Advancing the experimental design for simultaneous acquisition of laser induced plasma and Raman signals using a single pulse

Choi, S.J.,Choi, J.J.,Yoh, J.J. Pergamon Press ; Elsevier Science Ltd 2016 Spectrochimica acta. Part B, Atomic spectroscopy Vol.123 No.-

<P>Simultaneous acquisition was performed of combined signals that show highly resolved and identifiable peaks of both LIBS and Raman signals. A LIBS-Raman combination using a single light source is a daunting task, because the energy required for Raman shift is relatively low, compared to the energy required for laser ablation. Here, we utilize an expanded-focused beam that allows simultaneous detection of the signals of laser induced plasma and Raman shift. A beam expander obtains the Raman signal with minimized interference from the plasma, and a focusing lens of small diameter generates strong laser induced plasma for LIBS. The position of the focusing lens can be adjusted to control the area of Raman scattering to ensure a strong Raman signal. In the proposed design, the key to minimized interference is to generate the Raman scattering apart from the plasma, which allows for sufficiently long gate width and wide area for Raman detection. Furthermore, axial relocation of the end of the optical fiber can easily optimize the Raman, LIBS, or combined Raman-LIBS signal. (C) 2016 Elsevier B.V. All rights reserved.</P>

Line-scan Raman imaging and spectroscopy platform for surface and subsurface evaluation of food safety and quality

Qin, J.,Kim, M.S.,Chao, K.,Schmidt, W.F.,Cho, B.K.,Delwiche, S.R. Applied Science Publishers 2017 Journal of food engineering Vol.198 No.-

<P>Both surface and subsurface food inspection is important since interesting safety and quality attributes can be at different sample locations. This paper pregents a multipurpose line-scan Raman platform for food safety and quality research, which can be configured for Raman chemical imaging (RCI) mode for surface inspection and spatially offset Raman spectroscopy (SORS) mode for subsurface inspection. In the RCI mode, macro-scale imaging was achieved using a 785 nm line laser up to 24 cm long with a push broom method. In the SORS mode, a 785 nm point laser was used and a complete set of SORS data was collected in an offset range of 0-36 mm with a spatial interval of 0.07 mm using one CCD exposure. The RCI and SOPS modes share a common detection module including a dispersive imaging spectrograph and a CCD camera, covering a Raman shift range from 674 to 2865 cm(-1). A pork shoulder and an orange carrot were used to test large-field-of-view (230 min wide) and high-spatial-resolution (0.07 mm/pixel) settings of the RCI mode for food surface evaluation. Fluorescence-corrected images at selected Raman peak wavenumbers Were used to view Raman-active analytes on the whole sample surfaces (e.g., fat on the pork shoulder and carotenoids over the carrot cross section). Also, three layered samples, which were created by placing carrot slices with thicknesses of 2, 5, and 8 mm on top of melamine powder, were used to test the SORS mode for subsurface food evaluation. Raman spectra from carrot and melamine were successfully resolved for all three layered samples using self-modeling mixture analysis. The line-scan Raman imaging and spectroscopy platform provides a new tool for surface and subsurface inspection for food safety and quality. Published by Elsevier Ltd.</P>

이산화탄소 원격 계측을 위한 광 계수 방식의 라만 라이다 장치 개발

박선호,최인영,윤문상 한국광학회 2024 한국광학회지 Vol.35 No.2

이산화탄소 원격 계측을 위한 라만 라이다 장치를 개발하기 위해 라만 라이다 장치의 소형화를 진행하고, 이에 스캐닝 장치를 결합하여 라만 라이다 시스템을 개발하였다. 개발한 시스템의 성능 검증을 위하여 가스 챔버를 약 87 m 거리에 위치시킨 후, 이산화탄소의 농도 변화에 따른라만 산란 신호를 계측하였다. 그 결과 개발된 라만 라이다 장치를 이용하였을 때 약 0.67–40 vol%의 사이의 농도에서 높은 선형성을 나타냄을 확인하였다. This research is about the development of a Raman Lidar system for remote measurement of carbon dioxide present in atmospheric space. An aircooled laser with 355-nm wavelength and a 6-inch optical receiver were used to miniaturize the Raman Lidar system, and a scanning Raman Lidar system was developed using a two-axis scanning device and a light counter. To verify the performance of the developed Raman Lidar system, a gas chamber capable of maintaining a concentration was located at a distance of about 87 m, and the change in Raman signal according to the change inthe concentration of carbon dioxide was measured. As a result, it was confirmed that the change in the Raman-scattering signal of carbon dioxide, that appeared for a change in carbon dioxide concentration from about 0.67 to 40 vol% was linear, and the coefficient of determination (R 2 ) value, which indicates the correlation between carbon-dioxide concentration and Raman-scattering signal, showed a high linearity of 0.9999.

