Won-young Chung

Direct and nondestructive verification of PNA immobilization using click chemistry

The fluorogenic 1,3-Huisgen dipolar cycloaddition reaction was used as part of a novel immobilization strategy of PNA capture probes on a microarray. By using this click chemistry, azidocoumarin-anchored PNA probes were immobilized on phenyl acetylene-modified glass slides with the simultaneous generation of the fluorescent triazolylcoumarin moiety. Since the emitting moieties are generated in the immobilization reaction itself, fluorescent signals can be used to directly monitor the integrity of immobilization in a nondestructive manner. By using this strategy, PNA microarrays were prepared and successfully employed to perform microarray-based diagnosis of selected mutations in the breast cancer susceptibility gene BRCA1.

Mismatch DNA-specific enzymatic cleavage employed in a new method for the electrochemical detection of genetic mutations

Utilizing enzymatic mismatched DNA-specific cleavage and electrocatalytic signaling, a new electrochemical method for the detection of DNA mutations was developed and successfully applied to detect various mutations in the BRCA1 gene.

A Sexually Transmitted Disease (STD) DNA chip for the diagnosis of genitourinary infections

The results of an investigation aimed at the development of a DNA chip for the detection of genitourinary infections are described. Through analysis of over 35,000 clinical cases, 14 pathogens which are most abundantly found among Koreans were selected and candidate sequences for capture probes were accordingly chosen by considering their sequences and β-globin house-keeping gene. Among this group, the most suitable capture probe sequences were selected by employing repeated chip tests in which they are immobilized on a glass chip by using a recently developed novel gold nanoparticles-based method. A multiplex PCR method was established to generate fluorescence-labeled sequences for all 14 pathogens along with the β-globin gene. By using optimized hybridization conditions, the final chip was constructed and employed to diagnose reliably both single and multiple infections in clinical human samples for 14 target pathogens. The results show that the novel chip methodology serves as a highly reliable and convenient tool for the diagnosis of Sexually Transmitted Diseases (STDs). Furthermore, this study has its great significance in that it demonstrates the entire process from statistical analysis of a large number of clinical cases to the final development of STD DNA chip just ready to be applied or commercialized in the clinical diagnostic field.