Porous silica nanoparticles capped with polyethylenimine/green carbon dots for pH/redox responsive drug release

Abstract

Porous silica (pSiO2) nanoparticles (NPs) were prepared by hydrolysis method and engineered with disulfide-linked gatekeepers for controlled drug release. The pSiO2 NPs with large pores have an average diameter of 60 nm and are suitable for loading drug. Cysteine (Cys) molecules as disulfide-linkers were grafting on the surface of pSiO2 carriers. After loading doxorubicin (DOX), polyethylenimine (PEI) and green carbon dots (gCDs) were used to cap the drug-loading pores. The PEI/gCDs shell can be detached from the surface of pSiO2 carriers at tumor-relevant glutathione (GSH) levels and facilitate the release of the encapsulated cargo. Meanwhile, the PEI chains would be highly protonated and lead to the swelling of PEI layer at low pH value. The pSiO2-PEI/gCDs displayed good pH/redox-responsive release behavior and gCDs can be used to monitor the drug release.