Aqueous Synthesis of Triphenylphosphine‐Modified Gold Nanoparticles for Synergistic In Vitro and In Vivo Photothermal Chemotherapy

Triphenylphosphine (TPP) surface‐functionalized and F‐108 Pluronic‐stabilized gold nanoparticles (F‐108@TPP‐AuNPs) have been synthesized through a one‐step approach, leading to well‐defined (9.6±1.6 nm) and water‐soluble nanoparticles by microwave heating an aqueous solution of TPP‐Au I Cl in the presence of a Pluronic polymer under basic conditions. TPP release was negligible under physiological conditions, but enhanced significantly at an acidic pH (5.4) mimicking that of a cancer cell. Laser irradiation (532 nm) raised the temperature of an aqueous solution of F‐108@TPP‐AuNPs to 51.7 °C within 5 min, confirming efficient light‐to‐heat conversion capabilities without significant photodegradation. TEM confirmed intracellular localization of F‐108@TPP‐AuNPs in the cytosol, endosomes and lysosomes of HeLa cells. F‐108@TPP‐AuNPs were well tolerated by HeLa cells and zebrafish embryos at ambient temperatures and became toxic upon heat activation, suggesting synergistic interactions between heat and cytotoxic action by TPP.