Synthesis and fabrication of 2D Tungsten trioxide nanosheets based platform for impedimetric sensing of cardiac biomarker

Herein, we report the development of a two-dimensional (2D) label-free matrix for cardiac biomarker detection. Tungsten trioxide nanosheets (WO3 NS) were synthesized by a facile, environmentally friendly hydrothermal method and subsequently functionalized chemically using 3-aminopropyletriethoxysilane (APTES). Thin film of APTES functionalized WO3 NS was deposited on indium tin oxide (ITO) substrate using electrophoretic deposition technique. The fabricated APTES/WO3 NS/ITO electrode endows with large surface area for high loading of cardiac troponin I antibodies (anti-cTnI), good stability and strong adsorption platform for the biomolecules immobilization. The selective and quantitative detection of cTnI biomarker was accomplished by immobilizing anti-cTnI on APTES/WO3 NS/ITO platform. The electrochemical sensing using anti-cTnI/APTES/WO3 NS/ITO immunoelectrode was studied as a label-free immunoassay format using EIS (electrochemical impedance spectroscopy) technique. The performance of the sensor as investigated with the measurement of charge transfer resistance (RCT) for variant concentrations of cTnI antigen demonstrated good sensitivity as 30.8 Ω mL ng−1 cm−2 for a linear detection range 0.1 to 100 ng mL−1 along with good stability up to 6 weeks. The competency of the biosensor was also tested by detecting cTnI antigen in spiked human serum samples.