Cetyl-chitosan, prepared by reacting chitosan with chlorocetane under alkaline condition, is soluble and spontaneously forms nanoparticles about 100 nm in diameter. Infrared spectra (IR) revealed that there was a subs...Cetyl-chitosan, prepared by reacting chitosan with chlorocetane under alkaline condition, is soluble and spontaneously forms nanoparticles about 100 nm in diameter. Infrared spectra (IR) revealed that there was a substitution reaction mainly on the amine groups of chitosan (CS). By using paracetamol (PCTM) as a model drug, the balanced release concentration of PCTM in phosphate buffer solution (pH=7.4) can be decreased with the increase of degree of substitution alkyl and can be reduced effectively even under a lower PCTM loading.展开更多
Mesoporous silica nanoparticles （MSNs） are promising for drug delivery and other biomedical applications owing to their excellent chemical stability and biocompatibility. For these applications, a hollow morphology ...Mesoporous silica nanoparticles （MSNs） are promising for drug delivery and other biomedical applications owing to their excellent chemical stability and biocompatibility. For these applications, a hollow morphology with thin shell and open mesopores is preferred for MSNs in order to maximize the loading capacity of drugs. Herein we report a novel and direct synthesis of such an ideal drug delivery system in a dilute and alkaline solution of benzylcetyl- dimethylammonium chloride and diethylene glycol hexadecyl ether. The mixed surfactants can guide the formation of MSNs with cubic Ia3d mesostructure, and at a concentration of sodium hydroxide between 9.8 and 13.5 mM, hollow MSNs with uniform sizes of 90-120 nm and a single-unit-cell-thick shell are formed. A mechanism for the formation of the hollow Ia3d MSNs, designated as MMT-2, is proposed based on in situ small-angle X-ray scattering measurements and other analyses. MMT-2 exhibits much higher loading capacity of ibuprofen and degrades faster in simulated body fluid and phosphate buffered saline than non-hollow MSNs. The degradation of MMT-2 can be significantly retarded by modification with polyethylene glycol. More interestingly, the degradation of MMT-2 involves fragmentation instead of void formation, a phenomenon beneficial for their elimination. The results demonstrate the uniqueness of the hollow Ia3d MSNs and the great potential of the material for drug delivery and biomedical applications.展开更多
文摘Cetyl-chitosan, prepared by reacting chitosan with chlorocetane under alkaline condition, is soluble and spontaneously forms nanoparticles about 100 nm in diameter. Infrared spectra (IR) revealed that there was a substitution reaction mainly on the amine groups of chitosan (CS). By using paracetamol (PCTM) as a model drug, the balanced release concentration of PCTM in phosphate buffer solution (pH=7.4) can be decreased with the increase of degree of substitution alkyl and can be reduced effectively even under a lower PCTM loading.
文摘Mesoporous silica nanoparticles （MSNs） are promising for drug delivery and other biomedical applications owing to their excellent chemical stability and biocompatibility. For these applications, a hollow morphology with thin shell and open mesopores is preferred for MSNs in order to maximize the loading capacity of drugs. Herein we report a novel and direct synthesis of such an ideal drug delivery system in a dilute and alkaline solution of benzylcetyl- dimethylammonium chloride and diethylene glycol hexadecyl ether. The mixed surfactants can guide the formation of MSNs with cubic Ia3d mesostructure, and at a concentration of sodium hydroxide between 9.8 and 13.5 mM, hollow MSNs with uniform sizes of 90-120 nm and a single-unit-cell-thick shell are formed. A mechanism for the formation of the hollow Ia3d MSNs, designated as MMT-2, is proposed based on in situ small-angle X-ray scattering measurements and other analyses. MMT-2 exhibits much higher loading capacity of ibuprofen and degrades faster in simulated body fluid and phosphate buffered saline than non-hollow MSNs. The degradation of MMT-2 can be significantly retarded by modification with polyethylene glycol. More interestingly, the degradation of MMT-2 involves fragmentation instead of void formation, a phenomenon beneficial for their elimination. The results demonstrate the uniqueness of the hollow Ia3d MSNs and the great potential of the material for drug delivery and biomedical applications.
