3D Printed Hydrogels: Engineering the Properties and Performance via Side Chain Design of Block Co-Polypeptides Stars

Polypeptide-based hydrogels are of increasing importance due to their intrinsic biodegradability and tunable functionality that make them desirable for biological applications. While mechanical stability and shear processing properties has been demonstrated in many extrusion-based applications, ranging from injectable therapeutic carriers to recent 3D printing of living materials, probing the relationship between polypeptide structure and self-assembly has not been well studied. Herein we describe the synthesis and properties of a library of amphiphilic block-co-polypeptide stars with various canonical and non-canonical amino acid building blocks. Structure-function relationships were characterized using various rheological and scattering techniques to elucidate design rules for 3D printing. Significantly, non-natural amino acid building blocks were observed to form more stable networks with superior material properties compared to their natural analogs. The rational design of these materials provides a novel strategy for accessing tunable material properties based on molecular design that further expand the palette of 3D printable biomaterials.