We report on dopamine-conjugated hyaluronic acid (HA-D), a mussel-inspired facile capping material that can modify tungsten oxide (WO3) nanoparticles to be both biocompatible and targetable, allowing precise delivery (WO3-HA) to a tumor site. Near-infrared (NIR) irradiated WO3-HA showed a rapid and substantial rise in photothermal heat to complete in vitro thermolysis of malignant MDAMB and A549 cancer cellsbut was found to be relatively less sensitive to normal MDCK cells. A long-term in vivo investigation of similar to 10 nm HA thickness on WO3 (WO3-HA) nanoparticles demonstrated efficient photo-thermal conversion with time-dependent tumor target accumulation. This long-term in vivo survival study of WO3-HA showed promising biocompatibility, with a complete recovery from malignant tumor. Due to the importance of keeping simplicity in the design of therapeutic nanoparticles, we therefore expect that this facile scheme (HA-D) would contribute to the biocompatible development of versatile metallic nanoparticles for photothermal applications.