Integration of a microfluidic chip with multiplexed optical fluorescence detector through anisotropic etching of Si using Tetramethylammonium hydroxide (TMAH)

Point of care testing (POCT) systems, are widely used to firstly, diagnose and secondly, monitor a number of illnesses and infectious diseases. This research aims to develop the integration between an optical fluorescence system and a microfluidic chip - through the use of advanced manufacturing techniques, such as anisotropic wet etching of Silicon (Si) wafers. The fabricated Si microfluidic chips may integrate into an existing POCT system and provide a potential avenue into multiplexed detection. Zemax and OptiCAD simulation packages were used to confirm the validity of the integrated microfluidic chip design. A testable microfluidic chip, using anisotropic wet etching of a Si wafer by Tetramethylammonium hydroxide (TMAH) etching solution, was fabricated. The process used a mask-less photoresist design, allowing for an easier and cost effective developmental stage in order to provide a proof of concept design. Currently, the TMAH etching process provides the required 370μm etch depth, to house a micro-capillary.