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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. [ABSTRACT FROM AUTHOR]

VSe2 is a typical two-dimensional (2D) transition-metal dichalcogenide material with various physical properties, such as ultrahigh electrical conductivity, controversial magnetism, and active catalytic properties. However, controllable preparation of VSe2 2D structures poses many challenges, and their application has not yet been developed. Here, we controllably synthesize VSe2 2D flakes on highly oriented pyrolytic graphite (HOPG) using molecular beam epitaxy. By controlling the growth temperature and the evaporation rate of the source, we obtained various morphologies of VSe2 flakes, including single- and multilayers with triangular and belt shapes. Compared with the triangular structures of the flakes, the one-dimensional nanobelt structures have a larger edge density and can provide more catalytic active sites. Hydrogen evolution reaction results indicate that the belt-shaped VSe2 flakes exhibit superior catalytic performance. Due to the presence of plenty of edges, the overpotential of the belt-shaped VSe2 is 543 mV at a current density of 1 mA/cm2, which is much lower than that in the triangular flakes. The VSe2 flakes with a larger edge density are more conductive than the regular triangular flakes after loading metal atoms due to the efficient dispersion of the metal atoms. As a result, the multistructure of Co particle-decorated VSe2 flakes achieves a high catalytic performance with 352 mV overpotential at a current density of 10 mA/cm2, demonstrating their potential applications in the catalyst field. [ABSTRACT FROM AUTHOR]

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 Bi 2 Se 3 for sensitive IFN-γ quantification. The high-quality Bi 2 Se 3 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 Bi 2 Se 3 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 Bi 2 Se 3 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.

In this work, we reported a sensitive, label-free electrochemical biosensor based on the intrinsic topological insulator (TI) BiSbTeSe 2 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 BiSbTeSe 2 , 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.