1
|
Tomasetti B, Lauzin C, Delcorte A. Enhancing Ion Signals and Improving Matrix Selection in Time-of-Flight Secondary Ion Mass Spectrometry with Microvolume Expansion Using Large Argon Clusters. Anal Chem 2023; 95:13620-13628. [PMID: 37610942 DOI: 10.1021/acs.analchem.3c02404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/25/2023]
Abstract
The molecular environment has an important impact on the ionization mechanism in time-of-flight secondary ion mass spectrometry (ToF-SIMS). In complex samples, desorption/ionization, and thus the detection of a molecular signal, can be hampered by molecular entanglement, ionization-suppressive neighbors, or even an unfavorable sample substrate. Here, a method called microvolume expansion is developed to overcome these negative effects. Large argon clusters are able to transfer biomolecules from a target to a collector in vacuum. In this study, argon gas cluster ion beams (Arn+-GCIB with n centered around 3000 or 5000) are used to expand a microvolume from the sample to a collector, which is a material ideally enhancing the ionization yield. The collector is then analyzed using a liquid metal ion gun. The signal amplification factor corresponding to the expansion of phosphatidylcholine (PC) lipid on collectors partially covered with acidic matrices was evaluated as an initial proof of concept. In one experiment, the PC expansion on a pattern of four drop-casted matrix-assisted laser desorption/ionization matrices led to the selection of α-cyano-4-hydroxycinnamic (CHCA) as the optimal candidate for cationic PC detection. The ion signal is increased by at least three orders of magnitude when PC was expanded using 10 keV Ar3000+ and Ar5000+ on a sublimated layer of CHCA. Finally, the expansion of the gray matter of a mouse on different materials (Si, Au-coated Si, CHCA, and polyethylene) was achieved with varying degrees of success, demonstrating the potential of the method to further analyze complex and fragile biological assemblies.
Collapse
Affiliation(s)
- Benjamin Tomasetti
- Institute of Condensed Matter and Nanosciences, Université catholique de Louvain, 1348 Louvain-la-Neuve, Belgium
| | - Clément Lauzin
- Institute of Condensed Matter and Nanosciences, Université catholique de Louvain, 1348 Louvain-la-Neuve, Belgium
| | - Arnaud Delcorte
- Institute of Condensed Matter and Nanosciences, Université catholique de Louvain, 1348 Louvain-la-Neuve, Belgium
| |
Collapse
|
2
|
Schneider P, Verloh F, Dürr M. Cluster-Induced Desorption/Ionization of Polystyrene: Desorption Mechanism and Effect of Polymer Chain Length on Desorption Probability. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2022; 33:832-839. [PMID: 35426303 DOI: 10.1021/jasms.2c00021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Soft cluster-induced desorption/ionization of polystyrene oligomers was investigated with respect to application in mass spectrometry. Clear peak progressions corresponding to intact polystyrene molecules were observed in the mass spectra, and no fragmentation was detected; efficient desorption was deduced from quartz crystal microbalance measurements. Molecular dynamics (MD) simulations of the process revealed that even in the case of the nonpolar polystyrene molecules cluster-induced desorption proceeds via dissolvation in the polar clusters. Experimentally, a significantly lower desorption efficiency was observed for polystyrene molecules with larger chain length. Taking into account MD simulations and further experiments with mixed samples consisting of long- and short-chain polystyrene oligomers, the reduced desorption efficiency for longer chain polystyrene molecules was attributed to a stronger entanglement of the larger polystyrene molecules.
Collapse
Affiliation(s)
- Pascal Schneider
- Institut für Angewandte Physik and Zentrum für Materialforschung, Justus-Liebig-Universität Giessen, Heinrich-Buff-Ring 16, D-35392 Giessen, Germany
| | - Felix Verloh
- Institut für Angewandte Physik and Zentrum für Materialforschung, Justus-Liebig-Universität Giessen, Heinrich-Buff-Ring 16, D-35392 Giessen, Germany
| | - Michael Dürr
- Institut für Angewandte Physik and Zentrum für Materialforschung, Justus-Liebig-Universität Giessen, Heinrich-Buff-Ring 16, D-35392 Giessen, Germany
| |
Collapse
|
3
|
Zhang Y, Tang J, Ni Z, Zhao Y, Jia F, Luo Q, Mao L, Zhu Z, Wang F. Real-Time Characterization of the Fine Structure and Dynamics of an Electrical Double Layer at Electrode-Electrolyte Interfaces. J Phys Chem Lett 2021; 12:5279-5285. [PMID: 34061525 DOI: 10.1021/acs.jpclett.1c01134] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The chemisorption of an electrolyte species on electrode surfaces is ubiquitous and affects the dynamics and mechanism of various electrochemical reactions. Understanding of the chemical structure and property of the resulting electrical double layer is vital but limited. Herein, we operando probed the electrochemical interface between a gold electrode surface and a common electrolyte, phosphate buffer, using our newly developed in situ liquid secondary ion mass spectrometry. We surprisingly found that, on the positively charged gold electrode surface, sodium cations were anchored in the Stern layer in a partially dehydrated form by a formation of compact ion pairs with the accumulated phosphate anions. The resulting strong adsorption phase was further revealed to retard the electro-oxidation reaction of ascorbate. This finding addressed one major gap in the fundamental science of electrode-electrolyte interfaces, namely, where and how cations reside in the double layer to impose effects on electrochemical reactions, providing insights into the engineering of better electrochemical systems.
