Key Lab for Agro-Product Processing and Quality Control of Nanchang City, College of Food Science and Engineering, Jiangxi Agricultural University, Nanchang 330045, China.
Department of Clinical Laboratory, Jiujiang NO.1 People's Hospital, Jiujiang 332000, China.
J Pharm Biomed Anal. 2018 Sep 5;158:361-369. doi: 10.1016/j.jpba.2018.06.021. Epub 2018 Jun 15.
Prostate-Specific Antigen (PSA) is a crucial biomarker for screening prostate cancer, but a sensitive and selective immunosensor for rapid quantification of serum PSA remains to be developed. In this study, a sandwich pair of nanobodies (Nbs) (i.e., Nb2 and Nb40) against PSA surface antigen was obtained from an alpaca-derived immune phage display library. A sandwich-type immunosensor for the sensitive and selective detection of PSA in serum samples was ingeniously designed based on the pair of Nbs. The small size of Nb40 allowed high capture densities on the surface of reduced graphene oxide (rGO) nanocomposed with massive Au nanoparticles (rGO@AuNPs), which significantly improved the conductivity and provided a large area to anchor many primary antibodies. The secondary antibody Nb2 fused with streptavidin -binding peptide (SBP) cooperated with Nb40 for PSA sandwiching. Accompanying introduction of horseradish peroxidase-streptavidin (HRP-SA) coupled with Nb2-SBP, the faradaic current was linearly correlated with the logarithm of PSA concentration in a range of 0.1-100 ng mL. More importantly, this immunosensor exhibited excellent selectivity, stability, and reproducibility due to the sandwich pair Nbs. The proposed immunosensor was successfully applied in determining PSA in serum samples and could be used for the sensitive and specific detection of PSA.
前列腺特异性抗原（PSA）是筛查前列腺癌的重要生物标志物，但仍需要开发一种用于快速定量血清 PSA 的灵敏和选择性免疫传感器。在这项研究中，从骆驼科动物衍生的免疫噬菌体展示文库中获得了针对 PSA 表面抗原的一对纳米抗体（Nb）（即 Nb2 和 Nb40）。基于这对 Nb，巧妙地设计了一种用于灵敏和选择性检测血清中 PSA 的夹心型免疫传感器。Nb40 的小尺寸允许在还原氧化石墨烯（rGO）纳米复合材料上高密度捕获大量金纳米粒子（rGO@AuNPs），这显著提高了导电性并提供了一个大的面积来固定许多的抗体。与链霉亲和素结合肽（SBP）融合的二级抗体 Nb2 与 Nb40 合作用于 PSA 的夹心结合。伴随着与 Nb2-SBP 偶联的辣根过氧化物酶-链霉亲和素（HRP-SA）的引入，由于夹心对 Nb 的存在，法拉第电流与 PSA 浓度的对数在 0.1-100ng mL 的范围内呈线性相关。更重要的是，由于使用了夹心对 Nb，该免疫传感器表现出出色的选择性、稳定性和重现性。该免疫传感器已成功应用于血清样品中 PSA 的测定，可用于 PSA 的灵敏和特异性检测。
