Journal articles: 'Redox labels'

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Koyappayil, Aneesh, and Min-Ho Lee. "Ultrasensitive Materials for Electrochemical Biosensor Labels." Sensors 21, no. 1 (December 25, 2020): 89. http://dx.doi.org/10.3390/s21010089.

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Since the fabrication of the first electrochemical biosensor by Leland C. Clark in 1956, various labeled and label-free sensors have been reported for the detection of biomolecules. Labels such as nanoparticles, enzymes, Quantum dots, redox-active molecules, low dimensional carbon materials, etc. have been employed for the detection of biomolecules. Because of the absence of cross-reaction and highly selective detection, labeled biosensors are advantageous and preferred over label-free biosensors. The biosensors with labels depend mainly on optical, magnetic, electrical, and mechanical principles. Labels combined with electrochemical techniques resulted in the selective and sensitive determination of biomolecules. The present review focuses on categorizing the advancement and advantages of different labeling methods applied simultaneously with the electrochemical techniques in the past few decades.

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Le Gal La Salle, A., B. Limoges, S. Rapicault, C. Degrand, and P. Brossier. "New immunoassay techniques using Nafion-modified electrodes and cationic redox labels or enzyme labels." Analytica Chimica Acta 311, no. 3 (August 1995): 301–8. http://dx.doi.org/10.1016/0003-2670(95)00064-7.

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Evtugyn, Gennady A., Anna V. Porfireva, and Ivan I. Stoikov. "Electrochemical DNA sensors based on spatially distributed redox mediators: challenges and promises." Pure and Applied Chemistry 89, no. 10 (September 26, 2017): 1471–90. http://dx.doi.org/10.1515/pac-2016-1124.

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AbstractDNA and aptasensors are widely used for fast and reliable detection of disease biomarkers, pharmaceuticals, toxins, metabolites and other species necessary for biomedical diagnostics. In the overview, the concept of spatially distributed redox mediators is considered with particular emphasis to the signal generation and biospecific layer assembling. The application of non-conductive polymers bearing redox labels, supramolecular carriers with attached DNA aptamers and redox active dyes and E-sensor concept are considered as examples of the approach announced.

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Iglesias-Mayor, Alba, Olaya Amor-Gutiérrez, Agustín Costa-García, and Alfredo de la Escosura-Muñiz. "Nanoparticles as Emerging Labels in Electrochemical Immunosensors." Sensors 19, no. 23 (November 23, 2019): 5137. http://dx.doi.org/10.3390/s19235137.

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This review shows recent trends in the use of nanoparticles as labels for electrochemical immunosensing applications. Some general considerations on the principles of both the direct detection based on redox properties and indirect detection through electrocatalytic properties, before focusing on the applications for mainly proteins detection, are given. Emerging use as blocking tags in nanochannels-based immunosensing systems is also covered in this review. Finally, aspects related to the analytical performance of the developed devices together with prospects for future improvements and applications are discussed.

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Ben Jrad, Amani, Hussein Kanso, Delphine Raviglione, Thierry Noguer, Nicolas Inguimbert, and Carole Calas-Blanchard. "Salen/salan metallic complexes as redox labels for electrochemical aptasensors." Chemical Communications 55, no. 85 (2019): 12821–24. http://dx.doi.org/10.1039/c9cc07575e.

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Smiljanic, Milutin, Pierre Bleteau, Alexia Papageorgiou, Nathan Goffart, Catherine Adam, and Thomas Doneux. "Introducing common oxazine fluorophores as new redox labels for electrochemical DNA sensors." Bioelectrochemistry 155 (February 2024): 108582. http://dx.doi.org/10.1016/j.bioelechem.2023.108582.

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Ma, Xiaohua, Dehua Deng, Ning Xia, Yuanqiang Hao, and Lin Liu. "Electrochemical Immunosensors with PQQ-Decorated Carbon Nanotubes as Signal Labels for Electrocatalytic Oxidation of Tris(2-carboxyethyl)phosphine." Nanomaterials 11, no. 7 (July 5, 2021): 1757. http://dx.doi.org/10.3390/nano11071757.

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Nanocatalysts are a promising alternative to natural enzymes as the signal labels of electrochemical biosensors. However, the surface modification of nanocatalysts and sensor electrodes with recognition elements and blockers may form a barrier to direct electron transfer, thus limiting the application of nanocatalysts in electrochemical immunoassays. Electron mediators can accelerate the electron transfer between nanocatalysts and electrodes. Nevertheless, it is hard to simultaneously achieve fast electron exchange between nanocatalysts and redox mediators as well as substrates. This work presents a scheme for the design of electrochemical immunosensors with nanocatalysts as signal labels, in which pyrroloquinoline quinone (PQQ) is the redox-active center of the nanocatalyst. PQQ was decorated on the surface of carbon nanotubes to catalyze the electrochemical oxidation of tris(2-carboxyethyl)phosphine (TCEP) with ferrocenylmethanol (FcM) as the electron mediator. With prostate-specific antigen (PSA) as the model analyte, the detection limit of the sandwich-type immunosensor was found to be 5 pg/mL. The keys to success for this scheme are the slow chemical reaction between TCEP and ferricinum ions, and the high turnover frequency between ferricinum ions, PQQ. and TCEP. This work should be valuable for designing of novel nanolabels and nanocatalytic schemes for electrochemical biosensors.

