NIR Light-Degradable Antimony Nanoparticle-Based Drug-Delivery Nanosystem for Synergistic Chemo–Photothermal Therapy in Vitro

A novel drug-delivery nanosystem based on near-infrared (NIR) light-degradable antimony nanoparticles (AMNP) have been developed for synergistic chemo–phototherapy in vitro. The monodispersed AMNP were synthesized by using a simple and cost-effective method. Positively charged doxorubicin hydrochloride (DOX) was loaded onto the negatively charged surface of AMNP via electrostatic interaction and finally modified by polyacrylic acid (PAA) to enhance biocompatibility. Under NIR (808 nm) laser irradiation of the AMNP–DOX–PAA nanosystem, not only was high photothermal conversion efficiency of AMNP achieved but also pH-dependent DOX release was enhanced due to laser-induced hyperthermia. As a consequence, almost all of the HeLa cells (around 97%) were killed because of the combined effects of chemotherapy and photothermal therapy. More interestingly, AMNP showed very fast (about 10 min) laser-induced degradation that may help to minimize long-term toxicity after therapy by using same-wavelength NIR laser irradiation (808 nm). Computational total energy calculations and molecular dynamics simulations based on density functional theory (DFT) suggest that the NIR laser irradiation induces a photothermally activated reaction on the surface of AMNP in water, which can lead to surface degradation via the formation of Sb–H bonds first and then Sb–OH bonds upon further increase of temperature. This work demonstrates a simple platform that has potential applications for synergistic and highly effective chemo–photothermal therapy based on photodegradable nanoparticles.