Dual irradiation-triggered anticancer therapeutics composed of polydopamine-coated gold nanoparticles

The therapeutic efficacy of nanoparticles depends on their ability to release encapsulated photosensitizers. Here, surface-engineered metallic gold nanoparticles (AuNP) were irradiated with dual near-infrared (NIR) light to enhance the release of photosensitizer. Dopamine hydrochloride was surface-polymerized to polydopamine (PDA) layers on AuNP, and chlorin-e6 (Ce6) was chemically tethered to primary amines of PDA. The resulting Ce6-conjugated AuNP were characterized by Raman and X-ray photoelectron spectroscopy and visualized by electron microscopy and light scattering. The generation of reactive oxygen species was increased following dual NIR irradiation at 650 nm and 808 nm, which was attributed to the increased liberation of Ce6. In vitro, dual NIR irradiation significantly enhanced the anticancer effect of Ce6-incorporating AuNP by increasing the population of apoptotic cells. In vivo, tumor xenografted animals exhibited much better tumor suppression when subjected to dual NIR irradiation. Thus, we propose the use of Ce6-incorporating AuNP coupled to dual NIR irradiation for future anticancer treatment of solid tumors.