Multicellular spheroids formation and recovery in microfluidics-generated thermoresponsive microgel droplets

Abstract

Multicellular spheroids (MCSs) have a unique structure to represent the in vivo tissues and they have many potential applications, such as in drug screening and evaluation. Traditional methods of fabricating MCSs are incapable of controlling the MCS size and size distribution. For MCS formation in the ion- or photo-crosslinked hydrogel, recovery of MCSs from these hydrogels may need strong chemicals or enzymes to break the crosslinked network for release of MCSs. We are the first to develop a microfluidic approach to encapsulate Hela cells in thermoresponsive microgel-based droplets to generate Hela MCSs. The microgel network provided a physical scaffold for cells so that cell aggregates formed in a biomimicking condition. Due to the thermal reversibility of microgels, MCSs were released and harvested from the microgels droplets by simply cooling the droplets down to room temperature. This approach may open a new door for generating uniform-sized MCSs.