Printable Polypeptide-Poly(ethylene glycol)-Polypeptide triblock copolymer hydrogels based on O-benzyl-L-serine and O-benzyl-L-tyrosine Building blocks

This study investigates the hydrogelation, injectability, and printability of polypeptide-poly(ethylene glycol)-polypeptide triblock copolymer hydrogels derived from poly(O-benzyl-_L-serine) (PBLS) and poly(O-benzyl-_L-tyrosine) (PBLY) peptide segments. Experimental results demonstrate that the sheet-like PBLS and PBLY segments effectively function as hydrogelators, facilitating hydrogel formation in aqueous solutions. Key parameters such as polymer chain length, block ratio, and sheet-like peptide assemblies significantly influence the molecular packing of the triblock copolymers and the resulting nano-/microstructures of the hydrogel networks, thereby modulating their mechanical properties. Among all the studied samples, the PBLS_6.5-PEG20000-PBLS_6.5 exhibits the best hydrogelation ability and mechanical property, highlighting the importance of the additional PEG chain entanglement. The d-spacing between peptide assemblies is found to be mainly dictated by PEG chain length. The as-prepared hydrogels exhibit exceptional shear-thinning behavior and rapid recovery, enabling high-fidelity patterning via direct-ink-writing printing (DIWP) technology. This study underscores the utility of PBLS and PBLY segments as hydrogelators when tethered to hydrophilic polymers like PEG. Furthermore, the as-prepared hydrogels, with superior mechanical properties, hold promise as inks for DIWP-based applications. Functional conjugation at the polymer chain ends offers potential for versatile applications in biomedical and engineering fields.