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.

Topological insulator Bi2Se3 based electrochemical aptasensors for the application of sensitive detection of interferon-γ.

Interferon-γ (IFN-γ) is one of the crucial inflammatory cytokines as an early indicator of multiple diseases. A fast, simple, sensitive and reliable IFN-γ detection method is valuable for early diagnosis and monitoring of treatment. In this work, we creatively developed an electrochemical aptasensor based on the topological material Bi2Se3 for sensitive IFN-γ quantification. The high-quality Bi2Se3 sheet was directly exfoliated from a single crystal, which immobilized the synthesized IFN-γ aptamer. Under optimal conditions, the electrochemical signal revealed a wide linear relation along with the logarithmic concentration of IFN-γ from 1.0 pg mL-1 to 100.0 ng mL-1, with the limit of detection as low as 0.5 pg mL-1. The topological material Bi2Se3 with Dirac surface states improved the electrochemical signal/noise ratio and thus the sensitivity of the sensors. Furthermore, this electrochemical aptasensor exhibited excellent specificity and stability, which could be attributed to the large-scale smooth surface of the Bi2Se3 sheet with few defects decreasing the non-specific absorption. The developed biosensor has the same good performance as the ELISA method for detecting the real serum samples. Our work demonstrates that the developed electrochemical aptasensors based on topological materials have great potential in the field of clinical determination.

Electrochemical DNA Biosensors Based on the Intrinsic Topological Insulator BiSbTeSe2 for Potential Application in HIV Determination.

In this work, we reported a sensitive, label-free electrochemical biosensor based on the intrinsic topological insulator (TI) BiSbTeSe2 for potential application in the determination of the HIV gene. With strong spin-obit coupling, TIs could have robust surface states with low electronic noise, which might be beneficial for the stable and sensitive electron transport between the electrode and electrolyte interface. Under optimized conditions of the biosensors using BiSbTeSe2, the differential pulse voltammetry (DPV) peak currents showed a linear relationship with the logarithm of target DNA concentrations ranging from 1.0 × 10-13 to 1.0 × 10-7 M, with a detection limit of 1.07 × 10-15 M. The sensing assay also displayed good selectivity and stability after storage at 4 °C for 7 days. This work provides an effective way to develop biosensors with topological materials, which have a potential application in the clinical determination and monitoring field.