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Grabowska, Iwona, Maria Hepel, and Katarzyna Kurzątkowska-Adaszyńska. "Advances in Design Strategies of Multiplex Electrochemical Aptasensors." Sensors 22, no. 1 (December 27, 2021): 161. http://dx.doi.org/10.3390/s22010161.

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In recent years, the need for simple, fast, and economical detection of food and environmental contaminants, and the necessity to monitor biomarkers of different diseases have considerably accelerated the development of biosensor technology. However, designing biosensors capable of simultaneous determination of two or more analytes in a single measurement, for example on a single working electrode in single solution, is still a great challenge. On the other hand, such analysis offers many advantages compared to single analyte tests, such as cost per test, labor, throughput, and convenience. Because of the high sensitivity and scalability of the electrochemical detection systems on the one hand and the specificity of aptamers on the other, the electrochemical aptasensors are considered to be highly effective devices for simultaneous detection of multiple-target analytes. In this review, we describe and evaluate multi-label approaches based on (1) metal quantum dots and metal ions, (2) redox labels, and (3) enzyme labels. We focus on recently developed strategies for multiplex sensing using electrochemical aptasensors. Furthermore, we emphasize the use of different nanomaterials in the construction of these aptasensors. Based on examples from the existing literature, we highlight recent applications of multiplexed detection platforms in clinical diagnostics, food control, and environmental monitoring. Finally, we discuss the advantages and disadvantages of the aptasensors developed so far, and debate possible challenges and prospects.

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Chunglok, Wilanee, Porntip Khownarumit, Patsamon Rijiravanich, Mithran Somasundrum, and Werasak Surareungchai. "Electrochemical immunoassay platform for high sensitivity protein detection based on redox-modified carbon nanotube labels." Analyst 136, no. 14 (2011): 2969. http://dx.doi.org/10.1039/c1an15079k.

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Degrand, Chantal, Benoit Limoges, Arnaud Gautier, and Ronald L. Blankespoor. "Synthesis of cobaltocenium salts for use as redox labels and their incorporation into Nafion films." Applied Organometallic Chemistry 7, no. 4 (July 1993): 233–41. http://dx.doi.org/10.1002/aoc.590070403.

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Shundrin, Leonid A., Irina G. Irtegova, Nadezhda V. Vasilieva, and Irina A. Khalfina. "Benzoquinone and naphthoquinone based redox-active labels for electrochemical detection of modified oligonucleotides on Au electrodes." Tetrahedron Letters 57, no. 3 (January 2016): 392–95. http://dx.doi.org/10.1016/j.tetlet.2015.12.035.

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Fojta, Miroslav, Ludek Havran, Hana Pivonkova, Petra Horakova, and Michal Hocek. "Redox Labels and Indicators Based on Transition Metals and Organic Electroactive Moieties for Electrochemical Nucleic Acids Sensing." Current Organic Chemistry 15, no. 17 (September 1, 2011): 2936–49. http://dx.doi.org/10.2174/138527211798357173.

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Kim, Gyeongho, Hyejin Cho, Ponnusamy Nandhakumar, Jin Kyoon Park, Kwang-Sun Kim, and Haesik Yang. "Wash-Free, Sandwich-Type Protein Detection Using Direct Electron Transfer and Catalytic Signal Amplification of Multiple Redox Labels." Analytical Chemistry 94, no. 4 (January 19, 2022): 2163–71. http://dx.doi.org/10.1021/acs.analchem.1c04615.

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Yang, Xi-Qiang, and Liang-Hong Guo. "Enhanced electrochemical activity of redox-labels in multi-layered protein films on indium tin oxide nanoparticle-based electrode." Analytica Chimica Acta 632, no. 1 (January 2009): 15–20. http://dx.doi.org/10.1016/j.aca.2007.09.039.

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Kaladari, Fatema, Naoya Kishikawa, Ai Shimada, Mahmoud El-Maghrabey, and Naotaka Kuroda. "Anthracycline-Functionalized Dextran as a New Signal Multiplication Tagging Approach for Immunoassay." Biosensors 13, no. 3 (March 3, 2023): 340. http://dx.doi.org/10.3390/bios13030340.