Collapse
Affiliation(s)
- Yanyan Zhang
- Beijing National Laboratory for Molecular Sciences, National Centre for Mass Spectrometry in Beijing, CAS Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Jilin Tang
- Beijing National Laboratory for Molecular Sciences, National Centre for Mass Spectrometry in Beijing, CAS Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhigang Ni
- College of Materials, Chemistry and Chemical Engineering, Hangzhou Normal University, Hangzhou 311121, China
| | - Yao Zhao
- Beijing National Laboratory for Molecular Sciences, National Centre for Mass Spectrometry in Beijing, CAS Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Feifei Jia
- Beijing National Laboratory for Molecular Sciences, National Centre for Mass Spectrometry in Beijing, CAS Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Qun Luo
- Beijing National Laboratory for Molecular Sciences, National Centre for Mass Spectrometry in Beijing, CAS Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Lanqun Mao
- Beijing National Laboratory for Molecular Sciences, National Centre for Mass Spectrometry in Beijing, CAS Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zihua Zhu
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland 99354, Washington, United States
| | - Fuyi Wang
- Beijing National Laboratory for Molecular Sciences, National Centre for Mass Spectrometry in Beijing, CAS Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| |
Collapse
|
4
|
Dimovska Nilsson K, Karagianni A, Kaya I, Henricsson M, Fletcher JS. (CO 2) n+, (H 2O) n+, and (H 2O) n+ (CO 2) gas cluster ion beam secondary ion mass spectrometry: analysis of lipid extracts, cells, and Alzheimer's model mouse brain tissue. Anal Bioanal Chem 2021; 413:4181-4194. [PMID: 33974088 PMCID: PMC8222020 DOI: 10.1007/s00216-021-03372-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Revised: 03/07/2021] [Accepted: 04/22/2021] [Indexed: 02/07/2023]
Abstract
This work assesses the potential of new water cluster-based ion beams for improving the capabilities of secondary ion mass spectrometry (SIMS) for in situ lipidomics. The effect of water clusters was compared to carbon dioxide clusters, along with the effect of using pure water clusters compared to mixed water and carbon dioxide clusters. A signal increase was found when using pure water clusters. However, when analyzing cells, a more substantial signal increase was found in positive ion mode when the water clusters also contained carbon dioxide, suggesting that additional reactions are in play. The effects of using a water primary ion beam on a more complex sample were investigated by analyzing brain tissue from an Alzheimer’s disease transgenic mouse model. The results indicate that the ToF-SIMS results are approaching those from MALDI as ToF-SIMS was able to image lyso-phosphocholine (LPC) lipids, a lipid class that for a long time has eluded detection during SIMS analyses. Gangliosides, sulfatides, and cholesterol were also imaged. ![]()
Collapse
Affiliation(s)
- Kelly Dimovska Nilsson
- Department of Chemistry and Molecular Biology, University of Gothenburg, 405 30, Gothenburg, Sweden
| | - Anthi Karagianni
- Department of Chemistry and Molecular Biology, University of Gothenburg, 405 30, Gothenburg, Sweden
| | - Ibrahim Kaya
- Department of Chemistry and Molecular Biology, University of Gothenburg, 405 30, Gothenburg, Sweden
- Department of Psychiatry and Neurochemistry, Sahlgrenska Academy at the University of Gothenburg, 413 45, Mölndal, Sweden
- Medical Mass Spectrometry Laboratory, Department of Pharmaceutical Biosciences, Uppsala University, 751 05, Uppsala, Sweden
| | - Marcus Henricsson
- Department of Molecular and Clinical Medicine/Wallenberg Laboratory, Institute of Medicine, University of Gothenburg, 41345, Gothenburg, Sweden
| | - John S Fletcher
- Department of Chemistry and Molecular Biology, University of Gothenburg, 405 30, Gothenburg, Sweden.
| |
Collapse
|
5
|
Surface cleaning and sample carrier for complementary high-resolution imaging techniques. Biointerphases 2020; 15:021005. [PMID: 32212739 DOI: 10.1116/1.5143203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Nowadays, high-resolution imaging techniques are extensively applied in a complementary way to gain insights into complex phenomena. For a truly complementary analytical approach, a common sample carrier is required that is suitable for the different preparation methods necessary for each analytical technique. This sample carrier should be capable of accommodating diverse analytes and maintaining their pristine composition and arrangement during deposition and preparation. In this work, a new type of sample carrier consisting of a silicon wafer with a hydrophilic polymer coating was developed. The robustness of the polymer coating toward solvents was strengthened by cross-linking and stoving. Furthermore, a new method of UV-ozone cleaning was developed that enhances the adhesion of the polymer coating to the wafer and ensures reproducible surface-properties of the resulting sample carrier. The hydrophilicity of the sample carrier was recovered applying the new method of UV-ozone cleaning, while avoiding UV-induced damages to the polymer. Noncontact 3D optical profilometry and contact angle measurements were used to monitor the hydrophilicity of the coating. The hydrophilicity of the polymer coating ensures its spongelike behavior so that upon the deposition of an analyte suspension, the solvent and solutes are separated from the analyte by absorption into the polymer. This feature is essential to limit the coffee-ring effect and preserve the native identity of an analyte upon deposition. The suitability of the sample carrier for various sample types was tested using nanoparticles from suspension, bacterial cells, and tissue sections. To assess the homogeneity of the analyte distribution and preservation of sample integrity, optical and scanning electron microscopy, helium ion microscopy, laser ablation inductively coupled plasma mass spectrometry, and time-of-flight secondary ion mass spectrometry were used. This demonstrates the broad applicability of the newly developed sample carrier and its value for complementary imaging.
