Study On Multifunctional Mesoporous Silica Nanoparticles For Targeted Drug Delivery

As new inorganic nonmetal nanomaterials, Mesoporous silica nanoparticles, dueto the good biocompatibility, high specific surface area, tunable pore structure andexcellent properties, have been widely used in the field of medicine.So far, more andmore researches focuse on stimuli-responsive controlled drug release systerm. Thenthere little studies about targeted drug release and traceable delivery have beenreported. So we use Mesoporous silica nanoparticles as carrier to design the targetedand traceable drug release systerm in this paper. The contents of this paper are asfollows:(1) DNA-Engineered Mesoporous silica nanocarriers: cell-Specific targeting andhydrogen peroxide-controlled drug releaseIn this paper, we developed a multifunctional nanocarrier that specifically targetsto breast cancer and responds to the over-procreant hydrogen peroxide (H2O2) in thecancer cells. The system represents DNA aptamer AS1411-engineered mesoporoussilica nanoparticles (MSNs) that incorporate anticancer agents and ferrocenederivatives in the channels. The nanogated architecture was constructed bypolymerization of positively charged perylene compounds to the MSNs surface withthe aptamer as template. Once the nanocarrier had been delivered into cancer cells byaptamer-mediated recognition and endocytosis, the innate over-procreant H2O2in thecancer cells is split into hydroxyl anions and highly reactive hydroxyl radicalsthrough the Fenton reaction by the present of ferrocene. The hydroxyl radicals causeoxidative aptamer damage that disassembles the perylene aggregates, resulting in thepore opening and drug releasing. This cancer cell-targeting feature andtumor-associated intracellular drug release led to excellent capability to selectivelykill cancer cells and prevent the damage to normal cells. Moreover, if the aptamer isdye-labeled, the nanocarrier allows real-time monitoring of drug release efficacy andfacile visualization of in vivo delivery event.(2) Cyclodextrin-engineered mesoporous silica nanoparticles: photo-responsivenanoreservoirs for targeted drug deliveryIn this paper, we designed a nanocarrier that specifically targets to CCRF-CEMcell and gated by host-gast interaction between azobenzene and cyclodextrins. Thesystem represents cyclodextrin-engineered mesoporous silica nanoparticles (MSNs) that incorporate anticancer agents in the channels. Then we gated the pore withSgc8c-labeled azobenzene. Once the nanocarrier had been delivered into cancer cellsby aptamer-mediated recognition, Sgc8c would combine to the receptor, as soon as a365nm UV light was given, the azobenzene molecule would leave the pore ofβ-cyclodextrins, resulting in the pore opening and drug releasing. With the help of thereceptor, the illumination time perhaps can be cut down in this systerm, which cangreatly prevent the damage to normal cells.