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• Using electrochemical biosensors for rapid detection of SARS-CoV-2 gene fragments. • Electrode material selection is Bi2Se3 single crystal obtained by mechanical peeling. • The peak current has a linear relationship with the logarithm of DNA concentration. • There is excellent specificity in identifying DNA, RNA, and viruses. • Sensors can clearly distinguish between positive and negative results. In this study, we have designed an electrochemical biosensor based on topological material Bi 2 Se 3 for the sensitive detection of SARS-CoV-2 in the COVID-19 pandemic. Flake-shaped Bi 2 Se 3 was obtained directly from high-quality single crystals using mechanical exfoliation, and the single-stranded DNA was immobilized onto it. Under optimal conditions, the peak current of the differential pulse voltammetry method exhibited a linear relationship with the logarithm of the concentration of target-complementary-stranded DNA, ranging from 1.0 × 10-15 to 1.0 × 10-11 M, with a detection limit of 3.46 × 10-16 M. The topological material Bi 2 Se 3 , with Dirac surface states, enhanced the signal-to-interference plus noise ratio of the electrochemical measurements, thereby improving the sensitivity of the sensor. Furthermore, the electrochemical sensor demonstrated excellent specificity in recognizing RNA. It can detect complementary RNA by amplifying and transcribing the initial DNA template, with an initial DNA template concentration ranging from 1.0 × 10-18 to 1.0 × 10-15 M. Furthermore, the sensor also effectively distinguished negative and positive results by detecting splitting-synthetic SARS-CoV-2 pseudovirus with a concentration of 1 copy/μL input. Our work underscores the immense potential of the electrochemical sensing platform based on the topological material Bi 2 Se 3 in the detection of pathogens during the rapid spread of acute infectious diseases. [ABSTRACT FROM AUTHOR]

In this work, we designed a facile and label-free electrochemical biosensor based on intrinsic topological insulator (TI) Bi 2 Se 3 and peptide for the detection of immune checkpoint molecules. With topological protection, Bi 2 Se 3 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/Bi 2 Se 3 was developed as a suitable working electrode for the electrochemical biosensor. The basic performance of the designed peptide/Bi 2 Se 3 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. [Display omitted] • Sensitive electrochemical biosensors combined with topological materials and peptides. • High-quality and large-scale topological crystal with few defects as electrodes. • Effective recognition units of peptides for the immune checkpoint. • A large detection range, good selectivity and stability with low detection limit of the sensing assay. • Excellent discernment in the complicated serum environment for clinical application. [ABSTRACT FROM AUTHOR]