The Synthesis Of ZnO Quantum Dots And Their Applications In Biological Imaging And Nano-drug Loading

In this work, we systhesis a new water soluble and tunable photoluminescence ZnO@ploymer nanoparticle through sol-gel method.The polymer shell of this organic-inorganic composite nanoparticle comband with ZnO inner core by covalent bond, and this polmer shell has two layers, the inner is hydrophobic organic shell, the outer is hydrophilic shell which has lots of hydrophilic groups, and this organic shell can prevent ZnO quantum dot from water damage. In this experiment, we systhesize two fluorescent colors ZnO nanoparticle, green and yellow. They have good water solubility and stability, they can stable in water for several weeks, the transmission electron microscopy and dynamic light scattering results show that radius of ZnO nanoparticle is about3-4nm, infrared spectra showing the amide groups are perfectly modified on the surface of the ZnO quantum dots, as the organic shell has good biological compatibility, they have good application in biological fluorescence label. In cell label test, these samples with the zinc concentrations below10μg/mL are nontoxic to human cells. The fluorescent confocal microscopy result show, they penetrate into living cells and locate in the cytoplasm, and they have good application in cell labeling.As the quantum dot we have systhesized has the pH responsive feature, when pH blow5, ZnO quantum dot can be easily resolved. Meanwhile,as the quantum dot has the bioaccumulation to DOX, we can development the ZnO quantum dot as a drug carrier, they can carry the DOX enter the cancer cell,and kill the cancer cell;the experiment result show that DOX can easily modified on the surface of the zinc oxide inner core, and1mg ZnO can bear the weight of200μg DOX, The optimum reaction time is about20h, TEM results show that ZnO quantum dots can still be maintain intact polymorphs after loaded DOX, UV spectra and fluorescence spectra of ZnO@DOX before or after in acid solution show that ZnO quantum dots did not change the nature of the DOX, did not affect the killing effect on cells.as the different corrosion degree of ZnO quantum dot under different pH conditions, this leading to a different DOX release rate under different pH condition,When pH is7.4, the release rate of DOX is15%, When pH is6.0, the release rate of DOX is68%, When the pH blow5, the release rate of DOX can reach90%,in all,the zinc oxide quantum dot can be a promising drug carrier in the future,and in the future for a long period of time, ZnO quantum dots will be more widely used in the biological aspects.