Enhanced electrochemical detection of thrombin via a dual signal amplification strategy based on Au Nanoparticles@Carbon nanosheets and PtCu3 nanoparticles

Abstract

Thrombin (TB) is an enzyme involved in blood coagulation and associated with various diseases such as thromboembolic disease, Alzheimer's disease, and cancer. This study introduces an electrochemical biosensor with a sandwich-type structure designed for the highly sensitive detection of TB. The working electrode (WE) was modified with gold nanoparticles loaded onto the carbonization product of two-dimensional Cu-bond tetrakis(4-carboxyphenyl)porphyrin (Cu-TCPP) nanosheets (referred to as Au@CNSs), enhancing the electrical conductivity and specific surface area of the WE. The modified electrode exhibited notable catalytic activity for H2O2 reduction. One aptamer of TB (Apt1), with a sulfhydryl group (-SH-) at the end, can tightly bound to Au@CNSs through a S-Au bond. Additionally, PtCu3 alloy nanocrystals, possessing high electrocatalytic activity towards H2O2 reduction, were prepared and modified with another TB aptamer (Apt2). In the presence of TB, a sandwich-type biosensing interface formed, resulting in an increased reduction current for H2O2. Under optimized conditions, the proposed aptasensor demonstrated a broad linear range from 0.01 pM to 32 nM and a low detection limit of 0.005 pM. Furthermore, the aptasensor exhibited excellent performance in terms of stability, reproducibility, and sensitivity, making it a promising tool for TB detection in human serum.