Collapse
|
6
|
Gnaser H, Oki R, Aoki T, Seki T, Matsuo J. Optimized Alkali-Metal Cationization in Secondary Ion Mass Spectrometry of Polyethylene Glycol Oligomers with up to m/ z 10000: Dependence on Cation Species and Concentration. Anal Chem 2020; 92:1511-1517. [PMID: 31800216 DOI: 10.1021/acs.analchem.9b04770] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In secondary ion mass spectrometry (SIMS), the detection of large organic molecules is accomplished using cluster ion bombardment. Ion formation often proceeds via cationization, through the attachment of (alkali) metal ions to the molecule. To study this process, the emission of secondary ions sputtered from polyethylene glycol (PEG) samples with molecular weights (MW) of 1000-10000 was examined. They were mixed with alkali-metal trifluoroacetic acid (X-TFA, where X = Li, Na, K, or Cs) in a wide range of concentrations to investigate the efficiency of cationization for 10 keV Ar2000+ cluster irradiation. Typically, cationized molecular ions [M + X]+ (with repeat units n of up to ∼250, corresponding roughly to m/z 11000) and some characteristic fragment species were observed in the mass spectra. For all alkali cations, the oligomer intensities increase strongly with the molecular composition ratios X-TFA/PEG in the samples, and values of 5-10 seem to be optimal. With increasing molecular weight, the intensity of oligomer ions relative to the total number of ions decreases; as the latter remains rather constant, this implies that more fragment species are formed. The ion yields (detected ions per primary ions) of cationized [M + Na]+ oligomers sputtered from a PEG decrease very strongly with their size n: from 5.2 × 10-6 at n = 21 (MW ∼ 1000) to 4.5 × 10-10 at n ∼ 245 (MW ∼ 11000). By contrast, the total yields Ytot+ show only a small variation for these different specimens, from 1.3 × 10-5 to 3.7 × 10-5.
Collapse
Affiliation(s)
- Hubert Gnaser
- Quantum Science and Engineering Center , Kyoto University , Gokasho, Uji , Kyoto 611-0011 , Japan.,Department of Physics , University of Kaiserslautern , 67663 Kaiserslautern , Germany
| | - Rika Oki
- Quantum Science and Engineering Center , Kyoto University , Gokasho, Uji , Kyoto 611-0011 , Japan
| | - Takaaki Aoki
- Department of Electronic Science and Engineering , Kyoto University , Nishikyo-ku , Kyoto 615-8510 , Japan
| | - Toshio Seki
- Department of Nuclear Engineering , Kyoto University , Gokasho, Uji , Kyoto 611-0011 , Japan
| | - Jiro Matsuo
- Quantum Science and Engineering Center , Kyoto University , Gokasho, Uji , Kyoto 611-0011 , Japan.,SENTAN, Japan Science and Technology Agency (JST) , Chiyoda , Tokyo 102-0075 , Japan
| |
Collapse
|
7
|
Metal-assisted polyatomic SIMS and laser desorption/ionization for enhanced small molecule imaging of bacterial biofilms. Biointerphases 2016; 11:02A325. [PMID: 26945568 DOI: 10.1116/1.4942884] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Mass spectrometry imaging (MSI) has become an important analytical tool for many sectors of science and medicine. As the application of MSI expands into new areas of inquiry, existing methodologies must be adapted and improved to meet emerging challenges. Particularly salient is the need for small molecule imaging methods that are compatible with complex multicomponent systems, a challenge that is amplified by the effects of analyte migration and matrix interference. With a focus on microbial biofilms from the opportunistic pathogen Pseudomonas aeruginosa, the relative advantages of two established microprobe-based MSI techniques-polyatomic secondary ion mass spectrometry (SIMS) and laser desorption/ionization-are compared, with emphasis on exploring the effect of surface metallization on small molecule imaging. A combination of qualitative image comparison and multivariate statistical analysis demonstrates that sputtering microbial biofilms with a 2.5 nm layer of gold selectively enhances C60-SIMS ionization for several molecular classes including rhamnolipids and 2-alkyl-quinolones. Metallization also leads to the reduction of in-source fragmentation and subsequent ionization of media-specific background polymers, which improves spectral purity and image quality. These findings show that the influence of metallization upon ionization is strongly dependent on both the surface architecture and the analyte class, and further demonstrate that metal-assisted C60-SIMS is a viable method for small molecule imaging of intact molecular ions in complex biological systems.
