Polysarcosine as a PEG Alternative Feedstock for 3D Digital Light Processing of Tunable Biocompatible Hydrogels.

In this contribution, a series of 4-arm and 8-arm star-shaped polysarcosine methacrylates (4-PSar-MA and 8-PSar-MA) macromers were developed through controlled ring-opening polymerization of sarcosine N-carboxyanhydride (NCA) followed by terminal methacrylation. Photorheological analysis of these well-defined macromers demonstrated rapid light-induced gelation and tunable viscoelastic behavior, with controllable swelling and compression properties, revealing topology-dependent mechanical tunability. The 4-PSar-MA resin could readily produce high-fidelity 3D hydrogel constructs via digital light processing (DLP) 3D printing, including complex geometries such as a panda, a chess rook, and a 3DBenchy boat, with smooth interfaces and features. Encapsulated MC3T3 preosteoblasts maintained high viability under in situ photo-cross-linking, confirming cytocompatibility of the PSar-based matrix. Collectively, this work introduces the first photocurable star-polysarcosine system for DLP 3D printing, providing a chemically defined and structurally tunable hydrogel platform for advanced soft-material and biomedical applications.