中文摘要：

选用两种典型的稀土上转换发光纳米粒子,即表面包覆氨基带正电的Na YF4：Yb3＋,Er3＋纳米粒子（HINPs）和包裹巯基带负电的Na YF4：Yb3＋,Er3＋纳米粒子（HMNPs）,探究这两种粒子与细胞相互作用的机制。虽然HINPs和HMNPs的表面电性不同,但是理化性质相近、荧光发光强度相差不大,因此不会造成显著的成像差异。通过使用共聚焦成像和流式细胞仪进行检测,对比三种培养环境（正常培养条件、抑制膜蛋白活性培养条件和阻碍细胞内消耗能量运输过程的培养条件）的实验结果,发现HINPs和HMNPs的跨膜是一种消耗能量的受体介导的胞吞运输过程。另外,细胞对HINPs的摄取量要远大于对HMNPs的摄取量,说明带正电的粒子更容易和带负电的细胞膜相结合并进入细胞。

英文摘要：

Two typical upconversion nanoparticles that are positively charged amino groups modified-Na YF4： Yb3 ＋,Er3 ＋nanoparticles（ HINPs） and negatively charged sulfhydryl groups modified-Na YF4： Yb3 ＋,Er3 ＋nanoparticles（ HMNPs） were chosen to study their interactions with cells. Though surface charge of HINPs and HMNPs were different,the physicochemical properties and fluorescence intensity of HINPs and HMNPs were so close that two particles won＇t display much difference in biological imaging. Cells were cultured in the medium containing HINPs or HMNPs under three situations which include the normal culture situation,inhabiting membrane protein activity and impeding the energy dependent transport process of cells. Combined with analyses of confocal imaging and flow cytometry,two particles entering cells was an energy dependent of receptor-mediated endocytosis process. The cellular uptake number of HINPs was higher than that of HMNPs,which indicated positively charged HINPs are relatively easy to bind the negatively charged cell and translocate across the membrane.