<p>Vat photopolymerization 3D printing provides new</p><p>opportunities for the fabrication of tissue scaffolds and medical</p><p>devices. However, it usually requires the use of organic solvents or</p><p>diluents to dissolve the solid photoinitators, making this process</p><p>environmentally unfriendly, and not optimal for biomedical</p><p>applications. Here, we report biodegradable liquid polymeric</p><p>photoinitiators for solvent-free 3D printing of biodegradable polymeric</p><p>materials by digital light processing. These photoinitiators enable</p><p>systematic investigation of structure-property relationship of 3D</p><p>printing polymeric materials without the interference from the reactive</p><p>diluents and offer new perspectives for the solvent-free 3D additive</p><p>manufacturing of bioresorbable medical implants as well as other</p><p>functional devices.</p>