Search

This paper describes preparations of nano-scale patterned electric circuit based on high purity DNA molecules which are obtained from Salmon roe. The patterning on silicon substrate was carried out by an ink-jet method of aqueous solution of DNA. However, the Salmon-based DNA has a so huge molecular weight of over billions that even only 1wt% aqueous solution of DNA becomes gel without any fluidity. So, it is necessary to reduce molecular weights of DNA to increase fluidity of the aqueous solution of DNA, keeping the characteristic feature of double helical structures of DNA molecules to form metal-chlating complexes with various metal cations such as silver or copper cations. Several methods to reduce the molecular weight of DNA, including hydrolytic , enzymatic degradations and ultra-sonification. It was found that the best method to reduce the molecular weights (MW) of DNA was an enzymatic degradation of DNA to increase fluidity, thus being able to apply an ink-jet method for nano-scale patterning on a silicon wafer to form DNA circuit, followed by ion-crosslinking of DNA by dipping the patterned DNA circuit into aqueous solution of copper chloride. The DNA-CuCl 2 patterned circuit was reduced to copper nano-lines for electric circuit, by using hydrazine as a reducing agent. Thus, all DNA devices can be prepared by the combination of DNA transistor and circuit.

The large enhancements of optical properties of the dye-intercalated DNA lead us to apply the dye-intercalated DNA as various sensors with a high sensitivity to detect environmentally toxic gases such as dioxine, NOx or carbon monoxide. This paper retorts on DNA sensors for the further applications of DNA as materials. Also, bio-medical applications of DNA sensors such as a glucose sensor are reported.

DNA-CTMA or DNA-CTMA-PMMA films have been studied as a potential material for waveguide type thin-film photonic devices such as dye-doped thin film lasers, optical waveguide amplifiers, or optical waveguide switches. For the purpose of evaluate processability, not only optical characteristics of the fluorescence intensity but also moisture resistance of the film have been investigated. It is found that optical characteristics of those films are equally matched to the conventional DNA-CTMA films with better moisture resistivity. Waveguide fabrication experiments by using DNA-CTMA-PMMA films showed good moisture resistant nature and processability.

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.

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.

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.

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.

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. Physical properties of DN-lipid complexes are greatly dependent on kinds of lipids and chiral lipids from α-amino acids were prepared so that self-assembled structure of DNA molecules was organized. DNA-L-alanine-derived lipid formed a self-assembled film with a liquid crystalline structure, which showed a less water absorption. DNA devices absorbed water under high humidity which led to decreases of optical functions. However, it was possible to encapsulate the DNA-lipid complexes into sol-gel materials so that a water permeation was prevented by glass to stabilize and to keep the optical functions for a long time.

A DFB laser structure utilizing dye-doped-DNA-lipid films and etchless grating has been studied for potential application to thin-film single longitudinal mode lasers. Although further improvement should be necessary for laser characteristic, the lasing threshold of about 1 mJ/cm 2 was obtained and single longitudinal mode operation has been successfully achieved.

We succeeded to prepare the microsphere of polymer to which the marine DNA was doped. Moreover, ASE (Amplified Spontaneous Emission) was observed since the optical property of the microsphere to which the DNA was doped was discussed. In addition, an excellent optical property was found being shown in the comparison with DNA doped polymer thin film. The DNA shows a very interesting optical property like the improvement of the fluorescent intensity and the control of the concentration quenching of the dye by inserting the functional dye between the base pairs. On the other hand, the research using the surface is advanced to the microsphere for the reasons why the surface area is large. Light can be confined highly effective in the miniature space, and the microsphere of polymer is a material that is promising as optical micro cavity.

DNA polymer gel was prepared by combining DNA-lipid and polymer gel. A hemicyanine dye, trans-4-{4- (dibutylamino)-styryl}-1 methylpyridinium iodide (DBASMPI) doped DNA polymer gel was obtained by soaking it in dye solution. We observed optical properties of dye-doped DNA polymer gel. Amplified spontaneous emission (ASE) properties of dye-doped DNA polymer gel at ambient temperature were investigated. We measured the intensity of output light from samples as a function of pump pulse energy in order to determine the threshold energies. The emission spectra were obtained under several values of excitation intensity to confirm spectral narrowing. We discussed the lasing capability by dye-doped DNA polymer gel.

