生物降解高分子胶束-金壳纳米结构的制备和性能研究

聚己内酯-聚赖氨酸嵌段共聚物(PCL-b-PLys)在水中自组装形成了聚赖氨酸为壳和聚己内酯为核的球形胶束.以胶束为模板,利用聚赖氨酸的胺基与金的配位作用,引导金在胶束壳层上生长,形成了胶束-金壳纳米结构(micelle@gold nanoshell).用紫外可见光谱、X射线光电子能谱、广角X射线衍射、透射电镜、动态光散射、热重分析、光热转化实验、以及体外光热杀死癌细胞实验等对金壳结构进行了结构确认和性能表征.胶束-金壳结构比原胶束增大约30%～40%,金约占总重量2/3.而且,其具有很强的近红外吸收性能和高达63%的近红外光-热转化效率.近红外激光照射10 min,可杀死约60%的宫颈癌细胞,且自身的细胞毒性低.

PREPARATION AND PROPERTIES OF BIODEGRADABLE COPOLYMER MICELLE@GOLD NANOSHELLS

Poly(ε-caprolactone)-b-poly(L-lysine)(PCL-b-PLys) that was synthesized by ring-opening polymerization,self-assembled into spherical micelles with PCL core and PLys shell in aqueous solution,and the intensity-averaged diameter was about 287 nm.Using the micelle as template,HAuCl4 was reduced by HCHO in basic solution(i.e.,pH > 10) and with ultrasonication for 4 min,the coordination of the primary amines of PLys with gold resulted in the growth and accumulation of gold in the micellar shell,and finally led to the formation of the micelle@gold nanoshell.To the best of our knowledge,the micelle@gold nanoshell was prepared for the first time,and then fully characterized by UV-Vis,XPS,WXRD,TEM,DLS,TGA,photothermal conversion and in vitro tumor cell-killing experiment.The average diameter of the micelle@gold nanoshell was about 380 nm,which was about 30%~40% bigger than the original micelle,and the mass fraction of gold accounted for about 2/3.Moreover,it showed strong surface plasmon resonance absorption in the near infrared region,and gave a high photothermal conversion efficiency of 63%.After near-infrared laser irradiation for 10 min,about 60% of Hela cells were killed,while the gold nanoshells had low cytotoxicity.Collectively,the micelle@gold nanoshells demonstrated good biocompatibility,and could efficiently kill tumor cells in vitro,making them potential for photothermal tumor therapy.