Functional oligo(ethylene glycol) methacrylate copolymers enabling combined thermal and photocrosslinking for additive manufacturing of thermoresponsive soft biomaterials.

Thermogelling materials are attractive candidates for advanced biofabrication and 4D printing. However, achieving materials that combine reversible thermal responsiveness with sufficient mechanical stability and compatibility with multiple additive manufacturing techniques remains an important challenge. To address this limitation, we synthesized POEGMA-based diblock copolymers with pendant amine groups, capable of temperature-induced physical gelation with additional chemical crosslinking to produce structurally stable inks for advanced printing applications. The diblock copolymers (P(A(+)O)-b-PD or P(AO)-b-PD) consisted of a shorter block with randomly distributed units of 2-aminoethyl methacrylate (in A(+)NH3+ and A NH2 form) and oligo(ethylene glycol) methacrylate (O) and a longer block of poly[di(ethylene glycol) methacrylate] (D). The presence and ionization state of amine groups as well as polymer concentration were found to influence thermogel formation and rheological behavior. Thermogels were additionally chemically crosslinked using poly(ethylene glycol) diacrylate and N,N'-methylenebisacrylamide by photo-induced radical crosslinking coupled with nucleophilic amine addition. Rheological analysis confirmed shear-thinning behavior, suitable viscoelastic properties and rapid structural recovery, enabling extrusion-based 3D printing. In addition, the materials were successfully processed into well-defined structures by volumetric additive manufacturing (VAM), demonstrating their versatility across multiple additive manufacturing platforms. Temperature-induced swelling-deswelling cycles revealed the responsiveness of the constructs, demonstrating characteristics that may be beneficial for the future development of 4D printed thermoresponsive materials. In vitro studies supported cytocompatibility of the material toward fibroblasts and keratinocytes, which maintained cell viability within the gel matrix. Overall, the obtained results highlight that the incorporation of functional amine groups into diblock copolymers enhances thermogel strength and expands the design space of POEGMA-based materials, especially toward advanced manufacturing techniques for biomedical applications.