the preparation of a Cu/polymer nanocomposite with potential exploitation in bioapplications; however, it should be borne in mind that significant post-deposition oxidation of the Cu nanowire occurs, which may open up new strategies for further biological applications.
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Abdulbaqi, Mustafa R. "EVALUATION THE EFFECT OF NANOTECHNOLOGY ON PHARMACEUTICAL AND BIOLOGICAL PROPERTIES OF METRONIDAZOLE". International Journal of Pharmacy and Pharmaceutical Sciences 9, nr 8 (1.08.2017): 139. http://dx.doi.org/10.22159/ijpps.2017v9i8.19806.
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Objective: This study aimed to evaluate the application of nanotechnology in improving the solubility and biologic activity as the antibacterial and antifungal drug of metronidazole (MTZ).Methods: Nanoparticles of bismuth sulfide (Bi2S3) were used as the nanocarriers for metronidazole (MTZ) and they were synthesized by chemical co-precipitation method. Drug loading on Bi2S3 nanoparticles, lattice property alteration and average particles sizes were evaluated using fourier transform infrared (FTIR) spectroscopy, atomic force microscopy (AFM), and powder X-ray diffraction (PXRD). The evaluation of the release of MTZ from Bi2S3 nanoparticles was carried out using USP type II rotating paddle apparatus. The antimicrobial activity of MTZ before and after loading was carried out by disc diffusion method against two aerobic gram+ve and one aerobic gram–ve bacteria, in addition to two fungi.Results: This study showed successful loading process as well as particles size reduction of MTZ after loading on Bi2S3 nanoparticles. In vitro release study showed a significant* increase in solubility and dissolution of MTZ after loading on Bi2S3 nanoparticles. MTZ showed a significant* increase in antibacterial (against gram+ve aerobic staphylococcus aureus and bacillus subtilis) and antifungal (Candida glabrata and Candida tropicalis) activities after loading process.Conclusion: Nanotechnology was applied successfully to improve both, solubility and biologic activity of the model drug used, metronidazole (MTZ).
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Iconaru, Simona Liliana, Daniela Predoi, Carmen Steluta Ciobanu, Mikael Motelica-Heino, Régis Guegan i Coralia Bleotu. "Development of Silver Doped Hydroxyapatite Thin Films for Biomedical Applications". Coatings 12, nr 3 (5.03.2022): 341. http://dx.doi.org/10.3390/coatings12030341.
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Silver doped hydroxyapatite [AgHAp, Ca10−xAg(PO4)6(OH)2], due to its antimicrobial properties, is an advantageous material to be used for various coatings. The AgHAp thin films with xAg = 0.05 and xAg = 0.1 were achieved using the spin-coating method. The resulting samples were examined by X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). XRD analysis revealed that the particles of both samples are ellipsoidal. Also, in agreement with the results obtained by XRD measurements, the results of the SEM studies have shown that the particles shape is ellipsoidal. Optical properties of silver doped hydroxyapatite thin films deposited on Si substrate were investigated through Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy. The results obtained by the two complementary techniques highlighted that the molecular structure of the studied samples is not influenced by the increase of the silver concentration in the samples. Our studies revealed that the surface morphology of the obtained samples consist of uniform and continuous layers. The biocompatibility of the obtained thin films was also evaluated with the aid of human osteosarcoma MG63 (ATCC CRL 1427) cell line. Moreover, the in vitro antifungal activity against Candida albicans fungal strain of the AgHAp thin films was studied and the obtained results revealed their antifungal effect. The results of the biological assays showed that the AgHAp thin films are a very promising material for biomedical applications.
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Bongaerts, Maud, Koceila Aizel, Emilie Secret, Audric Jan, Tasmin Nahar, Fabian Raudzus, Sebastian Neumann i in. "Parallelized Manipulation of Adherent Living Cells by Magnetic Nanoparticles-Mediated Forces". International Journal of Molecular Sciences 21, nr 18 (8.09.2020): 6560. http://dx.doi.org/10.3390/ijms21186560.
