Figure 3.

Schematic representation of photosensitive hydrogel. After exposure to light, the formulation suffers a chemical and/or physical alteration including (A,B) photoclevage, (C) photoisomeration, and (D) photo-thermal transition. In the case of photo-thermal transition, the increase in the temperature promoted by the activation of photo-thermal agents could lead to a sol-to-gel or a gel-to-sol transition, accordingly the nature of the thermo-responsive polymer. The red circles represent the drugs loaded in the hydrogels. Created with BioRender.com (accessed on 15 January 2021).