Recent Progress in Nanogel Technology: From Molecular Design to Biomedical Applications

Nanogels, a hydrophilic polymer network at the nanoscale, combine the structural flexibility of hydrogels with the dynamic behavior of nanoparticles, offering unprecedented control over drug loading and release. Their large surface area, tunable porosity, high water content, biocompatibility, and stimuli-responsive behavior enable transport across biological barriers. This review critically examines nanogels’ unique properties, classifications, diverse methods of preparation, drug release mechanisms, characterization techniques, and various applications in therapeutic areas, such as cancer therapy, wound healing, transdermal and ocular drug delivery, and theranostics. Highlights are shed on nanogels’ potential to target specific sites, both by functionalization and stimuli-responsive behavior, therefore improving treatment safety and efficacy. Crosslinking complexity are thoroughly discussed, with critical comparison between the physically and chemically crosslinked types, as well as the challenges of characterization. Novel techniques such as microfluidics and photolithographic techniques are discussed for their role at achieving reproducible, scalable systems. By integrating insights from synthesis through clinical translation, this article offers thorough insights into the revolutionary potential of nanogel in transforming the medication delivery systems.