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The remote actuation of cellular processes such as migration or neuronal outgrowth is a challenge for future therapeutic applications in regenerative medicine. Among the different methods that have been proposed, the use of magnetic nanoparticles appears to be promising, since magnetic fields can act at a distance without interactions with the surrounding biological system. To control biological processes at a subcellular spatial resolution, magnetic nanoparticles can be used either to induce biochemical reactions locally or to apply forces on different elements of the cell. Here, we show that cell migration and neurite outgrowth can be directed by the forces produced by a switchable parallelized array of micro-magnetic pillars, following the passive uptake of nanoparticles. Using live cell imaging, we first demonstrate that adherent cell migration can be biased toward magnetic pillars and that cells can be reversibly trapped onto these pillars. Second, using differentiated neuronal cells we were able to induce events of neurite outgrowth in the direction of the pillars without impending cell viability. Our results show that the range of forces applied needs to be adapted precisely to the cellular process under consideration. We propose that cellular actuation is the result of the force on the plasma membrane caused by magnetically filled endo-compartments, which exert a pulling force on the cell periphery.
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Peña, Brisa, Mostafa Adbel-Hafiz, Maria Cavasin, Luisa Mestroni i Orfeo Sbaizero. "Atomic Force Microscopy (AFM) Applications in Arrhythmogenic Cardiomyopathy". International Journal of Molecular Sciences 23, nr 7 (28.03.2022): 3700. http://dx.doi.org/10.3390/ijms23073700.
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Arrhythmogenic cardiomyopathy (ACM) is an inherited heart muscle disorder characterized by progressive replacement of cardiomyocytes by fibrofatty tissue, ventricular dilatation, cardiac dysfunction, arrhythmias, and sudden cardiac death. Interest in molecular biomechanics for these disorders is constantly growing. Atomic force microscopy (AFM) is a well-established technic to study the mechanobiology of biological samples under physiological and pathological conditions at the cellular scale. However, a review which described all the different data that can be obtained using the AFM (cell elasticity, adhesion behavior, viscoelasticity, beating force, and frequency) is still missing. In this review, we will discuss several techniques that highlight the potential of AFM to be used as a tool for assessing the biomechanics involved in ACM. Indeed, analysis of genetically mutated cells with AFM reveal abnormalities of the cytoskeleton, cell membrane structures, and defects of contractility. The higher the Young’s modulus, the stiffer the cell, and it is well known that abnormal tissue stiffness is symptomatic of a range of diseases. The cell beating force and frequency provide information during the depolarization and repolarization phases, complementary to cell electrophysiology (calcium imaging, MEA, patch clamp). In addition, original data is also presented to emphasize the unique potential of AFM as a tool to assess fibrosis in cardiac tissue.
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Akartasse, Noureddine, Khalil Azzaoui, Elmiloud Mejdoubi, Lhaj Lahcen Elansari, Belkhir Hammouti, Mohamed Siaj, Shehdeh Jodeh, Ghadir Hanbali, Rinad Hamed i Larbi Rhazi. "Chitosan-Hydroxyapatite Bio-Based Composite in Film Form: Synthesis and Application in Wastewater". Polymers 14, nr 20 (11.10.2022): 4265. http://dx.doi.org/10.3390/polym14204265.
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Water purification from toxic metals was the main objective of this work. A composite in film form was prepared from the biomaterials hydroxyapatite, chitosan and glycerol using the dissolution/recrystallization method. A nanoparticle-based film with a homogenous and smooth surface was produced. The results of total reflectance infrared spectroscopy (ATR-FTIR) and thermal gravimetric analysis (TGA/DTA) demonstrated the presence of a substantial physical force between composite components. The composite was tested for its ability to absorb Cd2+ and Zn2+ ions from aqueous solutions. Cd2+ and Zn2+ adsorption mechanisms are fit using the Langmuir model and the pseudo-second-order model. Thermodynamic parameters indicated that Cd2+ and Zn2+ ion adsorption onto the composite surface is spontaneous and preferred at neutral pH and temperatures somewhat higher than room temperature. The adsorption studies showed that the maximum adsorption capacity of the HAp/CTs bio-composite membrane for Cd2+ and Zn2+ ions was in the order of cadmium (120 mg/g) > Zinc (90 mg/g) at an equilibrium time of 20 min and a temperature of 25 °C. The results obtained on the physico-chemical properties of nanocomposite membranes and their sorption capacities offer promising potential for industrial and biological activities.
