Microfluidic Synthesis of Micrometer-size Collagen Hydrogel Particles for Cell Manipulation Applications

In this paper, we present a microfluidic system to produce micrometer-size collagen hydrogel particles. Aqueous droplets containing collagen molecules were generated in the continuous phase of a polar organic solvent at a microchannel junction, and then, collagen molecules were concentrated by the dehydration of the droplets. The collagen molecules in the shrunk droplets were chemically cross-linked, forming collagen hydrogel particles with sizes of 10~20 !m. As a biological application of the obtained particles, heterogeneous spheroids made of cells and magnetic beads-incorporated collagen particles were formed by incubating them in non-adhesive hydrogel microwells, and the formed cell-particle complexes were manipulated and recovered by applying a magnetic field. The presented collagen particles would be useful as functional materials for cell manipulation and tissue engineering applications.