Numerical Characterization and Experimental Optimization of Microfluidic DNA Microarray Hybridization

Background/Objectives: Mathematical modelling and computational simulation are important tools in the analysis of transport phenomena and surface reactions. These include surface hybridization that takes place in a microfluidic channel, creating a DNA microarray. Methods: In this work, the surface hybridization with multiple DNA probe spots immobilized on the bottom of a microfluidic channel was investigated using computational modelling. The model incorporates the 2D transport process, coupled with convective/diffusive mass transport (infinite dilution) and surface binding models for both non-specific adsorption and specific hybridization. Results: Hybridization signals obtained at different reaction times, various flow rates, and two different channel depths were analyzed, targeting enhanced surface hybridization while minimizing assay time and sample usage. It was found that a high aspect ratio (width/height) channel geometry with electrodes placed on the top and bottom walls would enable significantly improved fuel utilization and reduced inter-diffusional mixing width. Conclusions: The numerical study also suggested the implementation of a tapered electrode design that accommodates the growth of the co-laminar mixing zone in the downstream direction.