Electrochemical cardiac troponin I immunosensor platform integrated with electrochemically deposited Au nanoparticles decorated PtNi bimetallic sponge-like structures.

In this study, a novel, reproducible, and stable electrochemical detection platform was developed for the detection of cardiac troponin I (cTnI), one of the most common biomarkers of cardiovascular diseases. The immunosensing platform consisted of antibody functionalized electrochemically gold (Au) deposited sponge-like platinum‑nickel (PtNi)-based nanoparticles modified screen-printed carbon electrodes (SPCEs). A sponge-like surface yielded a high surface area that enabled effective Au deposition and enhanced electrochemical properties through a synergistic effect. Electrochemically deposited Au onto this surface not only improved electrochemical characteristics but also created an environment in which the antibody could settle effectively. The final version of the electrode demonstrated high sensitivity. The sensor (anti-cTnI/Au@Pt-Ni/SPCE) performance was achieved in the linear working range of 0.01 pg/mL-100 ng/mL with a low limit of detection (LOD) value of 8.09 fg/mL using EIS technique. The selectivity studies showed that the proposed electrode had successful results in the presence of important interfering species. Good recovery was obtained in diluted serum samples ranging between 97.3 and 103.6%. Amperometric detection strategy was also evaluated with the metal-based nanoparticles modified electrode, and a low LOD value of 3.93 fg/mL was obtained. The modified electrode was successfully characterized using microscopic, spectroscopic, contact angle, and electrochemical techniques.