• Agricultural and Biosystems Engineering
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• v.5 no.1
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• pp.21-24
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• 2004

Antibody based biosensors are very selective and ultra-sensitive. Antigen-antibody reactions have been used in immunoassays. In this research, a biosensor which uses antigen-antibody reaction was developed to measure and detect rat IgG. Because the antigen-antibody reaction is a physical bounding between antigen and antibody, there are several ways to measure an antigen-antibody reaction. Among the methods, impedance analysis has short measuring time and possibilities of analyzing various properties of the reaction using frequency analysis. Rat IgG could be detected with developed biosensor and impedance analyzer. The biosensor showed good repeatability and availability of detecting concentration changes of rat IgG.

• Journal of Microbiology and Biotechnology
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• v.17 no.6
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• pp.1031-1035
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• 2007

Prostate specific $antigen-{\alpha}_1-antichymotrypsin$ was detected by a double-enhancement strategy involving the exploitation of both colloidal gold nanoparticles (AuNPs) and precipitation of an insoluble product formed by HRP-biocatalyzed oxidation. The AuNPs were synthesized and conjugated with horse-radish peroxidase-PSA polyclonal antibody by physisorption. Using the protein-colloid for SPR-based detection of the PSPJACT complex showed their enhancement as being consistent with other previous studies with regard to AuNPs enhancement, while the enzyme precipitation using DAB substrate was applied for the first time and greatly amplified the signal. The limit of detection was found at as low as 0.027 ng/ml of the PSA/ACT complex (or 300 fM), which is much higher than that of previous reports. This study indicates another way to enhance SPR measurement, and it is generally applicable to other SPR-based immunoassays.

• Journal of Biomedical Engineering Research
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• v.14 no.3
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• pp.209-220
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• 1993

Microspheres are expected to be applied to biomedical areas such as solid-phase immunoassays, drug delivery systems, Immunomagnetic cell separation. To synthesize micro-spheres for biomedical application, "two stage shot growth method" was developed. The uniformity ratio or synthesized microspheres was always smatter than 1.05. And the surface charge density (or the number of ionizable functional groups) of the microspheres synthesized by "two stage shot growth method" was 6-13 times higher than thats of the ml crospheres synthesized by conventional seeded batch copolymerization. As a previous step for biomedical application, adsorption experiments of bovine albumin on microspheres were carried out under various conditions. The maximum adsorbed amount was obtained in the neighborhood of pH 4.5. Isoelectric point of bovine albumin Is pH 5.0, so experimental result shows that it shifted to acid area. The adsorption Isotherm was obtained, the plateau region was always reached at 2.Og/L (bulk concentration of bovine albumin ) . The effect of the kind and the amount of surface functional group was also examined.p was also examined.

• Journal of Biomedical Engineering Research
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• v.7 no.2
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• pp.183-190
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• 1986

Microspheres are expected to be applied to biomedical areas such as solid-phase immunoassays, drug delivery systems, immunomagnetic cell separation. To synthesize microspheres for biomedical application, "two stage shot growth method" was developed. The uniformity ratio of synthesized microspheres was always smaller than 1.05. And the surface charge density (or the number of ionizable functional groups) of the microspheres synthesized by "two stage shot growth method" was 6~13 times higher than that of the microspheres synthesized by conventional seeded batch copolymerization. As a previous step for biomedical application, adsorption experiments of bovine albumin on microspheres were carried out under various conditions. The maximum adsorbed amount was obtained in the neighborhood of pH 4.5. Isoelectric point of bovine albumin is pH 5.0, so experimental result shows that it shifted to acid area. The adsorption isotherm was obtained, the plateau region was always reached at 2.Og/L (bulk concentration of bovine albumin).The effect of the kind and the amount of surface functional group was also examined.p was also examined.

• The Magazine of the IEIE
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• v.29 no.3
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• pp.41-48
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• 2002

This paper presents a basic concept of lab-on-a-chip systems and their advantages in chemical and biological analyses. In addition, magnetic bead-based immunoassay on a microfluidic system is also presented as a typical example of lab-on-chip systems. Rapid and low volume immunoassays have been successfully achieved on the demonstrated lab-on-a-chip using magnetic beads, which are used as both immobilization surfaces and bio-molecule carriers. Total time required for an immunoassay was less than 20 minutes including sample incubation time, and sample volume wasted was less than $50{\mu}l$ during five repeated assays. Lab-on-a-chip is becoming a revolutionary tool for many different applications in chemical and biological analysis due to its fascinating advantages (fast and low cost) over conventional chemical or biological laboratories. Furthermore, simplicity of lab-on-a-chip systems will enable self-testing capability for patients or health consumers overcoming space limitation.

