Study On Interaction Between CdS Nanoparticles,Cds-EcoRI Complex And DNA

Nanobiotechnology is the fusion of nanotechnology and molecular biology, and itis one of the current international frontier and hot research topic. It led to a kind ofnew multi-function devices and systems for biological and chemical analyses. Thesedevices and systems not only with ultra high sensitivity and recognition rate, but alsowith specificity is widely used in molecular recognition, medical diagnosis, drugdelivery, gene transfection, biomolecular separation and detection, etc.Nanobiotechnology was also applied in some important areas including developmentof body sensor, and nanoscale particles are assumed to inject into the human body, asa test in some critical reporter analytes. These nanoparticles can transfer signal to anexternal signal capture system. The nanoparticles in a state of constant vigilance willprovide a completely personal health status in real time and all-weather monitoring.However, whether these nanoparticles injected in the body will interact with thebiological mancromolecules or not directly will endanger the normal physiologicalactivities of the people even life. This will become one of urgent problems innanobiotechnology. This paper explores the interaction between semiconductornanoparticles CdS and DNA of the organism important macromolecular, specificwork is as follows:1. The interaction between two kinds of shapes of DNA （linear λ-DNA andcircular pBR322DNA） and two kinds of particle size of the CdS-COOHnanoparticles was investigated by using infrared spectroscopy, UV-vis spectroscopy,fluorescence spectroscopy, CD spectroscopy, atomic force microscope, agarose gelelectrophoresis, ect. The effect of CdS-COOH nanoparticles size and the DNA shapeon the interaction between them was discussed. And the interaction between theEcoRI restriction enzymes and DNA in the presence of CdS-COOH nanoparticleswas also explored. Results show that the interaction of CdS-COOH nanoparticleswith DNA by groove mode. The interaction between the CdS-COOH nanoparticleswith small size and DNA is stronger than that big size of the CdS-COOHnanoparticles. The interaction between circular pBR322DNA and CdS-COOHnanoparticles is better than that the linear λ-DNA. The CdS-COOH nanoparticleshindered the EcoRI enzyme digestion of DNA to some extent.2. The interaction between DNA and CdS-NH₂nanoparticles with-NH₂groups was investigated by using infrared spectroscopy, UV-vis spectroscopy, fluorescencespectroscopy, CD spectroscopy, atomic force microscope, agarose gel electrophoresis,ect. Results show that the CdS-NH₂nanoparticles with amino groups and theinteraction of DNA is stronger than the CdS-COOH nanoparticles with carboxylgroups and the interaction of DNA and CdS-NH₂nanoparticles was by the groovebinding. The CdS-NH₂nanoparticles also hindered the EcoRI enzyme digestion ofDNA to a certain extent.3. The interaction between CdS-COOH-EcoRI complex and DNA wasinvestigated by using spectroscopy, atomic force microscope, agarose gelelectrophoresis, ect. The effect of CdS-COOH nanoparticles size and interaction timeon the interaction between CdS-COOH-EcoRI complex and DNA was discussed.Results show that the big CdS-COOH-EcoRI complex can be specially bond DNA,and the small CdS-COOH-EcoRI complex exhibit specific binding and asteriskbinding. Long interaction time resulted in but also a non-specific combining, but alsospecial cutting of the DNA molecule. The activity of EcoRI enzymes was partiallyhindered because CdS-COOH and EcoRI combine to form complex.