DNA-CTMA solutions in ethanol doped by various azobenzene compounds were prepared and their absorbance transition by irradiate UV were measured. It was found that trans-cis transition took place in the cases of doped azobenzene and azobenzene-4,4'-dicarboxylic acid diethyl ester(ADCDE). It did not depend for the speed of trans-cis transition of solution which doped both azobenzene and ADCDE to DNA-CTMA with those amount of doping. To the next DNA-CTMA films doped by azobenzene and ADCDE were prepared and their absorbance transition by irradiate UV were measured. Consequently, trans-cis transition took place only by only the films doped azobenzene and was not transferred by the films doped ADCDE. It was found that trans-cis transition of DNA-CTMA films doped by azobenzene (100:1) was faster than PMMA films doped same amount of azobenzene. It is considered that because azobenzene molecules were isolated by intercalation to DNA and the spatial flexibility of azobenzene molecules became large, the speed of trans-cis transition of azobenzene became early compared with the case where it doped to PMMA.

Optical and photochromic properties of spiropyran-doped DNA-surfactant complex films have been studied. They strongly depended on the type of spiropyran as well as the type of surfactant. Spiropyrans containing the oxazine ring and intercalated into DNA showed very rapid photochromic response. It is also shown that photochromic response times are expected much faster by increasing the intensity of the excitation light.

DNA fibers were prepared by melt spinning method from DNA-CTMA powder. A hemicyanine dye, trans-4-{4-(dibutylamino)-styryl}-1-methylpyridinium iodide (DBASMPI) doped DNA-CTMA fiber with core diameter of 1 mm and dye concentration of 3.6 wt% was obtained by soaking it in an aqueous dye solution. Laser (532 nm) pumped amplified spontaneous emission (ASE) at 610 nm was observed in the dye-doped DNA-CTMA fiber. The ASE occurred at energy density 50 mW. The amplification of optical signals at 607 nm wavelength was confirmed. The results from ASE emphasize that DBASMPI doped DNA-CTMA fiber is appealing as a good candidate for optical amplifiers and superfluorescence sources in a variety of communication and sensor applications.

We observed optical properties of organic fluorescence materials doped DNA-CTMA and PMMA. The quantum yield in DNA-CTMA was higher than in PMMA. Amplified spontaneous emission properties of dye-doped DNA-CTMA film at ambient temperature were investigated. The narrowing of line shape and amplified spontaneous emission dependence occur at the same intensity indicates that both effects are the results of light amplification. We discussed the lasing capability by interacting DNA-CTMA.

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.

Optical materials for waveguiding applications must possess the desired optical and electromagnetic properties for optimal device performance. Purified deoxyribonucleic acid (DNA), derived from salmon sperm, has been investigated for use as an optical waveguide material. In this paper we present the materials processing and optical and electromagnetic characterization of this purified DNA to render a high quality, low loss optical waveguide material.

When one thinks of suitability in space environments, irradiation tolerance typically is the first property that comes to mind. In addition to irradiation tolerance, however, suitable photonic materials must also possess the desired optical and electromagnetic properties for optimal device performance. Extracted and purified deoxyribonucleic acid (DNA), derived from salmon, has been investigated for use in photonic applications and has shown promise as an excellent optical waveguide material. In this paper we present the properties of DNA that are applicable for both ground and space based photonic applications. Such properties include optical loss, temperature stability, refractive index, resistivity, dielectric constant, microwave insertion loss and gamma ray irradiation tolerance.

Optical properties of spiropyran-doped DNA-CTMA films have been studied. They strongly depended on molar ratio of DNA/spiropyran. Switching experiments was performed for 1.55-μm signal light. Measured slow transition times indicate much precise adjustment and optimization.

We observed optical properties from several kinds of Eu-chelates doped DNA-CTMA and PMMA films. The lifetime in DNA-CTMA was longer than in PMMA, and the quantum yield in DNA-CTMA was also higher than in PMMA. Among them, we calculated each cross section because we compared laser properties of Eu-chelates by interacting DNA-CTMA with PMMA. We will discuss the lasing capability by interacting DNA-CTMA.

Highly purified deoxyribonucleic acid (DNA) was isolated from salmon and scallop sperm by an enzymatic isolation process. Characterization of the optical and electromagnetic properties of DNA suggested suitability for optical waveguide applications. One of the characteristic features of DNA we discovered was an intercalation of aromatic compounds into stacked layers within the double helix of DNA molecules. We found that various optical dyes inserted into the double helix of DNA molecules render optical waveguide films of dye-intercalated DNA suitable for active photonic devices. Our investigation includes intercalation of fluorescent dyes, photochromic dyes, nonlinear optic chromophores, two photon dyes and rare earth compounds into DNA comparing results with poly(methyl methacrylate) (PMMA) based materials.

