Papers by Author: Jong Heop Yi

Abstract: Mutation and aggregation of superoxide dismutase (SOD) are reported as one of the causes of amyotrophic lateral sclerosis (ALS). To detect SOD1 protein from the motor neuron, surface plasmon resonance (SPR) analysis was adopted due to its advantages in the in-situ biomolecular recognition by surface analysis without labeling. For the patterning of protein antigens at Au surface for use in SPR imaging experiments, microfluidic devices were fabricated with polydimethylsiloxane (PDMS) by replica molding method. They were designed for the solution to flow by capillary force only without using any additional pumping equipments or flow controllers. Performance of microfluidic devices was verified by the simple microfluidic experiments, and multiple protein-patterned sensor surfaces were constructed by using these microfluidic devices.

Abstract: AuNP (gold nanoparticle) supported by oxide shows a high reactivity for a PROX (preferential oxiation) reaction at low temperature. Au catalysts were usually prepared by conventional methods such as precipitation, impregnation and vapor phase grafting. In this study, we developed a novel method for the preparation of AuNPs supported on a bimodal nanoporous alumina. The AuNPs were prepared in a toluene phase by the modified Brust method. The metal particle size was able to be controlled from 2 to 50 nm via the control of the surfactant concentrations. The resulting materials were characterized by BET, FE-SEM, TEM, and XRD analyses. After calcinations at 700oC, AuNP/Al2O3 catalyst revealed a bimodal nanoporous structure, with the pore sizes of 3.5 and 7 nm, and demonstrated both a high surface area (350 m2/g) and pore volume (0.9 cm3/g).

Abstract: Site-defined metal microstructure was fabricated on the pre-designed organic template via a surface modification of Si(100) wafer. Site-defined substrate with octadecyltrichlorosilane (OTS) was oxidized by AFM (Atomic Force Microscopy) at threshold voltage (Vo). Terminal group (-CH3) of OTS was changed into carboxyl group (-COOH). Then, locally modified monolayer surface was used to induce the site-selective self-assembly of different materials (organic, metal, and semiconductor), according to the predefined patterns. The target metal selected is copper ions for the feasibility examination of conductive metal line fabrication

Abstract: Mesoporous carbon (MCs) was synthesized using mesoporous silica as a template. Prepared mesoporous carbon materials were found to have high surface area and large pore volume with uniform pore size. Resulting materials showed a different pore arrangement from mesoporous silica templates. Pt catalysts supported on mesoporous carbon prepared were applied to an anode catalyst for Direct Methanol Fuel Cell (DMFC). Results indicate that a mesoporous carbon having 3-dimensional pore system (3D-MC) had higher catalytic activity than 2-dimensional one (2D-MC) due to a favorable pore structure in methanol electro-oxidation.

Abstract: This study demonstrates the measurement and analysis of interfacial reactions of metal ions with organic ligands using the time-resolved SPR instrument. For the substrate, an HDT (1,6-hexanedithiol) ligand was immobilized on a gold thin film using the SAM method. The 50-nm-thick gold thin film was fabricated by thermal evaporation. The target metal ions were Pt ions in an aqueous solution. The adsorption kinetics of metal ions to HDT ligands was obtained.