Spectroscopy, Lb Composite Film Of The Dna Molecules

In the progress of turning the functionality compound into practical use, the fabrication of the ultr-thin film plays a very important role. The Langmuir-Blodgett film, Assembly film, Vacuum Evaporation Film, bio-layers lipid membrane are all the frequently investigated ultra thin films. As we know, information is the characteristic of 21 century, and the new micro-apparatus investigations are focus on the new nano system. Therefore, as an prototype of the some ultr-thin film apparatus, the LB film has the special important status. The LB film is related to chemic, physics, biology, medicinal, electrodynamic and even the optical researches, and forms the intersection of these subjects. As a high inerratic aggregated system of the molecules, LB film can serve as an ideal film for research in the aspects of new materials, biology technology and the micro-electric study, and it is one of the hopeful new materials for the next century. Among varies research techniques of the thin film, spectroscopy methods are frequently used, especially the light absorption spectrum, the Raman spectrum, and etc.Surface-enhanced Raman Scattering (SERS), compared with the traditional Raman technique, is an powerful in-situ technique for studying the film's property and the mechanism of interaction between the molecules and the substrate, with the excellency of high sensibility and high distinguish ability. Also, by the merits of high sensitivity, the ability of avoiding the fluorescence, the UV-Raman spectroscopy also attracts much intention of the researchers.In this paper, we prepared the DNA film by the means of LB technique. Firstly,AFM images of DNA LB film under different surface pressures were obtained and discussed. It found that the structure properties of DNA /ODA mixed Langmuir monolayers at the air/water interface were affected greatly by the surface pressure. And the fractal domains in the mixed films changed from network structure to aggregated clusters with the enhancement of the surface pressure. And the fractal network become to interconnection more crowed network with layers increasing.Afterward the DNA molecules were deposited on the active substrate by LB technique, and SERS of DNA LB film was tested and obtained. The enhancement of SERS is probably related to orderly structure of DNA LB film.Lastly, high-quality SERS spectra of DNA were obtained by incorporation of the silver nanoparticles forming to the"silver nano-particles/DNA LB films /rough silver"system. The mechanism of SERS for DNA molecules was also discussed.So it is well way to get better SERS of DNA by using LB technique to fixup DNA on SERS-active substrates and the incorporation of silver nanoparticles. SERS technology is not only an effective means on studying the structure of DNA molecular, but also on the mechanisms for nano-technology devices made of DNA molecules.