NSE protein detection in a microfluidic channel integrated an electrochemical biosensor

This study proposed a microfluidic chip for the detection and quantification of NSE proteins, aimed at developing a rapid point-of-care testing system for early lung cancer diagnosis. The proposed chip structure integrated an electrochemical biosensor within a straight PDMS microchannel, enabling a significant reduction in sample volume. Additionally, a method was developed to deposit silver and silver chloride layers onto the reference electrode. Following fabrication, the working electrode was modified to immobilize NSE antibodies on its surface, facilitating specific protein detection. Electrochemical impedance spectroscopy (EIS) measurements were utilized to investigate the alterations in surface impedance resulting from the specific binding of anti-NSE on the electrode surface across varying concentrations of NSE, ranging from 10 ng ml^-1to 1000 ng ml^-1. The experimental results demonstrated a direct correlation between NSE concentration and surface impedance. Specifically, the charge transfer resistance exhibited an increase from 24.54 MΩ to 89.18 MΩ as the NSE concentration varied from 10 ng ml^-1to 1000 ng ml^-1. Moreover, the concentration of NSE can be quantified by relating it to the charge transfer resistance, which follows a logarithmic equation. The limit of detection (LoD) of the chip was evaluated to be approximately 1.005 ng ml^-1. The proposed chip lays a crucial foundation for developing a Lab-on-a-chip platform dedicated to diagnosing NSE testing and lung cancer.