Department of Applied Chemistry for Environment, School of Science and Technology, Kwansei Gakuin University , Sanda 669-1337, Japan.
ACS Appl Mater Interfaces. 2016 Aug 31;8(34):22032-8. doi: 10.1021/acsami.6b06917. Epub 2016 Aug 22.
Polydopamine (PDA) thin films are introduced to the surface modification of biosensor surfaces utilizing surface plasmon enhanced fluorescence spectroscopy (SPFS) as the linker layer of capture antibody on to the sensor surfaces. The capture antibody can be directly attached to the sensor surface without using any coupling agent by functionalizing the gold sensor surface with PDA thin films. The PDA coating is performed by a single-step preparation process by applying the dopamine solution on the sensor surface, which requires an extremely short incubation time (10 min). The real-time in situ measurement of the adsorption kinetics of the capture antibody onto the PDA-coated sensor surface is studied by surface plasmon resonance (SPR) spectroscopy. It reveals that the immobilization of capture antibody immediately occurs after introduction of a solution containing capture antibody, and the sensor surface is fully covered with the capture antibody. The sensitive detection of the cytokine marker interleukin-6 (IL-6) is performed by SPFS using a sandwich assay format with fluorescently labeled detection antibody. The sensor chips functionalized by PDA chemistry exhibited sensitive sensor responses with low nonspecific adsorption of the detection antibody onto the sensor surface. The detection limit of IL-6 with the developed SPFS biosensor is determined to be 2 pg/mL (100 fM), which is within the range of the diagnostic criteria. Our observation elucidates the remarkable utility of PDA coatings for chemical modification of the metallic sensor surfaces by a simple, brief, and inexpensive manner.
聚多巴胺（PDA）薄膜被引入到生物传感器表面的改性中，利用表面等离子体增强荧光光谱（SPFS）作为传感器表面上捕获抗体的连接层。通过在金传感器表面上功能化 PDA 薄膜，可以直接将捕获抗体固定在传感器表面上，而无需使用任何偶联剂。PDA 涂层是通过在传感器表面上施加多巴胺溶液来进行的一步制备工艺完成的，这需要极短的孵育时间（10 分钟）。通过表面等离子体共振（SPR）光谱研究了捕获抗体在 PDA 涂层传感器表面上的吸附动力学的实时原位测量。结果表明，在引入含有捕获抗体的溶液后，捕获抗体的固定立即发生，并且传感器表面完全被捕获抗体覆盖。通过夹心测定法，使用荧光标记的检测抗体，通过 SPFS 进行细胞因子标志物白细胞介素-6（IL-6）的灵敏检测。通过 PDA 化学功能化的传感器芯片表现出对检测抗体在传感器表面上的低非特异性吸附的灵敏传感器响应。用开发的 SPFS 生物传感器测定的 IL-6 的检测限为 2 pg/mL（100 fM），处于诊断标准范围内。我们的观察结果阐明了 PDA 涂层在通过简单、简短和廉价的方式对金属传感器表面进行化学改性方面的显著实用性。
