Single-molecule and Nanobiology Laboratory, Department of Biophysics, School of Basic Medical Sciences and Biomed-X Center, Peking University, Beijing 100191, China.
Langmuir. 2009 Oct 20;25(20):12250-5. doi: 10.1021/la9016596.
In recent years, silica coating has been extensively investigated to fabricate the biocompatible interface of quantum dots (QDs) for biomedical applications. We here describe a facile and efficient method of synthesizing high-quality silica-coated CdSeS QDs (CdSeS QD/SiO(2)), where an immediate photoluminescence-favorable microenvironment is first created by assembling amphiphilic molecules around the CdSeS core, and a thin silica shell is further introduced to protect this hydrophobic interlayer. The prepared CdSeS QD/SiO(2) exhibits excellent properties such as good water solubility, low cytotoxicity, and high quantum yield (QY, up to 0.49) as well as the resistance of photobleaching in aqueous solution. Also, the CdSeS QD/SiO(2) nanoparticles homogeneously comprise single CdSeS cores and hold a comparatively small size up to about 11 nm in diameter. Particularly, this method leads to a significant increase in QY as compared to the uncoated CdSeS QDs ( approximately 109% of the initial QY), though only thin silica shells formed in the CdSeS QD/SiO(2) structure. By coupling with folic acids, the CdSeS QD/SiO(2) conjugates were successfully used for tumor cell labeling. Our results demonstrated a robust hydrophobic QDs-based approach for preparing highly photoluminescent, biocompatible QD/SiO(2) through creation of a stable hydrophobic interlayer surrounding the QD cores, which could be also suitable for silica coating of other kinds of hydrophobic nanoparticles.
近年来，人们广泛研究了二氧化硅涂层来构建量子点（QDs）的生物相容性界面，以应用于生物医学领域。我们在这里描述了一种简便有效的合成高质量二氧化硅包覆的 CdSeS QDs（CdSeS QD/SiO2）的方法，该方法首先通过组装两亲分子在 CdSeS 核周围形成一个即时的有利于光致发光的微环境，然后进一步引入一个薄的二氧化硅壳来保护这个疏水性夹层。所制备的 CdSeS QD/SiO2 具有良好的水溶性、低细胞毒性和高量子产率（QY，高达 0.49）以及在水溶液中抗光漂白的特性。此外，CdSeS QD/SiO2 纳米粒子均匀地包含单个 CdSeS 核，并且尺寸相对较小，直径约为 11nm。特别是，与未包覆的 CdSeS QDs 相比，这种方法导致 QY 显著增加（约为初始 QY 的 109%），尽管 CdSeS QD/SiO2 结构中只形成了薄的二氧化硅壳。通过与叶酸偶联，成功地将 CdSeS QD/SiO2 缀合物用于肿瘤细胞标记。我们的结果表明，通过在 QD 核周围形成稳定的疏水性夹层，可以制备出高发光、生物相容的 QD/SiO2，这是一种基于 QDs 的强疏水性方法，也适用于其他类型的疏水性纳米粒子的二氧化硅包覆。
