Kyo Seon Hwang

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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)
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)
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)
A highly sensitive nanomechanical cantilever sensor assay based on an electrical measurement has been developed for detecting activated cyclic adenosine monophosphate (cyclic AMP)-dependent protein kinase (PKA). Employing a peptide derived from the heat-stable protein kinase inhibitor (PKI), a magnetic bead system was first selected as a vehicle to(More)
Lead Zirconate Titanate (PZT)-embedded microcantilevers were fabricated with dimensions of 30 × 90 × 3 μm(3) (width × length × thickness). A thicker PZT layer improved the actuation and enabled long-term data acquisition in common aqueous buffers with a frequency resolution of 20 Hz. A quantitative assay was conducted in the range of 1-20 μM and the(More)
In this paper, we report the novel electrical measurement for the label-free detection of C-reactive protein (CRP) using resonant frequency shift in the monolithic thin film cantilever of micromachined Pb(Zr0.52Ti0.48)O3 (PZT) which was fabricated with the composition of SiO2/Ta/Pt/PZT/Pt/SiO2 on silicon nitride (SiNx) supporting layer for the dual purpose(More)
Recent research trends in biosensing have been geared toward developing bioanalytical devices that are label free, small in size, and portable and that can operate in a rapid manner. The performance of these devices has been dramatically improved through the advent of new materials and micro-/nanofabrication technologies. This is especially true for(More)
We report Hepatitis B Virus (HBV) DNA detection using a silica nanoparticle-enhanced dynamic microcantilever biosensor. A 243-mer nucleotide of HBV DNA precore/core region was used as the target DNA. For this assay, the capture probe on the microcantilever surface and the detection probe conjugated with silica nanoparticles were designed specifically for(More)
Microfluidic paper-based analytical devices (μPADs) for molecular detection have great potential in the field of point-of-care diagnostics. Currently, a critical problem being faced by μPADs is improving their detection sensitivity. Various preconcentration processes have been developed, but they still have complicated structures and fabrication processes(More)