Chung-Ang University, South Korea
Seok-min Kim has received his PhD degree from the School of Mechanical Engineering at Yonsei University, South Korea. He is currently an Associate Professor in the School of Mechanical Engineering at Chung-Ang University, South Korea. His current research interests include design and fabrication of micro/nanostructures for optical biosensors, micro fl uidic chips, concentrator photovoltaic system, digital display, LED lighting and enhanced boiling heat transfer surface.
Metal-enhanced fl uorescence is a powerful technology to improve the sensitivity of fl uorescence analysis by allowing fl uorophores to interact with enhanced electromagnetic fi elds generated by the localized surface Plasmon resonance (LSPR) eff ects of metallic nanostructures. To apply metal-enhanced fl uorescence technology to disposable DNA or protein microarray analysis, metallic nanostructures need to be fabricated on the full area of a glass slide at low cost. We used a glancing angle deposition (GLAD) process to fabricate Ag nanorods on the whole area of glass slide to serve as an inexpensive and large-area metal-enhanced fl uorescence substrate. Th e GLAD is a physical vapor deposition process in which the substrate is placed at an angle of <15° between the evaporating fl ux and the substrate surface. When atomic mobility is limited, a self-shadowing eff ect during deposition results in a highly porous fi lm of isolated nanorods. One can obtain various lengths, densities and shapes of nanorod structures by controlling deposition time, glancing angle and in-plane rotation speed of substrate, respectively. To examine the feasibility of the proposed substrate for the microarray analysis and maximize the signal enhancement, Ag nanorods with diff erent lengths and shape were deposited on glass slides. A 10 nm thick Ni layer and a 40 nm thick Ag layer were sequentially deposited on the glass slide to improve adhesion between the Ag nanorods and the substrate before the GLAD process. To examine the enhancement factor of the GLAD MEF substrates, Streptavidin-conjugated Cy5 was dissolved in buff er solution at 100 ng per ml to 100 μg per ml and spotted onto the substrates. Aft er drying for 24 hours in a refrigerator, the fl uorescence signal was measured using a microarray scanner at an excitation wavelength of 635 nm. From the fl uorescence measurement experiments, the maximum signal enhancement of ~91x was obtained from the substrate with 750 nm long tilted nanorod structure.