Cell-Laden Particulate-Composite Hydrogels with Tunable Mechanical Properties Constructed with Gradient-Interface Hydrogel Particles

Hydrogels have long been studied as cell encapsulants for engineered tissue, yet diffusive limitations, suboptimal mechanical properties, and poor cell distribution limit the use of single-phase hydrogels for complex tissues scaffolds. Here, a composite hydrogel structure is presented to overcome these limitations. It is shown that oxygen inhibition during chain-growth photopolymerization of microgel particles can be used to directly manipulate the interfacial bond strength between two hydrogel interfaces in the particulate-composite hydrogels. Using this principle, a cell-laden particulate-composite hydrogel is fabricated that overcomes the low cell viability of a single-phase hydrogel, while allowing the stiffness to be arbitrarily tuned.