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The most used kind of immunoassay is enzyme-linked immunosorbent assay (ELISA); however, enzymes suffer from steric effects, low stability, and high cost. Our research group has been developing quinone-linked immunosorbent assay (QuLISA) as a new promising approach for stable and cost-efficient immunoassay. However, the developed QuLISA suffered from low water-solubility of synthesized quinone labels and their moderate sensitivity. Herein, we developed a new approach for signal multiplication of QuLISA utilizing the water-soluble quinone anthracycline, doxorubicin, coupled with dextran for signal multiplication. A new compound, Biotin-DexDox, was prepared in which doxorubicin was assembled on oxidized dextran 40, and then it was biotinylated. The redox-cycle-based chemiluminescence and the colorimetric reaction of Biotin-DexDox were optimized and evaluated, and they showed very good sensitivity down to 0.25 and 0.23 nM, respectively. Then, Biotin-DexDox was employed for the detection of biotinylated antibodies utilizing avidin as a binder and a colorimetric assay of the formed complex through its contained doxorubicin redox reaction with NaBH4 and imidazolium salt yielding strong absorbance at 510 nm. The method could detect the plate-fixed antibody down to 0.55 nM. Hence, the application of Biotin-DexDox in QuLISA was successfully demonstrated and showed a significant improvement in its sensitivity and applicability to aqueous assays.

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Roh, Terrence T., Aneesh Alex, Janet E. Sorrells, Prasanna Chandramouleeswaran, Marina Marjanovic, Steve R. Hood, BanuPriya Sridharan, and Stephen A. Boppart. "Abstract 6613: Label-free multimodal multiphoton microscopy for predicting DNA damage response in patient derived non-small cell lung cancer organoids." Cancer Research 83, no. 7_Supplement (April 4, 2023): 6613. http://dx.doi.org/10.1158/1538-7445.am2023-6613.

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Abstract Background: DNA damage response (DDR) is a fundamental mechanism for evaluating efficacy of cancer therapeutics, many of which target DNA or associated processes (e.g., etoposide: inhibits DNA synthesis, cisplatin: crosslinks DNA). Current techniques to evaluate DDR rely on immunostaining for gamma H2AX foci (γH2AX), which is an indicator of DNA double-strand break formation. While γH2AX immunostaining can provide a snapshot of DDR in fixed cellular and tissue samples, this method is technically cumbersome as: 1) temporal monitoring of DDR requires timepoint replicates; 2) extensive assay development efforts for 3D samples such as organoids, and 3) protocols for γH2AX immunostaining and its evaluation are time-consuming. The goal of this project is to reduce overall burden on assay duration and development in NSCLC organoids by leveraging label-free multiphoton imaging. Method: To predict DDR in 3D organoid samples, label-free multimodal multiphoton techniques such as simultaneous label-free autofluorescence multiharmonic (SLAM) imaging can provide intracellular information based on endogenous contrast mechanisms. SLAM makes use of a single laser to excite autofluorescence in multiple cellular components including FAD and NAD(P)H, enabling the calculation of the optical redox ratio, which estimates the equilibrium of electron donating versus accepting species in cells. Moreover, label-free, multiphoton systems enable imaging of live samples without the need to add labels or generate sacrificial samples and have improved image acquisition in 3D space over conventional confocal microscopy. Using SLAM, we propose to predict DDR in non-small cell lung cancer (NSCLC) organoids. NSCLC organoids recapitulate histological and genetic features of their derived patient tissue, retaining tumor variability. Results: Predictive modeling via gradient boost regressor between handcrafted SLAM image features and γH2AX immunostained images on weakly-paired images confirmed strong correlation between SLAM image features and γH2AX speckles/nuclei. Across multiple patient derived NSCLC organoid lines and multiple DNA targeting chemotherapeutics, the optical redox ratio was demonstrated to robustly predict DDR. Conclusion: Label-free imaging via SLAM can be used to predict DDR in live 3D NSCLC organoids with minimal sample handling and without the need to add labelled reporters, enabling quicker and less technically involved DDR assaying. Citation Format: Terrence T. Roh, Aneesh Alex, Janet E. Sorrells, Prasanna Chandramouleeswaran, Marina Marjanovic, Steve R. Hood, BanuPriya Sridharan, Stephen A. Boppart. Label-free multimodal multiphoton microscopy for predicting DNA damage response in patient derived non-small cell lung cancer organoids [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6613.

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Bordes, Anne-Line, Benoı̂t Limoges, Pierre Brossier, and Chantal Degrand. "Simultaneous homogeneous immunoassay of phenytoin and phenobarbital using a Nafion-loaded carbon paste electrode and two redox cationic labels." Analytica Chimica Acta 356, no. 2-3 (December 1997): 195–203. http://dx.doi.org/10.1016/s0003-2670(97)00557-6.

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Li, Di, Ron Gill, Ronit Freeman, and Itamar Willner. "Probing of enzyme reactions by the biocatalyst-induced association or dissociation of redox labels linked to monolayer-functionalized electrodes." Chemical Communications, no. 48 (2006): 5027. http://dx.doi.org/10.1039/b614141b.

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Cheeveewattanagul, Nopchulee, Patsamon Rijiravanich, Werasak Surareungchai, and Mithran Somasundrum. "Loading of silicon nanoparticle labels with redox mediators for detection of multiple DNA targets within a single voltammetric sweep." Journal of Electroanalytical Chemistry 779 (October 2016): 61–66. http://dx.doi.org/10.1016/j.jelechem.2016.05.002.

