The cationic folic acid（CFA） was prepared by introducing triethylenetetramine into folic acid with EDCI/NHS and characterized by IR, NMR and mass spectra. It was found that approximately one of two carboxyls in the folic acid molecule was substituted to form CFA. The conversion of γ-carboxyl is found to be 59% higher than 30% of γ-carboxyl. The CFA and doxorubicin hydrochloride can be loaded on the ionic shell of PTX-encapsulated micelle to form CFA loaded binary drug carrier via static interaction in aqueous solutions. The successful loading was demonstrated by zeta potential measurement and the drug load amount（DLA） of CFA was measured by HPLC. In vitro cytotoxicity results revealed the CFA drug carrier showed higher cytotoxicity to cancer cell MDA-MB-321 than the binary drug carrier without CFA and the positive control, while it showed lower cytotoxicity to normal cell HUVEC than the positive control, and similar cytotoxicity with the binary drug carrier without CFA. These results as well as confocal laser scanning microscopy observation indicate the synthesized CFA drug carrier possesses active tumor-targeting property.
Yang HuLu GanQian-xuan LiHong Tao叶霖Ai-ying ZhangZeng-guo Feng
The methylated polyrotaxane （MePR） copolymer was prepared via the methylation of hydroxyl of threaded α-cyclodextrin （α-CDs） in polyrotaxane （PR） copolymer by CH3I/NaH. Its structure was characterized by GPC, IR and NMR. The WXRD and TGA measurements showed the destruction of channel-like crystalline structure in MePR copolymer. The sliding of threaded α-CDs along PEG axis in PR and MePR copolymers was demonstrated by their dielectric spectra that also evidenced the presence of rotating of threaded α-CDs around PEG axis in MePR eopolymer. The frequent and vigorous molecular mobility in MePR and PR copolymers was also verified by dynamic mechanical analysis （DMA） and rheological measurement, which was possibly assigned to the sliding and rotating of threaded α-CDs. DMA and rheological results showed that the mobility of α-CDs could simultaneously strengthen and toughen PR copolymer proved by stress-stain curves. In this paper, we report the CD mobility in PR and MePR copolymers. The macroscopic behaviors of PR copolymer, such as mechanical properties in solid state, were also found to be benefited from CD mobility.
