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目的设计一种基于AgI模拟酶纳米材料的阻抗型免疫传感器,对血清样品中的癌胚抗原(CEA)进行高灵敏检测。方法合成一种壳聚糖修饰的碘化银(CS-AgI)纳米材料,利用透射电镜(TEM)和傅里叶红外光谱(FTIR)法对合成的CS-AgI进行表征,以CS-AgI为信号标记物修饰CEA抗体,采用夹心式免疫分析法在金电极表面制备一种高效、灵敏的电化学免疫传感器,采用电化学工作站定量分析检测所构建免疫传感器的电化学性能。结果成功合成CS-AgI纳米颗粒,颗粒呈球形,粒径约为100nm。以CS-AgI纳米颗粒为信号标记物构建的免疫传感器在pH 7.0的磷酸盐缓冲液中检测CEA时表现出良好的电化学性能,其交流阻抗响应值与样品中的CEA浓度的对数呈线性增加趋势,并在CEA浓度为0.1~80ng/mL范围内展现出良好的线性关系(r=0.996),检测限达到0.05ng/mL。结论基于AgI模拟酶纳米材料构建的阻抗型免疫传感器可以高灵敏检测CEA,同时具有较好的精确性、重现性和选择性,为癌症的早期诊断和早期治疗提供了实验依据。
OBJECTIVE: To design a sensitive immunosensor based on AgI-mimicking enzyme nanomaterials for highly sensitive detection of carcinoembryonic antigen (CEA) in serum samples. Methods CS-AgI nanomaterials modified by chitosan were synthesized. The synthesized CS-AgI was characterized by transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy (FTIR) CEA antibody was modified by sandwich immunoassay to prepare an efficient and sensitive electrochemical immunosensor on the surface of gold electrode. The electrochemical performance of the constructed immunosensor was tested by electrochemical workstation. Results CS-AgI nanoparticles were successfully synthesized. The particles were spherical and the particle size was about 100 nm. Immunosensors constructed with CS-AgI nanoparticles as a signal marker showed good electrochemical performance when CEA was detected in phosphate buffer pH 7.0, and the AC impedance response was linear with the logarithm of CEA concentration in the sample And showed a good linear relationship (r = 0.996) in the range of 0.1 ~ 80 ng / mL of CEA with a detection limit of 0.05 ng / mL. Conclusion Impedance-type immunosensor based on AgI-mimicking enzyme nanomaterials can detect CEA highly sensitively, and has good accuracy, reproducibility and selectivity. It provides an experimental basis for the early diagnosis and early treatment of cancer.