Kanji Yamaoka

Novel Applications of DNA Materials

This paper describes preparations of innovative photonic devices based on high purity DNA molecules which are obtained from Salmon roe. DNA molecules have characteristic features of double helical chain structures where aromatic compounds can intercalate into the stacked layers so that various optically active aromatic dyes indicate strong enhancement effects of photonic activities. Thus, various DNA photonic devices have been developed in the world in terms of optical switches, electro-luminescence (EL), lasers and so on. However, these DNA photonic devices adsorb moisture in the air because of hydrophilic character of DNA molecules, leading to decrease photonic activities. Nevertheless, it was found by my group that a novel hybridization method of the dye-intercalated DNA molecules by means of so-called so-gel process increased stabilities and durability of DNA photonic devices under environmental changes. Also, hybridization of dye-intercalated DNA devices with synthetic polymers including fluorinated poly(methylmethacrylate ) or polycarbonates was successfully carried out by solution blending method, followed by casting the solution to obtain these films which showed stability and durability increases of these DNA photonic devices. DNA-lipid complexes showed a very strong fluorescence amplification by chelating with rare earth metals such as Europium or Telbiumu compounds. This paper also describes the chelate effects of rare earth metal compounds for light amplifications.

Optoelectronic applications of marine DNA

Various DNA-cationic lipid complexes and their bulk films were prepared and their physical properties were measured. Consequently, it was found that physical properties were greatly dependent on each lipids. The DNA-lipid complexes film formed by C-12 lipid of single-chain trimethylammonium type showed largest value on mechanical strength. Water absorption behaviors of the films were also dependent on kinds of lipids. It was found that fluorescence quantum yields of cyanine doped DNA-lipid films decreased nonlinearly with increasing relative humidity, while the fluorescence quantum yields were high compared with that of PMMA in whole range of relative humidity.

Progress of DNA biotronics and other applications

Crosslinking reactions of DNA film by UV irradiation were investigated in terms of structural changes which indicated the formation of -O-P-O- bond. The UV-cured DNA films were applied to medical uses for cell culture and wound-healing of skin, which were very effective for medical applications.

Stability improvements of DNA photonic devices

Recent research results on DNA-lipid complexes have shown various attractive features on E/O or O/E devices, optical memories, switches and sensors by intercalating optical dye into DNA double helix. DNA devices absorbed water under high humidity which led to decreases of optical functions. However, it is possible to improve the stability of DNA devices by encapsulating the DNA-lipid complexes into sol-gel materials or synthetic polymers so that water permeation is prevented by glass or synthetic polymers to stabilize and to keep the optical functions for a long time. This research aims at stability improvements of the DNA photon devices by sealing the DNA devices either by sol-gel glass or polymer blending.

Fabrication of waveguide structure of dye-doped DNA-lipid complex films

Laser-dye-doped-DNA-CTMA-PMMA hybrid films have been studied as a potential material for waveguide type thin-film laser devices. For the purpose of evaluate improving processability, not only optical characteristics of the fluorescence intensity and ASE spectrum but also moisture resistance of the hybrid film have been investigated. It is found that optical characteristics of those films are equally matched to the conventional laser-dye-doped- DNA-CTMA films with better moisture resistivity.