Multi-layer microfluidic device was integrated with out-of-plane optical fiber bridge in order to create multiple excitation and detection spots with single excitation source and single detector. A multimode optical fiber was inserted through a ~5mm thick layer of polydimethyl siloxane (PDMS) such that vertical gap between detection channel and fiber cross section was 30μm. Excitation laser was focused through microscope objective and shined on the first detection spot. Bridge configuration was then used to transmit light and excite the second spot. Optical tunneling mode was then used to split second detection spot in to another two excitation lines. Ability of using tunneling mode to accurately measure particle/ cell velocity and size discrimination of 5μm, 7μm and 10 μm particles were demonstrated. This technique was further advanced to monitor fluorescent labeled T-lymphocytes which were automatically transported and lysed in the presence of electric field across separation channel. Furthermore, this set up was used to determine lysing/injection efficiency coefficient (K) by monitoring signals from intact cell and lysate. Ability of using K in order to reliably determine the injection amount was demonstrated.<br/>

Integration of out-of-plane optical fiber for multipoint detection in microfluidic platforms and using fiber tunneling mode for particle/cell counting, velocimetry and size discrimination

253rd National Meeting (2017)

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