Biodegradable poly（L-lactide-r-trimethene carbonate） copolymers （P（LLA-co-TMC）） with different compositions were synthesized. The degradation of the copolymers was carried out in phosphate buffer saline solutions （pH = 7.4） at 37℃. The compositions, structure and properties of the copolymers in degradation were characterized with IH-NMR, DSC, XRD, GPC, and SEM. The weight loss of the P（LLA-co-TMC） 50/50 was much faster than that of P（LLA-co-TMC） 85/15 and PLLA homopolymer. Interestingly, though the molecular weight of the compolymers decreased greatly during degradation, the compositions were rarely varied. After long time degradation, the PLLA segments were induced to crystallize in the P（LLA-co-TMC） 85/15 copolymer. The SEM observation of the surface and cross-section of P（LLA-co- TMC） 85/15 copolymer films found it was similar to the bulk degradation of PLLA homopolymer.
An anti-tumor drug doxorubicin was encapsulated in micelles of poly（ethylene glycol）-b-poly（2,2-dihydroxyl- methyl propylene carbonate） （PEG-b-PDHPC） diblock copolymers. The morphololgy of both blank miceiles and drug loaded micelles was characterized by TEM. The in vitro drug release profiles of micelles were investigated, The cytotoxicity of the micelles was evaluated by incubating with Hela tumor cells and 3T3 fibroblasts. The drug loaded micelles were co-cultured with HepG2 cells to evaluate the in vitr9 anti-tumor efficacies. The results showed that the mean sizes of both micelles with different copolymer compositions increased after being loaded with drugs. The drug release rate of PEG45-b-PDHPC34 micelles was faster than that of mPEGt14-b-PDHPC26 micelles. Both of the two block copolymers were non-toxic. The confocal laser scanning microscopy a：ad flow cytometry results showed that both the drug loaded micelles could be internalized efficiently in HepG2 cells. The PEG45-b-PDHPC34 micelles exhibited higher anti-tumor activity comparing to mPEGxla-b-PDHPC26 micelles.
Inorganic polyhedral oligomeric silsesquioxane （POSS） was used as the core for the synthesis of poly（t- lysine） peptide dendrimer via copper-catalyzed azide-alkyne click chemistry. The inorganic/organic composite dendrimer was characterized by MS, 1H NMR, FTIR, GPC and DLS.
α-Cyclodextrin/poly(ethylene glycol)(α-CD/PEG) polyrotaxane nanoparticles were prepared via a self-assembly method. Anticancer drug methotrexate(MTX) was loaded in the nanoparticles. The interaction between MTX and polyrotaxane was investigated. The formation, morphology, drug release and in vitro anticancer activity of the MTX loaded polyrotaxane nanoparticles were studied. The results show that the MTX could be efficiently absorbed on the nanoparticles, and hydrogen bonds were formed between MTX andα-CDs. The typical channel-type stacking assembly style of polyrotaxane nanoparticles was changed after MTX was loaded. The mean diameter of drug loaded polyrotaxane nanoparticles were around 200 nm and the drug loading content was as high as about 20%. Drug release profiles show that most of the loaded MTX was released within 8 hours and the cumulated release rate was as high as 98%. The blank polyrotaxane nanoparticles were nontoxicity to cells. The in vitro anticancer activity of the MTX loaded polyrotaxane nanoparticles was higher than that of free MTX.
Mesoporous silica nanoparticles (MSNs) have been extensively studied and proposed as promising candidates for numerous biomedical applications.In this study,we report the design,preparation,characterization and biosafety evaluation of peptide dendron functionalized mesoporous silica nanohybrid.This nanohybrid was prepared by surface modification of MSNs via click reaction of azido-MSNs with alkynyl peptide dendrons,and characterized by TEM,SEM,TGA,dynamic light scattering (DLS).In vitro cytotoxicity of the nanohybrid was evaluated against different cell lines by CCK-8 assay.The in vivo toxicity evaluation was measured by body weight shift,blood routine test and histological analysis,suggesting that the peptide functionalized nanohybrid possessed good biocompatibility due to the non-observed significant side effects to normal organs of healthy mice.Overall,considering our results we believe that the peptide dendron functionalized mesoporous silica nanohybrid is very promising in further biomedical applications.
A novel method to prepare crosslinked polyethyleneimine （CPEI） hollow nanospheres was reported. Uniform silica nanospheres were used as templates, 3-aminopropyl trimethoxysilane （APS） was immobilized on the surface of silica nanospheres as couple agent. Aziridine was initiated ring-opening polymerization with the amino groups in APS to form polyethyleneimine （PEI） shell layer. 1,4-Butanediol diacrylate was utilized to crosslink PEI polymeric shell. The silica nanospheres in core were etched by hydrofluoric acid to obtain hollow CPEI nanospheres. The hollow nanospheres were characterized by X-ray photoelectron spectroscopy （XPS）, transmission electron microscopy （TEM）, and thermogravimetric analysis （TGA）.
Inclusion complexes(ICs) composed ofα-cyclodextrins(α-CD) and biodegradable comblike copolymers with poly(α,β-malic acid)(PMA) backbones and methylated poly(ethylene glycol)(mPEG) side chains were prepared by the host-guest reaction.Two series of ICs with mPEG750 and mPEG2000 were prepared.The stoichiometry(EG/CD) of all the ICs in mPEG2000 series was 3.1,no matter what the graft degree was.While in mPEG750 series,the stoichiometry(EG/CD) was very different:it increased with the amount of mPEG decreasing.Th...
