Enhancing the Mechanical Properties of Microgels through Interstitial Matrix Addition in 3D Printing

Microgels have excellent biocompatibility and tunable physicochemical properties but poor mechanical properties that severely limit their application. In this study, a strategy is developed to synergistically enhance the mechanical properties of microgels by absorbing secondary cross-linked hydrogel precursor solution and adding an interstitial matrix. The results show that PEGDA-NAGA microgels enhanced by an interstitial matrix exhibit excellent mechanical properties, with a tensile breaking stress up to 0.7 MPa and tensile breaking strain up to 120%, improving the performance of conventional microgels. Furthermore, the microgel ink viscosity increases 10-fold and significantly improves printing fidelity. The mechanical properties of the printing ink can be flexibly regulated by adjusting the type of hydrogel precursor solution and interstitial matrix addition. This flexible and versatile method improves the mechanical properties 5-fold. The modular cross-linking method provides an approach to microgel ink development and offers broad application prospects in tissue engineering and regenerative medicine.