Aqueous green synthesis of organic/inorganic nanohybrids with an unprecedented synergistic mechanism for enhanced near-infrared photothermal performance

Abstract

Silver sulfide (Ag₂S) nanoparticles (NPs) represent one of the most popular inorganic reagents for near-infrared (NIR) photothermal therapy (PTT). However, the extensive biomedical applications of Ag₂S NPs are greatly compromised by the hydrophobicity of the NPs prepared in organic solvents, their low photothermal conversion efficiency, certain surface modification-induced damage to their intrinsic properties and short circulation time. To develop a facile yet efficient green approach to overcome these shortcomings for improved properties and performance of Ag₂S NPs, we report herein the construction of Ag₂S@polydopamine (PDA) nanohybrids via a “one-pot” organic–inorganic hybridization strategy, which produces uniform Ag₂S@PDA nanohybrids with well-modulated sizes in the range of 100–300 nm via the self-polymerization of dopamine (DA) and subsequent synergistic assembly of PDA with Ag₂S NPs in a three-phase mixed medium containing water, ethanol and trimethylbenzene (TMB). Integration of dual photothermal moieties, i.e., Ag₂S and PDA at a molecular level, endows Ag₂S@PDA nanohybrids with synergistically enhanced NIR photothermal properties that are much better than those of either PDA or Ag₂S NPs due to calculated combination indexes (CIs) of 0.3–0.7 between Ag₂S NPs and PDA based on a modified Chou–Talalay method. Therefore, this study not only developed a facile “one-pot” green approach toward producing uniform Ag₂S@PDA nanohybrids with well-modulated dimensions, but also revealed an unprecedented synergistic mechanism for organic/inorganic nanohybrids that is based on dual photothermal moieties providing enhanced near-infrared photothermal performance.