Collapse
|
8
|
Study of Thickness Distributions of Sputtered Gold Particles Deposited on a Perpendicular Section for Enhancement of 3D MetA-SIMS. E-JOURNAL OF SURFACE SCIENCE AND NANOTECHNOLOGY 2016. [DOI: 10.1380/ejssnt.2016.87] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|
9
|
Multi-dimensional TOF-SIMS analysis for effective profiling of disease-related ions from the tissue surface. Sci Rep 2015; 5:11077. [PMID: 26046669 PMCID: PMC4457153 DOI: 10.1038/srep11077] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Accepted: 05/13/2015] [Indexed: 12/12/2022] Open
Abstract
Time-of-flight secondary ion mass spectrometry (TOF-SIMS) emerges as a promising tool to identify the ions (small molecules) indicative of disease states from the surface of patient tissues. In TOF-SIMS analysis, an enhanced ionization of surface molecules is critical to increase the number of detected ions. Several methods have been developed to enhance ionization capability. However, how these methods improve identification of disease-related ions has not been systematically explored. Here, we present a multi-dimensional SIMS (MD-SIMS) that combines conventional TOF-SIMS and metal-assisted SIMS (MetA-SIMS). Using this approach, we analyzed cancer and adjacent normal tissues first by TOF-SIMS and subsequently by MetA-SIMS. In total, TOF- and MetA-SIMS detected 632 and 959 ions, respectively. Among them, 426 were commonly detected by both methods, while 206 and 533 were detected uniquely by TOF- and MetA-SIMS, respectively. Of the 426 commonly detected ions, 250 increased in their intensities by MetA-SIMS, whereas 176 decreased. The integrated analysis of the ions detected by the two methods resulted in an increased number of discriminatory ions leading to an enhanced separation between cancer and normal tissues. Therefore, the results show that MD-SIMS can be a useful approach to provide a comprehensive list of discriminatory ions indicative of disease states.
Collapse
|
10
|
Kim YP, Shon HK, Shin SK, Lee TG. Probing nanoparticles and nanoparticle-conjugated biomolecules using time-of-flight secondary ion mass spectrometry. MASS SPECTROMETRY REVIEWS 2015; 34:237-247. [PMID: 24890130 DOI: 10.1002/mas.21437] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2012] [Revised: 12/04/2013] [Accepted: 03/26/2014] [Indexed: 06/03/2023]
Abstract
Bio-conjugated nanoparticles have emerged as novel molecular probes in nano-biotechnology and nanomedicine and chemical analyses of their surfaces have become challenges. The time-of-flight (TOF) secondary ion mass spectrometry (SIMS) has been one of the most powerful surface characterization techniques for both nanoparticles and biomolecules. When combined with various nanoparticle-based signal enhancing strategies, TOF-SIMS can probe the functionalization of nanoparticles as well as their locations and interactions in biological systems. Especially, nanoparticle-based SIMS is an attractive approach for label-free drug screening because signal-enhancing nanoparticles can be designed to directly measure the enzyme activity. The chemical-specific imaging analysis using SIMS is also well suited to screen nanoparticles and nanoparticle-biomolecule conjugates in complex environments. This review presents some recent applications of nanoparticle-based TOF-SIMS to the chemical analysis of complex biological systems.
Collapse
Affiliation(s)
- Young-Pil Kim
- Department of Life Science, Institute of Nano Science and Technology, and Research Institute for Natural Sciences, Hanyang University, Seoul, 133-791, Republic of Korea
| | | | | | | |
Collapse
|
11
|
Lanni EJ, Dunham SJB, Nemes P, Rubakhin SS, Sweedler JV. Biomolecular imaging with a C60-SIMS/MALDI dual ion source hybrid mass spectrometer: instrumentation, matrix enhancement, and single cell analysis. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2014; 25:1897-907. [PMID: 25183225 DOI: 10.1007/s13361-014-0978-9] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2014] [Revised: 08/07/2014] [Accepted: 08/08/2014] [Indexed: 05/09/2023]
Abstract
We describe a hybrid MALDI/C(60)-SIMS Q-TOF mass spectrometer and corresponding sample preparation protocols to image intact biomolecules and their fragments in mammalian spinal cord, individual invertebrate neurons, and cultured neuronal networks. A lateral spatial resolution of 10 μm was demonstrated, with further improvement feasible to 1 μm, sufficient to resolve cell outgrowth and interconnections in neuronal networks. The high mass resolution (>13,000 FWHM) and tandem mass spectrometry capability of this hybrid instrument enabled the confident identification of cellular metabolites. Sublimation of a suitable matrix, 2,5-dihydroxybenzoic acid, significantly enhanced the ion signal intensity for intact glycerophospholipid ions from mammalian nervous tissue, facilitating the acquisition of high-quality ion images for low-abundance biomolecules. These results illustrate that the combination of C60-SIMS and MALDI mass spectrometry offers particular benefits for studies that require the imaging of intact biomolecules with high spatial and mass resolution, such as investigations of single cells, subcellular organelles, and communities of cells.
Collapse
Affiliation(s)
- Eric J Lanni
- Department of Chemistry and Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | | | | | | | | |
Collapse
|
12
|
Kraft ML, Klitzing HA. Imaging lipids with secondary ion mass spectrometry. Biochim Biophys Acta Mol Cell Biol Lipids 2014; 1841:1108-19. [PMID: 24657337 DOI: 10.1016/j.bbalip.2014.03.003] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Revised: 03/11/2014] [Accepted: 03/12/2014] [Indexed: 10/25/2022]
Abstract
This review discusses the application of time-of-flight secondary ion mass spectrometry (TOF-SIMS) and magnetic sector SIMS with high lateral resolution performed on a Cameca NanoSIMS 50(L) to imaging lipids. The similarities between the two SIMS approaches and the differences that impart them with complementary strengths are described, and various strategies for sample preparation and to optimize the quality of the SIMS data are presented. Recent reports that demonstrate the new insight into lipid biochemistry that can be acquired with SIMS are also highlighted. This article is part of a Special Issue entitled Tools to study lipid functions.
