Sangkug Lee

Functionalized biocompatible WO3 nanoparticles for triggered and targeted in vitro and in vivo photothermal therapy.

We report on dopamine-conjugated hyaluronic acid (HA-D), a mussel-inspired facile capping material that can modify tungsten oxide (WO3) nanoparticles to be both biocompatible and targetable, allowing precise delivery (WO3-HA) to a tumor site. Near-infrared (NIR) irradiated WO3-HA showed a rapid and substantial rise in photothermal heat to complete in vitro thermolysis of malignant MDAMB and A549 cancer cellsbut was found to be relatively less sensitive to normal MDCK cells. A long-term in vivo investigation of ~10 nm HA thickness on WO3 (WO3-HA) nanoparticles demonstrated efficient photo-thermal conversion with time-dependent tumor target accumulation. This long-termin vivo survival study ofWO3-HA showed promising biocompatibility, with a complete recovery from malignant tumor. Due to the importance of keeping simplicity in the design of therapeutic nanoparticles, we therefore expect that this facile scheme (HA-D) would contribute to the biocompatible development of versatile metallic nanoparticles for photothermal applications.

Spiropyran‐Conjugated Pluronic as a Dual Responsive Colorimetric Detector

Novel spiropyran-conjugated Pluronic [polyethylene oxide (PEO)-b-polypropylene oxide (PPO)-b-polyethylene oxide (PEO)] micelles are developed as a new colorimetric detector showing photo- or thermo-switchable behavior. Facile conjugation of spiropyran to Pluronic was confirmed by (1)H NMR, UV-Vis, and Fluorescence spectroscopy. A switchable photoluminescence is found depending on the irradiation with either UV or visible light, and temperature resulting from structural isomerization of spiropyran between spiropyran (SP) and merocyanine (MC) form. Cytotoxicity of the spiropyran-conjugated Pluronic (SP-PL) was evaluated following an MTT assay, whereas photo responsiveness of spiropyran within the micelles was determined by confocal laser scanning microscopy.

Zwitterionic fluorescent nanoparticles prepared using BODIPY conjugated polysulfobetaines for cancer cell imaging

Zwitterionic fluorescent nanoparticles are developed by using polysulfobetaine methacrylate, NIPAAm and BODIPY fluorophores to identify the cancer cells in response to intra and extracellular stimuli. The fluorescent nanoparticles exhibit minimal fluorescence intensity at physiological temperature and pH, while strong emissions are observed in acidic and basic environments enabling the nanoparticles to act as novel fluorescence probes.

Influence of chemical structure on the optical properties of new side-chain polymers containing cholesterol

Poly[1-(cholesteryloxyhexyloxy)ethylene] (PHET) and poly[1-(cholesteryloxycarbonyl-hexyloxy)ethylene] (PHES) were prepared by reacting poly(vinyl alcohol) with cholesteryloxyhexyloxy bromides (CHB) or cholesteryloxycarbonylhexyloxy bromides (CEHB), and their thermal and optical properties were investigated. PHET and PHES exhibited monotropic cholesteric phases; however, their thermal behaviours depended on the cholesteryl groups and alkylene spacers with different chemical structures. PHET did not display reflection colours over its entire cholesteric range, whereas PHES did display reflection colours. These results suggested that the thermal stability and helical twisting power (HTP) of these polymers strongly depend on the difference in the chemical structures of the flexible spacer via cholesterol. The mesophase properties of PHET and PHES differed substantially from those of poly(cholesteryl-ω-acryloyloxyalkanoates). The results indicate that the mode of chemical linkage between the side-chain group and the main chain as well as that between the alkylene spacer and side chain play important roles in determining the thermal stability, mesophorphic structure and HTP of the cholesteric mesophases.

Target-specific induced hyaluronic acid decorated silica fluorescent nanoparticles@polyaniline for bio-imaging guided near-infrared photothermal therapy

We describe a novel synthesis method for silica nanoparticles, which involves a combination of these nanoparticles with targetable and nontargetable fluorescent dopamine-conjugated hyaluronic acid (HA-DA) via rational chemical dehydration. The resulting HA-decorated silica fluorescent nanoparticles, electrostatically linked to polyaniline (PANI) to form ionic complexes, possessed high fluorescence intensity and were monodisperse in solution, near-infrared light responsive, and amenable to specific labeling of cancer cell lines. When exposed to near-infrared irradiation, the fluorescent silica nanoparticles exerted photothermal cytotoxicity guided by bioimaging and distinguished malignant cancer cells from normal cells via receptor CD44. Different heating properties of nanoparticles depend on local interactions between different structures, and determination of their efficacy could lead to new thermal treatment options such as noninvasive photothermal therapy.

Development of Organic Semiconductors Based on Quinacridone Derivatives for Organic Field-Effect Transistors: High-Voltage Logic Circuit Applications

Poly[quinacridone-alt-quaterthiophene] (PQCQT) was synthesized, using a Suzuki coupling reaction, to investigate the potential of quinacridone derivatives as organic semiconductors in organic fieldeffect transistors (OFETs) and circuits. A PQCQT film annealed at 150 °C yielded quite high field-effect performances, including a hole mobility of

Thermal annealing effects of C22-Quinolium(TCNQ) Langmuir-Blodgett films☆

2.0 \times 10^{-2}

Annealing Temperature-Dependent Dielectric Properties of C22-Quinolinium(TCNQ) Langmuir-Blodgett Films

cm2/(Vs). In addition, to confirm the feasibility of using PQCQT in high-voltage circuit applications, electrical behaviors of PQCQT-based OFETs were described by extracting the model parameters of the industry standard compact Berkeley short-channel IGFET model. From the developed OFET model parameter set, we successfully evaluated the circuit operation of a p-type organic inverter with a frequency of 45.5 kHz in an 80 V supply condition.

Effects of Organic Acids and a Fluoropolymer on the Conductivity and Transparency of Poly(3,4-ethylenedioxythiophene) Films

Abstract Thermal annealing effects of C 22 -Quinolium(TCNQ) LB films were investigated through a study of frequency-dependent dielectric properties. Thermal annealing was performed in the range of 20∼240 °C. Thickness measurement by ellipsometry shows that there is a thickness drop near 100 °C, which is supposed to be due to a softening of the alkyl chains. The film thickness above 120 °C becomes ∼ 20 % of the room-temperature value. Frequency-dependent dielectric properties show that there are two characteristics dispersions; one is a dispersion occuring ∼ 1 MHz coming from the electric polarization of the molecules. The other one is an interfacial polarization effect below ∼ 1 kHz when the annealing temperature is above 80 °C.

P‐111: Analysis of Fully Driving Electronic Paper Fabricated Using Particle‐Transfer Method

Abstract Frequency-dependent dielectric properties of C22-Quinolinium(TCNQ) Langmuir-Blodgett(LB) films were investigated in a frequency range of 10 Hz ∼ 13 MHz along a perpendicular direction to the films. The films were heat-treated in a temperature range of 20 ∼ 240°C. Frequency-dependent dielectric constants show that there are two characteristic dispersions; one is a dispersion occurring near 1 MHz coming from the orientational polarization of the molecules and the other one is probably due to an interfacial polarization below 1 kHz when the annealing temperature is above 80°C. The annealing temperature-dependent dielectric constants show that there are two maxima, one at near 80°C and the other one at near 180°C. The first peak seems to be related to a disorder of the alkyl chains. The second peak may be due to a chemical structure change of the TCNQ-molecules. Several other methods were employed to understand between the dielectric constants and the internal structure change of the films. DSC (diff...