Sodium alginate hydrogel scaffolds with internal channels using 3D-printed polyvinyl alcohol (PVA) sacrificial molds

3D bioprinting of biomimetic tissue is critical for engineering artificial soft tissues and organs. However, the lack of simultaneously printed multiscale blood vessels within the scaffolds and the cell damage in the bioprinting nozzle decreased viability and limited the potential of printed tissues. This paper adopted 3D-printed sacrificial molds for the fabrication of hydrogel scaffolds with internal channels. The process fills slow-gelling sodium alginate into 3D-printed water-soluble PVA molds to create channels within the hydrogel. The results showed that hydrogel and crosslinker concentration have significant effects on gelation time, channel width, and scaffold compressive strength. Simulation results showed that both higher hydrogel and crosslinker concentrations contribute to higher residual stress within the scaffolds. This novel scaffold fabrication process has the potential for the vascularization of various organ and tissue models for tissue engineering applications.