Construction of magnetic self-assembled electrochemical biosensor with TiO2@Co/C@Au nanocomposite for sensitive detection of PIK3CA gene.

Abstract

PIK3CA gene mutations are key drivers in various malignant tumors, and their highly sensitive detection is crucial for tumor diagnosis. This study aims to develop a label-free electrochemical biosensor based on a TiO2@Co/C@Au nanocomposite for highly sensitive detection of the PIK3CA gene. By optimizing the synthesis conditions of the composite, electrode modification process, and hybridization detection parameters, the synergistic effects of multiple components are utilized to enhance electrode conductivity and biomolecule loading capacity. Leveraging the magnetic properties of cobalt enables simple, controllable electrode modification, establishing a "signal-off" detection platform. The sensor has a linear range of 1 fM to 1 μM and a detection limit of 2.26 fM, enabling low femtomole detection of the PIK3CA gene with excellent specificity, reproducibility, and stability. In real serum sample testing, the sensor demonstrated good recovery rates (99.92%-117.75%), and the measured values closely matched the added concentrations, confirming its reliability and practicality in complex biological matrices. This provides a cost-effective, simple, and reliable new strategy for point-of-care detection of tumor-related genes.