Enhancement of local surface plasmon resonance (LSPR) effect by biocompatible metal clustering based on ZnO nanorods in Raman measurements

Lee, Sanghwa,Lee, Seung Ho,Paulson, Bjorn,Lee, Jae-Chul,Kim, Jun Ki Elsevier 2018 Spectrochimica acta. Part A, Molecular and biomole Vol.204 No.-

<P><B>Abstract</B></P> <P>The development of size-selective and non-destructive detection techniques for nanosized biomarkers has many reasons, including the study of living cells and diagnostic applications. We present an approach for Raman signal enhancement on biocompatible sensing chips based on surface enhancement Raman spectroscopy (SERS). A sensing chip was fabricated by forming a ZnO-based nanorod structure so that the Raman enhancement occurred at a gap of several tens to several hundred nanometers. The effect of coffee-ring formation was eliminated by introducing the porous ZnO nanorods for the bio-liquid sample. A peculiarity of this approach is that the gold sputtered on the ZnO nanorods initially grows at their heads forming clusters, as confirmed by secondary electron microscopy. This clustering was verified by finite element analysis to be the main factor for enhancement of local surface plasmon resonance (LSPR). This clustering property and the ability to adjust the size of the nanorods enabled the signal acquisition points to be refined using confocal based Raman spectroscopy, which could be applied directly to the sensor chip based on the optimization process in this experiment. It was demonstrated by using common cancer cell lines that cell growth was high on these gold-clad ZnO nanorod-based surface-enhanced Raman substrates. The porosity of the sensing chip, the improved structure for signal enhancement, and the cell assay make these gold-coated ZnO nanorods substrates promising biosensing chips with excellent potential for detecting nanometric biomarkers secreted by cells.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A surface enhanced Raman spectroscopy (SERS) chip was fabricated by depositing gold on a ZnO - based nanorod structure. </LI> <LI> The nanorod heads grow first to form clusters as gold is sputtered on the ZnO nanorods. </LI> <LI> The process was optimized by adjusting the ZnO nanorod size and Au clusters, and verified by finite element analysis (FEM). </LI> <LI> Biocompatibility testing confirmed that the Raman-based sensing chip was suitable for monitoring of living cells. </LI> </UL> </P> <P><B>Graphical Abstract</B></P> <P>[DISPLAY OMISSION]</P>

High Resolution Live Cell Raman Imaging Using Subcellular Organelle-Targeting SERS-Sensitive Gold Nanoparticles with Highly Narrow Intra-Nanogap

Kang, Jeon Woong,So, Peter T. C.,Dasari, Ramachandra R.,Lim, Dong-Kwon American Chemical Society 2015 NANO LETTERS Vol.15 No.3

<P>We report a method to achieve high speed and high resolution live cell Raman images using small spherical gold nanoparticles with highly narrow intra-nanogap structures responding to NIR excitation (785 nm) and high-speed confocal Raman microscopy. The three different Raman-active molecules placed in the narrow intra-nanogap showed a strong and uniform Raman intensity in solution even under transient exposure time (10 ms) and low input power of incident laser (200 μW), which lead to obtain high-resolution single cell image within 30 s without inducing significant cell damage. The high resolution Raman image showed the distributions of gold nanoparticles for their targeted sites such as cytoplasm, mitochondria, or nucleus. The high speed Raman-based live cell imaging allowed us to monitor rapidly changing cell morphologies during cell death induced by the addition of highly toxic KCN solution to cells. These results strongly suggest that the use of SERS-active nanoparticle can greatly improve the current temporal resolution and image quality of Raman-based cell images enough to obtain the detailed cell dynamics and/or the responses of cells to potential drug molecules.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/nalefd/2015/nalefd.2015.15.issue-3/nl504444w/production/images/medium/nl-2014-04444w_0006.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nl504444w'>ACS Electronic Supporting Info</A></P>