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Fojta, Miroslav, Ludek Havran, Hana Pivonkova, Petra Horakova, and Michal Hocek. "ChemInform Abstract: Redox Labels and Indicators Based on Transition Metals and Organic Electroactive Moieties for Electrochemical Nucleic Acids Sensing." ChemInform 44, no. 3 (January 15, 2013): no. http://dx.doi.org/10.1002/chin.201303221.

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Zhurko, Irina F., Sergey Dobrynin, Artem A. Gorodetskii, Yuri I. Glazachev, Tatyana V. Rybalova, Elena I. Chernyak, Nargiz Asanbaeva, Elena G. Bagryanskaya, and Igor A. Kirilyuk. "2-Butyl-2-tert-butyl-5,5-diethylpyrrolidine-1-oxyls: Synthesis and Properties." Molecules 25, no. 4 (February 14, 2020): 845. http://dx.doi.org/10.3390/molecules25040845.

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Nitroxides are broadly used as molecular probes and labels in biophysics, structural biology, and biomedical research. Resistance of a nitroxide group bearing an unpaired electron to chemical reduction with low-molecular-weight antioxidants and enzymatic systems is of critical importance for these applications. The redox properties of nitroxides are known to depend on the ring size (for cyclic nitroxides) and electronic and steric effects of the substituents. Here, two highly strained nitroxides, 5-(tert-butyl)-5-butyl-2,2-diethyl-3-hydroxypyrrolidin-1-oxyl (4) and 2-(tert-butyl)-2-butyl-5,5-diethyl-3,4-bis(hydroxymethyl)pyrrolidin-1-oxyl (5), were prepared via a reaction of the corresponding 2-tert-butyl-1-pyrroline 1-oxides with butyllithium. Thermal stability and kinetics of reduction of the new nitroxides by ascorbic acid were studied. Nitroxide 5 showed the highest resistance to reduction.

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Song, Zhongju, Ruo Yuan, Yaqin Chai, Ying Zhuo, Wen Jiang, Huilan Su, Xin Che, and Jingjing Li. "Horseradish peroxidase-functionalized Pt hollow nanospheres and multiple redox probes as trace labels for a sensitive simultaneous multianalyte electrochemical immunoassay." Chemical Communications 46, no. 36 (2010): 6750. http://dx.doi.org/10.1039/c0cc01537g.

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Wehmeyer, Kenneth R., Ryan J. White, Peter T. Kissinger, and William R. Heineman. "Electrochemical Affinity Assays/Sensors: Brief History and Current Status." Annual Review of Analytical Chemistry 14, no. 1 (June 5, 2021): 109–31. http://dx.doi.org/10.1146/annurev-anchem-061417-125655.

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The advent of electrochemical affinity assays and sensors evolved from pioneering efforts in the 1970s to broaden the field of analytes accessible to the selective and sensitive performance of electrochemical detection. The foundation of electrochemical affinity assays/sensors is the specific capture of an analyte by an affinity element and the subsequent transduction of this event into a measurable signal. This review briefly covers the early development of affinity assays and then focuses on advances in the past decade. During this time, progress on electroactive labels, including the use of nanoparticles, quantum dots, organic and organometallic redox compounds, and enzymes with amplification schemes, has led to significant improvements in sensitivity. The emergence of nanomaterials along with microfabrication and microfluidics technology enabled research pathways that couple the ease of use of electrochemical detection for the development of devices that are more user friendly, disposable, and employable, such as lab-on-a-chip, paper, and wearable sensors.

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Shundrin, Leonid A., Irina A. Os’kina, Irina G. Irtegova, and Alexandr F. Poveshchenko. "9H-Thioxanthen-9-one S,S-dioxide based redox active labels for electrochemical detection of DNA duplexes immobilized on Au electrodes." Mendeleev Communications 30, no. 3 (May 2020): 296–98. http://dx.doi.org/10.1016/j.mencom.2020.05.011.

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Usatov, Mikhail S., Sergey A. Dobrynin, Yuliya F. Polienko, Denis A. Morozov, Yurii I. Glazachev, Sergey V. An’kov, Tatiana G. Tolstikova, et al. "Hydrophilic Reduction-Resistant Spin Labels of Pyrrolidine and Pyrroline Series from 3,4-Bis-hydroxymethyl-2,2,5,5-tetraethylpyrrolidine-1-oxyl." International Journal of Molecular Sciences 25, no. 3 (January 26, 2024): 1550. http://dx.doi.org/10.3390/ijms25031550.

