This PDF file contains the front matter associated with SPIE Proceedings Volume 8103-0, including the Title Page, Copyright information, Table of Contents, Introduction, and the Conference Committee listing.

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.

The photophysical properties of the DNA-CTMA/Eu(tta)₃(H₂O)₂ were investigated in order to apply them for novel photonic materials. From absorption and CD measurements, the intercalation of Eu(tta)₃(H₂O)₂ into DNA-CTMA backbones was indicated. Furthermore, the emission properties of the DNA-CTMA/Eu(tta)₃(H₂O)₂ were superior to that of PMMA/Eu(tta)₃(H₂O)₂ films. We expect achievements of our research help development of organic electronic device used biomaterials as typified by DNA-hybrid materials.

DNA is an interesting material from the viewpoint of the materials science. This paper discusses the electronic states of the metal incorporated M-DNA complexes with several species of metal ions. M-DNA prepared by the ordinary methanol precipitation technique has been investigated with ESR, STM and optical absorption, and concluded that the metal ion hydrated with several water molecules locates in between the bases of a base pair and that the divalent metal ions are incorporated into DNA in place of two Na cations as the counter ion for PO^-₄in the DNA backbones. Only in Fe-DNA, it was confirmed that the Fe2+ in the FeCl₂ aqueous solution reacts with DNA to form Fe-DNA complex with Fe³⁺, where the charge would transfer to DNA. Within 30 min, the hydrolysis of Fe²⁺ to form Fe³⁺O(OH) did not occur in the FeCl₂ aqueous solution at room temperature. The optical absorption spectra of Fe-DNA is similar to that for FeCl₃ with the ionic character, but definitely differs from that of Fe³⁺O(OH) with the covalent bonding nature, suggesting the ionic character of Fe³⁺ in Fe-DNA. Finally, the possible two kinds of electronic states for Zn-DNA with different bonding nature will be discussed in relation to the recent report on Zn-DNA.

The potential of using a DNA biopolymer in an electro-optic device is presented. A complex of DNA with the cationic surfactant cetyltrimethylammonium-chloride (CTMA) was used to obtain an organic-soluble DNA material (DNA-CTMA). Poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS) was added to the DNACTMA to increase the electrical conductivity of the biopolymer. The CW absorbance and time-resolved photoluminescence of the resulting DNA-CTMA and DNA-CTMA-PEDOT:PSS were investigated. Both DNA materials have absorbance peaks at ~260 nm and a broad, Stokes shifted, photoluminescence peak around 470nm. The photoluminescence lifetime of the materials was observed to decrease with increasing UV excitation. Specifically, excitation with a high power ultrafast (~150fs) UV (266nm) laser pulse resulted in a drastic decrease in the photoluminescence lifetime decreases after a few minutes. Moreover, the observed decrease was faster in an air ambient than in a nitrogen ambient. This is most likely due to photo-oxidation that degrades the polymer surface resulting in an increase in the non-radiative recombination. In order to investigate the photoconductivity of these two materials, metal-biopolymer-metal (MBM) ultraviolet photodetectors with interdigitated electrodes were fabricated and characterized. The photoresponsivity of these devices was limited by the transport dynamics within the film. The prospects for the use of these materials in optical devices will be discussed.

The semi-intercalation of an azo-dye Disperse Red 1 (DR1) molecule into a biopolymeric material made of deoxyribonucleic acid (DNA) complexed with the cationic surfactant hexadecyltrimethyl-ammonium chloride (CTMA) formulated recently^1-3 has successfully explained the main experimental results⁴ of laser dynamic inscription of diffraction gratings: short response time, low diffraction efficiency, single-exponential kinetics and flat wavelength dependence.5 In this paper we generalize the analytic model of Ref.² to account for a more realistic dynamics of DNA-CTMA matrix. To this end we extend the model of paper⁵ by including into it probabilistic features of local free volume in DNA matrix which characterize, in a simple way, the spatial distribution of local voids which, in turn play the central role for the kinetics of photoinduced trans-cis-trans cycles of DR1 dye under the polarized laser light illumination. We discuss a stochastic master equation which generalizes the simple model of Ref.2 and address briefly the topic of non-exponential grating inscription in modelling and in recent experiments.

