组成图示
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传感器类型
表面等离子共振(SPR)生物传感器
检测对象
免疫球蛋白G（IgG，兔IgG/人IgG，HBS-EP缓冲液）、磺胺甲噁唑（sulfamethoxazole, SMOZ，PBS缓冲液标准品）、磺胺甲噁嗪（sulfamethazine, SMZ，PBS缓冲液标准品）
检测原理
该传感器采用Kretschmann构型SPR成像：650 nm He-Ne激光经棱镜激发SPR阵列芯片金膜中的表面等离子体，反射光强度随金膜表面折射率/质量变化而改变。芯片表面通过EDC/NHS活化羧甲基葡聚糖并固定识别分子。IgG实验中，流动抗体与固定IgG特异性结合，表面质量增加，SPR响应增强，CCD实时记录传感器图。磺胺实验采用抑制免疫分析：样品中磺胺与抗体预孵育，竞争占据抗体结合位点；随后抗体结合芯片上磺胺-BSA，被测物浓度越高，结合到芯片的抗体越少，归一化结合斜率S/S0降低。微流控流池提供稳定流路，无酶或核酸放大，直接光学读出。
检测灵敏度
LOD: 3.5 ng/mL（磺胺甲噁唑）；0.6 ng/mL（磺胺甲噁嗪）
效应效果
该硬-软流池在塑料-PDMS界面粘附强度约为411–510 kPa，与有机功能硅烷法相当；可逆密封的流池/SPR阵列芯片堆叠在水环境中可承受185±19 kPa（N=4）而不泄漏，比文献玻璃-PDMS可逆密封微流控芯片高5倍以上。SPR成像免疫分析中，IgG阵列反应非特异吸附低，可实时监测多通道相互作用。磺胺检测中，零浓度S/S0的RSD分别为9%（SMOZ）和6%（SMZ），检出限3.5和0.6 ng/mL，与商用Biacore SPR生物传感器相当。作者认为该器件紧凑、鲁棒、易使用，适合高通量筛查、食品残留和即时医疗等应用。
传感器的构成
- SPR换能芯片：显微镜玻璃片（glass slide）溅射Cr/Au（2 nm/50 nm）形成3×5 Au阵列，提供SPR换能界面
- 识别元件：芯片表面羧甲基葡聚糖经EDC/NHS活化后点样固定兔IgG、人IgG或磺胺甲噁唑-BSA/磺胺甲噁嗪-BSA偶联物，用于特异性识别
- 封闭剂：1 M乙醇胺（ethanolamine, pH 8.0）淬灭剩余活性基团，降低非特异吸附
- 微流控软层：Sylgard 184 PDMS（10:1固化）形成环绕微通道，与SPR阵列芯片可逆密封形成封闭流路
- 微流控硬基底：CNC加工PMMA基底，表面沉积200 nm PECVD SiO2薄膜，作为PDMS不可逆粘附中间层和刚性支撑
- 管路连接：塑料螺钉与PTFE管连接宏-微接口，实现HBS-EP缓冲液和样品进样
- 信号标记物：无外源标记，依赖SPR对表面结合质量/折射率变化的直接光学响应
- 信号读出：自制SPR成像仪（Kretschmann构型，650 nm He-Ne激光，CCD）采集反射光强度变化
中文摘要
理想的微流控生物传感器流池既需要与生物传感芯片形成高强度密封的“软”界面，又需要用于管路连接的“硬”宏-微界面，而单一材料难以同时满足。本文探索将等离子体增强化学气相沉积（PECVD）制备的SiO2薄膜作为中间层，使聚二甲基硅氧烷（PDMS）不可逆粘附于塑料基底，并开发了一种硬-软、紧凑、鲁棒的微流控生物传感器流池，用于表面等离子共振（SPR）成像多阵列免疫分析。该流池由一个经计算机数控（CNC）加工、涂覆200 nm SiO2薄膜的刚性聚甲基丙烯酸甲酯（PMMA）基底和一个柔性PDMS微流控层组成。该器件不仅保留传统PDMS流池软界面、易制备和低成本等优点，还具有刚性、鲁棒、易用的管路连接界面，并可在水环境中承受185 kPa压力而不失效。通过与SPR成像生物传感器耦合，成功演示了免疫球蛋白G（IgG）相互作用的实时监测，以及磺胺甲噁唑（SMOZ）和磺胺甲噁嗪（SMZ）的检测，灵敏度分别为3.5和0.6 ng/mL。该新型硬-软微流控器件也可用于其他生物传感器流池。
英文摘要
An ideal microfluidic-based biosensor flow cell should have not only a "soft" interface for high strength sealing with biosensing chips, but also "hard" macro-to-micro interface for tubing connection. Since these properties are exclusive of each other, no one material can provide the advantages of both. In this paper, we explore the application of a SiO(2) thin film, deposited by plasma-enhanced chemical vapor deposition (PECVD) technology, as an intermediate layer for irreversibly adhering polydimethylsiloxane (PDMS) to plastic substrate, and develop a hard-soft, compact, robust microfluidic-based biosensor flow cell for the multi-array immunoassay application of surface plasmon resonance (SPR) imaging. This hard-soft biosensor flow cell consists of one rigid, computer numerically controlled (CNC)-machined poly(methyl methacrylate) (PMMA) base coated with a 200 nm thick SiO(2) thin film, and one soft PDMS microfluidic layer. This novel microfluidic-based biosensor flow cell does not only keep the original advantage of conventional PDMS-based biosensor flow cell such as the intrinsically soft interface, easy-to-fabrication, and low cost, but also has a rigid, robust, easy-to-use interface to tubing connection and can be operated up to 185 kPa in aqueous environments without failure. Its application was successfully demonstrated with two types of experiments by coupling with SPR imaging biosensor: the real-time monitoring of the immunoglobulin G (IgG) interaction, as well as the detection of sulfamethoxazole (SMOZ) and sulfamethazine (SMZ) with the sensitivity of 3.5 and 0.6 ng/mL, respectively. This novel hard-soft microfluidic device is also useful for a variety of other biosensor flow cells.