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Dixit, D., D. Gangadharan, K. M. Popat, C. R. K. Reddy, M. Trivedi i D. K. Gadhavi. "Synthesis, characterization and application of green seaweed mediated silver nanoparticles (AgNPs) as antibacterial agents for water disinfection". Water Science and Technology 78, nr 1 (2.07.2018): 235–46. http://dx.doi.org/10.2166/wst.2018.292.
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Abstract A simple and eco-friendly method for the synthesis of hybrid bead silver nanoparticles (AgNPs) employing the aqueous extract derived from natural and renewable source namely tropical benthic green seaweed Ulva flexuosa was developed. This route involves the reduction of Ag+ ions anchored onto macro porous methacrylic acid copolymer beads to AgNPs for employing them as antibacterial agents for in vitro water disinfection. The seaweed extract itself acts as a reducing and stabilizing agent and requires no additional surfactant or capping agent for forming the AgNPs. The nanoparticles were analyzed using high-resolution transmission electron microscopy, UV–Vis spectroscopy, Fourier transform infrared spectroscopy, scanning electron microscopy, energy dispersive X-ray analysis and inductively coupled plasma optical emission spectroscopy. The study elucidates that such biologically synthesized AgNPs exhibit potential antibacterial activity against two Gram positive (Bacillus subtilis, Staphylococcus aureus) and two Gram-negative (Escherichia coli, Pseudomonas aeruginosa) bacterial strains tested. The bacterial count in treated water was reduced to zero for all the strains. Atomic force microscopy was performed to confirm the pre- and post-state of the bacteria with reference to their treatment with AgNPs. Attributes like facile environment-friendly procedure, stability and high antibacterial potency propel the consideration of these AgNPs as promising antibacterial entities.
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Singh, Priyanka, Santosh Pandit, VRSS Mokkapati, Jørgen Garnæs i Ivan Mijakovic. "A Sustainable Approach for the Green Synthesis of Silver Nanoparticles from Solibacillus isronensis sp. and Their Application in Biofilm Inhibition". Molecules 25, nr 12 (16.06.2020): 2783. http://dx.doi.org/10.3390/molecules25122783.
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The use of bacteria as nanofactories for the green synthesis of nanoparticles is considered a sustainable approach, owing to the stability, biocompatibility, high yields and facile synthesis of nanoparticles. The green synthesis provides the coating or capping of biomolecules on nanoparticles surface, which confer their biological activity. In this study, we report green synthesis of silver nanoparticles (AgNPs) by an environmental isolate; named as AgNPs1, which showed 100% 16S rRNA sequence similarity with Solibacillus isronensis. UV/visible analysis (UV/Vis), transmission electron microscopy (TEM), atomic force microscopy (AFM), dynamic light scattering (DLS), and Fourier-transform infrared spectroscopy (FTIR) were used to characterize the synthesized nanoparticles. The stable nature of nanoparticles was studied by thermogravimetric analysis (TGA) and inductively coupled plasma mass spectrometry (ICP-MS). Further, these nanoparticles were tested for biofilm inhibition against Escherichia coli and Pseudomonas aeruginosa. The AgNPs showed minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values of 3.12 µg/mL and 6.25 µg/mL for E. coli, and 1.56 µg/mL and 3.12 µg/mL for P. aeruginosa, respectively.
