Biomedical subjects

Suhyeon Kim

Publications and source records attributed to Suhyeon Kim.

6 recordsLinked to original sources

PubMed2006

DNA biosensor based on the electrochemiluminescence of Ru(bpy)3(2+) with DNA-binding intercalators.

This paper reports a novel detection method for DNA hybridization based on the electrochemiluminescence (ECL) of Ru(bpy)(3)(2+) with a DNA-binding intercalator as a reductant of Ru(bpy)(3)(3+). Some ECL-inducible intercalators have been screened in this study using electrochemical methods combined with a chemiluminescent technique. The double-stranded DNA intercalated by doxorubicin, daunorubicin, or 4',6-diamidino-2-phenylindole (DAPI) shows a good ECL with Ru(bpy)(3)(2+) at +1.19 V (versus Ag/AgCl), while the non-intercalated single-stranded DNA does not. In order to stabilize the self-assembled DNA molecules during ECL reaction, we constructed the ECL DNA biosensor separating the ECL working electrode with an immobilized DNA probe. A gold electrode array on a plastic plate was assembled with a thru-hole array where oligonucleotide probes were immobilized in the side wall of thru-hole array. The fabricated ECL DNA biosensor was used to detect several pathogens using ECL technique. A good specificity of single point mutations for hepatitis disease was obtained by using the DAPI-intercalated Ru(bpy)(3)(2+) ECL.

Biosensing Techniques↗

PubMed2006

Microchip-based one step DNA extraction and real-time PCR in one chamber for rapid pathogen identification.

Optimal detection of a pathogen present in biological samples depends on the ability to extract DNA molecules rapidly and efficiently. In this paper, we report a novel method for efficient DNA extraction and subsequent real-time detection in a single microchip by combining laser irradiation and magnetic beads. By using a 808 nm laser and carboxyl-terminated magnetic beads, we demonstrate that a single pulse of 40 seconds lysed pathogens including E. coli and Gram-positive bacterial cells as well as the hepatitis B virus mixed with human serum. We further demonstrate that the real-time pathogen detection was performed with pre-mixed PCR reagents in a real-time PCR machine using the same microchip, after laser irradiation in a hand-held device equipped with a small laser diode. These results suggest that the new sample preparation method is well suited to be integrated into lab-on-a-chip application of the pathogen detection system.

DNA, Bacterial↗

PubMed2006

DNA chip replication for a personalized DNA chip.

We report the replication technology of DNA chip using by sequence specific localization of nucleic acids via hybridization and electric transfer of the nucleic acids onto a new substrate without losing their array information. The denatured DNA fragments are first spotted and UV-cross-linked on a nylon membrane. The membrane is then immersed and hybridized in a DNA mixture solution that contains all complementary sequences of the nucleic acids to be hybridized with the DNA fragments on the membrane. The hybridized DNA fragments are transferred to another membrane at the denatured condition. After separating two membranes, the transferred membrane contains a complementary array of DNA fragments. This method can be used for the replication of the same copy of DNA chip repeatedly and moreover could be applied for a personalized DNA chip fabrication, where specific information of each spot of DNA chip is originated from the genetic information of a personal sample.

Carbocyanines↗

PubMed2005

Clinical evaluation of micro-scale chip-based PCR system for rapid detection of hepatitis B virus.

The polymerase chain reaction (PCR) is widely used to amplify a small amount of DNA in samples for genetic analysis. Rapid and accurate amplification is prerequisite for broad applications including molecular diagnostics of diseases, food safety, and biological warfare tests. We have developed a rapid real-time micro-scale chip-based PCR system, which consists of six individual thermal cycling modules capable of independent control of PCR protocols. The PCR volume is 1 microl and it takes less than 20 min to complete 40 thermal cycles. To test utility of a chip-based PCR system as a molecular diagnostic device, we have conducted the first large-scale clinical evaluation study. Three independent clinical evaluation studies (n = 563) for screening the hepatitis B virus (HBV) infection, the most popular social epidemic disease in Asia, showed an excellent sensitivity, e.g. 94%, and specificity, e.g. 93%, demonstrating micro-scale chip-based PCR can be applied in molecular diagnostics.

DNA, Viral↗

PubMed2005

World-to-chip microfluidic interface with built-in valves for multichamber chip-based PCR assays.

We report a practical world-to-chip microfluidic interfacing method with built-in valves suitable for microscale multichamber chip-based assays. One of the primary challenges associated with the successful commercialization of fully integrated microfluidic systems has been the lack of reliable world-to-chip microfluidic interconnections. After sample loading and sealing, leakage tests were conducted at 100 degrees C for 30 min and no detectable leakage flows were found during the test for 100 microchambers. To demonstrate the utility of our world-to-chip microfluidic interface, we designed a microscale PCR chip with four chambers and performed PCR assays. The PCR results yielded a 100% success rate with no contamination or leakage failures. In conclusion, we have introduced a simple and inexpensive microfluidic interfacing system for both sample loading and sealing with no dead volume, no leakage flow and biochemical compatibility.

DNA, Viral↗

PubMed2003

Cylindrical compact thermal-cycling device for continuous-flow polymerase chain reaction.

A compact, thermal-cycling device for high-throughput continuous-flow polymerase chain reaction (PCR) has been developed, which consists of a flow-through capillary and a cylindrical heating-block assembly. A 3.5-m-long fused-silica capillary coils helically, with 33 turns, up around the 30-mm-diameter assembly of three equally divided thermostating copper blocks for melting, annealing, and extension. An injected PCR mixture undergoes one cycle of PCR each turn. A continuous-flow PCR of one sample and also a segmented-flow PCR of four different samples have been successfully demonstrated. The present device can easily evolve into a parallel-processing, multistation compact device and be modified to have real-time PCR capability. This solid-based compact PCR device, therefore, has a potentiality to be the format of choice when developed for a portable system.

Journal Article↗