Spadix-Bract Structured Nanobowls for Bimodal Imaging-Guided Multidrug Chemo-Photothermal Synergistic Therapy

Multifunctional nanoparticles (NPs) simultaneously having functions of multimodal therapy and imaging are highly needed in biomedical applications. A unique monstera flower-like gold nanorod/polydopamine bowl (GNR/PDA bowl) with spadix-bract nanostructure was fabricated by a novel and facile approach. The possible formation mechanism of the GNR/PDA bowl spadix-bract NPs was proposed by monitoring the synthetic process. The obtained monstera flower-like GNR/PDA bowl spadix-bract NPs were further selectively functionalized with 1-dodecanethiol (DT) on GNR domains (spadix) to achieve efficient hydrophobic drug delivery capability; meanwhile, the PDA bowl (bract) can load the hydrophilic anticancer drug doxorubicin (DOX). The resultant monstera flower-like DT-GNR/PDA bowl spadix-bract NPs possess an excellent biocompatibility, high dual-drug-loading contents, excellent photothermal conversion efficiency, strong near-infrared (NIR) absorbance, effective attenuation of X-rays, and pH/NIR dual-responsive properties, which enable the NPs to be applied for synergistic bimodal computed tomography/photoacoustic (CT/PA) imaging-guided multidrug chemotherapy and photothermal therapy (PTT). Moreover, the synthetic approach could be extended to prepare Au/PDA bowl NPs and Fe2O3/PDA bowl NPs, which may greatly expand the application of the PDA-based bowl NPs.