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Dobos, Adina-Maria, Elena-Laura Ursu, Luiza-Madalina Gradinaru, Marius Dobromir i Anca Filimon. "Matching the Cellulose/Silica Films Surface Properties for Design of Biomaterials That Modulate Extracellular Matrix". Membranes 11, nr 11 (29.10.2021): 840. http://dx.doi.org/10.3390/membranes11110840.
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The surface properties of composite films are important to know for many applications from the industrial domain to the medical domain. The physical and chemical characteristics of film/membrane surfaces are totally different from those of the bulk due to the surface segregation of the low surface energy components. Thus, the surfaces of cellulose acetate/silica composite films are analyzed in order to obtain information on the morphology, topography and wettability through atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and contact angle investigations. The studied composite films present different surface properties depending on the tetraethyl orthosilicate (TEOS) content from the casting solutions. Up to a content of 1.5 wt.% TEOS, the surface roughness and hydrophobicity increase, after which there is a decrease in these parameters. This behavior suggests that up to a critical amount of TEOS, the results are influenced by the morphology and topographical features, after which a major role seems to be played by surface chemistry—increasing the oxygenation surfaces. The morphological and chemical details and also the hydrophobicity/hydrophilicity characteristics are discussed in the attempt to design biological surfaces with optimal wettability properties and possibility of application in tissue engineering.
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Nguyen, Tuan Ngoc, Vincent Humblot, Véronique Migonney i Raphaël Lévy. "Atomic force microscopy characterization of polyethylene terephthalate grafting with poly(styrene sulfonate)". Nanotechnology 33, nr 20 (21.02.2022): 205702. http://dx.doi.org/10.1088/1361-6528/ac50ef.
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Abstract Polyethylene terephthalate (PET) is widely used to elaborate biomaterials and medical devices in particular for long-term implant applications but tuning their surface properties remains challenging. We investigate surface functionalization by grafting poly(sodium 4-styrene sulfonate, PNaSS) with the aim of enhancing protein adhesion and cellular activity. Elucidating the topography and molecular level organization of the modified surfaces is important for understanding and predicting biological activity. In this work, we explore several grafting methods including thermal grafting, thermal grafting in the presence of Mohr’s salt, and UV activation. We characterize the different surfaces obtained using atomic force microscopy (AFM), contact angle (CA), and x-ray photoelectron spectroscopy (XPS). We observe an increase in the percentage of sulfur atoms (XPS) that correlates with changes in (CA), and we identify by AFM characteristic features, which we interpret as patches of polymers on the PET surfaces. This work demonstrates tuning of biomaterials surface by functionalization and illustrates the capability of AFM to provide insights into the spatial organization of the grafted polymer.
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Nithya Deva Krupa, A., i Vimala Raghavan. "Biosynthesis of Silver Nanoparticles UsingAegle marmelos(Bael) Fruit Extract and Its Application to Prevent Adhesion of Bacteria: A Strategy to Control Microfouling". Bioinorganic Chemistry and Applications 2014 (2014): 1–8. http://dx.doi.org/10.1155/2014/949538.
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Marine biofilms formed due to adhesion of bacteria and other microorganisms on submerged surfaces are generally considered to be a major form of microfouling. Subsequent attachment of larvae of higher organisms like barnacles, mussels, and so forth, on marine biofilms, causes macrofouling. Several approaches have been used to prevent micro- and macrofouling. Silver nanoparticles (AgNPs) are known to exhibit strong inhibitory and antimicrobial activity. Biological synthesis of AgNPs is rapidly gaining importance due to its growing success. Hence, the present study is focused on the biosynthesis of AgNPs using fruit extract ofAegle marmelosand its characterization through UV-Vis spectrophotometer, X-ray diffractometer (XRD), Fourier transform infrared spectroscopy (FTIR), and atomic force microscopy (AFM). Further isolation and identification of marine biofilm forming bacteria were carried out through 16S rDNA analysis. The antimicrofouling effect of the biosynthesized AgNPs was tested against marine biofilm forming bacteria and the results suggested that it could effectively inhibit biofilm formation. This preliminary study has proved that AgNPs may be used as antimicrofouling agent for the prevention of biofouling in the early stages.
