Hydrogel microspheres for precision biomedicine: network engineering, microfabrication, and therapeutic applications.

Hydrogels and hydrogel microspheres have emerged as highly adaptable biomaterial platforms for precision biomedicine, owing to their hydrated polymer networks, tissue-like physicochemical properties, and capacity to host drugs, biomacromolecules and living cells. In particular, hydrogel microspheres extend the utility of bulk hydrogels by introducing injectability, large interfacial area, modular assembly, tunable microporosity and spatially programmable microenvironments. These features make them attractive for localized drug delivery, cell transplantation, tissue regeneration and emerging therapeutic systems. In this review, we summarize the major physical and chemical strategies used to construct hydrogel networks, and compare representative fabrication methods for hydrogel microspheres, including emulsion polymerization, electrospraying, microfluidics and photolithography. We further discuss how network chemistry, particle geometry, fabrication precision and microsphere assembly influence cargo loading, release behavior, cell compatibility, mechanical performance and