Diffusion- and Chemometric-Based Separation of Complex Electrochemical Signals That Originated from Multiple Redox-Active Molecules

Abstract

In situ analysis of multiple biomarkers in the body provides better diagnosis and enables personalized health management. Since many of these biomarkers are redox-active, electrochemical sensors have shown promising analytical capabilities to measure multiple redox-active molecules. However, the analytical performance of electrochemical sensors rapidly decreases in the presence of multicomponent biofluids due to their limited ability to separate overlapping electrochemical signals generated by multiple molecules. Here we report a novel approach to use charged chitosan-modified electrodes to alter the diffusion of ascorbic acid, clozapine, L-homocysteine, and uric acid—test molecules with various molecular charges and molecular weights. Moreover, we present a complementary approach to use chemometrics to decipher the complex set of overlapping signals generated from a mixture of differentially charged redox molecules. The partial least square regression model predicted three out of four redox-active molecules with root mean square error, Pearson correlation coefficient, and R-squared values of 125 µM, 0.947, and 0.894; 51.8 µM, 0.877, and 0.753; 55.7 µM, 0.903, and 0.809, respectively. By further enhancing our understanding of the diffusion of redox-active molecules in chitosan, the in-situ separation of multiple molecules can be enabled, which will be used to establish guidelines for the effective separation of biomarkers.

On-Chip Electrochemical Sensing with an Enhanced Detecting Signal Due to Concentration Polarization-Based Analyte Preconcentration

“…Electrochemical sensors shift the systems equilibrium state by applying potential or charge and detecting electron transfer based on reduction–oxidation (redox) properties of the target analyte, thus detecting a specific redox analyte in the solution. − These sensors have major advantages such as high sensitivity, speed, and cost-effectiveness. − In microfluidic channels, electrochemical sensors can be used and monitored with higher efficiency due to analytes convection, miniaturization, portability, low sample and reagent consumption, and high throughput. − Thus, electrochemistry can be a fast and efficient method to detect changes in the analyte concentrations and properties in a flowing system.…”

“… 25 − 27 These sensors have major advantages such as high sensitivity, speed, and cost-effectiveness. 28 − 30 In microfluidic channels, electrochemical sensors can be used and monitored with higher efficiency due to analytes convection, miniaturization, portability, low sample and reagent consumption, and high throughput. 31 − 33 Thus, electrochemistry can be a fast and efficient method to detect changes in the analyte concentrations and properties in a flowing system.…”