A label-free electrochemical aptasensor based on Ti3C2Tx-Ag/Au nanoparticles as a signal amplification strategy for CRP detection

Abstract

C-reactive protein (CRP) is an essential biomarker that is associated to acute inflammation and infectious illnesses. This study developed a label-free electrochemical aptasensor utilizing Ti3C2Tx-silver/gold nanoparticles (Ti3C2Tx-Ag/Au NPs) for the first time for CRP detection. Based on the unique capacity of Ti3C2Tx of self-adsorbing and reducing silver ions (Ag+), Ag signal probes with strong redox activity and good electrical conductivity were synthesized. Electrodeposition of Au NPs on the electrode surface modified with Ti3C2Tx-Ag, not merely improved the adsorption capacity of the immobilized aptamer and prevented Ag loss; it also collaborated with Ti3C2Tx-Ag to create a dual-amplified signal strategy. Aptamer molecules bind to Au NPs through the Au-S bond for precise capture of CRP. The detection was performed by differential pulse voltammetry (DPV), the current was proportional to the logarithm of CRP antigen, and the linear range of CRP detection was 0.1–200 ng mL−1 with a limit of detection (LOD) 41 pg mL−1. Simultaneously, the label-free aptasensor presented superior detection selectivity, reproducibility, and stability. This study provided an ideal electrochemical biosensor for determining CRP in serum, with an excellent prospect for clinical diagnostic applications at the point of care testing (POCT).