• Bulletin of the Korean Chemical Society
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• v.32 no.12
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• pp.4281-4285
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• 2011

We introduced a promising patterned substrate by using a microcontact printing method that can be used for SERS immunoassays based on antigen-antibody binding. SERS spectrum of the Raman reporter with antibody, which is rhodamine 6G (R6G) adsorbed on colloidal gold nanoparticles, was observed only for the surfaces in which prostate-specific antigen (PSA) is present on the substrate that is attached to an immobilized layer of antibody on the gold nanoparticles layer of the patterned substrate. Raman mapping images clearly showed that the antibodies on the Raman reporter were successfully and selectively conjugated with the antigen on the patterned substrate. This method could be potentially extended to multi-protein detections and ultrasensitive biosensors.

• Korean Journal of Clinical Laboratory Science
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• v.44 no.3
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• pp.142-146
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• 2012

Hepatitis B surface antigen (HBsAg) seroclearance is a rare event in chronic hepatitis B virus (HBV) infection which acquires the disease early in life. A case study have examined with asymptomatic chronic hepatitis B carrier who exhibits HBsAg seroclearance in anti-HBe positive. We comprehensively studied the biochemical, virological and clinical aspects of a patient with HBsAg seroclearance. Liver biochemistry, serological markers, serum HBV DNA levels, and development of clinical complications were monitored. Mutation of hepatitis B virus is suspected serum HBsAg detected by the HBsAg assay systems of VITROS (OrthoClinical Diagnostics, USA), AxSYM (Abbott Laboratories, USA), Elecsys (Roche Diagnostics, Germany) and ADVIA Centaur (Bayer Diagnostics, USA). These four immunoassays showed negative results. Also, the patient had undetectable serum HBV DNA. Therefore, no mutation within the "a" determinant of HBsAg, which might escape detection from HBsAg immunoassay were found. Natural seroclearance was confirmed.

• BMB Reports
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• v.44 no.11
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• pp.705-712
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• 2011

Advances in the fields of proteomics and genomics have necessitated the development of high-throughput screening methods (HTS) for the systematic transformation of large amounts of biological/chemical data into an organized database of knowledge. Microfluidic systems are ideally suited for high-throughput biochemical experimentation since they offer high analytical throughput, consume minute quantities of expensive biological reagents, exhibit superior sensitivity and functionality compared to traditional micro-array techniques and can be integrated within complex experimental work flows. A range of basic biochemical and molecular biological operations have been transferred to chip-based microfluidic formats over the last decade, including gene sequencing, emulsion PCR, immunoassays, electrophoresis, cell-based assays, expression cloning and macromolecule blotting. In this review, we highlight some of the recent advances in the application of microfluidics to biochemistry and molecular biology.

• Proceedings of the KOSOMBE Conference
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• v.1993 no.05
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• pp.7-14
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• 1993

Nowadays, microspheres are expected to be applied to biomedical areas and many studies are being performed. For biomedical applications, many kinds of microspheres were synthesized by emulsion polymerization, emulsifier-free emu]sion polymerization, and emulsifier-free emulsion polymerization with ionic surface-active comonomers. Further synthesis techniques about microencapsulation and magnetic microspheres are introduced. Among the practical applications of microspheres, some interesting subjects are introduced. These include solid-phase immunoassays, labeling and identification of lymphocyte populations, extracorporeal and hemoperfusion systems, drug delivery systems, and immunomagnetic cell separation. In addition, basic theories, problems and research trends are also introduced.

• Bulletin of the Korean Chemical Society
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• v.34 no.2
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• pp.595-599
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• 2013

The coordination of pyridyl-N to pentacyanoferrate for the detection of small organic antigens in solution is presented. The unique contribution of this paper is the direct conjugation of pyridyl-N in small organic antigens to pentacyanoferrate. Pentacyanoferrate is promising as an electrochemical label owing to its good electro-chemical properties, which can be utilized to generate an electrical signal in homogeneous electrochemical immunoassays. The facilely synthesized pyridyl-N to pentacyanoferrate was characterized by the electrochemical and spectroscopic methods. Hippuric acid (HA) has been detected competitively on the interaction of free HA and pentacyanoferrate-(4-aminomethylpyridine-hippuric acid) (Fe-HA) to its antibody, with the detection limit of 0.50 ${\mu}g\;mL^{-1}$. While pentacyanoferrate-based immunoassay is in its simplicity and infancy, the proposed immunoassay offers attractive opportunities for developing pyridyl-N-based the electrochemical detection of small organic antigens in the health care area.