Collapse
Affiliation(s)
- Mary L Kraft
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA; Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
| | - Haley A Klitzing
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| |
Collapse
|
13
|
Shen K, Mao D, Garrison BJ, Wucher A, Winograd N. Depth Profiling of Metal Overlayers on Organic Substrates with Cluster SIMS. Anal Chem 2013; 85:10565-72. [DOI: 10.1021/ac402658r] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Kan Shen
- The Pennsylvania State University, Department
of Chemistry, University Park, Pennsylvania 16802, United States
| | - Dan Mao
- The Pennsylvania State University, Department
of Chemistry, University Park, Pennsylvania 16802, United States
| | - Barbara J. Garrison
- The Pennsylvania State University, Department
of Chemistry, University Park, Pennsylvania 16802, United States
| | - Andreas Wucher
- University of Duisburg-Essen, Department of Physics, 47048 Duisburg, Germany
| | - Nicholas Winograd
- The Pennsylvania State University, Department
of Chemistry, University Park, Pennsylvania 16802, United States
| |
Collapse
|
14
|
Restrepo OA, Gonze X, Bertrand P, Delcorte A. Computer simulations of cluster impacts: effects of the atomic masses of the projectile and target. Phys Chem Chem Phys 2013; 15:7621-7. [PMID: 23591660 DOI: 10.1039/c3cp50346a] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Cluster secondary ion mass spectrometry is now widely used for the characterization of nanostructures. In order to gain a better understanding of the physics of keV cluster bombardment of surfaces and nanoparticles (NPs), the effects of the atomic masses of the projectile and of the target on the energy deposition and induced sputtering have been studied by means of molecular dynamics simulations. 10 keV C60 was used as a model projectile and impacts on both a flat polymer surface and a metal NP were analyzed. In the first case, the mass of the impinging carbon atoms was artificially varied and, in the second case, the mass of the NP atoms was varied. The results can be rationalized on the basis of the different atomic mass ratios of the projectile and target. In general, the emission is at its maximum, when the projectile and target have the same atomic masses. In the case of the supported NP, the emission of the underlying organic material increases as the atomic mass of the NP decreases. However, it is always less than that calculated for the bare organic surface, irrespective of the mass ratio. The results obtained with C60 impacts on the flat polymer are also compared to simulations of C60 and monoatomic Ga impacts on the NP.
Collapse
Affiliation(s)
- Oscar A Restrepo
- Institute of Condensed Matter and Nanosciences, Université catholique de Louvain, Croix du Sud, 1 bte 3, B-1348 Louvain-la-Neuve, Belgium.
| | | | | | | |
Collapse
|
15
|
Nittler L, Delcorte A, Bertrand P, Migeon HN. Insights into the yield enhancement and ion emission process in metal-assisted SIMS. SURF INTERFACE ANAL 2013. [DOI: 10.1002/sia.5045] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
| | - A. Delcorte
- Institute of Condensed Matter and Nanosciences (ICMN); Université Catholique de Louvain; 1 Croix du Sud; B-1348; Louvain-la-Neuve; Belgium
| | - P. Bertrand
- Institute of Condensed Matter and Nanosciences (ICMN); Université Catholique de Louvain; 1 Croix du Sud; B-1348; Louvain-la-Neuve; Belgium
| | - H.-N. Migeon
- Institute of Condensed Matter and Nanosciences (ICMN); Université Catholique de Louvain; 1 Croix du Sud; B-1348; Louvain-la-Neuve; Belgium
| |
Collapse
|
16
|
Fletcher JS, Vickerman JC. Secondary Ion Mass Spectrometry: Characterizing Complex Samples in Two and Three Dimensions. Anal Chem 2012; 85:610-39. [DOI: 10.1021/ac303088m] [Citation(s) in RCA: 112] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- John S. Fletcher
- Manchester Institute
of Biotechnology, University of Manchester, Manchester M13 9PL, U.K
| | - John C. Vickerman
- Manchester Institute
of Biotechnology, University of Manchester, Manchester M13 9PL, U.K
| |
Collapse
|
17
|
Surface analysis for compositional, chemical and structural imaging in pharmaceutics with mass spectrometry: A ToF-SIMS perspective. Int J Pharm 2011; 417:61-9. [DOI: 10.1016/j.ijpharm.2011.01.043] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2010] [Revised: 01/13/2011] [Accepted: 01/19/2011] [Indexed: 11/22/2022]
|
18
|
Aminlashgari N, Hakkarainen M. Emerging Mass Spectrometric Tools for Analysis of Polymers and Polymer Additives. MASS SPECTROMETRY OF POLYMERS – NEW TECHNIQUES 2011. [DOI: 10.1007/12_2011_152] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
|
19
|
Heile A, Muhmann C, Lipinsky D, Arlinghaus HF. Investigations of secondary ion yield-enhancing methods in combination. SURF INTERFACE ANAL 2010. [DOI: 10.1002/sia.3556] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