Comparison of spectroscopic identification methods for microplastics: Manual, semi-auto and automated FTIR analysis and Raman spectroscopy

Young Kyoung Song(송영경),Soeun Eo(어소은),Sang Hee Hong(홍상희),Won Joon Shim(심원준) 환경독성보건학회 2021 한국독성학회 심포지움 및 학술발표회 Vol.2021 No.5

The vibrational spectroscopy such as Fourier transform infrared (FTIR) and Raman microscope is popular microplastic analytical method for their quality and quantity. The spectroscopy can confirm the polymer composition, however, still it is unavoidable to human bias by manually selecting plastic-like particles for FTIR analysis using microscope. We tried to find best practice for microplastic analysis by reducing time demand, human bias (false negative) and automatic identification bias (false positive and false negative) using spectroscopy (FTIR and Raman microscopy). The manual analysis under transmission mode, semi-automated method using ultrafast mapping and spectrum profiling, and automated method using ultrafast mapping, spectrum profiling and fully automatic identification were compared. In the automated method, to check false positive rate during identification, all spectra were manually duble-checked after automated method have done. The automated method took the shortest time (3.2±0.5 h, which is occupied time by operator) to analyze whole filterpaper (Ø25 mm), but the polymer types were limited to the number of profile spectrums, fiber could not be detected, and the rate of false positive was 80±15%. While, semi-auto analytical method using spectrum profiling was suitable for microplastic analysis in all aspects. It took shorter time than those of manual analysis (manual: 6.1±0.8 h and semi-auto: 4.0±0.6 h), fiber could be distinguished by chemical and mapping image. And 22±12% (false negative) more microplastic particles were detected using semi-auto than 43 using manual analysis. Two types of spectroscopic analysis (FTIR and Raman) for microplastics were compared in four different methods, manual identification in ATR and transmission mode and semi-auto method using FTIR, and manual using Raman. The analysis duration was overwhelmingly taken for long time (34 ± 1.5 h) in Raman followed by transmission (5.6 ± 0.3 h), ATR (4.8 ± 0.9 h) and semiauto (3.6 ± 0.5 h). However, the detected number of microplastics using Raman were 1.4, 1.9 and 3 times higher than using semiauto, transmission and ATR mode, respectively. And the range of 0-50 ㎛ was peaked in size distribution of Raman, but the range of 50-100 ㎛ was peaked in size distribution of the others. Depending on the microplastic size range of interest, it could be appropriate identification method.

Selective isolation and noninvasive analysis of circulating cancer stem cells through Raman imaging

Cho, Hyeon-Yeol,Hossain, Md. Khaled,Lee, Jin-Ho,Han, Jiyou,Lee, Hun Joo,Kim, Kyeong-Jun,Kim, Jong-Hoon,Lee, Ki-Bum,Choi, Jeong-Woo Elsevier 2018 Biosensors & Bioelectronics Vol.102 No.-

<P><B>Abstract</B></P> <P>Circulating cancer stem cells (CCSCs), a rare circulating tumor cell (CTC) type, recently arose as a useful resource for monitoring and characterizing both cancers and their metastatic derivatives. However, due to the scarcity of CCSCs among hematologic cells in the blood and the complexity of the phenotype confirmation process, CCSC research can be extremely challenging. Hence, we report a nanoparticle-mediated Raman imaging method for CCSC characterization which profiles CCSCs based on their surface marker expression phenotypes. We have developed an integrated combinatorial Raman-Active Nanoprobe (RAN) system combined with a microfluidic chip to successfully process complete blood samples. CCSCs and CTCs were detected (90% efficiency) and classified in accordance with their respective surface marker expression <I>via</I> completely distinct Raman signals of RANs. Selectively isolated CCSCs (93% accuracy) were employed for both <I>in vitro</I> and <I>in vivo</I> tumor phenotyping to identify the tumorigenicity of the CCSCs. We utilized our new method to predict metastasis by screening blood samples from xenograft models, showing that upon CCSC detection, all subjects exhibited liver metastasis. Having highly efficient detection and noninvasive isolation capabilities, we have demonstrated that our RAN-based Raman imaging method will be valuable for predicting cancer metastasis and relapse <I>via</I> CCSC detection. Moreover, the exclusion of peak overlapping in CCSC analysis with our Raman imaging method will allow to expand the RAN families for various cancer types, therefore, increasing therapeutic efficacy by providing detailed molecular features of tumor subtypes.</P> <P><B>Highlights</B></P> <P> <UL> <LI> RANs are designed for detection, isolation, and analysis of CCSCs and CTCs. </LI> <LI> CCSCs and CTCs are distinguished without signal overlapping by Raman imaging. </LI> <LI> Noninvasive isolation of detected cells is conducted by using restriction enzyme. </LI> <LI> The secondary tumor's subtype can be predicted with differentiated CCSC's profile. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

