Song Hong Yan, Wong Ten It, Sadovoy Anton, Wu Lin, Bai Ping, Deng Jie, Guo Shifeng, Wang Yi, Knoll Wolfgang, Zhou Xiaodong
Institute of Materials Research and Engineering, A*STAR (Agency for Science, Technology and Research), 3 Research Link, Singapore 117602.
Lab Chip. 2015 Jan 7;15(1):253-63. doi: 10.1039/c4lc00978a.
We designed and fabricated two new nanostructured biosensing chips, with which the sensitive detection of prostate specific antigen (PSA) as low as 100 pg ml(-1) can be achieved, by measuring the plasmon enhanced fluorescence through a conventional dark field microscope. The gold nanostructure arrays, one with gold nanopillars of 140 nm, the other with gold nanoholes of 140 nm, were fabricated via nanoimprinting onto glass substrate, as localized surface plasmon resonance (LSPR) generators to enhance the fluorescent emission of fluorophore, e.g. quantum dot (QD). A sandwich bioassay of capture anti-PSA antibody (cAb)/PSA/detection anti-PSA (dAb) labeled by QD-655 was established on the nanostructures, and the perfect LSPR excitation distance (10-15 nm) between the nanostructure and QD-655 was simulated and controlled by a cleft cAb fragment and streptavidin modified QD. QD was chosen in this study due to its photo stability, broad Stokes shift, and long lifetime. As far as we know, this is the first time that QD is applied for PSA detection on the uniform nanostructured sensing chips based on the LSPR enhanced fluorescence. Due to the miniaturized nanoarray sensing chip (1.8 mm × 1.8 mm), the convenience and specificity for the detection of PSA via the sandwich assay, and the high optical detection sensitivity, the platform has great potential for the development of a portable point-of-care (POC) system for outpatient diagnosis and treatment monitoring.
我们设计并制造了两种新型纳米结构生物传感芯片，通过传统暗场显微镜测量等离子体增强荧光，可实现低至100 pg ml⁻¹的前列腺特异性抗原（PSA）的灵敏检测。通过纳米压印在玻璃基板上制备了金纳米结构阵列，一种是140 nm的金纳米柱，另一种是140 nm的金纳米孔，作为局域表面等离子体共振（LSPR）发生器以增强荧光团（如量子点（QD））的荧光发射。在纳米结构上建立了由QD-655标记的捕获抗PSA抗体（cAb）/PSA/检测抗PSA（dAb）的夹心生物测定法，通过裂隙cAb片段和链霉亲和素修饰的QD模拟并控制纳米结构与QD-655之间完美的LSPR激发距离（10 - 15 nm）。本研究中选择QD是因其光稳定性、宽斯托克斯位移和长寿命。据我们所知，这是首次将QD应用于基于LSPR增强荧光的均匀纳米结构传感芯片上的PSA检测。由于纳米阵列传感芯片小型化（1.8 mm×1.8 mm），通过夹心测定法检测PSA具有便利性和特异性，以及高光学检测灵敏度，该平台在开发用于门诊诊断和治疗监测的便携式即时检测（POC）系统方面具有巨大潜力。
