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Physical Sciences and Mathematics

Plasmon

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Full-Text Articles in Biomedical Engineering and Bioengineering

Correct Spectral Conversion Between Surface‐Enhanced Raman And Plasmon Resonance Scattering From Nanoparticle Dimers For Single‐Molecule Detection, Kyuwan Lee Dec 2012

Correct Spectral Conversion Between Surface‐Enhanced Raman And Plasmon Resonance Scattering From Nanoparticle Dimers For Single‐Molecule Detection, Kyuwan Lee

Kyuwan Lee

Simultaneous measurement of surface-enhanced Raman scattering (SERS) and localized surface plasmon resonance (LSPR) in nanoparticle dimers presents outstanding opportunities in molecular identification and in the elucidation of physical properties, such as the size, distance, and deformation of target species. SERS–LSPR instrumentation exists and has been used under limited conditions, but the extraction of SERS and LSPR readouts from a single measurement is still a challenge. Herein, the extraction of LSPR spectra from SERS signals is reported and a tool for measuring the interparticle distance from Raman enhancement data by the standardization of the SERS signal is proposed. The SERS ...


Dna− Gold Nanoparticle Reversible Networks Grown On Cell Surface Marker Sites: Application In Diagnostics, Kyuwan Lee Feb 2011

Dna− Gold Nanoparticle Reversible Networks Grown On Cell Surface Marker Sites: Application In Diagnostics, Kyuwan Lee

Kyuwan Lee

Effective identification of breast cancer stem cells (CSC) benefits from a multiplexed approach to detect cell surface markers that can distinguish this subpopulation, which can invade and proliferate at sites of metastasis. We present a new approach for dual-mode sensing based on targeting using pointer and signal enhancement using enhancer particle networks for detection by surface plasmon resonance (SPR) and surface-enhanced Raman scattering (SERS). We demonstrate our concept to detect cell surface markers, CD44 and CD24, in three breast cancer cell lines to identify a CD44+/CD24− subpopulation of CSCs. The designed network structure can be well-controlled and has improved ...


Silver Nanosphere Sers Probes For Sensitive Identification Of Pathogens, Kyuwan Lee Sep 2010

Silver Nanosphere Sers Probes For Sensitive Identification Of Pathogens, Kyuwan Lee

Kyuwan Lee

The identification and timely detection of pathogenic bacteria is critical to ensuring safe food, health, and water. Although surface enhanced Raman scattering (SERS) methods have been used for pathogen characterization and single molecule sensing, the challenge of detecting pathogens in very low numbers using an optimal substrate that is sensitive and reproducible is still a challenge. In this report, we have developed and explored a novel SERS active substrate of 60−80 nm diameter through the assembly of Ag nanocrystals (AgNCs) into Ag nanospheres (AgNSs). A finite difference time domain (FDTD) analysis of the electromagnetic field produced by these structures ...


Periodic And Dynamic 3-D Gold Nanoparticle− Dna Network Structures For Surface-Enhanced Raman Spectroscopy-Based Quantification, Kyuwan Lee Mar 2009

Periodic And Dynamic 3-D Gold Nanoparticle− Dna Network Structures For Surface-Enhanced Raman Spectroscopy-Based Quantification, Kyuwan Lee

Kyuwan Lee

The enhancement factor of gold nanoparticles linked by DNA in a three-dimensional (3-D) network structure was evaluated as 1.12 × 107 and shown to be greater than a two-dimensional (2-D) array by a factor of 10, possibly due to the dimensional expansion of resonance and periodicity of the so formed structures. Uniform and higher level of enhancement was possible from these DNA linked gold nanoparticle networks because of the matching of the resonant condition and the excitation wavelength (785 nm) to enable dynamic quantification of analytes by surface-enhanced Raman spectroscopy (SERS). The structure was first validated by obtaining a SERS ...