Fabrication of phenylboronic acid modified graphene oxide-silica biosensor for label-free electrochemical detection of circulating tumor cells

Early and accurate detection of circulating tumor cells (CTCs) is vital for cancer diagnosis and personalized treatment. Despite their clinical significance, the identification of CTCs remains challenging because of the biological complexity and lower concentration. Therefore, a cost-effective, and label-free electrochemical biosensor based on phenyl boronic acid functionalized graphene oxide-silica (PBA@GO-SiO₂) is developed to selectively recognize sialic acid-rich glycoproteins on HepG2 cells. The electrochemical properties of developed biosensor confirm a concentration-dependent response upon interaction with HepG2 cells. The biosensor demonstrates a broad linear range of 50–10⁵ cells/mL with LOD of 26 cells/mL. Electrochemical surface area (ECSA) and optimization studies verify the stable sensor performance across different scan rates and pH conditions. It also exhibits selectivity, reproducibility, and reusability while retaining 85 % original signal after multiple regeneration cycles. Overall, PBA@GO-SiO₂ based biosensor is a scalable platform requiring small blood sample, eliminating the need for antibodies, ensuring long shelf life because of durable material, and carry translational potential at clinical level.