Microgel particles for use in a three-dimensional cell growth medium are described. The microgel particles may be swellable and may have properties conducive to improved function and health of cells distributed within the three-dimensional cell growth medium. Related compositions, systems, and methods are also described. Also provided is a plurality of microgel particles and a liquid cell culture medium, wherein the microgel particles are swelled with the liquid cell culture medium to form a granular gel. Also provided is a method of preparing a three-dimensional cell growth medium is disclosed. The method may comprise: mixing a plurality of microgel particles, such as those described above, in a liquid cell culture medium. Also provided is a method of placing cells in a three-dimensional cell growth medium is disclosed. Also provided is a method of synthesizing a protein is disclosed.