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Corey, Robin A., Euan Pyle, William J. Allen, Daniel W. Watkins, Marina Casiraghi, Bruno Miroux, Ignacio Arechaga, Argyris Politis i Ian Collinson. "Specific cardiolipin–SecY interactions are required for proton-motive force stimulation of protein secretion". Proceedings of the National Academy of Sciences 115, nr 31 (16.07.2018): 7967–72. http://dx.doi.org/10.1073/pnas.1721536115.
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The transport of proteins across or into membranes is a vital biological process, achieved in every cell by the conserved Sec machinery. In bacteria, SecYEG combines with the SecA motor protein for secretion of preproteins across the plasma membrane, powered by ATP hydrolysis and the transmembrane proton-motive force (PMF). The activities of SecYEG and SecA are modulated by membrane lipids, particularly cardiolipin (CL), a specialized phospholipid known to associate with a range of energy-transducing machines. Here, we identify two specific CL binding sites on the Thermotoga maritima SecA–SecYEG complex, through application of coarse-grained molecular dynamics simulations. We validate the computational data and demonstrate the conserved nature of the binding sites using in vitro mutagenesis, native mass spectrometry, biochemical analysis, and fluorescence spectroscopy of Escherichia coli SecYEG. The results show that the two sites account for the preponderance of functional CL binding to SecYEG, and mediate its roles in ATPase and protein transport activity. In addition, we demonstrate an important role for CL in the conferral of PMF stimulation of protein transport. The apparent transient nature of the CL interaction might facilitate proton exchange with the Sec machinery, and thereby stimulate protein transport, by a hitherto unexplored mechanism. This study demonstrates the power of coupling the high predictive ability of coarse-grained simulation with experimental analyses, toward investigation of both the nature and functional implications of protein–lipid interactions.
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Nemashkalo, A., M. E. Phipps, S. P. Hennelly i P. M. Goodwin. "Real-time, single-molecule observation of biomolecular interactions inside nanophotonic zero mode waveguides". Nanotechnology 33, nr 16 (25.01.2022): 165101. http://dx.doi.org/10.1088/1361-6528/ac467c.
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Abstract Living cells rely on numerous protein-protein, RNA-protein and DNA-protein interactions for processes such as gene expression, biomolecular assembly, protein and RNA degradation. Single-molecule microscopy and spectroscopy are ideal tools for real-time observation and quantification of nucleic acids-protein and protein-protein interactions. One of the major drawbacks of conventional single-molecule imaging methods is low throughput. Methods such as sequencing by synthesis utilizing nanofabrication and single-molecule spectroscopy have brought high throughput into the realm of single-molecule biology. The Pacific Biosciences RS2 sequencer utilizes sequencing by synthesis within nanophotonic zero mode waveguides. A number of years ago this instrument was unlocked by Pacific Biosciences for custom use by researchers allowing them to monitor biological interactions at the single-molecule level with high throughput. In this capability letter we demonstrate the use of the RS2 sequencer for real-time observation of DNA-to-RNA transcription and RNA-protein interactions. We use a relatively complex model–transcription of structured ribosomal RNA from E. coli and interactions of ribosomal RNA with ribosomal proteins. We also show evidence of observation of transcriptional pausing without the application of an external force (as is required for single-molecule pausing studies using optical traps). Overall, in the unlocked, custom mode, the RS2 sequencer can be used to address a wide variety of biological assembly and interaction questions at the single-molecule level with high throughput. This instrument is available for use at the Center for Integrated Nanotechnologies Gateway located at Los Alamos National Laboratory.
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Dudziak, Mateusz, Ievgeniia Topolniak, Dorothee Silbernagl, Korinna Altmann i Heinz Sturm. "Long-Time Behavior of Surface Properties of Microstructures Fabricated by Multiphoton Lithography". Nanomaterials 11, nr 12 (3.12.2021): 3285. http://dx.doi.org/10.3390/nano11123285.
