No abstract

An anti-tumor drug doxorubicin was encapsulated in micelles of poly(ethylene glycol)-b-poly(2,2-dihydroxylmethyl propylene carbonate) (PEG-b-PDHPC) diblock copolymers. The morphology of both blank micelles 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 vitro 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 PEG 45 -b-PDHPC 34 micelles was faster than that of mPEG 114 -b-PDHPC 26 micelles. Both of the two block copolymers were non-toxic. The confocal laser scanning microscopy and flow cytometry results showed that both the drug loaded micelles could be internalized efficiently in HepG2 cells. The PEG 45 -b-PDHPC 34 micelles exhibited higher anti-tumor activity comparing to mPEG 114 -b-PDHPC 26 micelles.

An effective strategy was developed to fabricate a supramolecular hydrogel with the complexation of α-cyclodextrins (α-CDs) and monoend-functionalized low molecular weight methoxy poly(ethylene glycol) (mPEG, Mn=2000) micelles. Hydrophobic cinnamic acid was immobilized on methoxy poly(ethylene glycol) via L-lysine as linker to prepare amphiphilic mPEG. The monoend-functionalized mPEG self-assembled micelles in aqueous solution. The size and size distribution of the micelles were tested by dynamic laser scattering (DLS). The morphology of the micelles was observed by SEM, TEM and AFM. The critical micelle concentration (CMC) was tested and it was 42.5 mg/L. The monodisperse micelles had core-shell structure and the mean diameter was around 40 nanometers. α-cyclodextrins were added in the suspension of micelles to form supramolecular hydrogel with the polypseudorotaxanes complexation. Hydrophilic drug doxorubicin hydrochloride was used as model drug to study the release profile. The results showed that the hydrogel was a promising carrier for drug delivery.

The biomedical applications of poly(e-caprolactone) (PCL) were limited for its high hydrophobicity and crystallinity. In this study, we copolymerized CL with amorphous 5-hydroxyl-trimethylene carbonate (HTMC) to solve the problem. The 5-benzyloxy-trimethylene carbonate (BTMC) was synthesized to copolymerize with CL, then hydrogenolyzed to obtain hydroxyl pendant groups. A serial of copolymers with different BTMC molar ratio were synthesized and their chemical structures and thermal properties were thoroughly studied with NMR, FT-IR, GPC, XRD, DSC, and TGA. Finally we examined the water contact angle of the copolymers. DSC and XRD results showed that the PCL segments in the copolymers crystallized below 16.8%. BTMC molar content and the crystallinity of the copolymers increased after hydrolysis. With the introduced hydroxyl pendant groups, the deprotected copolymers improved their hydrophilic property significantly, and the copolymer with 9.3% HTMC molar content had static water contact angle as low as 36.5 .