• Korean Journal of Clinical Laboratory Science
• /
• v.46 no.4
• /
• pp.136-139
• /
• 2014

Methicillin-resistant Staphylococcus aureus (MRSA) is one of the severe nosocomial infectious agents. The traditional diagnostic methods including biochemical test, antibiotic susceptibility test and PCR amplification are time consuming and require much work. The Surface enhanced Raman spectroscopy (SERS) biosensor is a rapid and powerful tool for analyzing the chemical composition within a single living cell. To identify the biochemical and genetic characterization of clinical MRSA, all isolates from patients were performed with VITEK2 gram positive (GP) bacterial identification and Antibiotic Susceptibility Testing (AST). Virulence genes of MRSA also were identified by DNA based PCR using specific primers. All isolates, which were placed on a gold coated nanochip, were analyzed by a confocal Raman microscopy system. All isolates were identified as S. aureus by biochemical tests. MRSA, which exhibited antibiotic resistance, demonstrated to be positive gene expression of both femA and mecA. Furthermore, Raman shift of S. aureus and MRSA (n=20) was perfectly distinguished by a confocal Raman microscopy system. This novel technique explained that a SERS based confocal Raman microscopy system can selectively isolate MRSA from non-MRSA. The study recommends the SERS technique as a rapid and sensitive method to detect antibiotic resistant S. aureus in a single cell level.

• Bulletin of the Korean Chemical Society
• /
• v.32 no.spc8
• /
• pp.2941-2948
• /
• 2011

A nanogap formed by a metal nanoparticle and a flat metal substrate is one kind of "hot site" for surface-enhanced Raman scattering (SERS). The characteristics of a typical nanogap formed by a planar Au and either an Au and Ag nanoparticle have been well studied using 4-aminobenzenethiol (4-ABT) as a probe. 4-ABT is, however, an unusual molecule in the sense that its SERS spectral feature is dependent not only on the kinds of SERS substrates but also on the measurement conditions; thus further characterization is required using other adsorbate molecules such as 1,4-phenylenediisocyanide (1,4-PDI). In fact, no Raman signal was observable when 1,4-PDI was selfassembled on a flat Au substrate, but a distinct spectrum was obtained when 60 nm-sized Au or Ag nanoparticles were adsorbed on the pendent -NC groups of 1,4-PDI. This is definitely due to the electromagnetic coupling between the localized surface plasmon of Au or Ag nanoparticle with the surface plasmon polariton of the planar Au substrate, allowing an intense electric field to be induced in the gap between them. A higher Raman signal was observed when Ag nanoparticles were attached to 1,4-PDI, irrespective of the excitation wavelength, and especially the highest Raman signal was measured at the 632.8 nm excitation (with the enhancement factor on the order of ${\sim}10^3$), followed by the excitation at 568 and 514.5 nm, in agreement with the finite-difference timedomain calculation. From a separate potential-dependent SERS study, the voltage applied to the planar Au appeared to be transmitted without loss to the Au or Ag nanoparticles, and from the study of the effect of volatile organics, the voltage transmission from Au or Ag nanoparticles to the planar Au also appeared as equally probable to that from the planar Au to the Au or Ag nanoparticles in a nanogap electrode. The response of the Au-Ag nanogap to the external stimuli was, however, not the same as that of the Au-Au nanogap.

• Journal of Korean Society for Atmospheric Environment
• /
• v.28 no.6
• /
• pp.688-696
• /
• 2012

The particle depolarization ratios were retrieved from the observation with a multi-wavelength Raman lidar at Gwangju, Korea ($35.11^{\circ}N$, $126.54^{\circ}E$). The measurements were carried out on 24 February and 9 March 2004. Using the particle depolarization ratios, the non-dust aerosol particles were distinguished from the Asian dust plume, and the proportion of the non-dust particle to total dust plume was retrieved. The calculated proportion of the non-dust particle was used for the retrieval of backscatter coefficients at 355, 532, and 1064 nm and extinction coefficients at 355 and 532 nm of non-dust particles in the dust plume. Microphysical parameters of non-dust particles including single-scattering albedo at 532 nm were retrieved using retrieved optical values. The retrieved single-scattering albedo of non-dust particles was 0.92~0.95 below 1 km height and 0.82~0.91 above 1 km height on 24 February 2004 and $0.81{\pm}0.03$ on 9 March 2004.

• Macromolecular Research
• /
• v.8 no.3
• /
• pp.103-115
• /
• 2000

The structural changes viewed from the molecular level have been investigated for the isothermal crystallization phenomena of polyethylene (PE) and the solvent-induced crystallization phenomenon of syndiotactic polystyrene (sPS) glassy sample. The data, which were collected by the time-resolved measurements of Fourier-transform infrared spectra, Raman spectra, synchrotron-sourced small-angle X-ray scattering, wide-angle X-ray scattering, and so on, were combined together to extract the detailed structural information in these phase transition phenomena. In the case of PE, the isothermal crystallization from the melt to the orthorhombic form was found to occur via the conformationally-disordered trans chain form, followed by the formation of the lamellar stacking structure of regular orthorhombic-type crystals. In the case of sPS, the amorphous chains in the glassy sample were found to enhance the mobility through the interaction with the injected solvent molecules, which act as a trigger to cause the conformational ordering from the random coil to the regular T$_2$G$_2$-type helical form. The thus created short helical segments were found to grow into longer helices, which gathered together to form the crystallites, as revealed by the organized coupling of the infrared, Raman and X-ray scattering data.

• Polymer Science and Technology
• /
• v.25 no.4
• /
• pp.322-328
• /
• 2014

• Proceedings of the Optical Society of Korea Conference
• /
• 2005.02a
• /
• pp.334-335
• /
• 2005

• Bulletin of the Korean Chemical Society
• /
• v.35 no.3
• /
• pp.953-954
• /
• 2014

• Proceedings of the Optical Society of Korea Conference
• /
• 2007.07a
• /
• pp.31-32
• /
• 2007

• Proceedings of the Korean Vacuum Society Conference
• /
• 1994.06a
• /
• pp.102-102
• /
• 1994

• Proceedings of the Korean Vacuum Society Conference
• /
• 2008.02a
• /
• pp.148-148
• /
• 2008