Fabrication of Mechanically Reinforced Photo-Cross-linked Hydrogels with Steep Post-Gelation Threshold Curing via Vinylated Self-Assembling Peptides.

Abstract

Tomographic volumetric 3D printing (TVP) enables the ultrafast, layer-free fabrication of hydrogel devices. However, its widespread application is hindered by insufficient curing within the narrow light-dose processing window, which ultimately compromises the fidelity and stability of the printed hydrogels. To address this challenge, we introduce a peptide self-assembly-mediated polymerization strategy to engineer mechanically reinforced hydrogels that exhibit steep curing immediately following the gelation threshold. In our approach, vinylated self-assembling peptides (vSAPs) are conjugated to tetra-arm polyethylene glycol macromers (vSAP-macromers). The self-assembly of vSAP-macromers induces nanoscale spatial confinement of vinyl groups, which substantially shortens the diffusion distance for radical propagation. Consequently, vSAP-macromers exhibit steep conversion and rapid network formation once the light dose exceeds the polymerization threshold. Moreover, the incorporation of vSAPs induces a potential nanoreinforced network, leading to substantial mechanical reinforcement. Owing to these features, vSAP-macromers ensure the in-process stability of hydrogel constructs under restricted light doses. Consequently, this leads to improvements in both the printing fidelity and mechanical performance of the final TVP-fabricated hydrogels. Collectively, this work offers a generalizable design framework for tailoring high-performance hydrogels for TVP and a solution to resolve the polymerization kinetic mismatch in hydrogel volumetric printing.