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The multiphoton lithography (MPL) technique represents the future of 3D microprinting, enabling the production of complex microscale objects with high precision. Although the MPL fabrication parameters are widely evaluated and discussed, not much attention has been given to the microscopic properties of 3D objects with respect to their surface properties and time-dependent stability. These properties are of crucial importance when it comes to the safe and durable use of these structures in biomedical applications. In this work, we investigate the surface properties of the MPL-produced SZ2080 polymeric microstructures with regard to the physical aging processes during the post-production stage. The influence of aging on the polymeric microstructures was investigated by means of Atomic Force Microscopy (AFM) and X-ray Photoelectron Spectroscopy (XPS). As a result, a time-dependent change in Young’s Modulus, plastic deformation, and adhesion and their correlation to the development in chemical composition of the surface of MPL-microstructures are evaluated. The results presented here are valuable for the application of MPL-fabricated 3D objects in general, but especially in medical technology as they give detailed information of the physical and chemical time-dependent dynamic behavior of MPL-printed surfaces and thus their suitability and performance in biological systems.
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Dinarelli, Simone, Andrzej Sikora, Angela Sorbo, Marco Rossi i Daniele Passeri. "Atomic force microscopy as a tool for mechanical characterizations at the nanometer scale". Nanomaterials and Energy 12, nr 2 (1.06.2023): 1–10. http://dx.doi.org/10.1680/jnaen.23.00016.
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The design, optimization, and realization of innovative nanocomposite materials for advanced applications in a broad range of fields, from energy, automotive, photonics, to biology and nanomedicine require the capability to characterize their physical (e.g., mechanical, electric, magnetic...) properties from a multiscale perspective, in particular, not only at the macroscopic scale, but also at the nanometer one. In particular, methods are needed to characterize mechanical properties with nanometer lateral resolution, in order to understand the contribution of the nanosized features of the materials and the related phenomena. Atomic force microscopy (AFM) has been evolved from a tool for the morphological analysis of the sample surface to an integrated platform for the physicochemical characterization of samples. Current AFM systems host several advanced techniques for the mechanical characterization of materials with high speed and high lateral resolution in a broad range of mechanical moduli, e.g., from stiff samples (e.g., coatings, crystals…) to soft materials (e.g., polymers, biological samples...), in different environments (e.g., air, vacuum, liquid), and conditions (controlled humidity, controlled temperature). Here, short review of AFM based methods for the nanomechanical characterization of materials, in particular force spectroscopy, is reported, with emphasis on the materials which can be analyzed.
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Pugliese, Raffaele, Martina Bartolomei, Carlotta Bollati, Giovanna Boschin, Anna Arnoldi i Carmen Lammi. "Gel-Forming of Self-Assembling Peptides Functionalized with Food Bioactive Motifs Modulate DPP-IV and ACE Inhibitory Activity in Human Intestinal Caco-2 Cells". Biomedicines 10, nr 2 (31.01.2022): 330. http://dx.doi.org/10.3390/biomedicines10020330.
