Microfluidic Slipchip-based Reaction Microarray with Dual Concentration Gradient

Microarray technology has attracted increasing attentions in the field of bioanalysis due to its advantages of high throughput and low sample and reagent consumptions. In this study, we developed a slipchip-based microfluidic system, in which sample and reagent could form two separate concentration gradients orthogonally. After sliding, samples and reagents of various concentrations could be mixed for multiplexed reactions. The performance of the developed microfluidic system was validated with food dyes and fluorescein. The reaction conditions involving β-galactosidase (β-gal) was investigated with the developed method. The solutions of 45 nM β-gal and 45 μM FDG (Fluorescein di-β-D-galactoside) were injected into the upper layer and lower layer of the slipchip respectively. After the formation of two concentration gradients, one-step sliding of the upper layer enabled mixing and reacting of the enzyme and the substrate with different concentrations. As a result, the amount of the reaction products increased with the increasing concentrations of substrate. At a given concentration of substrate, the amount of products rapidly reached a plateau with the increasing concentrations of enzyme. These results were consistent with those obtained using 384-well plate. This method was simple in operation with low consumption of sample and reagent, allowing rapid establishment of two orthogonal concentration gradients for multiplexed reactions.

The slipchip-based microfluidic system consists of two plates of PDMS/glass chips and a self-designed PMMA clip, in which sample and reagent could form two separate concentration gradients orthogonally in different planes. After sliding, samples and reagents of various concentrations could be mixed for multiplexed reactions.Figure optionsDownload as PowerPoint slide