NIR-Excitable PEG-Modified Au Nanorods for Photothermal Therapy of Cervical Cancer

Gold (Au) nanorods (NRs) have been extensively used in applications in biomedical fields, thanks to their adjustable optical and stable chemical properties. Especially for the photothermal therapy (PTT) of cancer, Au NRs show an excellent thermal effect in the near-infrared (NIR) light range. However, cetyltrimethylammonium bromide (CTAB), which has been traditionally widely used for the synthesis of Au NRs, is generally cytotoxic. Surface modification is one of the ideal nanotechnologies to reduce toxicity and enhance the biocompatibility of CTAB-stabilized Au NRs. Herein, we designed an NIR-I-excitable photothermal theranostic nanoplatform Au@PEG NRs via modifying Au NRs with [1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy(polyethyleneglycol)]] (molecular weight: 2000; DSPE-mPEG2000). The results show that due to the PEG-layer protection, Au@PEG NRs exhibit superior biocompatibility (cell survival rate > 90%) and chemical stability. Meanwhile, Au@PEG NRs exhibited excellent biocompatibility via a hemolysis test, blood routine assays, and histological examinations (H&E). The absorption spectra of Au@PEG NRs showed a negligible change in the different pH (5.5–7.5) solutions, and the in vitro maximum heat dissipation photothermal conversion efficiency was 36.83%. In vivo PTT effects of Au@PEG NRs on a cervical tumor can reach 58.8 °C. The intracellular localization suggests the efficient cellular uptake of Au@PEG NRs. The fact that in vitro Au@PEG NRs assisted PTT under laser irradiation (793 nm) extremely ablates HeLa cells. The ultrastable Au@PEG NRs have significant potential for PTT application of cervical cancer.