A Polydopamine Nanoparticle-Knotted Poly(ethylene glycol) Hydrogel for On-Demand Drug Delivery and Chemo-photothermal Therapy

Hydrogels have exhibited remarkable benefits in drug delivery such as local delivery, days or even weeks of continuous drug release with improved bioavailability, and minimized adverse effects. Here we report a polydopamine (PDA) nanoparticle-knotted poly(ethylene glycol) (PEG) hydrogel for on-demand drug delivery and combined chemo-photothermal therapy. Anticancer drugs such as 7-ethyl-10-hydroxycamptothecin (SN38) loaded on PDA nanoparticles via π–π interaction in the gel exhibit minimal leakage at physiological conditions and could be released in an on-demand fashion upon near-infrared light exposure. The hydrogel shows excellent biocompatibility and does not induce any foreign-body reaction over a four-month implantation. The in vivo results demonstrate that the PDA nanoparticle-knotted PEG hydrogel loaded with SN38 could efficiently suppress tumor growth by a combined chemo-photothermal therapy. This smart hydrogel would benefit a series of local treatments for diverse diseases.