Laboratoire de Chimie Organique, Université libre de Bruxelles (ULB), Avenue F. D. Roosevelt 50, CP160/06, B-1050 Brussels, Belgium.
Laboratory for the Structure and Function of Biological Membranes, Centre for Structural Biology and Bioinformatics, Université libre de Bruxelles (ULB), Boulevard du Triomphe, CP206/02, B-1050 Brussels, Belgium.
Langmuir. 2020 Oct 13;36(40):12068-12076. doi: 10.1021/acs.langmuir.0c02681. Epub 2020 Oct 2.
Germanium is particularly suitable for the design of FTIR-based biosensors for proteins. The grafting of stable and thin organic layers on germanium surfaces remains, however, challenging. To tackle this problem, we developed a calix[4]arene-tetradiazonium salt decorated with four oligo(ethylene glycol) chains and a terminal reactive carboxyl group. This versatile molecular platform was covalently grafted on germanium surfaces to yield robust ready-to-use surfaces for biosensing applications. The grafted calixarene monolayer prevents nonspecific adsorption of proteins while allowing bioconjugation with biomolecules such as bovine serum albumin (BSA) or biotin. It is shown that the native form of the investigated proteins was maintained upon immobilization. As a proof of concept, the resulting calix[4]arene-based germanium biosensors were used through a combination of ATR-FTIR spectroscopy and fluorescence microscopy for the selective detection of streptavidin from a complex medium. This study opens real possibilities for the development of sensitive and selective FTIR-based biosensors devoted to the detection of proteins.
锗特别适合设计基于傅里叶变换红外光谱（FTIR）的蛋白质生物传感器。然而，在锗表面接枝稳定且薄的有机层仍然具有挑战性。为了解决这个问题，我们开发了一种四元瓜环-四氮杂卟啉盐，它带有四个聚乙二醇链和一个末端反应性羧基。这种多功能分子平台被共价接枝到锗表面，得到了用于生物传感应用的坚固的即用型表面。接枝的杯[4]芳烃单层可以防止蛋白质的非特异性吸附，同时允许与生物分子（如牛血清白蛋白（BSA）或生物素）进行生物偶联。研究表明，在固定化过程中保持了所研究蛋白质的天然形式。作为概念验证，通过衰减全反射傅里叶变换红外光谱（ATR-FTIR）光谱和荧光显微镜的组合，将所得的基于杯[4]芳烃的锗生物传感器用于从复杂介质中选择性检测链霉亲和素。这项研究为开发用于蛋白质检测的灵敏和选择性 FTIR 生物传感器开辟了真正的可能性。
