中文摘要：

目的制备载水淬灭荧光探针的单甲氧基聚乙二醇-聚己内酯（mPEG-PCL）纳米粒,并评价其体外特性及稳定性。方法以聚己内酯（PCL）、mPEG-PCL为材料,采用乳化-溶剂挥发法分别制备包载水淬灭荧光探针P2的PCL纳米粒和具有不同mPEG链长（mPEG5k、mPEG2k）的mPEG-PCL纳米粒,对其体外特性（表面形态、粒径大小及分布）进行表征。P2探针包载于纳米粒中时发出荧光信号,但释放到水中时荧光迅速淬灭,利用P2探针的这一性质,考察各种纳米粒在不同水性溶媒中的稳定性。结果所制备的mPEG-PCL纳米粒形态圆整、表面光滑,粒径约200nm,分布较窄,多分散系数（PDI）均低于0.06,表面电荷近中性。在不同pH的缓冲介质和模拟生理体液中,所有纳米粒均表现出良好的稳定性,粒径、PDI、荧光强度均未发生明显变化。结论 mPEG-PCL纳米粒具有良好的体外特性与稳定性,以水淬灭探针为指示剂可以快速、方便地进行稳定性研究。

英文摘要：

Objective To prepare methoxy polyethylene glycol（mPEG）-polycaprolactone（PCL）nanoparticles loading a water-quenching fluorescent probe and to evaluate its in vitro characteristics and stability.Methods PCL nanoparticles and mPEG-PCL nanoparticles with different mPEG chain lengths（mPEG5k,mPEG2k）loading the waterquenching fluorescent probe P2 were prepared by an emulsification/solvent evaporation method using PCL and mPEGPCL as materials.In vitro characteristics such as morphology,particle size and distribution were evaluated.The P2 probe displayed fluorescent signals when encapsulated in the matrix of the nanoparticles,but quenched immediately when released into water.Based on this properties of P2 probe,the stability of various nanoparticles in different aqueous media was investigated.Results The prepared mPEG-PCL nanoparticles showed a particle size of about 200 nm,narrow size distribution,polydispersity index below 0.06 and near neutral surface potentials with spherical morphology and smooth surfaces.In buffers of different pHs and simulated bio-relevant media,all nanoparticles showed very good stability without significant change in particle size,polydispersity index and fluorescence intensity.Conclusion mPEG-PCL nanoparticles have promising in vitro characteristics and robust stability.It is fast and convenient to monitor the stability of nanoparticles by using the water-quenching probe.