Recent advances in smart responsive hydrogel microspheres for tissue regeneration: preparation, characteristics and applications

The tissue engineering strategy represents a balanced and dynamic approach that utilizes various tissue cells, bio-scaffolds and bio-agents (such as cells and drugs) to facilitate tissue repair and regeneration. Hydrogel microspheres (HMS), distinguished by their unique micrometer-scale spherical architecture featuring high specific surface area, high porosity, and low invasiveness, coupled with advantageous biochemical properties including biocompatibility, biodegradability, hydrophilicity, and lubricity, are regarded as promising bio-scaffolds in tissue engineering. Notably, smart responsive hydrogel microspheres (SRHMS) can intelligently release bio-agents to actively promote tissue regeneration in response to internal or external stimuli, in a spatiotemporally controlled manner. As a result, SRHMS have attracted escalating attention for their application potential in tissue engineering. This review summarizes recent advancements in SRHMS applications within tissue engineering, emphasizing their fabrication processes, functional characteristics, and therapeutic applications across diverse domains such as bone, cartilage, skin, nerve, and cardiac tissue engineering.