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Highly resistant to reduction nitroxides open new opportunities for structural studies of biological macromolecules in their native environment inside living cells and for functional imaging of pH and thiols, enzymatic activity and redox status in living animals. 3,4-Disubstituted nitroxides of 2,2,5,5-tetraethylpyrrolidine and pyrroline series with a functional group for binding to biomolecules and a polar moiety for higher solubility in water and for more rigid attachment via additional coordination to polar sites were designed and synthesized. The EPR spectra, lipophilicities, kinetics of the reduction in ascorbate-containing systems and the decay rates in liver homogenates were measured. The EPR spectra of all 3,4-disubstituted pyrrolidine nitroxides showed additional large splitting on methylene hydrogens of the ethyl groups, while the spectra of similar pyrroline nitroxides were represented with a simple triplet with narrow lines and hyperfine structure of the nitrogen manifolds resolved in oxygen-free conditions. Both pyrrolidine and pyrroline nitroxides demonstrated low rates of reduction with ascorbate, pyrrolidines being a bit more stable than similar pyrrolines. The decay of positively charged nitroxides in the rat liver homogenate was faster than that of neutral and negatively charged radicals, with lipophilicity, rate of reduction with ascorbate and the ring type playing minor role. The EPR spectra of N,N-dimethyl-3,4-bis-(aminomethyl)-2,2,5,5-tetraethylpyrrolidine-1-oxyl showed dependence on pH with pKa = 3, ΔaN = 0.055 mT and ΔaH = 0.075 mT.

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Wu, Dan, Aiping Guo, Zhankui Guo, Lili Xie, Qin Wei, and Bin Du. "Simultaneous electrochemical detection of cervical cancer markers using reduced graphene oxide-tetraethylene pentamine as electrode materials and distinguishable redox probes as labels." Biosensors and Bioelectronics 54 (April 2014): 634–39. http://dx.doi.org/10.1016/j.bios.2013.11.042.

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Medlin, Linda K., Maria Gamella, Gerardo Mengs, Verónica Serafín, Susana Campuzano, and José M. M. Pingarrón. "Advances in the Detection of Toxic Algae Using Electrochemical Biosensors." Biosensors 10, no. 12 (December 16, 2020): 207. http://dx.doi.org/10.3390/bios10120207.

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Harmful algal blooms (HABs) are more frequent as climate changes and tropical toxic species move northward, especially along the Iberian Peninsula, a rich aquaculture area. Monitoring programs, detecting the presence of toxic algae before they bloom, are of paramount importance to protect ecosystems, aquaculture, human health and local economies. Rapid, reliable species identification methods using molecular barcodes coupled to biosensor detection tools have received increasing attention as an alternative to the legally required but impractical microscopic counting-based techniques. Our electrochemical detection system has improved, moving from conventional sandwich hybridization protocols using different redox mediators and signal probes with different labels to a novel strategy involving the recognition of RNA heteroduplexes by antibodies further labelled with bacterial antibody binding proteins conjugated with multiple enzyme molecules. Each change has increased sensitivity. A 150-fold signal increase has been produced with our newest protocol using magnetic microbeads (MBs) and amperometric detection at screen-printed carbon electrodes (SPCEs) to detect the target RNA of toxic species. We can detect as few as 10 cells L−1 for some species by using a fast (~2 h), simple (PCR-free) and cheap methodology (~2 EUR/determination) that will allow this methodology to be integrated into easy-to-use portable systems.

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Yang, Yin, Shen-Na Chen, Feng Yang, Xia-Yan Li, Akiva Feintuch, Xun-Cheng Su, and Daniella Goldfarb. "In-cell destabilization of a homodimeric protein complex detected by DEER spectroscopy." Proceedings of the National Academy of Sciences 117, no. 34 (August 11, 2020): 20566–75. http://dx.doi.org/10.1073/pnas.2005779117.

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The complexity of the cellular medium can affect proteins’ properties, and, therefore, in-cell characterization of proteins is essential. We explored the stability and conformation of the first baculoviral IAP repeat (BIR) domain of X chromosome-linked inhibitor of apoptosis (XIAP), BIR1, as a model for a homodimer protein in human HeLa cells. We employed double electron–electron resonance (DEER) spectroscopy and labeling with redox stable and rigid Gd3+spin labels at three representative protein residues, C12 (flexible region), E22C, and N28C (part of helical residues 26 to 31) in the N-terminal region. In contrast to predictions by excluded-volume crowding theory, the dimer–monomer dissociation constantKDwas markedly higher in cells than in solution and dilute cell lysate. As expected, this increase was partially recapitulated under conditions of high salt concentrations, given that conserved salt bridges at the dimer interface are critically required for association. Unexpectedly, however, also the addition of the crowding agent Ficoll destabilized the dimer while the addition of bovine serum albumin (BSA) and lysozyme, often used to represent interaction with charged macromolecules, had no effect. Our results highlight the potential of DEER for in-cell study of proteins as well as the complexities of the effects of the cellular milieu on protein structures and stability.

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Hromadová, Magdaléna, Michèle Salmain, Romana Sokolová, Lubomı́r Pospı́šil, and Gérard Jaouen. "Novel redox label for proteins." Journal of Organometallic Chemistry 668, no. 1-2 (February 2003): 17–24. http://dx.doi.org/10.1016/s0022-328x(02)02093-4.

