Stimulus responsive nanogels for drug delivery

TLDR

Stimulus‑responsive nanogels are polymeric nanoparticles that alter properties such as volume, permeability, and hydrophilicity in response to external stimuli, enabling high‑stability, prolonged circulation, and site‑specific drug release. This article reviews recent advances in preparing and applying nanogels that respond to temperature, pH, light, magnetic fields, biomolecule recognition (e.g., glucose‑responsive insulin delivery), and multi‑stimuli. The authors describe preparation strategies and application approaches for nanogels that react to small temperature and pH changes, light, magnetic fields, biomolecule recognition, and combinations of these stimuli. They also discuss the current limitations of stimulus‑responsive nanogels and propose directions for future improvement.

Abstract

Stimulus responsive nanogels are polymeric nanoparticles which are capable of responding to external stimuli by changing their physico-chemical properties, such as volume, water content, refractive index, permeability, and hydrophilicity–hydrophobicity. Compared with other polymer nanoparticles used for drug delivery, stimulus responsive nanogels are noted for their ability to encapsulate bioactive drugs, their high stability for prolonged circulation in the blood stream, and their controlled release and site-specific targeting of loaded drugs modulated by environment stimuli. Particularly, the application of stimulus responsive nanogels provides an interesting opportunity for drug delivery in which the delivery system becomes an active participant, rather than a passive carrier, in the optimization of disease therapy. In this article, the authors review the recent developments in the preparation and application in drug delivery of stimulus responsive nanogels which can respond to small temperature and pH changes, light, magnetic field, biomolecule recognition (specifically glucose responsive nanogels for insulin delivery), and multi-responsive nanogels. The limitations and future improvements of stimulus responsive nanogels are also discussed.