Dong Yi, Phillips K Scott, Cheng Quan
Department of Chemistry, University of California, Riverside, CA 92521, USA.
Lab Chip. 2006 May;6(5):675-81. doi: 10.1039/b514902a. Epub 2006 Mar 15.
A versatile and novel method has been developed for microfluidic immunosensing of the food-borne pathogen Staphylococcus enterotoxin B (SEB) in poly(dimethylsiloxane) (PDMS) chips. Supported bilayer membranes (SBMs) were generated by vesicle fusion in oxidized PDMS microchannels for minimizing non-specific adsorption of biomolecules. The stability of SBMs was strengthened with a streptavidin layer to make them air-stable and allow for subsequent display of the biotin-functionalized antibodies. The reinforced supported bilayer membranes (r-SBMs) are fluid, exhibiting a lateral diffusion coefficient of approximately 1.9 microm(2) s(-1), and no detectable change of mobility was found after dehydration/rehydration. This is a substantial improvement over phosphatidylcholine (PC) membranes on PDMS, which suffered a roughly 10% reduction in the mobile fraction and 30% decrease in mobility after dehydration. Non-specific protein adsorption in the membrane-treated channels was reduced 100-1000 fold as compared to PDMS surfaces without a membrane coating. A flow-based microfluidic immunosensor for SEB was developed using antibodies linked to the r-SBMs in PDMS channels, and a detection limit of 0.5 ng mL(-1) was obtained from the linear portion of the calibration curve. The microchip was applied to detection of SEB in milk, and similar response and sensitivity were obtained, demonstrating the sensor's remarkable performance for real world samples. The r-SBMs overcome the stability hurdle in SBM-modified surfaces, opening up possibilities for transport and storage of membrane-functionalized microchips in the dehydrated form without compromising the performance, and facilitating the commercialization of disposable SBM-based microdevices.
一种通用且新颖的方法已被开发出来，用于在聚二甲基硅氧烷（PDMS）芯片中对食源性病原体肠毒素B（SEB）进行微流控免疫传感。通过在氧化的PDMS微通道中进行囊泡融合生成支撑双层膜（SBM），以最小化生物分子的非特异性吸附。用链霉亲和素层增强SBM的稳定性，使其在空气中稳定，并允许随后展示生物素功能化抗体。增强的支撑双层膜（r-SBM）具有流动性，其横向扩散系数约为1.9微米²秒⁻¹，脱水/再水化后未发现迁移率有可检测的变化。这比PDMS上的磷脂酰胆碱（PC）膜有了实质性的改进，后者在脱水后可移动部分大约减少了10%，迁移率降低了30%。与没有膜涂层的PDMS表面相比，膜处理通道中的非特异性蛋白质吸附减少了100 - 1000倍。利用连接到PDMS通道中r-SBM的抗体开发了一种用于SEB的基于流动的微流控免疫传感器，在校准曲线的线性部分获得了0.5纳克/毫升的检测限。该微芯片应用于牛奶中SEB的检测，获得了相似的响应和灵敏度，证明了该传感器对实际样品具有卓越的性能。r-SBM克服了SBM修饰表面的稳定性障碍，为以脱水形式运输和存储膜功能化微芯片开辟了可能性，而不会影响性能，并促进了基于一次性SBM的微型设备的商业化。