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Fernandes, Flávio C. Bedatty, Márcio S. Góes, Jason J. Davis, and Paulo R. Bueno. "Label free redox capacitive biosensing." Biosensors and Bioelectronics 50 (December 2013): 437–40. http://dx.doi.org/10.1016/j.bios.2013.06.043.

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Li, Weixiang, Qinfeng Rong, and Zhanfang Ma. "Hollow metal–organic nanoparticles as redox species for label-free voltammetric immunoassay of prostate specific antigen." New Journal of Chemistry 41, no. 3 (2017): 1124–28. http://dx.doi.org/10.1039/c6nj03463b.

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Milton, Ross D., David P. Hickey, Sofiene Abdellaoui, Koun Lim, Fei Wu, Boxuan Tan, and Shelley D. Minteer. "Rational design of quinones for high power density biofuel cells." Chemical Science 6, no. 8 (2015): 4867–75. http://dx.doi.org/10.1039/c5sc01538c.

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Cheng, Tzong-Jih, Hsien-Yi Hsiao, Pei-Chia Tsai, and Richie L. C. Chen. "Redoxless Electrochemical Capacitance Spectroscopy for Investigating Surfactant Adsorption on Screen-Printed Carbon Electrodes." Chemosensors 11, no. 6 (June 11, 2023): 343. http://dx.doi.org/10.3390/chemosensors11060343.

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Electrochemical impedance spectroscopy (EIS) is a sensitive analytical method for surface and bulk properties. Classical EIS and derived electrochemical capacitance spectroscopy (ECS) with a redox couple are label-free approaches for biosensor development, but doubts arise regarding interpretability when a redox couple is employed (redox EIS) due to interactions between electroactive probes and interfacial charges or forced potential. Here, we demonstrated redoxless ECS for directly determining surfactant adsorption on screen-printed carbon electrodes (SPCEs), validated through a simulation of equivalent circuits and the electrochemistry of electronic dummy cells. Redoxless ECS provides excellent capacitance plot loci for quantifying the interfacial permittivity of di-electric layers on electrode surfaces. Redoxless ECS was compared with redox EIS/ECS, revealing a favorable discrimination of interfacial capacitances under both low and high SDS coverage on SPCEs and demonstrating potential for probeless (reagentless) sensing. Furthermore, the proposed method was applied in an electrolyte without a redox couple and bare electrodes, obtaining a high performance for the adsorption of surfactants Tween-20, Triton-X100, sodium dodecyl sulfate, and tetrapropylammonium bromide. This approach offers a simple and straightforward means for a semi-quantitative evaluation of small molecule interactions with electrode surfaces. Our proposed approach may serve as a starting point for future probeless (reagentless) and label-free biosensors based on electrochemistry, eliminating disturbance with surface charge properties and minimizing forced potential bias by avoiding redox couples. An unambiguous and quantitative determination of physicochemical properties of biochemically recognizable layers will be relevant for biosensor development.

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Fang, Chiew San, Kyung Hwan Oh, Aram Oh, Kwangyeol Lee, Seonhwa Park, Sinyoung Kim, Jin Kyoon Park, and Haesik Yang. "An ultrasensitive and incubation-free electrochemical immunosensor using a gold-nanocatalyst label mediating outer-sphere-reaction-philic and inner-sphere-reaction-philic species." Chemical Communications 52, no. 34 (2016): 5884–87. http://dx.doi.org/10.1039/c6cc00353b.

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Kuntamung, Kulrisa, Jaroon Jakmunee, and Kontad Ounnunkad. "A label-free multiplex electrochemical biosensor for the detection of three breast cancer biomarker proteins employing dye/metal ion-loaded and antibody-conjugated polyethyleneimine-gold nanoparticles." Journal of Materials Chemistry B 9, no. 33 (2021): 6576–85. http://dx.doi.org/10.1039/d1tb00940k.

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Ungurianu, Anca, Anca Zanfirescu, Georgiana Nițulescu, and Denisa Margină. "Vitamin E beyond Its Antioxidant Label." Antioxidants 10, no. 5 (April 21, 2021): 634. http://dx.doi.org/10.3390/antiox10050634.

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Vitamin E, comprising tocopherols and tocotrienols, is mainly known as an antioxidant. The aim of this review is to summarize the molecular mechanisms and signaling pathways linked to inflammation and malignancy modulated by its vitamers. Preclinical reports highlighted a myriad of cellular effects like modulating the synthesis of pro-inflammatory molecules and oxidative stress response, inhibiting the NF-κB pathway, regulating cell cycle, and apoptosis. Furthermore, animal-based models have shown that these molecules affect the activity of various enzymes and signaling pathways, such as MAPK, PI3K/Akt/mTOR, JAK/STAT, and NF-κB, acting as the underlying mechanisms of their reported anti-inflammatory, neuroprotective, and anti-cancer effects. In clinical settings, not all of these were proven, with reports varying considerably. Nonetheless, vitamin E was shown to improve redox and inflammatory status in healthy, diabetic, and metabolic syndrome subjects. The anti-cancer effects were inconsistent, with both pro- and anti-malignant being reported. Regarding its neuroprotective properties, several studies have shown protective effects suggesting vitamin E as a potential prevention and therapeutic (as adjuvant) tool. However, source and dosage greatly influence the observed effects, with bioavailability seemingly a key factor in obtaining the preferred outcome. We conclude that this group of molecules presents exciting potential for the prevention and treatment of diseases with an inflammatory, redox, or malignant component.

