Efficient In Situ Nucleophilic Thiol-yne Click Chemistry for the Synthesis of Strong Hydrogel Materials with Tunable Properties.

Synthetic hydrogel materials offer the ability to tune the mechanical properties of the resultant networks by controlling the molecular structure of the polymer precursors. Herein, we demonstrate that the nucleophilic thiol-yne click reaction presents a highly efficient chemistry for forming robust high water content (ca. 90%) hydrogel materials with tunable stiffness and mechanical properties. Remarkably, optimization of the molecular weight and geometry of the poly(ethylene glycol) (PEG) precursors allows access to materials with compressive strength up to 2.4 MPa, which can be repeatedly compressed to >90% stress. Beyond this, we demonstrate the ability to access hydrogels with storage moduli ranging from 0.2 to 7 kPa. Moreover, we also demonstrate that by a simple precursor blending process, we can access intermediate stiffness across this range with minimal changes to the hydrogel structure. These characteristics present the nucleophilic thiol-yne addition as an excellent method for the preparation of hydrogels for use as versatile synthetic biomaterials.