Jong-Sik Moon

Biomimetic self-templating optical structures fabricated by genetically engineered M13 bacteriophage

Here, we describe a highly sensitive and selective surface plasmon resonance sensor system by utilizing self-assembly of genetically engineered M13 bacteriophage. About 2700 copies of genetically expressed peptide copies give superior selectivity and sensitivity to M13 phage-based SPR sensor. Furthermore, the sensitivity of the M13 phage-based SPR sensor was enhanced due to the aligning of receptor matrix in specific direction. Incorporation of specific binding peptide (His Pro Gln: HPQ) gives M13 bacteriophage high selectivity for the streptavidin. Our M13 phage-based SPR sensor takes advantage of simplicity of self-assembly compared with relatively complex photolithography techniques or chemical conjugations. Additionally, designed structure which is composed of functionalized M13 bacteriophage can simultaneously improve the sensitivity and selectivity of SPR sensor evidently. By taking advantages of the genetic engineering and self-assembly, we propose the simple method for fabricating novel M13 phage-based SPR sensor system which has a high sensitivity and high selectivity.

Specific Intracellular Uptake of Herceptin-Conjugated CdSe/ZnS Quantum Dots into Breast Cancer Cells

Herceptin, a typical monoclonal antibody, was immobilized on the surface of CdSe/ZnS core-shell quantum dots (QDs) to enhance their specific interactions with breast cancer cells (SK-BR3). The mean size of the core-shell quantum dots (28 nm), as determined by dynamic light scattering, increased to 86 nm after herceptin immobilization. The in vitro cell culture experiment showed that the keratin forming cancer cells (KB) proliferated well in the presence of herceptin-conjugated QDs (QD-Her, 5 nmol/mL), whereas most of the breast cancer cells (SK-BR3) had died. To clarify the mechanism of cell death, the interaction of SK-BR3 cells with QD-Her was examined by confocal laser scanning microscopy. As a result, the QD-Her bound specifically to the membrane of SK-BR3, which became almost saturated after 6 hours incubation. This suggests that the growth signal of breast cancer cells is inhibited completely by the specific binding of herceptin to the Her-2 receptor of SK-BR3 membrane, resulting in cell death.

Identification of Endocrine Disrupting Chemicals using a Virus-Based Colorimetric Sensor

A simple and portable colorimetric sensor based on M13 bacteriophage (phage) was devised to identify a class of endocrine disrupting chemicals, including benzene, phthalate, and chlorobenzene derivatives. Arrays of structurally and genetically modified M13 bacteriophage were fabricated so as to produce a biomimetic colorimetric sensor, and color changes in the phage arrays in response to several benzene derivatives were characterized. The sensor was also used to classify phthalate and chlorobenzene derivatives as representatives of endocrine disrupting chemicals. The characteristic color patterns obtained on exposure to various benzene derivatives enabled similar chemical structures in the vapor phase to be classified. Our sensing approach based on the use of a genetically surface modified M13 bacteriophage offers a promising platform for portable, simple environmental monitors that could be extended for use in numerous application areas, including food monitoring, security monitoring, explosive risk assessment, and point of care testing.

M13 Bacteriophage-Based Self-Assembly Structures and Their Functional Capabilities

Controlling the assembly of basic structural building blocks in a systematic and orderly fashion is an emerging issue in various areas of science and engineering such as physics, chemistry, material science, biological engineering, and electrical engineering. The self-assembly technique, among many other kinds of ordering techniques, has several unique advantages and the M13 bacteriophage can be utilized as part of this technique. The M13 bacteriophage (Phage) can easily be modified genetically and chemically to demonstrate specific functions. This allows for its use as a template to determine the homogeneous distribution and percolated network structures of inorganic nanostructures under ambient conditions. Inexpensive and environmentally friendly synthesis can be achieved by using the M13 bacteriophage as a novel functional building block. Here, we discuss recent advances in the application of M13 bacteriophage self-assembly structures and the future of this technology.

ABSORPTION AND REACTION OF CO2 WITH 2,3-EPOXYPROPYL PHENYL ETHER USING ALIQUAT 336 AS CATALYST

A kinetic study on the absorption and reaction of carbon dioxide with 2,3-epoxypropyl phenyl ether (phenyl glycidyl ether, PGE) in benzene solution has been carried out at room temperature in the presence of tricaprylylmethyl ammonium chloride (Aliquat 336) as catalyst. A simple method of measuring the absorbed volume of CO2 was proposed to obtain the reaction rate constant, and it was based on the film theory accompanied by a chemical reaction. The enhancement factor (β-NCO2/NCO2o) increased with increasing bulk concentration of PGE and Aliquat 336. The flux of CO2 was proportional to the agitation speed.