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Schaefer, Jacob. "REDOR-Determined Distances from Heterospins to Clusters of13C Labels." Journal of Magnetic Resonance 137, no. 1 (March 1999): 272–75. http://dx.doi.org/10.1006/jmre.1998.1643.

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Balintová, Jana, Jan Špaček, Radek Pohl, Marie Brázdová, Luděk Havran, Miroslav Fojta, and Michal Hocek. "Azidophenyl as a click-transformable redox label of DNA suitable for electrochemical detection of DNA–protein interactions." Chemical Science 6, no. 1 (2015): 575–87. http://dx.doi.org/10.1039/c4sc01906g.

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A new azido-based DNA redox label which can be transformed into nitrophenyltriazole by a CuAAC click reaction was developed. It was used for the mapping of DNA–protein interactions with electrochemical detection.

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Hun, Xu, Guoliang Xie, and Xiliang Luo. "Scaling up an electrochemical signal with a catalytic hairpin assembly coupling nanocatalyst label for DNA detection." Chemical Communications 51, no. 33 (2015): 7100–7103. http://dx.doi.org/10.1039/c5cc00680e.

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A new strategy for the electrochemical detection of DNA based on catalytic hairpin assembly combined with nanocatalyst label-based redox cycling reaction signal amplification. A superior detection limit of 0.3 aM toward DNA was achieved.

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Couto, Rosa A. S., Lifu Chen, Sabine Kuss, and Richard G. Compton. "Detection of Escherichia coli bacteria by impact electrochemistry." Analyst 143, no. 20 (2018): 4840–43. http://dx.doi.org/10.1039/c8an01675e.

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Employing the redox species N,N,N′,N′-tetramethyl-para-phenylene-diamine (TMPD), the label-free detection of E. coli, based on an electrochemical “on”-signal during impact electrochemistry, is reported for the first time.

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Chandra, Sudeshna, Christian Gäbler, Christian Schliebe, Heinrich Lang, and Dhirendra Bahadur. "Fabrication of a label-free electrochemical immunosensor using a redox active ferrocenyl dendrimer." New Journal of Chemistry 40, no. 11 (2016): 9046–53. http://dx.doi.org/10.1039/c6nj00830e.

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McDonagh, Brian, José Rafael Pedrajas, C. Alicia Padilla, and José Antonio Bárcena. "Thiol Redox Sensitivity of Two Key Enzymes of Heme Biosynthesis and Pentose Phosphate Pathways: Uroporphyrinogen Decarboxylase and Transketolase." Oxidative Medicine and Cellular Longevity 2013 (2013): 1–13. http://dx.doi.org/10.1155/2013/932472.

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Uroporphyrinogen decarboxylase (Hem12p) and transketolase (Tkl1p) are key mediators of two critical processes within the cell, heme biosynthesis, and the nonoxidative part of the pentose phosphate pathway (PPP). The redox properties of both Hem12p and Tkl1p fromSaccharomyces cerevisiaewere investigated using proteomic techniques (SRM and label-free quantification) and biochemical assays in cell extracts andin vitrowith recombinant proteins. Thein vivoanalysis revealed an increase in oxidized Cys-peptides in the absence of Grx2p, and also after treatment with H2O2in the case of Tkl1p, without corresponding changes in total protein, demonstrating a true redox response. Out of three detectable Cys residues in Hem12p, only the conserved residue Cys52 could be modified by glutathione and efficiently deglutathionylated by Grx2p, suggesting a possible redox control mechanism for heme biosynthesis. On the other hand, Tkl1p activity was sensitive to thiol redox modification and although Cys622 could be glutathionylated to a limited extent, it was not a natural substrate of Grx2p. The human orthologues of both enzymes have been involved in certain cancers and possess Cys residues equivalent to those identified as redox sensitive in yeast. The possible implication for redox regulation in the context of tumour progression is put forward.

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Lehr, Joshua, Flávio C. Bedatty Fernandes, Paulo R. Bueno, and Jason J. Davis. "Label-free Capacitive Diagnostics: Exploiting Local Redox Probe State Occupancy." Analytical Chemistry 86, no. 5 (February 12, 2014): 2559–64. http://dx.doi.org/10.1021/ac403727h.

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Ngoensawat, Umphan, Patsamon Rijiravanich, Werasak Surareungchai, and Mithran Somasundrum. "Electrochemical Immunoassay forSalmonellaTyphimurium Based on an Immuno-magnetic Redox Label." Electroanalysis 30, no. 1 (December 7, 2017): 146–53. http://dx.doi.org/10.1002/elan.201700568.

