载Ca2+温度敏感性脂质体的合成

目的合成包裹Ca2+的温度敏感性脂质体,仿生生物矿化过程中的基质小泡分泌钙磷离子,为仿生矿化的研究提供一种矿化离子供给的研究手段。方法采用相交融合(IF)法,以相变温度较低(24℃)的二肉豆蔻卵磷脂(DMPC)和相变温度较高的(41℃)二棕榈酰磷脂酰胆碱(DPPC)为原料,调节两者的质量比为9∶1,使合成的脂质体膜在37℃左右发生相变,致通透性增加,包裹物释放。通过与CaCl2溶液的水合,合成包裹Ca2+的温度敏感性脂质体,并对脂质体的特性进行表征。结果所获脂质体的平均粒径为161.3 nm,Ca2+的包裹率为60%～85%。室温条件下脂质体稳定,在37℃条件下,Ca2+可以持续释放。结论以DPPC和DMPC为原料,合成的包裹Ca2+温度敏感性脂质体,在生理条件下可以实现Ca2+释放,为仿生矿化的研究模型提供了一种仿生基质小泡分泌钙磷离子的研究工具。

Preparation of calcium-loaded temperature-sensitive liposomes

Objective To prepare the calcium-loaded temperature-sensitive liposomes and use it as tools to mode the matrix vesicles during calcication,to provide a new means of mineal ions supplying in biomimetic mineralization.Methods The liposomes were prepared by the interdigitation-fusion(IF) method.It composed of 1,2-bis(palmitoyl)-sn-glycero-3-phosphocholine(DMPC) whose the lipid chain melted transition temperature(Tm) was 24℃ and 1,2-bis(myristoyl)-sn-glycero-3-phosphocholine(DPPC) whose Tm was 41℃.By adjusting the rate of DPPC and DMPC(9 ∶ 1),we got the liposome whose Tm was 37℃.Above 37℃,the liposomes melted transition,increased permeability,and released encapsulated Ca2+.Hydrated with aqueous CaCl2 to gained calcium-loaded temperature-sensitive liposomes,and we characterized the calcium-loaded liposomes.Results We gained the liposomes which average diameters was 161.3 nm,and calcium encapsulation efficiency ranged from 60% to 85% of available calcium.It was stable at room temperature,but entrapped calcium rapidly diffused out of the liposomes at 37℃.Conclusion We could prepare temperature-sensitive liposomes which are composed of DPPC and DMPC.When heated to body temperature,calcium ions are released.Using of lipid vesicle compartments to sequester ions,it provides a new research tool in biomimetic mineralization.