Department of Biotechnology and Food Engineering, Israel Institute of Technology, Haifa, Israel.
Adv Exp Med Biol. 2012;733:37-45. doi: 10.1007/978-94-007-2555-3_4.
Optical label-free porous Si-based biosensors for rapid bacteria detection are introduced. The biosensors are designed to directly capture the target bacteria cells onto their surface with no prior sample processing (such as cell lysis). Two types of nanostructured optical transducers based on oxidized porous Si (PSiO(2)) Fabry-Pérot thin films are synthesized and used to construct the biosensors. In the first system, we graft specific monoclonal antibodies (immunoglobulin G's) onto a neat electrochemically-machined PSiO(2) surface, based on well-established silanization chemistry. The second biosensor class consists of a PSiO(2)/hydrogel hybrid. The hydrogel, polyacrylamide, is synthesized in situ within the nanostructured PSiO(2) host and conjugated with specific monoclonal antibodies to provide the active component of the biosensor. Exposure of these modified-surfaces to the target bacteria results in "direct-cell-capture" onto the biosensor surface. These specific binding events induce predictable changes in the thin-film optical interference spectrum of the biosensor. Our studies demonstrate the applicability of these biosensors for the detection of low bacterial concentrations, in the range of 10(3)-10(5) cell/ml, within minutes. The sensing performance of the two different platforms, in terms of their stability in aqueous media and sensitivity, are compared and discussed. This preliminary study suggests that biosensors based on PSiO(2)/hydrogel hybrid outperform the neat PSiO(2) system.
介绍了用于快速细菌检测的无标记光学多孔硅基生物传感器。这些生物传感器旨在直接将目标细菌细胞捕获到其表面，而无需进行任何预先的样品处理（例如细胞裂解）。两种基于氧化多孔硅（PSiO2）法布里-珀罗薄膜的纳米结构光传感器被合成并用于构建生物传感器。在第一个系统中，我们基于成熟的硅烷化化学，将特异性单克隆抗体（免疫球蛋白 G）接枝到纯净的电化学加工 PSiO2表面上。第二类生物传感器由 PSiO2/水凝胶杂化组成。水凝胶聚丙烯酰胺在纳米结构化 PSiO2主体内原位合成，并与特异性单克隆抗体偶联，提供生物传感器的活性成分。将这些修饰表面暴露于目标细菌中，导致“直接细胞捕获”到生物传感器表面。这些特异性结合事件会引起生物传感器薄膜光学干涉光谱的可预测变化。我们的研究表明，这些生物传感器适用于在几分钟内检测低浓度的细菌，范围在 103-105细胞/ml 之间。比较和讨论了两种不同平台在水介质中的稳定性和灵敏度方面的传感性能。这项初步研究表明，基于 PSiO2/水凝胶杂化的生物传感器优于纯净的 PSiO2系统。