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Food bioactive peptides are increasingly used for formulating food products, nutraceuticals, and functional food, since they are generally considered safe for human consumption and metabolic syndrome prevention. They are also becoming popular as sustainable sources of novel functional biomaterials such as hydrogels, edible nanonutraceuticals, delivery systems, and packing materials. However, such food peptides are mostly unstable, and degrade during food processing, or in a gastrointestinal environment, thus resulting in low bioavailability precluding their practical applications. Here, we decided to functionalize the well-known and characterized self-assembling peptide RADA16 with two synthetic analogues of food bioactive peptides deriving from the hydrolysis of soybean glycinin and lupin β-conglutin (namely IAVPTGVA and LTFPGSAED) for control of and improvement in their gel-forming nanostructures, biomechanics, and biological features. Extensive characterization was performed via Circular Dichroism (CD) spectroscopy, Fourier Transform Infrared spectroscopy (FT-IR), Thioflavin T (ThT) binding assay, rheological measurements, and Atomic Force Microscopy (AFM) analysis. Lastly, since self-assembling peptides (SAPs) can be co-assembled with diluent SAPs (without a bioactive epitope) as an approach to control the density of biological signals and therefore attain enhanced bioactivity, we investigated the effect of the co-assembly of RADA16 and functionalized food bioactive SAPs (dubbed cAP-Soy1 and cAP-Lup1) for the growth of Caco-2 human intestinal cells and contextually we characterized their biological activities as DPP-IV and ACE inhibitors, in order to demonstrate their potential use for the prevention of metabolic syndrome.
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Radhouani, Hajer, Cristiana Gonçalves, Fátima R. Maia, Joaquim M. Oliveira i Rui L. Reis. "Kefiran biopolymer: Evaluation of its physicochemical and biological properties". Journal of Bioactive and Compatible Polymers 33, nr 5 (18.08.2018): 461–78. http://dx.doi.org/10.1177/0883911518793914.
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Kefiran, an exopolysaccharide produced by lactic acid bacteria, has received a great interest due to a variety of health claims. In this study, we aim to investigate the physicochemical and biological properties of Kefiran polysaccharide extracted from Portuguese kefir grains. The kefir growth rate was about 56% (w/w) at room temperature and the kefir pH after 24 h was about 4.6. The obtained yield of Kefiran polysaccharide extracted from the kefir grains was about 4.26% (w/w). The Kefiran structural features were showed in the 1H nuclear magnetic resonance spectrum. The bands observed in the infrared spectrum confirmed that the Kefiran had a β-configuration; and the X-ray photoelectron spectroscopy analysis confirmed the structure and composition of Kefiran and revealed a C/O atomic ratio of 1.46. Moreover, Kefiran showed an average molecular weight (Mw) of 534 kDa and a number-average molecular weight (Mn) of 357 kDa. Regarding the rheological data obtained, Kefiran showed an interesting adhesive performance accompanied by a pseudoplastic behavior, and the extrusion force of Kefiran was 1 N. Furthermore, Kefiran exhibited a higher resistance to hyaluronidase degradation than hyaluronic acid. Finally, Kefiran showed a lack of cytotoxic response through its ability to support metabolic activity and proliferation of L929 cells, and had no effect on these cells’ morphology. Our research suggested that Kefiran polymer has attractive and interesting properties for a wide range of biomedical applications, such as tissue engineering and regenerative medicine.
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Park, Hyun-Chul, Jaeyoung Ryu, Seunggon Jung, Hong-Ju Park, Hee-Kyun Oh i Min-Suk Kook. "Effect of Hydroxyapatite Nanoparticles and Nitrogen Plasma Treatment on Osteoblast Biological Behaviors of 3D-Printed HDPE Scaffold for Bone Tissue Regeneration Applications". Materials 15, nr 3 (21.01.2022): 827. http://dx.doi.org/10.3390/ma15030827.
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The need for the repair of bone defects has been increasing due to various causes of loss of skeletal tissue. High density polyethylenes (HDPE) have been used as bone substitutes due to their excellent biocompatibility and mechanical strength. In the present study, we investigated the preosteoblast cell proliferation and differentiation on the adding nano-hydroxyapatite (n-HAp) particles into HDPE scaffold and treating HDPE/n-HAp scaffolds with nitrogen (N2) plasma. The three-dimensional (3D) HDPE/n-HAp scaffolds were prepared by fused modeling deposition 3D printer. The HDPE/n-HAp was blended with 10 wt% of n-HAp particle. The scaffold surface was reactive ion etched with nitrogen plasma to improve the preosteoblast biological response in vitro. After N2 plasma treatment, surfaces characterizations were investigated using Fourier transform infrared spectroscopy, scanning electron microscopy, and atomic force microscopy. The proliferation and differentiation of preosteoblast (MC3T3-E1) cells were evaluated by MTT assay and alkaline phosphatase (ALP) activity. The incorporation of n-HAp particles and N2 plasma surface treatment showed the improvement of biological responses of MC3T3-E1 cells in the HDPE scaffolds.
