Multi-functional Fe3O4@HMPDA@G5-Au core-releasable satellite nano drug carriers for multimodal treatment of tumor cells

We report a route of fabricating a hollow mesoporous nucleus-satellite Fe3O4@HMPDA@G5-Au drug delivery nano system, which with a large specific surface area and total pore volumes. The preparation process of the microcapsules was simple, mild and no toxic reagent participating. The average DOX capacity of the obtained nano carriers was up to 473.83 mg/g. The small size G5-Au NPs can be released by shell PDA peeling in acidic tumor environment; it can be used for deep penetrating delivery of drugs. The photothermal effect of PDA and AuNPs was also combined. In addition, it can also promote the decomposition of H2O2 to produce O2 to a certain extent and avoid tumor hypoxia. The vitro experiments showed that the nano drug carrier has obvious inhibitory effect on tumor cells with little side effects under the multi synergistic therapeutic effect. Scheme 1. Synthetic routes of the preparation of Fe3O4@HMPDA@G5-Au@DOX nano drug carrier. [Display omitted] •The two-component photothermal nanocomposite endowed the nano system have high photothermal conversion efficiency (46.53%).•The large cavity structure and shell mesoporous structure endowed the carrier greater drug capacity (473.83 mg/g).•In acidic tumor environment, small G5 Au NPs can be used for deep penetration drug delivery.•It can also promote the decomposition of H2O2 to produce O2 to a certain extent and avoid tumor hypoxia.•The cell experiments showed that the nonosystem had significant inhibition on tumor cells with little side effects. Combination therapy has become an effective strategy for tumor treatment, but the preparation of drug nanocarriers with the high requirements still lacked exploration. In this paper, hollow shell-layer mesoporous polydopamine (HMPDA) was constructed on Fe3O4 nanoparticles (the magnetic core), and small-sized G5-Au nanoparticles (AuNPs) as the releasable satellite carriers for tumor deep treatment were modified on HMPDA surface, then the nucleus-satellite Fe3O4@HMPDA@G5-Au nano drug delivery carriers were obtained. The therapy drug could be loaded in the mesoporous structure of HMPDA and G5-Au nanoparticles, so the drug loading capacity was relatively large. The Fe3O4@HMPDA@G5-Au composite nano carriers also had good photothermal properties, because polydopamine (PDA) and AuNPs were both good photothermal agents. Combination of photothermal therapy (PTT) and drug therapy could significantly enhance the ablation of tumor cells with minor side effects. In addition, the de