Fig. 2

Examples of flow-free microfluidic devices. a Gradient generation in paper device; b analysis of the paper gradient using fluorescent dextran. False color images of the gradient at 0 and 20 min (left). Normalized pixel intensity analysis over the image from left to right for the gradient at 0 and 20 min (right). Reprinted with permission from [63]. Copyright (2015) American Chemical Society