|
20
|
Becker N, Wirtz T, Migeon HN. The Storing Matter technique: Application to PVC using Au and Ag collectors. SURF INTERFACE ANAL 2010. [DOI: 10.1002/sia.3423] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
|
21
|
Becker N, Wirtz T, Migeon HN. The Storing Matter technique: application to polymer samples using Ag collectors. SURF INTERFACE ANAL 2010. [DOI: 10.1002/sia.3446] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
|
22
|
Restrepo OA, Delcorte A. Molecular dynamics study of metal-organic samples bombarded by kiloelectronvolt projectiles. SURF INTERFACE ANAL 2010. [DOI: 10.1002/sia.3411] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
|
23
|
Delcorte A, Bertrand P, Garrison BJ, Hamraoui K, Mouhib T, Restrepo OA, Santos CN, Yunus S. Probing soft materials with energetic ions and molecules: from microscopic models to the real world. SURF INTERFACE ANAL 2010. [DOI: 10.1002/sia.3270] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
24
|
Brewer TM, Szakal C, Gillen G. Method for improved secondary ion yields in cluster secondary ion mass spectrometry. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2010; 24:593-598. [PMID: 20155758 DOI: 10.1002/rcm.4423] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
A method to increase useful yields of organic molecules is investigated by cluster secondary ion mass spectrometry (SIMS). Glycerol drops were deposited onto various inkjet-printed arrays and the organic molecules in the film were rapidly incorporated into the drop. The resulting glycerol/analyte drops were then probed with fullerene primary ions under dynamic SIMS conditions. High primary ion beam currents were shown to aid in the mixing of the glycerol drop, thus replenishing the probed area and sustaining high secondary ion yields. Integrated secondary ion signals for tetrabutylammonium iodide and cocaine in the glycerol drops were enhanced by more than a factor of 100 compared with an analogous area on the surface, and a factor of 1000 over the lifetime of the glycerol drop. Once the analyte of interest is incorporated into the glycerol microdrop, the solution chemistry can be tailored for enhanced secondary ion yields, with examples shown for cyclotrimethylenetrinitramine (RDX) chloride adduct formation. In addition, depositing localized glycerol drops may enhance analyte secondary ion count rates to high enough levels to allow for site-specific chemical maps of molecules in complex matrices such as biological tissues.
Collapse
Affiliation(s)
- Tim M Brewer
- Surface and Microanalysis Science Division, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA.
| | | | | |
Collapse
|
25
|
Mahoney CM. Cluster secondary ion mass spectrometry of polymers and related materials. MASS SPECTROMETRY REVIEWS 2010; 29:247-293. [PMID: 19449334 DOI: 10.1002/mas.20233] [Citation(s) in RCA: 120] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Cluster secondary ion mass spectrometry (cluster SIMS) has played a critical role in the characterization of polymeric materials over the last decade, allowing for the ability to obtain spatially resolved surface and in-depth molecular information from many polymer systems. With the advent of new molecular sources such as C(60)(+), Au(3)(+), SF(5)(+), and Bi(3)(+), there are considerable increases in secondary ion signal as compared to more conventional atomic beams (Ar(+), Cs(+), or Ga(+)). In addition, compositional depth profiling in organic and polymeric systems is now feasible, without the rapid signal decay that is typically observed under atomic bombardment. The premise behind the success of cluster SIMS is that compared to atomic beams, polyatomic beams tend to cause surface-localized damage with rapid sputter removal rates, resulting in a system at equilibrium, where the damage created is rapidly removed before it can accumulate. Though this may be partly true, there are actually much more complex chemistries occurring under polyatomic bombardment of organic and polymeric materials, which need to be considered and discussed to better understand and define the important parameters for successful depth profiling. The following presents a review of the current literature on polymer analysis using cluster beams. This review will focus on the surface and in-depth characterization of polymer samples with cluster sources, but will also discuss the characterization of other relevant organic materials, and basic polymer radiation chemistry.
Collapse
Affiliation(s)
- Christine M Mahoney
- Chemical Science and Technology Laboratory, Surface and Microanalysis Science Division, National Institute of Standards and Technology, 100 Bureau Drive, Mail Stop 8371, Gaithersburg, MD 20899-8371, USA.
