| Nowadays, as the accomplishment of HGP (Human Genome Project) and the coming of Post Genome Era, biomedicine research has gradually focus on single cell, protein, and even on single base of the nucleic acid, researchers need to explore the distribution, composition and the interaction orientationally and in real-time among biomolecules such as the peptide, protein and nucleic acid at the microscopic level. All these biochemical information will do large contribution for the diagnosis of disease in early period and the research on the pathogenesis. In the process of researching on protein integration and gene expression, biological imaging technology with the fluorescent probe as the guidance, which has provided important technique for the research of those biochemical information. But there are also deficiencies concerning about the organic fluorescent probe, for they usually be easily photodegradated and it is also hard to pursue long-time, multi-molecules trace and dynamics process observation of the labeled molecules, in addition, the spectrum may be overlapped. However, quantu-mdots(QDs), one novel kind of nano-material as fluorescent probe, has got enormous attention for its excellent optical property and applicability in the biological imaging.Quantu-mdots(QDs) is one kind of colloidal semiconductor nanocrystal, which usually be constituted by chemical elements from family of Ⅱ-Ⅵ or Ⅲ-Ⅴ. It contains shell and core which formed by various of metallic and nonmetallic elements. In present, research almost focus on the Cd X (X=S, Se, Te), whose particle size is between1to10nm. Continuous band structure turns to the state of discrete energy with molecular characterization, and launch fluorescence when excited because of the quantum limit domain effect.Crystal core is the foundation of quantum dot producing fluorescence. The core is constituted by heavy metal element, so that whether the heavy metal element will be the biological hidden trouble of the QDs? Previous researches have showed that some of nanometer materials would cause unexpected toxic effects on animal organs. However, present research about threaten on organisms followed by the using of QDs on biomedical area is limited. At the same time, we also faced one problem that which level of doses concentration of quantum dots would produce toxic effects on organisms, i.e. the range of safe biological dose have not been measured. There had been research which demonstrated that the safe dose of QDs in vitro had been determined, but QDs exposed in vivo should be demonstrated further more. Another problem is about the variety of QDs. There is not unified standards and study method until now due to various of physical and chemical properties of QDs and the different synthesis processes. It is an urgently needed to establish a reasonable and effective evaluation method for QDs. And this also do large help in measuring safe range of biological dose. It has been supposed that QDs with heavy metal ion as its core would arouse Oxidative Stress Reaction of organisms which would be harmful. There have been large amounts of experiments in vitro showed that QDs were toxic to cell membrane, mitochondria or DNA, and they also could increase the concentration of ROS. In normal organism, ROS should be maintained at a low level, therefore, they can be easily neutralized by Antioxidants such as SOD and GSH. The antioxidant system will be unbalanced if the level of ROS was excessive, which would damage biomacromole such as DNA, protein and lipids. Therefore, this article selects the crosslink between MDA, DNA and protein as indicator besides ROS, GSH and SOD. TNF-α and MDA have also been considered as the TNA-α reflect the Cancerous and inflammation level in organisms.Results demonstrated that QDs(MSA/CdTe) did no harm to the oxidatie stress system of Liver cells and the biomacromole, so that there is enormous application potential as biological probe. Furthermore, a series of research in vivo should be carried out to explore the potential of this kind of Qds. |
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