中文摘要：

因为他们象单个刺激那样的优秀优点， Upconversion 光 nanoparticles (UCNP ) 与多色排放，低 autofluorescence，和深穿入作为光探针在生物医学的领域里显示出有希望的应用。但是如此的 nanomaterials 的生物应用仍然由于相反的表面性质被限制。在这个工作，我们开发获得 O-carboxymethyl chitosan (OCMC ) 的热水的线路包了的一个灵巧的一个壶 NaYF4：直接并且高效地被用于指向的房间光成像的 Yb3+/Tm3+/Er3+ 红 UCNP。由 OCMC 的 UCNP 的成功的涂层被 Fourier 变换证实了红外线(FTIR ) 散布的光谱学和动态光(DLS ) 学习。传播电子显微镜学(TEM ) ，粉末 X 光检查衍射(XRD ) ， thermogravimetric 分析(TGA ) ，和光致发光(PL ) 系列被用来分别地描绘尺寸，作文和样品的排放颜色。由于好 biocompatibility，水溶性，和强壮的 UC 光，这些吸水的 nanocrystals 将在进一步的 bioapplications 开创新大街。

英文摘要：

Upconversion luminescence nanoparticles （UCNPs） have shown promising applications in biomedical fields as luminescent probes because of their excellent advantages such as single excitation with multicolor emission, low autofluorescence, and deep penetration. But the biological applications of such nanomaterials are still restricted due to the unfavorable surface properties. In this work, we develop a facile one-pot hydrothermal route to obtain O-carboxymethyl chitosan （OCMC）-wrapped NaYF4： yb3＋/Tm3＋/Era＋ red UCNPs which have been used for targeted cell luminescence imaging directly and efficiently. The successful coating of the UCNPs by OCMC has been confirmed by Fourier-transform infrared （FTIR） spectroscopy and dynamic light scattering （DLS） studies. Transmission electron microscopy （TEM）, powder X-ray diffraction （XRD）, thermogravimetric analysis （TGA）, and photoluminescence （PL） spectra have been used to characterize the size, composition and emission color of the sam- ples, respectively. Due to the good biocompatibility, water-solubility, and strong UC luminescence, these hydrophilic nanocrystals will open up new avenues in further bioapplications.