Hybrid Nanogel-Wrapped Anisotropic Gold Nanoparticles Feature Enhanced Photothermal Stability

Abstract

Anisotropic gold nanoparticles (AuNPs) are renowned for their unique properties – including localized surface plasmon resonance (LSPR) and adjustable optical responses to light exposure – that enable the conversion of light into heat and make them a promising tool in cancer therapy. Nonetheless, their tendency to aggregate and consequently lose their photothermal conversion capacity during prolonged irradiation periods represents a central challenge in developing anisotropic AuNPs for clinical use. To overcome this issue, an innovative approach that facilitates the encapsulation of individual anisotropic AuNPs within thin nanogels, forming hybrid nanomaterials that mirror the inorganic core's morphology while introducing a negligible (2–8 nm) increase in overall diameter is proposed. The encapsulation of rod- and star-shaped anisotropic AuNPs within poly-acrylamide (pAA) or poly-(N-isopropylacrylamide) (pNIPAM) nanogels is successfully demonstrated. The ultrathin polymeric layers display remarkable durability, significantly enhancing the photothermal stability of anisotropic AuNPs during their interaction with near-infrared light and effectively boosting their photothermal capacities for extended irradiation periods. The outcomes of the research thus support the development of more stable and reliable AuNPs as hybrid nanomaterials, positioning them as promising nanomedicinal platforms.