Construction of Fluorescence Sensing Platform on the Basis of Carbon Nitride Nanosheet for the Detection of Interferon-<i>γ</i>

Purpose: Interferon-γ (INF-γ) is a cytokine that participates in the immune reaction of the body. Its level of secretion can reflect the immune response condition after the body is infected by pathogens, which is a significant indication of clinically-related diseases. Therefore, it is of great significance in application to develop a fluorescence biosensor to inspect INF-γ with rapidness, high sensitivity and high practicability. Method: The fluorescence sensor is made on the basis of the two-dimensional nano-material namely Carbon Nitride Nanosheet (CNNS) and the Aptamer probe to identify INF-γ (Apt®INF-γ). CNNS can quickly quench the Cy5 fluorescent dye modified on the Apt®INF-γ probe due to the Photoinduced Electron Transfer (PET), but when the INF-γ exists, Apt®INF-γ specifically identifies and combines it. The complex of Apt®INF-γ and INF-γ is away from CNNS, which can effectively block the fluorescent signal of Apt?INF-γ being quenched by CNNS. Result: The sensitive detection of IFN-γ protein can be achieved through the application of CNNS/Apt®INF-γ fluorescence sensing platform. In this method, the intensity of the fluorescent signal is positively correlated with the concentration of IFN-γ, of which the liner response range is 0.5 - 100 ng/mL and the limit of detection is 0.303 ng/mL. In addition, this fluorescence sensing platform has the advantages of high specificity, simple operation and low costs. It can inspect the content of IFN-γ in clinical serum samples without interference. The actual recovery rate of serum samples is 97.11% - 106.96%. Conclusion: Therefore, the CNNS/Apt®INF-γ sensing platform is expected to be implemented in the actual clinical detection, also conducive to developing a universal fluorescence biosensor to inspect other target materials.