Recent Advances in Responsive Microgels for Biomedical Application.

Responsive microgels have emerged as a versatile class of soft materials for biomedical applications owing to their tunable physicochemical properties, high water content, and ability to respond dynamically to external and biological stimuli. This review summarizes recent advances in the design, synthesis, and biomedical utilization of responsive microgels, with a focus on their functional roles across key application domains. First, the fundamental principles governing microgel responsiveness and structure-property relationships are briefly introduced. The application of responsive microgels in controlled drug delivery is then discussed, highlighting stimulus-triggered release mechanisms, payload protection, and spatiotemporal control of therapeutic delivery. Advances in tissue engineering are reviewed with emphasis on microgel-based scaffolds, injectable constructs, and cell-matrix interactions that promote tissue regeneration. The use of microgels in biomedical imaging is examined, including their roles as contrast agents, signal amplifiers, and carriers for imaging probes. Finally, recent developments in microgel-enabled diagnostics are presented, showcasing their utility in biosensing, biomarker detection, and point-of-care platforms. The literature was selected based on the authors' expertise, focusing on representative and recent studies, and identified through general academic databases and key references. Collectively, this review provides a comprehensive overview of the multifunctional capabilities of responsive microgels and discusses current challenges and future opportunities toward their clinical translation.