X-선회절과 Raman 분광분석을 이용한 2성분계(CaO-, $Y_2O_3$-, MgO-$ZrO_2$) 및 3성분계(MgO-$ZrO_2-Al_2O_3)$ Zirconia의 상전이연구

은희태,황진명 한국세라믹학회 1997 한국세라믹학회지 Vol.34 No.2

2성분계(CaO-, Y2O3-, MgO-ZrO2) 및 3성분계(MgO-ZrO2-Al2O3)ZrO2분말의 안정화제 종류, 첨가량 및 열처리온도 변화에 따른 ZrO2의 상전이를 X-선 회절과 Raman분광법으로 연구하였다. CaO-, 및 Y2O3-ZrO2계에서 CaO와 Y2O3의 첨가량이 각각 6~15mol% 및 3~15mol%로 증가에 따른 정방정상에서의 입방정상으로의 상전이를 X-선회절 pattern으로는 판별하기 어려웠으나, Raman spectra에서는 모든 Raman band가 저파수쪽으로 이동하고 band의 수 및 그 세기가 현저히 감소함을 관찰할 수 있었다. 이것은 정방정$\longrightarrow$입방정의 상전이가 발생한 것으로 ZrO2 격자내에서 Zr4+ 이온과 Ca2+ 혹은 Y3+이온의 치환에 의해 산소이온의 빈자리 생성으로 인한 구조적 불규칙성과 선택규칙(k=0)의 파괴에 기인한 것으로 해석된다. MgO의 경우에는 10mol%에서 단사정에서 입방정으로 상전이가 발생하였다. MgO-ZrO2-Al2O3계에서는 Al2O3의 첨가에 의해 입방정$\longrightarrow$단사정의 상전이가 발생하는데 이것은 MgO와 Al2O3의 반응에 의해 spinel(MgAl2O4)의 형성으로 인하여 MgO가 충분히 안정화제로서의 역할을 하지 못하기 때문으로 판단된다. 또한, 안정화제의 종류와 첨가량 변화에 따른 ZrO2의 상전이를 ZrO2의 격자상수값의 변화와 관련하여 설명할 수 있는데, 즉, 안정화제의 첨가량이 증가할수록 격자상수 a값은 증가하고 c값은 감소하여 10~13mol%사이에서는 c/a의 축비가 1에 근접하고, 따라서 정방정$\longrightarrow$입방정의 상전이가 진행됨을 알 수 있었다. ZrO2 phase transformations depending on the type and amount of dopants and the sintering temperatures were studied for the 2 components (CaO-, Y2O3-, MgO-ZrO2) and the 3 components(MgO-ZrO2-Al2O3)ZrO2 powder by X-ray diffraction and Raman spectroscopy. In the CaO- and Y2O3-ZrO2 systems, as the CaO and Y2O3 contents increased to 6~15mol% and 3~15mol% respectively, we were not able to identify between tetragonal and cubic in the X-ray diffraction patterns. On the other hand, all Raman modes shifted to lower wavenumbers, decreasing in intensity and the number of bands, markedly. These phenomena were caused by tetragonallongrightarrowcubic phase transformation and interpreted by the breakdown of the wave vector selection rule(k=0) and the structural disorder associated with the formation of oxygen sublattice which was caused by the substitution between Zr4+ ion and Ca2+ or Y3+ ion in ZrO2 matrix. The monoclinic to cubic phase transformation occurred in 10mol% MgO-ZrO2 system. As the Al2O3 content increased from 0 to 20mol% in the MgO-ZrO2-Al2O3 systems, cubic phase transformed to monoclinic phase, this is because the MgO didn't play a role in a stabilizer because of the formation of the spinel(MgAl2O4) by the reaction between MgO and Al2O3, Also, the ZrO2 phase transformation was explained by the change of it's lattice parameters depending on the type and amount of dopants. Namely, as the amount of dopant increased to 10~13mol%, the axial ra-tio c/a came close to unity with increasing the lattice parameter a and decreasing the lattice parameter c. At that time, the tetragonallongrightarrowcubic phase transformation occurred.

