A Synthetic Dynamic Polyvinyl Alcohol Photoresin for Fast Volumetric Bioprinting of Functional Ultrasoft Hydrogel Constructs

Abstract

Tomographic volumetric bioprinting (VBP) enables fast photofabrication of 3D cell-laden hydrogel constructs in one step, addressing the limitations of conventional layer-by-layer additive manufacturing. However, existing biomaterials that fulfill the physicochemical requirements of VBP are limited to photocurable protein derivatives. Reported here is the first synthetic resin composed of thiol-ene photo-clickable polyvinyl alcohol (PVA) for ultrafast VBP of defined 3D tissue models within 7-15 seconds. The incorporation of gelatin as a temporary thermo-reversible network allows VBP of perfusable hydrogels with PVA contents as low as 1.5%, providing a stress-relaxing environment for fast cell spreading and 3D growth of embedded human mesenchymal stem cells. Additionally, tomographic 4D photopatterning of a thiolated molecule of interest is demonstrated for site-specific immobilization of chemical cues within a pre-printed PVA hydrogel within seconds. Altogether, this study introduces a synthetic biomaterial enabling ultrafast VBP of functional hydrogel constructs with well-defined physicochemical properties with unprecedented efficiency.