Design of statistical copolypeptides as multipurpose hydrogel resins in 3D printing

Hydrogels possess desirable properties for the additive manufacturing of 3D objects, but a significant challenge is to expand the range of hydrogel feedstocks with defined molecular structure and functionality while retaining mechanical properties. To this end, the design of photopolymerizable copolypeptides, derived from linear or star-shaped architectures which can be tailored to provide control over mechanical properties and associated 3D printing performance, are reported. Based on hydroxy ethyl-L-glutamine and vinylbenzyl-L-cysteine residues, physical crosslinking via β-motif assembly is shown to afford hydrogels with viscoelastic properties that allow their use as resins for direct ink writing (DIW) and/or direct laser writing (DLW). The strategic incorporation of vinyl benzyl units permits rapid photocrosslinking of the self-assembled hydrogels leading to mechanically robust 3D objects. Significantly, copolypeptide architecture directly influences hydrogel resin viscosity, which affords materials with tailorable characteristics for different 3D printing techniques, highlighting the intrinsic versatility of these systems.