Analysis of Raman Spectral Characteristics of Chemical Warfare Agents by Using 248-nm UV Raman Spectroscopy

최선경,정영수,고영진,이재환,남현우,이준오 대한화학회 2019 Bulletin of the Korean Chemical Society Vol.40 No.3

Chemical warfare agents (CWAs) are extremely toxic and fatal to humans. It is required to quickly identify the released chemical agents and warn against the CWAs for protecting human life. The primary CWA contamination due to attacks occurs mostly on the ground surface, and Raman spectroscopy can quickly identify CWA on the surface in a non-contact manner. In particular, the interference can be reduced by avoiding the fluorescence of materials on the surface while increasing the Raman-scattering intensity with the excitation light source of deep ultra violet (UV) smaller than 250 nm. In this study, the Raman spectra of 18 chemical agents, including major CWAs, were measured using a Raman spectroscopy system with 248-nm deep-UV light source, and the spectral characteristics of each agent were analyzed. From the results, we confirmed that deep-UV Raman spectroscopy could be the main method for quickly and accurately detecting and identifying CWA contamination.

Tracking heavy water (D₂O) incorporation for identifying and sorting active microbial cells

Berry, David,Mader, Esther,Lee, Tae Kwon,Woebken, Dagmar,Wang, Yun,Zhu, Di,Palatinszky, Marton,Schintlmeister, Arno,Schmid, Markus C.,Hanson, Buck T.,Shterzer, Naama,Mizrahi, Itzhak,Rauch, Isabella,De National Academy of Sciences 2015 PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF Vol.112 No.2

<P><B>Significance</B></P><P>Measuring activity patterns of microbes in their natural environment is essential for understanding ecosystems and the multifaceted interactions of microorganisms with eukaryotes. In this study, we developed a technique that allows fast and nondestructive activity measurements of microbial communities on a single-cell level. Microbial communities were amended with heavy water (D<SUB>2</SUB>O), a treatment that does not change the available substrate pool. After incubation, physiologically active cells are rapidly identified with Raman microspectroscopy by measuring cellular D incorporation. Using this approach, we characterized the activity patterns of two dominant microbes in mouse cecum samples amended with different carbohydrates and discovered previously unidentified bacteria stimulated by mucin and/or glucosamine by combining Raman microspectroscopy and optical tweezer-based sorting.</P><P>Microbial communities are essential to the function of virtually all ecosystems and eukaryotes, including humans. However, it is still a major challenge to identify microbial cells active under natural conditions in complex systems. In this study, we developed a new method to identify and sort active microbes on the single-cell level in complex samples using stable isotope probing with heavy water (D<SUB>2</SUB>O) combined with Raman microspectroscopy. Incorporation of D<SUB>2</SUB>O-derived D into the biomass of autotrophic and heterotrophic bacteria and archaea could be unambiguously detected via C-D signature peaks in single-cell Raman spectra, and the obtained labeling pattern was confirmed by nanoscale-resolution secondary ion MS. In fast-growing <I>Escherichia coli</I> cells, label detection was already possible after 20 min. For functional analyses of microbial communities, the detection of D incorporation from D<SUB>2</SUB>O in individual microbial cells via Raman microspectroscopy can be directly combined with FISH for the identification of active microbes. Applying this approach to mouse cecal microbiota revealed that the host-compound foragers <I>Akkermansia muciniphila</I> and <I>Bacteroides acidifaciens</I> exhibited distinctive response patterns to amendments of mucin and sugars. By Raman-based cell sorting of active (deuterated) cells with optical tweezers and subsequent multiple displacement amplification and DNA sequencing, novel cecal microbes stimulated by mucin and/or glucosamine were identified, demonstrating the potential of the nondestructive D<SUB>2</SUB>O-Raman approach for targeted sorting of microbial cells with defined functional properties for single-cell genomics.</P>