Au nanostars@PDA@Fe3O4-based multifunctional nanoprobe for integrated tumor diagnosis and photothermal therapy

A multifunctional nanoprobe (based on Au nanostars@PDA@Fe3O4) is developed for tumor targeted imaging and targeted photothermal therapy. Au nanostars and Fe3O4 are connected with polydopamine, and combined with antibody-FITC or antibody-quantum dots for in vitro or in vivo fluorescence labeling (FL), respectively, to form the composite nanoprobe. The shape and lattice structure of Au nanostars and Fe3O4 were confirmed with TEM, HRTEM and XRD experiments. Compared with other Au nanoparticles@Fe3O4 composite probes, the Au nanostars@PDA@Fe3O4 structure has a low photothermal conversion threshold. Compared with the corresponding pure Au nanostars, the photothermal efficiency of the probe has increased by 50%, while maintaining 171% and 32% fluorescence enhancement in vitro and in vivo, respectively. Due to the charge transfer channel, the phonon emission of Au can go on in Fe3O4 via the PDA linking. Under the precise guidance of multimodal imaging, the nanoprobe conducts homogeneous photothermal ablation of bulky solid tumors (~ 400 mm3) in a xenograft mouse model. Animal model magnetic resonance imaging (MRI) results found that the MRI T2 signal intensity of the probe was 65% stronger than that of pure Fe3O4 nanoparticles. These results suggest that this nanoplatform is promising for integrated tumor diagnosis and targeted cancer therapy