The Preparation Of PH Sensitive Mesoporous Silica Nanoparticles And Their Properties In Vitro

The preparation of biocompatible and drug responsed release carrier system is a new trend in the field of nano-drug carriers.Mesoporous silica nanoparticles(MSNs)has unique advantages,such as high surface area and large pore volume,well defined pore structure,adjustable pore size as well as high loading capacity.But it still has some disadvantages,such as poor biocompatibility,drug can be easly leaked,and low uptake rate of tumor cells.Polyethylene glycol(PEG)and its phospholipid derivatives have series of advantages such as good biocompatibility and biodegradability.In this study,PEG2000,PEG2000-DSPE was used to modified the surface of MSNs,Soybean Lecithin as surfactant,preparing a pH sensitive composite carrier.The drug loading capacity of the composite carrier can be improved,and the carrier can release drug in the acid environment,this carrier was suitable for the tumor targetd treatment.In this study,MSNs were prepared by the method of modified St?ber.PEG-MSNs and PEG-DOX-MSNs were prepared by the method of emulsion diffused method.Doxorubicin Hydrochloride(DOX)as a drug model loaded by MSNs to prepared DOX-MSNs,DOX-PEG-MSNs and DOX-PEG-DSPE-MSNs.The micromorphology,particles size,phase characteristics,crystalline structure,thermal properties,surface area and pore volume of DOX-PEG-MSNs and DOX-PEG-DSPE-MSNs were characterized.The loading capacity,entrapment efficiency,antioxidant activity,in vitro release properties and storage stability of DOX-MSNs,DOX-PEG-MSNs and DOX-PEG-DSPE-MSNs were discussed.The in vitro release behavior and release mechanism of mesoporous silica nanoparticles were studied,the antioxidant properties of DOX were evaluated.The microstructure of PEG-MSNs and PEG-DSPE-MSNs were spherical particles,PEG-MSNs and PEG-DSPE-MSNs are still typical IV mesoporous structure,it's specific surface area and pore volume were still large when the proportions of PEG2000 and PEG2000-DSPE was appropriate.The FT-IR results confirmed that PEG polymer was effectively modified to the mesoporous silica skeleton,the DSC and XRD results shows thatDOX can be absorbed in the mesoporous silica channel with amorphous morphology or amorphous state.While mesoporous silica nanoparticles interior and exterior surface can be effectively modified by PEG polymer,doxorubicin linked with PEG by hydrogen bonds can avoid leakage.PEG polymer as a gate keeper,can effectively connected with silicon hydroxyl bond of mesoporous structure.The entrapment efficiency of DOX-PEG-MSNs and DOX-PEG-DSPE-MSNs are enchanced to(68.60 ± 0.85)% ?(76.58 ± 0.75)%,loading capacity are enchanced to(9.02±0.04)%?(9.34±0.03)%.While in pH 5.50 and pH 6.50,the release behavior of DOX-PEG-MSNs and DOX-PEG-DSPE-MSNs follow a Two-phase exponential kinetic model,with a diffused dissolution synergistic release,demonstrating a sustained-controlled release pattern.Molecular chain of the PEG2000-DSPE fractured in the weak acid environment,causing the nanoparticles broken,then drug capacity improved significantly.This composite carrier has a pH sensitive trigger release effect,which was suitable for a targeted and effective delivery to tumor site.when doxorubicin was loaded in mesoporous channels,the antioxidant activity of doxorubicin was enchanced significantly.Mesoporous silica nanoparticles modified by PEG polymer remained excellent properties of large pore volume and surface area,while endowed a property of pH sensitive release,and has a higher loading capacity.All of these results provided a scientific theory for a drug delivery system with a sustained-controlled release.