| |
Collapse
|
26
|
Mechanisms of metal-assisted secondary ion mass spectrometry: a mixed theoretical and experimental study. SURF INTERFACE ANAL 2010. [DOI: 10.1002/sia.3203] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
27
|
Wehbe N, Mouhib T, Prabhakaran A, Bertrand P, Delcorte A. Influence of the organic layer thickness in (metal-assisted) secondary ion mass spectrometry using Ga+ and C60+ projectiles. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2009; 20:2294-2303. [PMID: 19811931 DOI: 10.1016/j.jasms.2009.08.022] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2009] [Revised: 08/24/2009] [Accepted: 08/25/2009] [Indexed: 05/28/2023]
Abstract
This article investigates the influence of the organic film thickness on the characteristic and molecular ion yields of polystyrene (PS), in combination with two different substrates (Si, Au) or gold condensation (MetA-SIMS), and for atomic (Ga+) and polyatomic (C60+) projectile bombardment. PS oligomer (m/z approximately 2000 Da) layers were prepared with various thicknesses ranging from 1 up to 45 nm on both substrates. Pristine samples on Si were also metallized by evaporating gold with three different thicknesses (0.5, 2, and 6 nm). Secondary ion mass spectrometry was performed using 12 keV atomic Ga+ and C60+ projectiles. The results show that upon Ga+ bombardment, the yield of the fingerprint fragment C7H7+ increases as the PS coverage increases and reaches its maximum for a thickness that corresponds to a complete monolayer (approximately 3.5 nm). Beyond the maximum, the yields decrease strongly and become constant for layers thicker than 12 nm. In contrast, upon C60+ bombardment, the C7H7+ yields increase up to the monolayer coverage and they remain constant for higher thicknesses. A strong yield enhancement is confirmed upon Ga+ analysis of gold-metallized layers but yields decrease continuously with the gold coverage for C60+ bombardment. Upon Ga+ bombardment, the maximum PS fingerprint ion yields are obtained using a monolayer spin-coated on gold, whereas for C60+, the best results are obtained with at least one monolayer, irrespective of the substrate and without any other treatment. The different behaviors are tentatively explained by arguments involving the different energy deposition mechanisms of both projectiles.
Collapse
Affiliation(s)
- Nimer Wehbe
- Unité de Physico-Chimie et de Physique des Matériaux, Université catholique de Louvain, Louvain la Neuve, Belgium.
| | | | | | | | | |
Collapse
|
28
|
Investigation of polymer thin films by use of Bi-cluster-ion-supported time of flight secondary ion mass spectrometry. Anal Bioanal Chem 2009; 393:1889-98. [DOI: 10.1007/s00216-009-2624-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2008] [Revised: 01/14/2009] [Accepted: 01/15/2009] [Indexed: 11/26/2022]
|
29
|
Nieuwjaer N, Poleunis C, Delcorte A, Bertrand P. Depth profiling of polymer samples using Ga+
and C60
+
ion beams. SURF INTERFACE ANAL 2008. [DOI: 10.1002/sia.2931] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
30
|
Wehbe N, Heile A, Arlinghaus HF, Bertrand P, Delcorte A. Effects of metal nanoparticles on the secondary ion yields of a model alkane molecule upon atomic and polyatomic projectiles in secondary ion mass spectrometry. Anal Chem 2008; 80:6235-44. [PMID: 18630928 DOI: 10.1021/ac800568y] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
A model alkane molecule, triacontane, is used to assess the effects of condensed gold and silver nanoparticles on the molecular ion yields upon atomic (Ga(+) and In(+)) and polyatomic (C60(+) and Bi3(+)) ion bombardment in metal-assisted secondary ion mass spectrometry (MetA-SIMS). Molecular films spin-coated on silicon were metallized using a sputter-coater system, in order to deposit controlled quantities of gold and silver on the surface (from 0 to 15 nm equivalent thickness). The effects of gold and silver islets condensed on triacontane are also compared to the situation of thin triacontane overlayers on metallic substrates (gold and silver). The results focus primarily on the measured yields of quasi-molecular ions, such as (M - H)(+) and (2M - 2H)(+), and metal-cationized molecules, such as (M + Au)(+) and (M + Ag)(+), as a function of the quantity of metal on the surface. They confirm the absence of a simple rule to explain the secondary ion yield improvement in MetA-SIMS. The behavior is strongly dependent on the specific projectile/metal couple used for the experiment. Under atomic bombardment (Ga(+), In(+)), the characteristic ion yields an increase with the gold dose up to approximately 6 nm equivalent thickness. The yield enhancement factor between gold-metallized and pristine samples can be as large as approximately 70 (for (M - H)(+) under Ga(+) bombardment; 10 nm of Au). In contrast, with cluster projectiles such as Bi3(+) and C60(+), the presence of gold and silver leads to a dramatic molecular ion yield decrease. Cluster projectiles prove to be beneficial for triacontane overlayers spin-coated on silicon or metal substrates (Au, Ag) but not in the situation of MetA-SIMS. The fundamental difference of behavior between atomic and cluster primary ions is tentatively explained by arguments involving the different energy deposition mechanisms of these projectiles. Our results also show that Au and Ag nanoparticles do not induce the same behavior in MetA-SIMS of triacontane. The microstructures of the metallized layers are also different. While metallic substrates provide higher yields than metal islet overlayers in the case of silver, whatever the projectile used, the situation is reversed with gold.
