Institute of Technical Chemistry, Leibniz Universität Hannover , Callinstr. 5, 30167 Hanover, Germany.
IBM Research - Zürich , Säumerstrasse 4, 8803 Rüschlikon, Switzerland.
ACS Sens. 2017 Dec 22;2(12):1767-1773. doi: 10.1021/acssensors.7b00692. Epub 2017 Nov 27.
Porous silicon (PSi) nanomaterials have been widely studied as label-free optical biosensors for protein detection. However, these biosensors' performance, specifically in terms of their sensitivity (which is typically in the micromolar range), is insufficient for many applications. Herein, we present a proof-of-concept application of the electrokinetic isotachophoresis (ITP) technique for real-time preconcentration of a target protein on a PSi biosensor. With ITP, a highly concentrated target zone is delivered to the sensing area, where the protein target is captured by immobilized aptamers. The detection of the binding events is conducted in a label-free manner by reflective interferometric Fourier transformation spectroscopy (RIFTS). Up to 1000-fold enhancement in local concentration of the protein target and the biosensor's sensitivity are achieved, with a measured limit of detection of 7.5 nM. Furthermore, the assay is successfully performed in complex media, such as bacteria lysate samples, while the selectivity of the biosensor is retained. The presented assay could be further utilized for other protein targets, and to promote the development of clinically useful PSi biosensors.
多孔硅（PSi）纳米材料已被广泛研究作为用于蛋白质检测的无标记光学生物传感器。然而，这些生物传感器的性能，特别是在灵敏度方面（通常在微摩尔范围内），对于许多应用来说还不够。在此，我们提出了一种基于电动等速电泳（ITP）技术的概念验证应用，用于实时在 PSi 生物传感器上浓缩目标蛋白。通过 ITP，可以将高度浓缩的目标区域输送到传感区域，在该区域中，固定化的适体捕获目标蛋白。通过反射干涉傅里叶变换光谱（RIFTS）以无标记的方式检测结合事件。与未浓缩的情况相比，实现了 1000 倍的局部蛋白靶浓度增强和生物传感器灵敏度的提高，测量的检测限为 7.5 nM。此外，该测定法在复杂介质（如细菌裂解物样品）中成功进行，同时保留了生物传感器的选择性。所提出的测定法可进一步用于其他蛋白质靶标，并促进临床有用的 PSi 生物传感器的发展。
