Hydrogel-based Janus Structures for Asymmetrical Aster Nucleation

Microtubule networks control the spatial and temporal dynamics of a host of cellular processes including motility and division. These networks are nucleated at centrosomes anchored to the nuclear membrane. The distribution and density of centrosomes are therefore hypothesized to influence cellular function. This talk describes the production of immobilized and mobile hydrogel structures to serve as sites for the nucleation of microtubule asters. The surfaces of these structures have been asymmetrically decorated with beads which serve as surrogates for artificial centrosomes through a combination of microfabrication technologies. To create mobile-phase Janus particles, aspiration-driven microfluidic devices were used to precisely meter and spatially locate fluids and beads within droplets, which were crosslinked to form hydrogel microspheres. Oxygen inhibition of the free radical polymerization reaction was exploited to expose fluorescent beads upon a single hemisphere of the particle surface. We hypothesize that in future work these droplets may be used to organize microtubule asters at the droplet surfaces. This experimental platform holds broad utility for fundamental studies that will elucidate mechanisms by which microtubule asters regulate cell motility, cell organization, and cell division.