• Biotechnology and Bioprocess Engineering:BBE
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• v.9 no.4
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• pp.241-244
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• 2004

Protein A molecular thin film was fabricated as a platform of antibody-based biosensor. For the immobilization of the protein A thin film, a viologen multilayer was built up using the Langmuir-Blodgett (LB) technique, and then, protein A was adsorbed on the viologen LB film by an electrostatic interaction force, which was formed as a hetero-film structure. For the deposition of viologen, surface pressure area ($\pi$-A) isotherm was investigated. The fabricated protein A-viologen hetero LB film was investigated using atomic force microscopy (AFM). Using the developed molecular film, antibody immobilization and fluorescence measurement was carried out.

• Journal of Microbiology and Biotechnology
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• v.11 no.6
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• pp.979-985
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• 2001

A fluorometric detection technique for HDL (High Density Lipoprotein) and LDL (Low Density Lipoprotein) was developed for application in a fiber-optic immunosensor using a protein A Langmuir-Blodgget (LB) film. For the fluorescence immunoassay, antibodies specific to HDL or LDL were imobilied on the protein A LB film, and a fluorescence amplification method was developed to overcome their weak fluorescence. The deposition of protein A using the LB technique was monitored using a surface pressure-are $({\pi}-A)$ curve, and the antibody immobilization of the protein A LB film was experimentally verified. The immobilized antibody was used to separate only HDL and LDL from a sample, then the fluorescence of he separated HDL or LDL was amplified. The amount of LDL or HDL was measured using the developed fiber optic fluorescence detection system. The optical properties resulting from the reaction of HDL or LDL with o-phtaldialdehyde, detection range, response time, and stability of the immunoassay were all investigated. The respective detection ranges for HDL and LDL were sufficient to diagnose the risk of coronary heart disease. The amplification step increased the sensitivity, while selective separation using the immobilized antibody led to linearity in the sensor signal. The regeneration of the antibody-immobilized substrate could produce a stable and reproducible immunosensor.

• 한국생물공학회:학술대회논문집
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• 2001.11a
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• pp.859-862
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• 2001

For the development of preferable immunosensor and protein chip, the viologen Langmuir-Blodgett (LB) multilayer was fabricated on the surface, and then protein A was adsorbed on the proposed viologen LB film by electrostatic attractive force. The Immunoglobulin G (IgG) labeled with fluorescence marker was self-assembled on the fabricated protein A film. The topographies of the deposited films were investigated by using atomic force microscope (AFM). The immobilization of IgG was verified by fluorescence spectrum. Such structures can be used as sublayers for various kinds of IgG immobilization toward immunosensors and protein chip.

• 한국생물공학회:학술대회논문집
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• 2000.04a
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• pp.149-152
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• 2000

In recent years, various artificial molecular photodiode have been fabricated by mimicking the electron transport function of biological photosynthesis. And now, we have been investigated the protein-organic hetero thin film photodiode using GFP as an sensitizer based on the redox potential difference of functional molecules. In this paper, shows molecular photodiode consisting of green fluorescence protein(GFP). viologen and TCNQ. The TCNQ and viologen were deposited onto ITO coated glass by LB technique. And GFP molecule was adsorption onto the viologen LB film surface by self-assembly method. Finally, The Al deposition onto GFP/viologen/TCNQ film surface was performed to make a top electrode. As a result, The MIM(metal/Insulator/Metal) structured device was constructed. The input light of 460nm wavelength was generated by the xenon lamp system, and then the photocurrent produced from the molecular device was detected through a current-voltage(I-V) measuring unit (SMU Model 236, Keithley, USA). An artificial molecular photodiode using protein(GFP)-adsorbed hetero-LB film is presented as a model system for the bioelectronic device based on the biomimesis.

• Journal of Sensor Science and Technology
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• v.4 no.4
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• pp.81-87
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• 1995

A novel biomaterial capable of incorporating biotinylated biomolecule has been synthesized. Our strategy is to biotinylate one-dimensional electroactive polymers and use a bridging streptavidin protein on Langmuir-Blodgett (LB) organized films. These copolymers are derivatized with long alkyl chains and biotin moieties to bind, respectively, to the hydrophobic surface and the biotinylated species, through the biotin and streptavidin complexation. We utilize the polymer assembly approach to attach a signal transducing biomolecule biotinylated phycoerythrin (B-PE) into this novel biomaterial by binding the unoccupied biotin binding sites on the bound streptavidin (4 sites total). The pressure-area isotherm of the protein injected monolayer showed area expansion. A characteristic fluorescent emission peak at 576nm was detected from the monolayer transferred onto a solid substrate. These observations demonstrated the promise of the organized thin polymer assemblies for their application to the sensor system.