Woo-Jin Chang

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Single cell study is gaining importance because of the cell-to-cell variation that exists within cell population, even after significant initial sorting. Analysis of such variation at the gene expression level could impact single cell functional genomics, cancer, stem-cell research, and drug screening. The on-chip monitoring of individual cells in an(More)
We present a novel dielectrophoretic technique that can be used to characterize molecular interactions inside a microfluidic device. Our approach allows functionalized beads which are initially at rest on a functionalized surface to be pulled away from the surface by the dielectrophoretic force acting on the beads. As a result, the interaction between the(More)
In this paper, we present a new impedance-based method to detect viable spores by electrically detecting their germination in real time within microfluidic biochips. We used Bacillus anthracis Sterne spores as the model organism. During germination, the spores release polar and ionic chemicals, such as dipicolinic acid (DPA), calcium ions, phosphate ions,(More)
The simultaneous investigation of a large number of events with different types of intermolecular interactions, from nonequilibrium high-force pulling assays to quasi-equilibrium unbinding events in the same environment, can be very important for fully understanding intermolecular bond-rupture mechanisms. Here, we describe a novel dielectrophoretic force(More)
Highly selective mercury detection at partially oxidized graphene/poly(3,4-ethylenedioxythiophene):poly (styrenesulfonate) nanocomposite film-modified electrode Partially oxidized graphene flakes (po-Gr) were obtained from graphite electrode by an elec-trochemical exfoliation method. As-produced po-Gr flakes were dispersed in water with the assistance of
We report the electric field and pH sensitivity of fluid gated metal-semiconductor hybrid (MSH) Schottky structures consisting of a Titanium layer on n-type GaAs. Compared to standard field-effect sensors, the MSH Schottky structures are 21 times more sensitive to electric field of -46.6 V/cm and show about six times larger resistance change as pH of the(More)
  • A M Gilbertson, A K M Newaz, Woo-Jin Chang, R Bashir, S A Solin, L F Cohen
  • 2009
We report on the magnetotransport in a 90 nm thick n-type GaAs epitaxial thin film in the weak localization ͑WL͒ regime. Low temperature ͑T Յ 50 K͒ magnetotransport data are fit with WL theory, from which the phase coherence time, ␶ ␾ ϰ T −p ͑p = 1.22Ϯ 0.01͒, are extracted. We conclude that the dominant dephasing mechanism at these temperatures is(More)
In this study, a novel PDMS/silicon hybrid micro¯uidic biochip was fabricated and tested for the long-term batch culture of bacterial cells. The PDMS (poly(dimethylsiloxane)) cover with 3-dimensional micro-channels for ¯ow was fabricated using Te¯on tubing and hole-punch techniques, without photolithographic methods. The PDMS/silicon hybrid biochip was(More)
The direct quantification of weak intermolecular binding interactions is very important for many applications in biology and medicine. Techniques that can be used to investigate such interactions under a controlled environment, while varying different parameters such as loading rate, pulling direction, rupture event measurements, and the use of different(More)