中文摘要：

亲水性量子点的荧光性能是其作为生物检测探针的一个重要质量指标．不同结构的量子点在亲水性修饰过程中，其抵抗荧光淬灭的能力差异较大．设计与制备具有不同结构和成分的核、核壳量子点，再通过双亲性高分子对其亲水性改性，利用荧光光谱监测亲水性修饰过程中的荧光性能变化来度量所合成量子点的光化学稳定性．实验结果表明，在表面亲水性修饰过程中，未包覆壳层的裸核量子点其抵抗荧光淬灭的能力最弱；包覆壳层的核壳量子点，其抵抗荧光淬灭的能力增强，且壳层越多，抵抗能力越强．壳层的结构和成分直接影响核壳量子点抵抗荧光淬灭的能力，具有合理晶格匹配的核壳量子点，其抵抗荧光淬灭的能力较强．另外，通过优化设计与制备的核壳量子点经表面亲水性修饰后，再偶联叶酸，构建出特异性生物荧光探针，对乳腺癌细胞进行靶向性标记后，利用流式细胞仪进行细胞检测分析．实验结果表明，通过优化制备的核壳量子点，亲水性修饰后仍具有很好的荧光性能，偶联叶酸后具有较好的细胞靶向性．

英文摘要：

Quantum dots （QDs）, as a new class of biological nanoprobe, its fluorescence properties are re lated to the detection sensitivity. QDs with different coreshell structures vary in the resistance to the fluo rescence quenching during surface modification. In this study, a series of core and coreshell QDs with dif ferent structure and composition were designed and synthesized. And they were modified with amphiphilic polymer. Their fluorescence properties during the surface modification were monitored by fluorescence spectroscopy. Experimental results show core QDs are the most easily quenched during the surface modifi cation; the ability of resistance to quenching is enhanced after shell coating on core QDs, and this ability in- creases with the shell layers increase. Results also indicate the structure and composition of shells affect the resistance to fluorescence quenching. The resistance to fluorescence quenching is greatly enhanced when the core-shell QDs has a reasonable shell structure and composition. Furthermore, specific QD nanoprobes are constructed based on selecting appropriate structure of QDs and coupling with folic acid. The prepared QD nanoprobes are used for detection of breast cancer cells on flow cytometry. The results show that by optimizing the structure of core-shell QDs, the modified hydrophilic QDs have good fluorescence property. And the optimized hydrophilic QDs coupled with folic acid have targeting capability of cancer ceils.