Health & Environment Department, Nano Systems, AIT Austrian Institute of Technology GmbH, Donau-City-Strasse, Vienna, Austria.
Anal Chim Acta. 2011 Aug 12;699(2):206-15. doi: 10.1016/j.aca.2011.05.017. Epub 2011 May 20.
The process of surface functionalization involving silanization, biotinylation and streptavidin bonding as platform for biospecific ligand immobilization was optimized for thin film polyimide spin-coated silicon wafers, of which the polyimide film serves as a wave guiding layer in evanescent wave photonic biosensors. This type of optical sensors make great demands on the materials involved as well as on the layer properties, such as the optical quality, the layer thickness and the surface roughness. In this work we realized the binding of a 3-mercaptopropyl trimethoxysilane on an oxygen plasma activated polyimide surface followed by subsequent derivatization of the reactive thiol groups with maleimide-PEG(2)-biotin and immobilization of streptavidin. The progress of the functionalization was monitored by using different fluorescence labels for optimization of the chemical derivatization steps. Further, X-ray photoelectron spectroscopy and atomic force microscopy were utilized for the characterization of the modified surface. These established analytical methods allowed to derive information like chemical composition of the surface, surface coverage with immobilized streptavidin, as well as parameters of the surface roughness. The proposed functionalization protocol furnished a surface density of 144 fmol mm(-2) streptavidin with good reproducibility (13.9% RSD, n=10) and without inflicted damage to the surface. This surface modification was applied to polyimide based Mach-Zehnder interferometer sensors to realize a real-time measurement of streptavidin binding validating the functionality of the MZI biosensor. Subsequently, this streptavidin surface was employed to immobilize biotinylated single-stranded DNA and utilized for monitoring of selective DNA hybridization. These proved the usability of polyimide based evanescent photonic devices for biosensing application.
涉及硅烷化、生物素化和链霉亲和素键合的表面功能化过程被优化用于薄膜聚酰亚胺旋涂硅片，其中聚酰亚胺膜在渐逝波光子生物传感器中用作波导层。这种光学传感器对所涉及的材料以及层特性（如光学质量、层厚度和表面粗糙度）有很高的要求。在这项工作中，我们实现了将 3-巯丙基三甲氧基硅烷键合到氧等离子体激活的聚酰亚胺表面上，然后用马来酰亚胺-PEG(2)-生物素对反应性硫醇基团进行衍生化，并固定链霉亲和素。通过使用不同的荧光标记物来优化化学衍生化步骤，监测了功能化的进展。此外，还利用 X 射线光电子能谱和原子力显微镜对修饰表面进行了表征。这些建立的分析方法允许得出关于表面化学组成、固定化链霉亲和素的表面覆盖率以及表面粗糙度参数等信息。所提出的功能化方案提供了 144 fmol mm(-2)的链霉亲和素表面密度，具有良好的重现性（13.9%RSD，n=10），并且不会对表面造成损伤。这种表面修饰被应用于基于聚酰亚胺的马赫-曾德尔干涉仪传感器，以实现对链霉亲和素结合的实时测量，验证了 MZI 生物传感器的功能。随后，将该链霉亲和素表面用于固定生物素化的单链 DNA，并用于监测选择性 DNA 杂交。这些证明了基于聚酰亚胺的渐逝光光子器件在生物传感应用中的可用性。