Recent advances in M13 bacteriophage-based optical sensing applications

Recently, M13 bacteriophage has started to be widely used as a functional nanomaterial for various electrical, chemical, or optical applications, such as battery components, photovoltaic cells, sensors, and optics. In addition, the use of M13 bacteriophage has expanded into novel research, such as exciton transporting. In these applications, the versatility of M13 phage is a result of its nontoxic, self-assembling, and specific binding properties. For these reasons, M13 phage is the most powerful candidate as a receptor for transducing chemical or optical phenomena of various analytes into electrical or optical signal. In this review, we will overview the recent progress in optical sensing applications of M13 phage. The structural and functional characters of M13 phage will be described and the recent results in optical sensing application using fluorescence, surface plasmon resonance, Förster resonance energy transfer, and surface enhanced Raman scattering will be outlined.

Recent progress in organic photorefractive materials

ABSTRACT Photorefractive holograms have received great attention for decades due to their transmissive geometries and dynamic nature. The PR mechanism involves charge generation, charge transport, charge trapping, and modulation of the refractive index. So far, photorefractive hologram is regarded as one of the most important holographic materials with dynamic features. Since the first PR mechanism was described about 50 years ago, extensive investigations have been undertaken by many researchers and it is anticipated that PR materials will be the center of optoelectronic material research in the near future. This article reviews the current understanding of the mechanism responsible for the PR effect and current research trends, and briefly introduces recent progress in applications and material design.

Polarity Index Dependence of M13 Bacteriophage-based Nanostructure for Structural Color-based Sensing

Color sensor systems based on M13 bacteriophage are being considerably researched. Although many studies on M13 bacteriophage-based chemical sensing of TNT, endocrine disrupting chemicals, and antibiotics have been undertaken, the fundamental physical and chemical properties of M13 bacteriophagebased nanostructures require further research. A simple M13 bacteriophage-based colorimetric sensor was fabricated by a simple pulling technique, and M13 bacteriophage was genetically engineered using a phage display technique to exhibit a negatively charged surface. Arrays of structurally and genetically modified M13 bacteriophage that can determine the polarity indexes of various alcohols were found. In this research, an M13 bacteriophage-based color sensor was used to detect various types of alcohols, including methanol, ethanol, and methanol/butanol mixtures, in order to investigate the polarity-related property of the sensor. Studies of the fundamental chemical sensing properties of M13 bacteriophage-based nanostructures should result in wider applications of M13 bacteriophage-based colorimetric sensors.

Feasibility of using a bacteriophage-based structural color sensor for screening the geographical origins of agricultural products

An M13 bacteriophage-based color sensor, which can change its structural color upon interaction with a gaseous molecule, was evaluated as a screening tool for the discrimination of the geographical origins of three different agricultural products (garlic, onion, and perilla). Exposure of the color sensor to sample odors induced the self-assembled M13 bacteriophage bundles to swell by the interaction of amino acid residues (repeating units of four glutamates) on the bacteriophage with the odor components, resulting in a change in the structural color of the sensor. When the sensor was exposed to the odors of garlic and onion samples, the RGB color changes were considerable because of the strong interactions of the odor components such as disulfides with the glutamate residues on the sensor. Although the patterns of the color variations were generally similar between the domestic and imported samples, some degrees of dissimilarities in their intensities were also observed. Although the magnitude of color change decreased for perilla, the color change patterns between the two groups were somewhat different. With the acquired RGB data, a support vector machine was employed to distinguish the domestic and imported samples, and the resulting accuracies in the measurements of garlic, onion, and perilla samples were 94.1, 88.7, and 91.6%, respectively. The differences in the concentrations of the odor components between both groups and/or the presence of specific components exclusively in the odor of one group allowed the color sensor-based discrimination. The demonstrated color sensor was thus shown to be a potentially versatile and simple as an on-site screening tool. Strategies able to further improve the sensor performance were also discussed.

Liquid Sensing of a M-13 Bacteriophage-Based Colorimetric Sensor

Virus-based sensors using M-13 bacteriophages are considered as potentially useful techniques to detect harmful chemicals, such as endocrine disrupting chemicals and antibiotics. Despite their great potential, chemical detection using this color sensor is dependent entirely on gas phase samples. Here, a simple and rapid colorimetric sensor was fabricated using a genetically engineered M-13 bacteriophage for liquid detection. The hierarchical nanostructure with structural color can detect the target material with great sensitivity and selectivity. Liquid detection using a M-13 bacteriophage-based colorimetric sensor was performed to verify selectivity and sensitivity of the color sensor upon exposure to a liquid sample. Trinitrotoluene (TNT) was detected in ethanol solutions at concentrations as low as 40 pM, and 400 μM of three kinds of nitro-aromatic compounds could be identified using the M-13 bacteriophage-based colorimetric sensor. The liquid sensing technique described in this study may lead to the production of a viral color sensor for practical applications.