Preparation Of Water-Soluble ZnO Quantum Dots

The water soluble semiconductor quantum dots are new kind of biological tags materials. They are extensively used in the biological analysis realms, such as nucleic acid detection, cell imagination, protein analysis, due to their broad excitation spectrum, narrow emission spectrum, precise tunability of emission peak and negligible bleaching .ZnO quantum dots have unique fluorescent properties. But the preparation of water-soluble ZnO quantum dots for biological analysis has not been reported up to now. So some works and innovative results have been done as follow.(1) We have firstly prepared the water soluble quantum dots capped by (3-mercaptopropyl)triethoxysilicane. The analysis results show that quantum dots have good water solubility and unique fluorescent stability. Even under the higher NaCl concentration, the quantum dots haven't congregated between each other and could be used in the biological analysis. (2) We firstly report the water soluble blue ZnO quantum dots capped by SiO₂ Their emission spectra are very symmetrical and don't have obvious red tail. The full widths of half maximum are only 46nm.So they have unique fluorescent properties. (3)We have prepared the ZnO quantum dots directly capped by SiO₂ in ethanol. This preparation is simple and cheap, but stability of ZnO quantum dots are not very well in high NaCl concentration. (4) We have attained the ZnO quantum dots modified by mercaptoacetic acid. The quantum dots have well excion emission ability and good fluorescent stability in dilute water-free solution, but could not been stably existed in water solution.