Collapse
Affiliation(s)
- Nimer Wehbe
- Unite de Physico-Chimie et de Physique des Materiaux, Universite Catholique de Louvain, Croix du Sud 1, Louvain-la-Neuve B-1348, Belgium.
| | | | | | | | | |
Collapse
|
31
|
Valcárcel M, Simonet BM, Cárdenas S. Analytical nanoscience and nanotechnology today and tomorrow. Anal Bioanal Chem 2008; 391:1881-7. [DOI: 10.1007/s00216-008-2130-9] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2007] [Revised: 04/01/2008] [Accepted: 04/10/2008] [Indexed: 11/30/2022]
|
32
|
De Mondt R, Van Vaeck L, Heile A, Arlinghaus HF, Nieuwjaer N, Delcorte A, Bertrand P, Lenaerts J, Vangaever F. Ion yield improvement for static secondary ion mass spectrometry by use of polyatomic primary ions. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2008; 22:1481-1496. [PMID: 18401858 DOI: 10.1002/rcm.3533] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Static secondary ion mass spectrometry (S-SIMS) is one of the potentially most powerful and versatile tools for the analysis of surface components at the monolayer level. Current improvements in detection limit (LOD) and molecular specificity rely on the optimisation of the desorption-ionisation (DI) process. As an alternative to monoatomic projectiles, polyatomic primary ion (P.I.) bombardment increases ion yields non-linearly. Common P.I. sources are Ga+ (liquid metal ion gun (LMIG), SF5+ (electron ionisation) and the newer Au(n)+, Bi(n)q+ (both LMIG) and C60+ (electron ionisation) sources. In this study the ion yield improvement obtained by using the newly developed ion sources is assessed. Two dyes (zwitterionic and/or thermolabile polar functionalities on a largely conjugated backbone) were analysed as a thin layer using Ga+, SF5+, C60+, Bi+, Bi3(2+) and Bi5(2+) projectiles under static conditions. The study aims at evaluating the improvement in LOD, useful and characteristic yield and molecular specificity. The corrected total ion count values for the different P.I. sources are compared for different instruments to obtain a rough estimate of the improvements. Furthermore, tentative ionisation and fragmentation schemes are provided to describe the generation of radical and adduct ions. Characteristic ion yields are discussed for the different P.I. sources. An overview of the general appearances of the mass spectra obtained with the different P.I. sources is given to stress the major improvement provided by polyatomic P.I.s in yielding information at higher m/z values.
Collapse
Affiliation(s)
- Roel De Mondt
- MiTAC, University of Antwerp, Department of Chemistry (CDE), Universiteitsplein 1, B-2610 Wilrijk, Belgium.
| | | | | | | | | | | | | | | | | |
Collapse
|
33
|
Heile A, Lipinsky D, Wehbe N, Delcorte A, Bertrand P, Felten A, Houssiau L, Pireaux JJ, De Mondt R, Van Royen P, Van Vaeck L, Arlinghaus HF. Investigation of methods to enhance the secondary ion yields in TOF-SIMS of organic samples. SURF INTERFACE ANAL 2008. [DOI: 10.1002/sia.2810] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
34
|
Chen YY, Yu BY, Wang WB, Hsu MF, Lin WC, Lin YC, Jou JH, Shyue JJ. X-ray Photoelectron Spectrometry Depth Profiling of Organic Thin Films Using C60 Sputtering. Anal Chem 2007; 80:501-5. [DOI: 10.1021/ac701899a] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Ying-Yu Chen
- Research Center for Applied Sciences, Academia Sinica, Taipei 115, Taiwan, Republic of China, Department of Materials Science and Engineering, National Tsing Hua University, Hsin-Chu, Taiwan 300, Republic of China, and Department of Materials Science and Engineering, National Taiwan University, Taipei, Taiwan 106, Republic of China
| | - Bang-Ying Yu
- Research Center for Applied Sciences, Academia Sinica, Taipei 115, Taiwan, Republic of China, Department of Materials Science and Engineering, National Tsing Hua University, Hsin-Chu, Taiwan 300, Republic of China, and Department of Materials Science and Engineering, National Taiwan University, Taipei, Taiwan 106, Republic of China
| | - Wei-Ben Wang
- Research Center for Applied Sciences, Academia Sinica, Taipei 115, Taiwan, Republic of China, Department of Materials Science and Engineering, National Tsing Hua University, Hsin-Chu, Taiwan 300, Republic of China, and Department of Materials Science and Engineering, National Taiwan University, Taipei, Taiwan 106, Republic of China
| | - Mao-Feng Hsu
- Research Center for Applied Sciences, Academia Sinica, Taipei 115, Taiwan, Republic of China, Department of Materials Science and Engineering, National Tsing Hua University, Hsin-Chu, Taiwan 300, Republic of China, and Department of Materials Science and Engineering, National Taiwan University, Taipei, Taiwan 106, Republic of China
| | - Wei-Chun Lin
- Research Center for Applied Sciences, Academia Sinica, Taipei 115, Taiwan, Republic of China, Department of Materials Science and Engineering, National Tsing Hua University, Hsin-Chu, Taiwan 300, Republic of China, and Department of Materials Science and Engineering, National Taiwan University, Taipei, Taiwan 106, Republic of China
| | - Yu-Chin Lin
- Research Center for Applied Sciences, Academia Sinica, Taipei 115, Taiwan, Republic of China, Department of Materials Science and Engineering, National Tsing Hua University, Hsin-Chu, Taiwan 300, Republic of China, and Department of Materials Science and Engineering, National Taiwan University, Taipei, Taiwan 106, Republic of China
| | - Jwo-Huei Jou
- Research Center for Applied Sciences, Academia Sinica, Taipei 115, Taiwan, Republic of China, Department of Materials Science and Engineering, National Tsing Hua University, Hsin-Chu, Taiwan 300, Republic of China, and Department of Materials Science and Engineering, National Taiwan University, Taipei, Taiwan 106, Republic of China
| | - Jing-Jong Shyue
- