Large‐Scale Dried Reagent Reconstitution and Diffusion Control Using Microfluidic Self‐Coalescence Modules

The positioning and manipulation of large numbers of reagents in small aliquots are paramount to many fields in chemistry and the life sciences, such as combinatorial screening, enzyme activity assays, and point‐of‐care testing. Here, a capillary microfluidic architecture based on self‐coalescence modules capable of storing thousands of dried reagent spots per square centimeter is reported, which can all be reconstituted independently without dispersion using a single pipetting step and ≤5 μL of a solution. A simple diffusion‐based mathematical model is also provided to guide the spotting of reagents in this microfluidic architecture at the experimental design stage to enable either compartmentalization, mixing, or the generation of complex multi‐reagent chemical patterns. Results demonstrate the formation of chemical patterns with high accuracy and versatility, and simple methods for integrating reagents and imaging the resulting chemical patterns. Complex chemical patterns are generated by spotting reagents and reconstituting them in large‐scale arrays of microfluidic “self‐coalescence modules.” The experimental and theoretical data demonstrate that thousands of dried reagents can be reconstituted using a single pipetting step, kept separate from each other, mixed or used to form gradients with precise spatiotemporal control.