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Search Publications by: Jeeseong C. Hwang (Fed)

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Displaying 101 - 125 of 171

Monitoring Photothermally Excited Nanoparticles via Multimodal Microscopy

May 19, 2010
Author(s)
Matthew L. Clarke, Shin G. Chou, Jeeseong Hwang
Generation of heat using optically excited nanoparticles can be beneficial or detrimental depending on the application. Therefore, clinically applicable studies are being pursued in an effort to achieve safe practices of nanoparticle-induced hyperthermia

Shell-dependent Blinking of CdSe-Based Core/Shell Nanocrystals

May 10, 2010
Author(s)
Seung Koo Shin, Bonghwan Chon, Sung Jun Lim, Wonjung Kim, Hyeong G. Kang, Taiha Joo, Jeeseong C. Hwang
Blinking of zinc-blende CdSe-based core/shell nanocrystals are studied as a function of shell materials. CdSe/ZnS, CdSe/ZnSe/ZnS, and CdSe/CdS/ZnS core/shell nanocrystals are prepared by epitaxial growth of two-to-six monolayers (MLs) of shell materials

Low-Cost, High-Throughput, Automated Counting of Bacterial Colonies

January 5, 2010
Author(s)
Matthew L. Clarke, Robert L. Burton, A. N. Hill, Maritoni A. Litorja, Moon H. Nahm, Jeeseong Hwang
Research involving bacterial pathogens often requires enumeration of bacteria colonies. Here we present a low-cost, high-throughput colony counting system consisting of colony counting software and a consumer-grade digital camera or document scanner. We

Probing Dynamic Fluorescence Properties of Single and Clustered Quantum Dots Towards Quantitative Biomedical Imaging of Cells

October 28, 2009
Author(s)
Hyeong G. Kang, Fuyuki Tokumasu, Matthew L. Clarke, Zhenping Zhou, Jianyong Tang, Tinh Nguyen, Jeeseong Hwang
We present results on dynamical fluorescence properties of bioconjugated nanocrystals or quantum dots (QDs) in different chemical and physical environments. A variety of QD samples were prepared and compared: isolated individual QDs, QDs aggregated into

Multimodal, Nanoscale, Hyperspectral Imaging Demonstrated on Heterostructures of Quantum Dots and DNA-Wrapped Single-Wall Carbon Nanotubes

October 21, 2009
Author(s)
Hyeong G. Kang, Matthew L. Clarke, Jianyong Tang, John T. Woodward IV, Shin G. Chou, Zhenping Zhou, Angela R. Hight Walker, Tinh Nguyen, Jeeseong Hwang
A multimodality imaging technique integrating atomic force, polarized Raman, and fluorescence lifetime microscopy and a 2D autocorrelation image analysis is applied to study the properties of a mesoscopic heterostucture of nanoscale materials. This

NIST s Integrated Colony Enumerator (NICE)

August 11, 2009
Author(s)
Matthew L. Clarke, Jeeseong Hwang
Enumeration of bacterial colonies in an agar plate is simple in concept, but automated colony counting is difficult due to variations in colony color, size, shape, contrast, and density, as well as colony overlap. Furthermore, in applications where high

Quantitative Characterization of Quantum Dot-labeled Lambda Phage for Escherichia coli Detection

July 24, 2009
Author(s)
Peter Yim, Matthew L. Clarke, Michael McKinstry, Silvia H. De Paoli Lacerda, Leonard F. Pease III, Marina A. Dobrovolskaia, Hyeong G. Kang, David T. Read, Shanmuga Sozhamannan, Jeeseong C. Hwang
We rapidly and quantitatively detect biological pathogens by combining the specificity of bacteriophage lambda with the sensitivity of CdSe/ZnS quantum dot (QD)-based fluorescence. Specifically, QD-decorated lambda phages bind to and allow detection of

Probing the dynamic fluorescence properties of single water-soluble quantum dots

April 1, 2008
Author(s)
J R. Krogmeier, Hyeong G. Kang, Matthew L. Clarke, p Yim, Jeeseong Hwang
The influence of surface modifications, including carboxyl-, amine-, and mercaptoundecanoicacid-functionalized chemistries, on the dynamic fluorescence properties of single quantum dots (QDs) are probed using a combined confocal fluorescence microscopy and

Biophotonic tools in cell and tissue diagnostics

May 1, 2007
Author(s)
Michael Brownstein, Robert A. Hoffman, Richard Levenson, Thomas E. Milner, Marla L. Dowell, Paul A. Williams, Grady S. White, Adolfas Gaigalas, Jeeseong C. Hwang
In order to maintain the rapid advance of biophotonics in the U.S. and to enhance our competitiveness worldwide, key measurement tools must be in place. As a part of a wide-reaching effort to improve the U.S. technology base, the National Institute of

Nanocrystal-Based Biomimetic System for Quantitative Flow Cytometry

February 6, 2007
Author(s)
Marina Dobrovolskaia, Hyeong G. Kang, Matthew L. Clarke, Anil Patri, Jeeseong Hwang
Flow cytometry has been instrumental in rapid analysis of single cells since the 1970s. One of the common approaches is the immunofluorescence study involving labeling of cells with antibodies conjugated to organic fluorophores. More recently, as the

Fluorescence Intermittency and Spectral Shifts of Single Bio-Conjugated Nanocrystals Studied by Single Molecule Confocal Fluorescence Microscopy and Spectroscopy

January 21, 2007
Author(s)
Hyeong G. Kang, Mathew Maye, Dmytro Nykypanchuk, Matthew L. Clarke, Peter Yim, J R. Krogmeier, Kimberly A. Briggman, Oleg Gang, Jeeseong Hwang
We have fabricated a combined measurement system capable of confocal microscopy and fluorescence spectroscopy to simultaneously evaluate multiple optical characteristics of single fluorescent nanocrystals. The single particle detection sensitivity is