The process of creating natural DNA-containing bio-organic light emitting diodes is a fascinating journey from salmon fish to the highly-efficient BiOLED. DNA from salmon sperm is used as a high-performance electron blocking layer, to enhance the efficiency of the BiOLED over its conventional OLED counterpart. An overview of the BiOLED fabrication process and its key steps are presented in this paper.

A methodology that allows for the coupling of biology and electronic materials is presented, where double stranded DNA serves as a template for electronic material growth. Self-assembled DNA structures allow for a variety of patterns to be achieved on the nanometer size scale. These DNA architectures allow for feature sizes that are difficult to achieve using conventional patterning techniques. Herein, the procedures for the creation of self-assembled DNA nanostructures in aqueous and non-aqueous media are described, and these structures are subsequently deposited onto substrates of interest. DNA self assembly under non-aqueous conditions has yet to be presented in literature, and is necessary if unwanted oxidation of certain electronic substrates is to be avoided. Solubilization of the DNA in non-aqueous solvents is achieved by replacing charge stabilizing salts with surfactants. Retention of DNA hierarchical structure under both conditions will be presented by observing the structures using AFM imaging and circular dichroism spectroscopic studies.

We employed biopolymer DNA as a template to form J-aggregates of pseudoisocyanine (PIC), and succeeded to optimize the conditions for their formation in solutions and solid films. The optical characteristics of J-aggregates were investigated by absorption, fluorescence and circular dichroic (CD) spectra. For both films and solutions, polyvinylalcohol (PVA) introduced as a matrix for the films was proved to play a role to improve the film quality. We prepared the samples of several types of cyanine dyes systematically, finding the relationship among the molecular conjugated length and effects from the interaction with DNA. These results show possibility of application of J-aggregate into novel optical devices requiring optical nonlinearity or superradiant behavior.

Whispering gallery mode optical microresonators are devices used for performing ultra-sensitive optical detection. Although the majority of the sensor research has been focused on label-free detection strategies for diagnostics, a whispering gallery mode device is ideally suited to perform fluorescent label-based biodetection as well. However, previous research using optical microcavities to excite fluorescent molecules has focused on cavity quantum electrodynamics applications and fundamental studies of the interactions of large fluorescent nanoparticles with the resonant cavity. In the present work, a method for forming self-assembled lipid bilayers, a mimic for cell membranes, on a spherical microresonator is developed. Solid-supported lipid bilayers, which are approximately 5nm thick, have been shown to accurately model cell membranes, and researchers use lipid bilayers in combination with fluorescent microscopy when developing theoretical models for the transport of molecules across the cell membrane. The bilayernature is verified using both fluorescent resonance energy transfer and fluorescence recovery after photobleaching. The evanescent tail of the microresonator is used to excite a Cy5-conjugated lipid located within the bilayer while the underlying optical device behavior is characterized at 633nm and 980nm. The emission wavelength of the Cy5 dye and the optical performance (Q factor) of the microcavity agree with theoretical predictions.

Effect of ambient humidity on the photodegradation of melanin is investigated using an interferometric technique to fabricate gratings on thin films. A low power 355 nm diode laser is used to fabricate gratings on melanin thin films, while a 1 mW He-Ne laser is used to probe grating formation. Effects at several different UV intensities, ranging from 10 mW to 30 mW, and ambient humidities, ranging from 13% to 93%, are investigated on melanin thin films of two different thicknesses; 22 nm and 40nm. It is found that humidity has a great effect on the photodegradation of melanin. It is also found that existing gratings on melanin thin films can be enhanced by raising ambient humidity. These results have implications in the biological evolution of many mammals; as well as implications in fabrication and effective lifetime of organic electronics. The interferometric technique used shows great promise for fabricating grating to analyze photodegradation of different biomolecules under varying conditions. A simple mathematical model is developed to help explain the contribution of light intensity and ambient humidity to the photodegradation of melanin.nage.

