Department of Applied Chemistry for Environment, School of Science and Technology, Kwansei Gakuin University, Sanda, 669-1337, Japan.
Analyst. 2018 Feb 12;143(4):858-864. doi: 10.1039/c7an01577a.
A rapid and sensitive detection of a cancer marker, neuron specific enolase (NSE), is demonstrated by using a disposable silver plasmonic chip functionalized with a mussel-inspired polydopamine (PDA) coating. A plasmonic chip consisting of a diffraction grating coated with a silver thin film is used for the excitation of propagating surface plasmon resonance through a rear-side grating coupling method. Simple and quick bio-functionalization of the sensor surface is performed by PDA coating which requires 20 min for deposition, and allows direct attachment of the capture antibody without using any coupling agents. A fluorescence based sandwich immunoassay is used for the detection of NSE by utilizing surface plasmon enhanced fluorescence (SPF) spectroscopy. The developed biosensor scheme provides approximately linear sensor responses for the sample containing NSE with the concentration around the clinically important value (12 ng mL) in both buffer and diluted human serum (25 vol% to a buffer solution). The detection limit for NSE is 0.5 ng mL (11 pM) and 1.4 ng mL (30 pM) in a buffer solution and diluted human serum, respectively. The presented biosensor scheme requires a small amount of the sample down to 10 μL in human serum and a short incubation time (15 min) of the sample solution containing NSE, enabling less invasive and rapid detection of NSE. This is the first example of the sensitive sandwich immunoassay demonstrated by using a plasmonic chip for the measurement of the sample dissolved in a complex medium with a rear side coupling method, which progresses the universal use of the SPF biosensors with a disposable plasmonic chip.
一种基于贻贝类聚多巴胺（PDA）涂层的一次性银等离子体芯片，实现了对神经元特异性烯醇化酶（NSE）这一癌症标志物的快速灵敏检测。该等离子体芯片由涂覆有银薄膜的衍射光栅组成，通过后侧光栅耦合方法激发传播表面等离激元共振。通过 PDA 涂层可简单快速地对传感器表面进行生物功能化，该过程仅需 20 分钟即可完成沉积，并且无需使用任何偶联剂即可直接连接捕获抗体。基于夹心免疫测定法，利用表面等离激元增强荧光（SPF）光谱学来检测 NSE。所开发的生物传感器方案在缓冲液和稀释人血清（缓冲液的 25 体积%）中，针对 NSE 浓度约为临床重要值（12ng mL）的样品，提供了近似线性的传感器响应。在缓冲液和稀释人血清中，NSE 的检测限分别为 0.5ng mL（11pM）和 1.4ng mL（30pM）。该生物传感器方案在人血清中只需 10μL 左右的少量样品，且样品溶液中 NSE 的孵育时间（15min）较短，可实现对 NSE 的微创、快速检测。这是首例通过后侧耦合方法在复杂介质中测量溶解样品的等离子体芯片实现的灵敏夹心免疫测定，推进了具有一次性等离子体芯片的 SPF 生物传感器的通用应用。
