Measurement of small currents is often impeded by a suboptimal signal-to-noise ratio, largely due to background noise. This background noise significantly constrains the range of catalysts accessible for interrogation...
Measurement of small currents is often impeded by a suboptimal signal-to-noise ratio, largely due to background noise. This background noise significantly constrains the range of catalysts accessible for interrogation via micro- and nanoscale electrochemistry. In response, this work reveals how background noise scales in the presence of induced Faradaic reactions. We measured noise under a series of electrochemical conditions and discovered that the induced noise from a Faradaic reaction scales directly with current. Complementary electrochemical impedance spectroscopy measurements demonstrated that diffusional resistance dictates the noise of Faradaic reactions, independent of the electrochemical mechanism. The noise source is thermal in origin and propagates in a predictable trend, which is inversely proportional to the equivalent diffusional resistance of the analyte. The universality of the observed phenomenon allows for better deconvolution of measured charge from background noise, thus assisting in achieving higher resolution and measurement precision, which is a key in micro- and nanoscale electrochemical measurements.
The multiplexed,point-of-care measurement of specific antibodies could improve the speed with which diseases are diagnosed and their treatment *** this end,we are developing E-DNA scaffold sensors,which consist of a r...
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The multiplexed,point-of-care measurement of specific antibodies could improve the speed with which diseases are diagnosed and their treatment *** this end,we are developing E-DNA scaffold sensors,which consist of a rigid,nucleic acid“scaffold”attached on one end to an electrode and presenting both a redox reporter and an epitope on the *** the absence of antibody,the reporter efficiently transfers electrons when interrogated ***-induced steric hindrance limits movement,reducing electron transfer in a manner that is both easily measured and quantitatively related to target *** we have used monoclonal antibodies to explore the analytical performance of E-DNA sensors,showing that they support the rapid,single-step,quantitative detection of multiple antibodies in small volume ***,in contrast,we employ authentic human samples to better explore the platform’s clinical ***,we developed E-DNA sensors targeting three HIV-specific antibodies and then compared the analytical and clinical performance of these against those of gold standard serological *** so we find that,although the multistep amplification of an ELISA leads to a lower detection limits,the clinical sensitivity of ELISAs,E-DNA sensors and lateral-flow dipsticks are indistinguishable across our test *** thus appears that,by merging the quantitation and multiplexing of ELISAs with the convenience and speed of dipsticks,E-DNA scaffold sensors could significantly improve on current serological practice.
Metabolomic analysis can indeed enhance the prime variable dataset for the monitoring of perfusion cultures by providing a higher resolution view of the metabolic state. Metabolic profiles can capture physiological st...
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Blocking electrochemistry, a subfield of single-entity electrochemistry, enables in-situ sizing of redox-inactive particles. This method exploits the adsorptive impact of individual insulating particles on a microelec...
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Metabolomic analysis can indeed enhance the prime variable dataset for the monitoring of perfusion cultures by providing a higher resolution view of the metabolic state. Metabolic profiles can capture physiological st...
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Metabolomic analysis can indeed enhance the prime variable dataset for the monitoring of perfusion cultures by providing a higher resolution view of the metabolic state. Metabolic profiles can capture physiological state shifts over the course of the perfusion cultures and indicate a metabolic “signature” of the phase transitions, which is not observable from prime variable data. Notably, metabolomics provides orthogonal (to prime variables) evidence that all cultures follow this same metabolic state shift with cell age, independently of bioreactor scale. Additionally, this analysis can increase the information content of process development experiments by helping better understand the impact of changes in bioreactor operating conditions on cell physiology. In this context, metabolic profiling could be integrated into the monitoring of cell physiology in perfusion cultures.
The real‐time monitoring of specific analytes in situ in the living body would greatly advance our understanding of physiology and the development of personalized medicine. Because they are continuous (wash‐free and...
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The real‐time monitoring of specific analytes in situ in the living body would greatly advance our understanding of physiology and the development of personalized medicine. Because they are continuous (wash‐free and reagentless) and are able to work in complex media (e.g., undiluted serum), electrochemical aptamer‐based (E‐AB) sensors are promising candidates to fill this role. E‐AB sensors suffer, however, from often‐severe baseline drift when deployed in undiluted whole blood either in vitro or in vivo. We demonstrate that cell‐membrane‐mimicking phosphatidylcholine (PC)‐terminated monolayers improve the performance of E‐AB sensors, reducing the baseline drift from around 70 % to just a few percent after several hours in flowing whole blood in vitro. With this improvement comes the ability to deploy E‐AB sensors directly in situ in the veins of live animals, achieving micromolar precision over many hours without the use of physical barriers or active drift‐correction algorithms.
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