It is important for cancer therapy to understand cancer mechanisms and develop a diagnostic method. We have developed a method for in vivo imaging with very high spatial accuracy (~9 nm) under a confocal microscope and succeeded in tracking the membrane protein during metastasis in living mice. We found that the tumor cells showed increases in membrane fluidity (over 1000-fold) and formed local pseudopodia in the process of metastasis, suggesting that membrane fluidity and morphological changes are critical for metastasis. To develop a novel immunohistochemistry (IHC), we newly-made organic fluorescent material-assembled nanoparticles. These nanoparticles have 1000-fold greater fluorescent intensity compared to representative organic fluorescent material. Consequently, the fluorescence of these nanoparticles exhibited a significantly high signal-to-noise ratio on IHC-imaged cancer tissue, including high-level autofluorescence. The IHC method using these nanoparticles was applied for the identification of estrogen receptor-expression levels in breast cancer tissue. The results demonstrated that the diagnostic accuracy and quantitative sensitivity were greatly improved compared to previous IHC methods. This technique would be useful for the prediction of clinical responses to ER-targeted therapy.
It has been proposed that melanin may play a role in the antimicrobial defense system of a human body. Furthermore, it has been found that melanin has efficacy against oxidative stress, tumor, venin, virus, and heavy metal ions. In view of the great potential of melanin in medical applications revealed by its photodynamic actions, we develop techniques based on mechanical stir and photo-fragmentation with femtosecond laser pulses respectively for nanonization of melanin to produce nanometer-sized and water-dispersible melanin, in order to more reliably study melanin as a photodynamic-inactivation photosensitizer. In vitro experiments on the antimicrobial efficacy of nanonized melanin were conducted. It was found that both Sepia melanin and synthetic melanin do not have a significant effect on lowering the survival rate of Gram-positive bacteria Streptococcus mutans with or without light irradiation. Therefore, it is concluded that melanin, though capable of generating melanin radicals and reactive oxygen species, is not a practical agent for photodynamic inactivation.
Ultralow-k (dielectric constant) films are promising substrates for next-generation flexible print circuits. Introducing numerous pores into the film can effectively reduce the substrate's dielectric constant because the relative dielectric constant of air is smaller than that of any polymer substrate. We recently developed a short-cycle time process employing high-pressure CO2 and the CO2-tertiaryamine zwitterions in polyimide precursor solutions to create 1-3 μm pores of >70% porosity. However, the film size was limited to 30 × 30 mm2. A larger film (70 × 150 mm2) was required to measure the signal attenuation of an electrical circuit on a porous PI film as a next-generation flexible cable. In this paper, the developed process was scaled up to obtain 10-fold-larger ultralow-k films of porous polyimide. The process involved a high-intensity UV lamp, thick-quartz window and hydraulically movable sealing plate and produces 70 × 150 mm2 films, which was a suitable size for high-speed data communication transmission tests. The preliminary results of building up a printed circuit on the porous substrate and signal attenuation measurements at 20 GHz demonstrated that the low-k porous PI substrate reduced the signal attenuation compared to a non-porous substrate with the same cross-sectional line area.
Carbazole and quinoline combined donor-acceptor (QUI-OCZ) conjugated oligomer was synthesized by Wittig route. The resulting oligomer structure was well established by FTIR, NMR, Gel permeation chromatography (GPC) and elemental analysis. The resulting oligomer exhibits good solubility in common organic solvents.The optical and potential charge transporting properties of the oligomer were investigated by UV-visible, fluorescence spectroscopy and cyclic voltammetry. The UV-visible spectrum of the oligomer exhibited a sharp absorption band at 275-325 nm with shoulder peak at 374 nm. The oligomer also showed the fluorescence emission at 420 - 451 nm. The optical energy band gap and quantum yield of the oligomer was found to be 2.58eV and 0.237. In addition, quenching effect of QUI-OCZ was carried out by adding N, N-dimethyl aniline (electron donor) and dimethyl terephthalate (electron acceptor). The morphology of the oligomer film was examinedby atomic force microscopy (AFM) and observed spherical shape of particles with micrometre in size. The electrochemical studies of QUI-OCZ revealed that the HOMO and LUMO energy level was -5.74 and -3.17 eV respectively. Preliminary reports suggested that the oligomer will behighly useful for organic light emitting diode application.
Nanoimprinting has become one of the advanced patterning methods for fabricating metal/polymer bi-layer nanostructures used for functional materials. How to control and avoid the emergence of various defects in nanoimprinting process is one of the key issues to improve the quality of nanofabrication. However, little attention has been paid to the demolding process which most likely lead to defects. In this paper, von Mises stress and deformation of bi-layer structure during demolding process were simulated and analyzed. In the finite element analysis model, the adhesion and friction forces were considered. The results presented that stress concentration occurred at four locations in the bi-layer structure. The curves of stresses were plotted to explain the stress concentration and deformation. By comparing the stresses at key locations, related regularities about how to avoid stress concentration were proposed. Depending on these regularities, corresponding measures can be applied to avoid the delamination defects in bi-layer structure in practice.
A novel strategy to prepare network structured polymer/clay nano composites, namely poly(cyclohexyl methacrylate-co-2-hydroxyethyl methacrylate)/ montmorillonite (PCHMA-co-PHEMA/MMT) nanocomposites by combination atom transfer radical polymerization (ATRP) and photoinduced cross-linking processes is described. In the first step, ATRP initiator modified clay (MMT-Br) was prepared by treating the organo-modified clay, Cloisite 30B (MMT-OH) with 2-bromoisobutyryl. Subsequent copolymerization of cyclohexyl methacrylate and 2-hydroxyethyl methacrylate via ATRP using MMT-Br as initiator resulted in the formation of PCHMA-co-PHEMA/MMT nanocomposites. Then, methacrylate groups were introduced to the nanocomposite structure by reacting 2-isocyanatoethyl methacrylate isocyanate with the hydroxyl groups on of PCHMA-co-PHEMA chains. Finally, upon irradiation of the functional nanocomposite in the presence of the long wavelength absorbing photoinitiator, bis(2,4,6-trimethylbenzoyl) phenylphosphine oxide yielded network structured nanocomposites. The structures, thermal and morphological properties of the nanocomposites were investigated by spectral, thermal and microscopic analyses.
With the slipping of the insertion node for extreme ultraviolet lithography, demands on resist resolution have increased further stressing sensitivity requirements. A variety of resists, both chemically amplified and not, have been developed meeting resolution needs, but falling short on sensitivity and line-width roughness (LWR). Note that resolution is an absolute mandatory requirement, the true tradeoff that must be considered is between sensitivity and contact hole printing is a crucial application for extreme ultraviolet lithography and is particularly challenged by resist sensitivity due to inherent inefficiencies in darkfield contact printing. Checkerboard strong phase shift masks have the potential to alleviate this problem through a 4× increase in optical efficiency. The feasibility of this method is demonstrated using the SEMATECH-Berkeley Microfield Exposure Tool pseudo phase shift mask configuration and preliminary results are provided on the fabrication of an etched multilayer checkerboard phase shift mask.