Sensitive biosensors based on topological insulator Bi₂Se₃ and peptide

In this work, we designed a facile and label-free electrochemical biosensor based on intrinsic topological insulator (TI) Bi₂Se₃ and peptide for the detection of immune checkpoint molecules. With topological protection, Bi₂Se₃ could have robust surface states with low electronic noise, which was beneficial for the stable and sensitive electron transport between electrode and electrolyte interface. The peptides are easily synthesized and chemically modified, and have good biocompatibility and bioavailability, which is a suitable candidate as the recognition units for immune checkpoint molecules. Therefore, the peptide/Bi₂Se₃ was developed as a suitable working electrode for the electrochemical biosensor. The basic performance of the designed peptide/Bi₂Se₃ biosensor was investigated to determine the Anti-HA Tag Antibody and PD-L1 molecules. The linear detection range was from 3.6 × 10⁻¹⁰ mg mL⁻¹ to 3.6 × 10⁻⁵ mg mL⁻¹, and the detection limit was 1.07 × 10⁻¹¹ mg mL⁻¹. Moreover, the biosensor also displayed good selectivity and stability.