Enhancing the Self-Assembled Monolayer Formation for Protein Detection Platform through L-Cysteine Utilization

Abstract

Electrochemical immunosensing has emerged as a contemporary sensing strategy based on the principles of specific antigen-antibody recognition, offering exceptional specificity, remarkable sensitivity, and seamless integration. In this study, we present a rapid, three-step and cost-effective modification process to establish an immunosensing platform using self-assembled monolayer (SAM) of L-Cysteine. This approach was experimentally implemented through quantitative BSA protein detection experiments spanning a concentration range from 0.5 µM to 8µM. Optical signals, along with observable changes in electrical signals from cyclic voltammetry (CV), square wave voltammetry (SWV) and electrochemical impedance spectroscopy (EIS), confirmed the formation of monolayers on the electrode surface and detection signals for BSA protein. The characteristic curve, employing ΔR_ct as a function of BSA protein concentration, was plotted with a coefficient of determination (R²) value of 0.95136. These findings underscore the potential of L-Cysteine-based SAMs in electrochemical biosensing applications for highly sensitive and cost-efficient protein detection.