基于金/银纳米三明治结构的表面增强拉曼散射(SERS)特性,实现了前列腺特异性抗原(PSA)高灵敏度免疫检测,检测结果具有特异性。采用化学还原法制备金、银纳米粒子, 用4-巯基苯甲酸(4-MBA)及前列腺特异性抗体(Anti-PSA)链接金、银纳米粒子制备免疫探针, 在硅片表面原位生长金、银纳米粒子并链接Anti-PSA制备得到免疫基底。将免疫探针、免疫基底以及PSA组成三明治结构, 进行基于SERS特性的免疫检测。实验结果表明, 纳米银免疫探针与纳米银免疫基底组成的三明治结构具有最佳的检测效果, PSA的检测灵敏度低至1.8 fg/mL(3.490×10-18 mol/L), 可应用于前列腺癌症的早期检测与诊断。

Based on surface enhanced Raman scattering (SERS), a super-sensitive immunoassay of prostate specific antigen (PSA) was developed with the sandwich-type structure consisted of the nano-Ag immune probes and nano-Ag immune substrate. Experimentally, the chemical reduction method was used to prepare Au and Ag nanoparticles, the nano-Au/Ag immune probes were prepared by immobilising Raman reporter molecule 4-mercaptobenzoic acid (4-MBA) and anti-prostate specific antigen antibody (Anti-PSA) onto the surfaces of Au/Ag nanoparticles. The nano-Ag/Au immune substrates were prepared by in-situ growing of Ag/Au nanoparticles on a silicon wafer and linking with Anti-PSA. The immunoassays of PSA were explored by the four kinds of sandwich-type structures consisted of the nano-Au/Ag immune probes and nano-Au/Ag immune substrates, respectively. It is found that the sandwich-type structure consisted of nano-Ag immune probe and nano-Ag immune substrate is the best one to the immunoassay of PSA, and the detection limit of PSA is as low as 1.8 fg/mL (3.490×10-18 mol/L), which is suitable to be applied in early detection and diagnosis of prostate cancer.