Fabrication Of Protein Microarray PDMS Chips With3-D Micro/nano Surface Structure

Protein microarray technology plays an important role in proteomics research. It can determinate protein activity, function, and their interactions in high throughput. In recent years, a variety of protein microarray substrate material and protein immobilization technology have been developed in order to increase the protein adsorption capacity and stability, thereby increasing the detected signal and sensitivity.Polydimethylsiloxane (polydimethylsiloxane, PDMS) which is an elastical polymer material with good biocompatibility, transparency and permeability, featuring cost-effective, easy to be fabricated, has been widely used for the fabrication of microfluidic chips and DNA microarray in recent years. PDMS is an ideal material for the fabrication of protein microarrays duo to its surface hydrophobicity and easily protein absorption. Especially, it can be used for high-sensitivity fluorescence detection duo to its low fluorescence background compared to other polymer material such as polystyrene (PS). To further enhance the PDMS protein adsorption capacity, a variety of physical or chemical surface modification technologies have been established. Changing the surface morphology of substrate, hence gaining high surface-area, is one of effective method. This work aims to fabricate PDMS substrate with three-dimensional (3-D) micro-nano structures and build efficient protein microarray chip through the combination of wet chemical etching and soft lithography technology.In chapter1, the progress in microfluidic immunoassay systerms and the method for fabrication of micro-nano structure on chips, is reviewed. The former includes homogeneous immunoassay and heterogeneous immunoassay, while latter includes wet etching, dry etching, anodic oxidation, synthesis, and natural template method.In chapter2, a simple, rapid and effective method for fabrication of protein microarray PDMS chips is established. PDMS substrates with three-dimensional (3-D) micro/nano structure were directly replicated by soft lithography using glass templates which was achieved by HF chemical etching. Antibodies were then immobilized onto the surface of the PDMS substrates via physical adsorption, forming the protein microarray PDMS chips with3-D micro/nano structured surface. The topographic property of glass templates and PDMS substrates were characterized by CCD image, scanning electron microscopy (SEM) and atomic force microscopies (AFM). The effect of topography on the adsorption of protein was studied. It was found that protein adsorption on such substrates significantly enhanced with the increase of roughness of the PDMS surface due to the increase of surface area.. The prepared PDMS substrate was successfully used for microarray immunoassay. The results of immunassay showed that sensitivity on PDMS substrate with3-D micro/nano structure was5times higher than that on the flat PDMS.