Measurements were carried out on salmon DNA-based films, including as-received DNA (molecular weight, MW>2000 kDa) without and with hexacetyltrimethl-ammonium chloride (CTMA) surfactant, and sonicated DNA of MW~200 kDa with CTMA. The test specimens were spin-coated or drop-cast films on ITO-coated quartz slides with a gold charge-collecting electrode. To protect the films from atmospheric influences, the TOF devices were coated with a 200-400 nm polyurethane passivation layer. A quadrupled 20 ns, pulsed Nd:YAG laser with output at 266 nm was used for charge injection. The room temperature photoconductive transients were dispersive to varying degrees with hole mobilities in DNA materials films ranging between 2E-5 to 6E-3 cm²/Vs for fields ranging from 8 to 58 kV/cm. Only hole response was observed in DNA. The dispersive data were analyzed using a simple, quasi-empirical equation for the photocurrent transient data.

The potential of DNA-based dielectrics for energy storage applications was explored via the incorporation of high dielectric constant (ε) ceramics such as TiO2 (rutile) and BaTiO3 in the DNA bio-polymer. The DNA-Ceramic hybrid films were fabricated from stable suspensions of the nanoparticles in aqueous DNA solutions. Dielectric characterization revealed that the incorporation of TiO2 (rutile) in DNA resulted in enhanced dielectric constant (14.3 at 1 kHz for 40 wt % TiO2) relative to that of DNA in the entire frequency range of 1 kHz-1 MHz. Variable temperature dielectric measurements, in the 20-80°C range, of both DNA-TiO2 and DNA-BaTiO3 films, revealed that the ceramic additive stabilizes DNA against large temperature-dependent variations in both ε and the dielectric loss factor tan δ. The bulk resistivity of the DNA-Ceramic hybrid films, in the case of both TiO2 and BaTiO3 additives in DNA, was measured to be two to three orders of magnitude higher than that of the control DNA films, indicating their potential for utilization as insulating dielectrics in capacitor applications. As a part of a baseline study, results based on a comparison of the temperature-dependent dielectric behavior of DNA and DNA-CTMA complex films as well as their frequency-dependent polarization behavior, are also discussed.

DNA-CTMA is an attractive material to explore for reconfigurable optical and electronic devices. Its dielectric constant at microwave frequencies can be tuned by applying a DC electric field. In this work, the origin of dielectric tunability and other ferroelectric-like behavior observed in DNA-CTMA films is investigated. Results suggest that the dominant polarization mechanism is ionic in nature and is caused by intentionally retaining excess ions in the DNA-CTMA precipitate during processing.

Recent examples of our works in the field of molecular engineering of chromophores for two-photon photodynamic therapy (PDT), and their vectorization into biological medium are presented and discussed. In a first section of this article, we show that a commercial amphiphilic diblock copolymer can be used as a micellar container for efficient delivery of s standard two-photon PDT sensitizer into cells. In a second section, we show how a simple molecular engineering strategy can be used to improve the performances of two-photon PDT sensitizer in the biological transparency-window.

All optical switching has been studied using the Optical Kerr Effect (OKE) configuration in a biopolymer matrix containing a photochromic molecule. The biopolymer system consisted of a deoxyribonucleic acid blended with cationic surfactant molecule cetyltrimethyl-ammonium chloride suitable for optical quality thin film fabrication. The excitation beams inducing birefringence were delivered from a continuous wave laser at 473 and chopped using a variable frequency chopper. Additionally auxiliary nanosecond pulses coming from Nd:YAG laser were used. The birefringence was instantaneously monitored by a weak non-absorbed light from a cw He-Ne laser working at 632.8 nm under crossed polarizer system. Excellent switching times in the range of microseconds and full reversibility of the studied processes have been observed.ïýïýïý

We succeeded to generate tunable laser emissions from hemicyanine dye, (4-[4-(dimethylamino)stylyl]-1- dococylpyridnium bromide) doped in DNA-surfactant complex through three methods. First, we constructed Littrow type cavity containing hemicyanine and DNA-CTMA complex solutions and observed tunable laser oscillation. Next, we showed a tunable laser oscillation from ethanol solutions of hemicyanine and DNA-CTMA complex under pumping of two interfering beams which formed a distributed feedback grating of population. Finally, we fabricated a thin film composed of hemicyanine and DNA-CTMA complex, and demonstrated tunable laser oscillation under pumping with two interfering beams. We evaluated the durability of the tunable thin film laser by continuous operation, and confirmed the lifetime of more than one hour.