Supramolecular assemblies of multifunctional microgels for biomedical applications

Biomedical materials with outstanding biochemical and mechanical properties have great potential in tissue engineering, drug delivery, antibacterial, and implantable devices. Hydrogels have emerged as a most promising family of biomedical materials because of their high water content, low modulus, biomimetic network structures, and versatile biofunctionalities. It is critical to design and synthesize biomimetic and biofunctional hydrogels to meet demands of biomedical applications. Moreover, fabrication of hydrogel-based biomedical devices and scaffolds remains a great challenge, largely due to the poor processibility of the crosslinked networks. Supramolecular microgels have emerged as building blocks for fabrication of biofunctional materials for biomedical applications due to their excellent characteristics, including softness, micron size, high porosity, heterogeneity and degradability. Moreover, microgels can serve as vehicles to carry drugs, bio-factors, and even cells to augment the biofunctionalities to support or regulate cell growth and tissue regeneration. This review article summarizes the fabrication and the mechanism of supramolecular assemblies of microgels, and explores their application in 3D printing, along with detailed representative biomedical applications of microgel assemblies in cell culture, drug delivery, antibacterial and tissue engineering. Major challenges and perspectives of supramolecular microgel assemblies are presented to indicate future research directions.