Nonlinear optic (NLO) polymer based electro-optic devices have been achieving world record low half wave voltages and high frequencies over the last 2-3 years. Part of the advancement is through the use of relatively more conductive polymers for the cladding layers. Based on the current materials available for these cladding materials, however, the desired optical and electromagnetic properites are being balanced for materials processability. One does not want the solvent present in one layer to dissovle the one deposited underneath, or be dissolved by the one being deposited on top. Optimized polymer cladding materials, to further enhance device performance, are continuing to be investigated. Thin films of deoxyribonucleic acid (DNA), derived from salmon sperm, show promise in providing both the desired optical and magnetic properties, as well as the desired resistance to various solvents used for NLO polymer device fabrication. Thin films of DNA were deposited on glass and silicon substrates and the film quality, optical and electromagnetic properties and resistance to various solvents were characterized.

A DNA-CTMA optical fiber was prepared by melt-spinning method for the first time. A hemicyanine dye, trans-4-(4-dibutylamino)-styryl)-1-methylpyridinium iodide (DBASMPI) doped DNA-CTMA fiber with core diameter of 1 mm and dye concentration of 3.6 wt% was obtained by soaking it in an aqueous dye solution. Laser (532 nm) pumped amplified spontaneous emission (ASE) at 610 nm was observed in the dye-doped DNA-CTMA fiber. The ASE occured at energy density 50 mW. The results from ASE emphasize that DBASMPI doped DNA-CTMA fiber is appealing as a good candidate for optical amplifiers and superfluorescence sources in a variety of communication and sensor applications.

A rare-earth chelate, Europium 6,6.7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5,-octanedionate, (Eu3+-FOD) doped DNACTMA complex as fiber and film materials was prepared by casting solution method and gel-spinning method. The Eu-FOD-DNA-CTMA complex was luminescent and has 750 μs of fluorescence lifetime, sharply-spiked emission spectra, excellent film and fiber formability, moderate absorption (40000M-1cm-1) at 327 nm and high quantum yield forlanthanide emission. By comparison of fluorescence lifetime of Eu-FOD doped DNA-CTMA solid matrix with that of Eu-FOD doped in PMMA, it was clear that energy transfer from DNA to FOD leads to enhancement of fluorescence emission at 613 nm. Analysis results for fluorescence spectra and fluorescence relaxation time of Eu3+ doped in the materials indicated that Eu3+-FOD is chemically bond within the DNA-CTMA matrix. Amplified spontaneous emission (ASE) at 612 nm by pumping with UV laser (355 nm) was observed in the materials. Fluorescence lifetime of the Eu-FOD doped in the DNA-CTMA solid matrix was evaluated to be 750 μs, which is ca. 230μs longer than that of Eu-FOD doped in PMMA solid matrix. Efficient Energy transfer from base of DNA to FOD, then to Eu, occurred when irradiated by UV light or 355 laser beams.

High concentration rare-earth metal ion chelates, Europium 6,6.7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5,- octanedionate, (Eu-FOD) doped PMMA fiber and film were successfully prepared for the first time by casting solution method and gel spinning method. The optical and photoelectric characteristics of Eu(3+)-FOD doped PMMA film and fiber were investigated. Amplified spontaneous emission (ASE) from the Eu-FOD doped PMMA film and fiber was observed. The high concentration Eu-FOD-doped PMMA fiber and film sample exhibited lasing threshold as low as o. 15 mJ/ cm2 when pumped with a 355 nm pulsed laser beam.© (2002) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Several class of dyes doped in deoxyribonucleic acid (DNA) derived from salmon show enhancement of fluorescence due to suppression of molecular aggregation. Also, some recent studies support electric conduction in DNA strands. Combination of these properties suggests the possibility to develop organic LED devices (OLED) based on biopolymer systems. Furthermore, the electroluminescence (EL) effect can be employed as a probe for electrical and optical properties of DNA. We fabricated OLED devices based on DNA- lipid complex and dopant dyes (ethidium bromide and fluorescein). Devices are composed of hole injection layer, dye-doped DNA-lipid layer and electrodues. OLED with ethidium bromide doped DNA showed LED emission under DC bias, but the origin of the emission was tris-(8- hydroxyquinolinato)aluminum(III)(Alq3) which was employed as an electron transporter. The current-voltage characteristics of the devices show apparent rectification behavior. From these experimental results, it is confirmed that DNA transports hole current under external DC bias. When employing fluorescein as a dopant in DNA and fabricating the devices without Alq3 layer, we observed emission from the dyes incorporated in DNA. Although the origins of the emission centers in spectra are not clear, it shows that the DNA-lipid complex will be basically applicable to OLED if additional improvements are made.

