Chitosan Hydrogel Equipped With Hollow Copper Sulfide/Polydopamine Nanoparticles for Near‐Infrared/pH Dual‐Responsive Drug Delivery

ABSTRACT In recent years, the remotely multi‐responsive chitosan (CS) hydrogel has been garnering extensive attention owing to its remarkable potential in biomedical applications. Meanwhile, it presents a wide range of uses in the realm of controlled drug delivery and photothermal chemical combination therapy. In this paper, the CS/β‐glycerophosphate disodium salt (β‐GP) physical crosslinked network was employed as the framework to encapsulate near‐infrared (NIR) responsive hollow copper sulfide (CuS)/polydopamine (PDA) nanoparticles, and the NIR/pH synergistic responsive CS/CuS/PDA hydrogel was fabricated. The negatively charged β‐GP, along with the hollow CuS/PDA nanoparticles, played a key role in promoting the creation of abundant electronegative cavities. As a result, the hybrid hydrogel achieved an impressively high DOX loading rate, reaching up to 95.5%. The CS/CuS/PDA hydrogel exhibits excellent pH responsiveness, which could be attributed to the disintegration of the CS/β‐GP network under acidic buffer solution. In addition, hollow CuS/PDA nanoparticles embedded in the hydrogel endow the hydrogel with excellent NIR photothermal responsiveness, which significantly promotes the release of DOX. Consequently, the CS/CuS/PDA hydrogel reveals excellent synergistically enhanced NIR, pH, and thermal triple‐responsiveness, indicating its tremendous promise in the field of controlled drug release.