Fig. 5

Examples of gel-based devices. A The device schematics of the 3D microfluidic chemotaxis device. The device consisted of four three-channel units. Cells and collagen were injected into the center channel together. The chemical gradient was generated in the center channel by introducing media containing different concentration chemoattractant through the two side channels. (Figure reproduced from Ref. [42]); B Schematic of gel-based neutrophil TEM microfluidic device. Endothelial cells are cultured on the side wall of the collagen gel, and the chemical gradients are developed by placing the chemoattractant solution or medium on the side channels. Neutrophils will across the endothelial cell layer and move towards the chemoattractant source as the black arrow. Reprinted from Ref. [41], Copyright (2015), with permission from The Royal Society of Chemistry