A generic model for diffusive dynamics of the substrate and fluorescein tagged enzyme in microfluidic platform

The aim of this study was to develop a model that describes enzymatic conversion in a microfluidic system along with convective and diffusive transport of substrate/product within the microchannels. Hence, a 1-D partial differential equation model based on Fick's Law was employed in order to describe the substrate/product concentration distributions within the system. Enzyme immobilized in PEO-inclusive/non-inclusive TEOS-based hydrogels were tagged with fluorescein and examined under confocal laser scanning microscopy to evaluate the distribution of the enzyme. The image processing analysis demonstrated that 88.2 +/- 5.9% of the PEO-inclusive gel fragment surface (pixelated) area was occupied by the enzyme-dye complex with an emission density of 29.92 +/- 1.07. Subsequent to ensuring the homogeneity throughout the microchannel, the effects of flow rate and the distance for a range of inlet substrate concentrations were considered in regards to various substrate concentrations and conversion rates. The developed model provided a quantification for the conversion of substrate into products and enhanced understanding of the transport phenomena in the hydrogel.