Dae Sung Yoon

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We report on a novel technique of resonant frequency shift measurement based on a nanomechanical cantilever with a PZT actuating layer for label-free detection of a prostate-specific antigen (PSA) in a liquid environment. The nanomechanical PZT thin film cantilever is composed of SiO(2)/Ta/Pt/PZT/Pt/SiO(2) on a SiN(x) supporting layer for simultaneous(More)
Lysophosphatidic acid (LPA) is a bioactive phospholipid that is involved in various cellular events, including tumor invasion and metastasis. In the present study, we investigated the effects of LPA and hypoxia on HIF-1alpha and VEGF expression, as well as the effect of resveratrol on LPA and hypoxia-induced HIF-1alpha and VEGF expression and human ovarian(More)
Glass-based microchannel chips were fabricated using photolithographic technology, and Pt thin-film microelectrodes, as coplanar impedance sensors, were integrated on them. Longitudinal design parameters, such as interelectrode spacing and electrode width, of coplanar impedance sensors were changed to determine AC frequency characteristics as design(More)
PURPOSE Laparoscopic totally extraperitoneal (TEP) herniorrhaphy has been recognized as a treatment option for inguinal hernia. The objective of this study was to clarify the learning curve for laparoscopic TEP herniorrhaphy using the moving average method. METHODS A total of 90 patients underwent laparoscopic TEP herniorrhaphy by a single surgeon between(More)
We report an electro-mechanical biosensor for electrical detection of proteins with disease markers using self-sensing piezoresistive micro-cantilevers. Electrical detection, via surface stress changes, of antigen-antibody (Ag-Ab) specific binding was accomplished through a direct nano-mechanical response of micro-fabricated self-sensing micro-cantilevers.(More)
We designed and fabricated the nanomechanical Pb(Zr0.52Ti0.48)O3 (PZT) cantilever; we demonstrated a novel electrical measurement, under a controlled ambient temperature and humidity, for label-free detection of a prostate-specific antigen (PSA); and we achieved a detection sensitivity as low as 10 pg/ml. For the fabrication of our nanomechanical PZT(More)
We report the nanomechanical microcantilevers operated in vibration modes (oscillation) with use of RNA aptamers as receptor molecules for label-free detection of hepatitis C virus (HCV) helicase. The nanomechanical detection principle is that the ligand-receptor binding on the microcantilever surface induces the dynamic response change of microcantilevers.(More)
We report two types of signal enhancement strategy derived from the origin of mechanical response, surface stress and mass, of the dynamic mode microcantilever for the detection of PSA at low picogram scales (low femtomolar concentration). The PSA detection at extremely low concentration levels is crucial to the early detection of relapses of prostate(More)
Recent advances in nanotechnology have led to the development of nano-electromechanical systems (NEMS) such as nanomechanical resonators, which have recently received significant attention from the scientific community. This is not only due to their capability of label-free detection of bio/chemical molecules at single-molecule (or atomic) resolution for(More)
We report the use of poly(thiophen-3-yl-acetic acid 1,3-dioxo-1,3-dihydro-isoindol-2-yl ester (PTAE) for application to electrochemical hybridization sensor. A synthetic route for the thiophen-3-yl-acetic acid 1,3-dioxo-1,3-dihydro-isoindol-2-yl ester (TAE) is described, which is used as a monomer of conducting polymer sensor. A direct chemical substitution(More)