Monodisperse Rattle-Structured Gold Nanorod-Mesoporous Silica Nanoparticles Core-Shell as Sulforaphane Carrier and its Sustained-Release Property.

Sulforaphane (SF) was loaded into the multi-functioned rattle-structured gold nanorod mesoporous silica nanoparticles core-shell to improve its stability and efficacy through its efficient delivery to tumors. The rattle-structured gold nanorod mesoporous silica nanoparticles (rattle-structured AuNR@mSiO2 core-shell NPs) were obtained by covering the surface of Au NPs with Ag and mSiO2 shell and subsequently selective Ag shell etching strategy. Then the surface of rattle-structured AuNR@mSiO2 NPs was decorated with thiolated polyethylene glycol-FITC and thiolated polyethylene glycol-folic acid to the designed form. The obtained FITC/FA@ [rattle-structured AuNR@mSiO2 ] NPs was characterized by different techniques including energy dispersive X-ray spectroscopy (EDX), scanning and transmission electron microscopy (SEM & TEM), UV-visible spectrophotometer and dynamic light scattering (DLS). The FITC/FA@ [rattle-structured AuNR@mSiO2 ] NPs has an average diameter around ~33 nm, which increases to ~38 nm after the loading of sulforaphane. The amount of the loaded drug was ~ 2.8×10-4 mol of SF per gram of FITC/FA@ [rattle-structured AuNR@mSiO2 ] NPs. The rattle-structured AuNR@mSiO2 and FITC/FA@ [rattle-structured AuNR@mSiO2 ] NPs showed little inherent cytotoxicity, whereas the SF loaded FITC/FA@ [rattle-structured AuNR@mSiO2 ] NPs was highly cytotoxic in the case of MCF-7 cell line. Finally, Fluorescence microscopy and flow cytometry were used to demonstrate that the nanoparticles could be accumulated in specific regions and SF loaded FITC/FA@ [Fe3 O4 @Au] NPs efficiently induce apoptosis in MCF-7 cell line Graphical Abstract.