Direct Laser Writing of Selectively Degradable Polypeptide Hydrogel Microstructures by Proteolytic Enzymes

The discovery of materials with on-demand, tunable degradability is of significant utility for (micro)structures generated through additive manufacturing techniques. Disclosed here are a series of star polypeptide cross-linkers comprising either l-lysine alone or l-lysine and l-alanine residues for use in direct laser writing of hydrogel microstructures, which are selectively degradable via intrinsic amino acid affinities to different proteolytic enzymes. Through multimaterial printing, direct laser writing permitted the formation of microstructural topographies through free radical polymerization of formulated polypeptide cross-linkers and commercial photoresists, whereby sections of the microstructures could undergo selective degradation in the presence of target proteases, thermolysin, and trypsin.