Novel Electrochemical Immunosensing Structure Based on a Functionalized Carbon Electrode with 11-MUA for NSE Protein Detection

The quantitative detection of neuron-specific enolase (NSE) protein plays a crucial role in early small-cell lung carcinoma (SCLC) diagnosis. Electrochemical biosensing is a modern sensing strategy developed based on specific antigen-antibody recognition. In this study, a simple modification process for the carbon electrode surface was proposed and implemented based on a self-assembled monolayer (SAM) made of 11- Mercaptoundecanoic acid on gold nanoparticles (AuNPs) immobilized on the electrode surface. The formation of the proposed structure was successfully implemented and verified by the electrochemical measurement and SEM method facilitations. The charge transfer resistance (
$R_{cT}$
) of the working electrode rises from 3.1 k Ω to 4.5 k Ω, corresponding to the presence of NSE protein with the concentration ranging from 10 ng mL
⁻¹
to 500 ng mL
⁻¹
, respectively. This developed sensor demonstrates sensitivity with a limit of detection (LoD) of 3.19 ng mL
⁻¹
. Thus, the proposed process for electrochemical immunosensor lays a good foundation for the convenient detection of tumor markers in clinical diagnosis.