| Quantum dots(QDs) which is a semiconductor nanocrystal of particle diameter between 1 and 10 nm. It's composition ofâ…¡-â…¥group orâ…¢-â…¤group elementals. This nanocrystal is used as marking materials from 90s in last century. Quantum dots has so many good characteristics for example:good biocompatibility, strong fluorescence intensity, anti-photobleaching and large excitation spectrum, et al. Because of these reasons, this nanocrystal is used in many areas, just like:drug screening, cell biology, fluorescence labelling, clinical detection and so on.On the present research stage,QDs is mainly used to study the function mechanism of certain medicines, or used to localization and target examination of cancer cells. Because of the heavy metal ion in the QDs, this material will injury the organism. So many scholars have thorough research on QDs'toxic improvement. QDs just only used as fluorescent probe but no used as medicine carriers. In this article I improved the cell toxic of QDs by introduce hydroxyl apatite, and use the hydroxyl apatite's structure to make QDs-HAP can be used as a medicine carrier. I have do as follows:1. I synthetic the three-layered quantum dots through aqueous phase. Then connect nano-hydroxyapatite to the three-layered quantum dots through chemical precipitation to gain a compound material, QDs-HAP. Through TEM detection can found that the QDs has 3-10nm particle diameter, the QDs-HAP's diameter is 10-20 nm and good dispersibility. Nano-hydroxyapatite coat the quantum dots uniformity, and the shape is globular. Through the detection of fluorescence intensity found that the best reaction time is 3 h. Connect the QDs-HAP to ciprofloxacin to gain the product----QDs-HAP-C. Diameter is 40-65nm, and also has good dispersibility.2. Use QDs, nano-hydroxyapatite, QDs-HAP, QDs-HAP-C and ciprofloxacin in the bacteriostasis experiment of E.coli and Staphylococcus aureus. Indicated that QDs-HAP can be used as medicine carrier by bacteriostasis rate reserch. The bacteriostasis rate from the biggest to the smallest is:ciprofloxacin, QDs-HAP-C, QDs-HAP, quantum dots, nano-hydroxyapatite. Explanted that the QDs-HAP has no intensification with ciprofloxacin in short times. Based on this experiment contrast QDs-HAP-C and ciprofloxacin's bacteriostasis rate through different incubate times. The result is:the bacteriostasis rate of ciprofloxacin is fall-off after incubate 18 h,and the rate of QDs-HAP-C is keep stabile through whole incubate procession. QDs-HAP-C's bacteriostasis rate in E.coli system is keep about 65%, and 70% in staphylococcus aureus. The conclusion is QDs-HAP can be used as carrier of drug delivery system.3. Carry out the toxicity test in mice. Inject 6 samples (CdSe, CdSe/CdTe, CdSe/CdTe/ZnSe, QDs-HAP, QDs-HAP-C, ciprofloxacin) into 6 mice through vena caudlis. Mice died at 7h after injection which inject of Cd/Se, and another died at 15h which inject of CdSe/CdTe, and all the others alive. The result showed that CdSe/CdTe/ZnSe, QDs-HAP, QDs-HAP-C, ciprofloxacin can used in vivo experiments. Then base this experiment I injection this CdSe/CdTe/ZnSe, QDs-HAP, QDs-HAP-C and ciprofloxacin into the internal of mice. Dissected after 5 d breed, and also do paraffin sections. Then take the mountings to the fluorescence microscope. We found that QDs and QDs-HAP are both dispersed in mice's heart, liver, spleen and kidney. And the QDs-HAP-C is dispersed only in mice's liver and kidney. This result showed that the ciprofloxacin's major active site in mouse is liver and kidney. The conclusion is: QDs-HAP can not only used as carrier of drug delivery but also can used as in vivo labels.
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