Ellipsoidal-Fe3O4@SiO2@mSiO2-C18@dopamine hydrochloride-graphene quantum dots-folic acid (ellipsoidal-HMNPs@PDA-GQDs-FA), a dual-functional drug carrier, was stepwise constructed. The α-Fe2O3 ellipsoidal nanoparticles were prepared by a hydrothermal method, and then coated with SiO2 by Stöber method. The resulting core-shell structure, Fe3O4@SiO2@mSiO2-C18 magnetic nano hollow spheres, abbreviated as HMNPs, was finally grafted with graphene quantum dots (GQDs), dopamine hydrochloride (PDA) and folic acid (FA) by amide reaction to finally obtain HMNPs@PDA-GQDs-FA. Transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), fluorescence spectroscopy and element analysis proved the successful construction of the HMNPs@PDA-GQDs-FA nanoscale carrier-cargo composite. The carrier HMNPs@PDA-GQDs-FA has higher load (51.63%) and release (38.56%) capacity for Gambogic acid (GA). While the cytotoxicity of the carrier-cargo is very low, cytotoxicity test showed that the cell survival rate was above 95%. The cell lethality is greatly improved after loading GA because of the magnetic targeting of HMNPs, the targeting performance of FA to tumor cells, and the pH response to the surrounding environment of tumor cells of PDA. All results showed that HMNPs@PDA-GQDs-FA had good biocompatibility and could be used in the treatment of VX2 tumor cells after loading GA.

Herein, we developed the dual-function template method to fabricate hollow magnetic nano-spheres (denoted as HMNPs-Cn, n = 16, 18) with a mesoporous shell and hollow interior structure using alkyl chain trimethoxysilane templating. The microstructure of the HMNPs-Cn was investigated by means of XRD, FT-IR, EDS, SEM, TEM and N2-BET analyses. The shorter chain template directed formation of HMNPs-C16 with size of 119 nm, having disordered inkbottle type mesopores and saturation magnetization of 50.01 emu/g. It can be observed that, mitomycin C (MMC) loaded HMNPs-Cn hollow spheres showed a clear pH-dependent drug release behavior, having a higher release rate in acidic environments of pH 5.7. For the pH 5.7 and 7.4 release, the diffusion through HMNPs-Cn hollow spheres is the rate limiting step, the release kinetic for HMNPs-C16-MMC composites follows pseudo-first-order attributable to its special pore structure. For this reason the inner cavity of HMNPs-C16 could be labeled with radioisotope 99Tcm to study the magnetic targeting distribution of HMNPs-C16 in vivo, and its cytotoxicity against in vitro HeLa cells was also studied. These results indicate the potential of HMNPs-C16 in the magnetic targeted drug delivery system.

Herein, we developed the dual-function template method to fabricate hollow magnetic nano-spheres (denoted as HMFe-Si-Cn, n=16, 18) with a mesoporous shell and hollow interior structure using alkyl chain trimethoxysilane templating. The shorter chain template directed formation of HMFe-Si-C16 with size of 119 nm, having disordered inkbottle type mesopores and saturation magnetization of 50.01 emu/g higher than that of HMFe-Si-C18 with cylindrical type mesopores. By contrast, Mitomycin C (MMC) loading efficiency of HMFe-Si-C16 was higher owing to the fact that the pore size, surface area, and pore volume of HMFe-Si-C16 were larger than those of HMFe-Si-C18. Besides, MMC loaded HMFe-Si-Cn hollow spheres showed a clear pH-dependent drug release behavior, having a higher release rate in acidic environments of pH 5.7. For the pH 5.7 and 7.4 release, the release kinetic for HMFe-Si-C16-MMC composites follows pseudo-first-order attributable to its special pore structure. For this reason the inner cavity of HMFe-Si-C16 could be labeled with radioisotope 99Tcm to study the magnetic targeting distribution of HMFe-Si-C16 in vivo, and its cytotoxicity against in vitro HeLa cells was also studied. These results indicate the potential of HMFe-Si-C16 in the magnetic targeted drug delivery system.