Fabrication of Microfluidic Devices and their Applications in Chemical and Biological Analysis

Microfluidic technologies are emerging as powerful tools for biological studyincluding tissue, single cell or even single molecule level analysis in parallel. A smallvolume reaction and delivery not only enhances the speed of analyses but also enablesthe high throughput in automation form. Regarding of the superior of microfluidicsapplied in biological study, my PhD work focus on developing new microfluidicdevices to study cell mechanics, subcellular level bio-detection, and new methods tofabricate 2D or 3D scaffolds for tissue engineering, which can be applied in biologicalstudy.;In this thesis, we first develop a Teflon-base lithography method, which enablesthe fabrication of either organic or inorganic materials in sub-micron level. We adoptthe Teflon-based lithography method to pattern microgrooves of drug-laden poly(lactic-co-glycolic acid) (PLGA), which can be used for engineered tendon-repairtherapeutics. Furthermore, we employ one Teflon series polymer-perfluoropolyether (PFPE) to encapsulate single-cells in each PFPE microcapsules. These PFPEmicrospheres can serve as robust and inert nanoliter reactors for single-cell analysis.;In the second part, we develop a convenient miniaturized 3D platform whichcould allow high-throughput analysis of the effects of mechanical strain. Wedemonstrate the capability of this array of microlenses as a general platform forstudying the influence of mechanical strain on adherent cells by using NIH 3T3fibroblasts and HeLa cells as our models.;In the last part, we explore novel methods to fabricate complex 3Dmicrostructures. We first demonstrate one-step direct molding method to fabricate 3Dmicrostructure using the cracked PDMS master. We also present a direct-writingstrategy to fabricate 1D and 3D vascular--like microchannels with micropatternedsurface in hydrogels. Our methods for fabricating complex 3D microstructures mayfind application in tissue engineering.