Anderson Aaron S, Dattelbaum Andrew M, Montaño Gabriel A, Price Dominique N, Schmidt Jurgen G, Martinez Jennifer S, Grace W Kevin, Grace Karen M, Swanson Basil I
Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
Langmuir. 2008 Mar 4;24(5):2240-7. doi: 10.1021/la7033438. Epub 2008 Jan 30.
We report a general procedure to prepare functional organic thin films for biological assays on oxide surfaces. Silica surfaces were functionalized by self-assembly of an amine-terminated silane film using both vapor- and solution-phase deposition of 3'-aminopropylmethyldiethoxysilane (APMDES). We found that vapor-phase deposition of APMDES under reduced pressure produced the highest quality monolayer films with uniform surface coverage, as determined by atomic force microscopy (AFM), ellipsometry, and contact angle measurements. The amine-terminated films were chemically modified with a mixture of carboxylic acid-terminated poly(ethylene glycol) (PEG) chains of varying functionality. A fraction of the PEG chains (0.1-10 mol %) terminated in biotin, which produced a surface with an affinity toward streptavidin. When used in pseudo-sandwich assays on waveguide platforms for the detection of Bacillus anthracis protective antigen (PA), these functional PEG surfaces significantly reduced nonspecific binding to the waveguide surface while allowing for highly specific binding. Detection of PA was used to validate these films for sensing applications in both buffer and complex media. Ultimately, these results represent a step toward the realization of a robust, reusable, and autonomous biosensor.
我们报道了一种制备用于氧化物表面生物测定的功能性有机薄膜的通用方法。通过使用3'-氨丙基甲基二乙氧基硅烷（APMDES）的气相和溶液相沉积，通过胺基封端的硅烷膜的自组装对二氧化硅表面进行功能化。我们发现，通过原子力显微镜（AFM）、椭偏仪和接触角测量确定，在减压下APMDES的气相沉积产生了具有均匀表面覆盖率的最高质量的单层膜。用不同功能的羧酸封端的聚乙二醇（PEG）链的混合物对胺基封端的膜进行化学修饰。一部分PEG链（0.1-10 mol%）以生物素封端，这产生了对链霉亲和素具有亲和力的表面。当用于波导平台上的伪夹心测定以检测炭疽芽孢杆菌保护性抗原（PA）时，这些功能性PEG表面显著降低了与波导表面的非特异性结合，同时允许高度特异性结合。PA的检测用于验证这些薄膜在缓冲液和复杂介质中的传感应用。最终，这些结果代表了朝着实现一种坚固、可重复使用和自主的生物传感器迈出的一步。