Some of cyanine dyes and ionic functional chromophore have been widely used to probe the conformation of DNA helix through measurement of induced circular dichroism (CD) spectrum, change of UV-visible spectrum and enhancement of fluorescence. In order to develop new type optical and optoelectric materials we studied the interaction between a hemicyamnine dye and DNA in aqueous solution and have prepared the NLO dye-DNA complex films. We first found that binding of the famous NLO dyes, C22HEMI to DNA induced strong CD band in the absorption spectra of the dyes in DNA aqueous solution and DNA-CTMA complex film1. The enhancement of the fluorescence quantum yield upon binding of the dye to DNA in aqueous solution is above 100-fold. Luminescence of the hemicyanine dyes-doped in DNA-CTMA film displayed enhancement fluorescence above three orders. Refractive indices and film thickness of the self-assembled thin film determined by using the prism coupling method revealed that the self-assembled DNA thin film has anisotropic structure in two-dimensional and the self- assembled DNA-CTMA thin film is isotropic. The functional dye-DNA-CTMA film may be used to fabrication of optical waveguide, and optoelectronic devices based on the strong flurorescence, and tunable optical properties.

We observed amplified spontaneous emission (laser action without cavities) from several kinds of dyes doped in films of salmon DNA (deoxyribonucleic acid) derivatives. We employed laser dye Rhodamine-6G, Pyrromethene 556, and nonlinear optical dye DMASDPB for dopants. Most of sample films with several micrometers thickness were prepared as follows: 1) DNA aqueous solution was mixed with hexadecyltrimethylammonium chloride aqueous solution. 2) precipitated DNA-lipid complex and dyes were dissolved in ethanol or chloroform. 3) Films were formed on substrates by casting from the solution. The amplified spontaneous emission was observed when the films were pumped with a nanosecond laser of 532 nm at the intensity above a threshold value. Spectral narrowing occurred at the threshold energy, and it was accompanied with superlinear dependence of the emission intensity on the pumping intensity. Dye molecules in DNA films can be intercalated in the double helix structure. Because molecules are separated form one another, it is possible to increase chromophore concentration without fluorescence quenching due to aggregation. Furthermore, it is known that DNA shows a good conducting property. We will discuss the possibility of optical and electronic devices utilizing these characteristics.© (2000) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Optical resolution of (alpha) -amino acids such as Tryptophan (Try) were carried out either by membranes or temperature-responsive polymeric adsorbents. Higher ordered supramolecular structures of polymers were recognized to be quite important for optical resolution by membranes. Optically active and temperature-responsive polymers derived from N-isopyropylacrylamide could be applied for optical resolutions of racemic Try by using dissolution-precipitation behaviors of the temperature-responsive polymeric adsorbents.

New biocomposites with dynamically active properties were synthesized containing the conducting electroactive polymer, polypyrrole, dextran sulphate and a range of proteins. These composites have a hydrophilic matrix with a high water content and confer on the conducting polymer several properties useful in the design of new 'smarter' biomaterials. The composite is an excellent surface for the culture of mammalian cells. Inclusion of the polyelectrolyte also allows incorporation of protein and control of its release by reducing the polypyrrole backbone. These properties were exploited to incorporate nerve growth factor into a composite of polypyrrole and sulphated polysaccharide and after reduction to cause release of the nerve growth factor and thereby stimulate phaeochromocytoma cells to differentiate. Inclusion of polyelectrolyte also allows the incorporation of whole relatively intact cells into a polymer composite. This was demonstrated by the incorporation of human erythrocytes into the composite. The electrochemical properties of the composite were maintained raising the possibility that they could be used as the basis of an electrochemical biosensor for the detection of blood cell antigens. These new composite polymers showing protein release could be used not only as vehicles to deliver proteinaceous pharmaceuticals but also to communicate with mammalian cells during critical phases of their growth and development. The immobilization of mammalian cells in the composites could not only form the basis of biosensors but can also be used for many other applications where immobilized cells are required. Moreover the ability to control the dynamic properties of the composite and possibly the cells within it could be exploited to advantage.