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Janiszewska, Natalia, Barbara Orzechowska, Kamil Awsiuk, Jakub Rysz, Svitlana Tymetska i Joanna Raczkowska. "Cell-Specific Response of NSIP- and IPF-Derived Fibroblasts to the Modification of the Elasticity, Biological Properties, and 3D Architecture of the Substrate". International Journal of Molecular Sciences 23, nr 23 (25.11.2022): 14714. http://dx.doi.org/10.3390/ijms232314714.
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The fibrotic fibroblasts derived from idiopathic pulmonary fibrosis (IPF) and nonspecific interstitial pneumonia (NSIP) are surrounded by specific environments, characterized by increased stiffness, aberrant extracellular matrix (ECM) composition, and altered lung architecture. The presented research was aimed at investigating the effect of biological, physical, and topographical modification of the substrate on the properties of IPF- and NSIP-derived fibroblasts, and searching for the parameters enabling their identification. Soft and stiff polydimethylsiloxane (PDMS) was chosen for the basic substrates, the properties of which were subsequently tuned. To obtain the biological modification of the substrates, they were covered with ECM proteins, laminin, fibronectin, and collagen. The substrates that mimicked the 3D structure of the lungs were prepared using two approaches, resulting in porous structures that resemble natural lung architecture and honeycomb patterns, typical of IPF tissue. The growth of cells on soft and stiff PDMS covered with proteins, traced using fluorescence microscopy, confirmed an altered behavior of healthy and IPF- and NSIP-derived fibroblasts in response to the modified substrate properties, enabling their identification. In turn, differences in the mechanical properties of healthy and fibrotic fibroblasts, determined using atomic force microscopy working in force spectroscopy mode, as well as their growth on 3D-patterned substrates were not sufficient to discriminate between cell lines.
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Alghuthaymi, Mousa A., Sunita Patil, Chandrasekaran Rajkuberan, Muthukumar Krishnan, Ushani Krishnan i Kamel A. Abd-Elsalam. "Polianthes tuberosa-Mediated Silver Nanoparticles from Flower Extractand Assessment of Their Antibacterial and Anticancer Potential: An In Vitro Approach". Plants 12, nr 6 (10.03.2023): 1261. http://dx.doi.org/10.3390/plants12061261.
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Plant-mediated metallic nanoparticles have beenreported for a diversified range of applications in biological sciences. In the present study, we propose the Polianthes tuberosa flower as a reducing and stabilizing agent for the synthesis of silver nanoparticles (PTAgNPs). The PTAgNPs were exclusively characterized using UV–Visible spectroscopy, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD), atomic force microscopy, zeta potential, and transmission electron microscopy (TEM) studies. In a biological assay, we investigated the antibacterial and anticancer activity of silver nanoparticles in the A431 cell line. The PTAgNPs demonstrated a dose-dependent activity in E. coli and S. aureus, suggesting the bactericidal nature of AgNPs. The PTAgNPs exhibited dose-dependent toxicity in the A431 cell line, with an IC50 of 54.56 µg/mL arresting cell growth at the S phase, as revealed by flow cytometry analysis. The COMET assay revealed 39.9% and 18.15 severities of DNA damage and tail length in the treated cell line, respectively. Fluorescence staining studies indicate that PTAgNPs cause reactive oxygen species (ROS) and trigger apoptosis. This research demonstrates that synthesized silver nanoparticles have a significant effect on inhibiting the growth of melanoma cells and other forms of skin cancer. The results show that these particles can cause apoptosis or cell death in malignant tumor cells. This suggests that they could be used to treat skin cancers without harming normal tissues.