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Ho, Man Yi, Sarah A. Goodchild, Pedro Estrela, Daping Chu, and Piero Migliorato. "Switching of electrochemical characteristics of redox protein upon specific biomolecular interactions." Analyst 139, no. 23 (2014): 6118–21. http://dx.doi.org/10.1039/c4an01591f.

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Label-free protein sensing platform based on a simplified and standardized immobilization process with Azurin redox self-assembled monolayer is fabricated. A significant change in the electrochemical characteristics of the assay upon specific interaction with target molecules is observed.

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Liu, Chang, Yingjie Yu, Daquan Chen, Jian Zhao, Yang Yu, Lele Li, and Yi Lu. "Cupredoxin engineered upconversion nanoparticles for ratiometric luminescence sensing of Cu2+." Nanoscale Advances 1, no. 7 (2019): 2580–85. http://dx.doi.org/10.1039/c9na00168a.

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The integration of zwitterion-coated UCNPs with azurin, a member of a family of redox-active copper proteins, can serve as an ideal platform for the label-free upconversion luminescence sensing of Cu²⁺ with a ratiometric response.

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Blottner, Dieter, Daniele Capitanio, Gabor Trautmann, Sandra Furlan, Guido Gambara, Manuela Moriggi, Katharina Block, et al. "Nitrosative Redox Homeostasis and Antioxidant Response Defense in Disused Vastus lateralis Muscle in Long-Term Bedrest (Toulouse Cocktail Study)." Antioxidants 10, no. 3 (March 3, 2021): 378. http://dx.doi.org/10.3390/antiox10030378.

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Increased oxidative stress by reactive oxygen species (ROS) and reactive nitrogen species (RNS) is a major determinant of disuse-induced muscle atrophy. Muscle biopsies (thigh vastus lateralis, VL) obtained from healthy male subjects enrolled in the Toulouse Cocktail bedrest (BR) study were used to assess efficacy of an antioxidant cocktail (polyphenols, omega-3, vitamin E, and selenium) to counteract the increased redox homeostasis and enhance the antioxidant defense response by using label-free LC–MS/MS and NITRO-DIGE (nitrosated proteins), qPCR, and laser confocal microscopy. Label-free LC–MS/MS indicated that treatment prevented the redox homeostasis dysregulation and promoted structural remodeling (TPM3, MYH7, MYBPC, MYH1, MYL1, HRC, and LUM), increment of RyR1, myogenesis (CSRP3), and skeletal muscle development (MUSTN1, LMNA, AHNAK). These changes were absent in the Placebo group. Glycolysis, tricarboxylic acid cycle (TCA), oxidative phosphorylation, fatty acid beta-oxidation, and mitochondrial transmembrane transport were normalized in treated subjects. Proteins involved in protein folding were also normalized, whereas protein entailed in ion homeostasis decreased. NITRO-DIGE analysis showed significant protein nitrosylation changes for CAT, CA3, SDHA, and VDAC2 in Treatment vs. Placebo. Similarly, the nuclear factor erythroid 2-related factor 2 (Nrf-2) antioxidant response element (Nrf-2 ARE) signaling pathway showed an enhanced response in the Treatment group. Increased nitrosative redox homeostasis and decreased antioxidant defense response were found in post-BR control (Placebo, n = 10) vs. the antioxidant cocktail treated group (Treatment, n = 10). Taken together, increased nitrosative redox homeostasis and muscle deterioration during BR-driven physical inactivity were prevented, whereas decreased antioxidant nitrosative stress defense response was attenuated by Treatment suggesting positive effects of the nutritional intervention protocol in bedrest.

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Li, Xiaofeng, Ying Huang, Mei Chen, Yuejin Tong, and Cuiyun Zhang. "A label-free electrochemical bisphenol A immunosensor based on chlorogenic acid as a redox probe." Analytical Methods 9, no. 14 (2017): 2183–88. http://dx.doi.org/10.1039/c6ay02997c.

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A simple and sensitive electrochemical immunosensor for bisphenol A was prepared with an acetylene black–chitosan–gold composite (AB–CS–Au) and gold nanoparticles (AuNPs) as electrode modifiers and chlorogenic acid (CGA) as the redox probe.

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Balintová, Jana, Medard Plucnara, Pavlína Vidláková, Radek Pohl, Luděk Havran, Miroslav Fojta, and Michal Hocek. "Benzofurazane as a New Redox Label for Electrochemical Detection of DNA: Towards Multipotential Redox Coding of DNA Bases." Chemistry - A European Journal 19, no. 38 (August 9, 2013): 12720–31. http://dx.doi.org/10.1002/chem.201301868.

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Bier, Frank F., Eva Ehrentreich-Förster, Rudolf Dölling, Arkadi V. Eremenko, and Frieder W. Scheller. "A redox-label immunosensor on basis of a bi-enzyme electrode." Analytica Chimica Acta 344, no. 1-2 (May 1997): 119–24. http://dx.doi.org/10.1016/s0003-2670(97)00050-0.

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Journal articles on the topic 'Redox labels'

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