A Three-Dimensional AgNPs/TiO₂/Ti₃C₂Tx Composite for Label-Free Thrombin Aptamer Sensor

Abstract

A one-step hydrothermal method was employed to synthesize a three-dimensional (3D) AgNPs/TiO2/Ti3C2Tx composite. Hydrothermal conditions were used to promote the growth of TiO2 nanorods on the Ti3C2Tx sheet, resulting in the formation of a three-dimensional composite nanomaterial. Glutamic acid served as both a reducing agent and a stabilizer to load Ag nanoparticles (AgNPs) onto the 3D composite nanomaterial. The structure of the composite material provided a large accessible surface area, facilitating the anchoring of Ag NPs. Thrombin aptamers were then linked to Ag NPs through Ag-S bonds, establishing a sensitive and label-free aptasensor for thrombin detection. The proposed aptasensor demonstrated excellent electrochemical performance, with a broad linearity range of 5.0 fM to 500 nM and a relatively low detection limit of 2.0 fM (S/N = 3). These findings indicate the potential of Ag NPs/TiO2/Ti3C2Tx in the development of promising electrochemical biosensors.