Fabrication of multifunctional polydopamine-coated gold nanobones for PA/CT imaging and enhanced synergistic chemo-photothermal therapy

Multimodal imaging-guided chemo-photothermal therapy is an excellent cancer treatment, which can not only efficiently against tumor, but also can offer precise treatment window and real-time monitoring of the treatment efficiency. In our work, polydopamine (PDA)-coated gold nanobones (AuNBs@PDA nanocomplexes) were designed for this approach. The AuNBs@PDA nanocomplexes have strong absorbance in the near infrared (NIR) region and higher photothermal conversion efficiency (75.48 %) than gold nanobones alone, which was facilitated for photoacoustic imaging and photothermal therapy. Besides, the loading efficiency of doxorubicin (DOX) by AuNBs@PDA nanocomplexes could be up to about 70 % and DOX release from AuNBs@PDA/DOX nanocomplexes sensitively response to the lower pH environment and NIR laser irradiation, which makes them become the excellent nano-carrier for the delivery of chemotherapy drug. In vitro and in vivo studies showed significant cytotoxicity and antitumor efficacy by the AuNBs@PDA/DOX nanoplatform with negligible side effects. Meanwhile, the nanoplatform was also successfully employed for computed tomography (CT) imaging, attributing to the high atomic number and high X-ray attenuation coefficient of gold. Therefore, we believed that the proposed PDA-coated gold nanobones would be a novel multifunctional theranostic nanoagent to realize the PA/CT imaging-guided chemo-photothermal therapy of cancer.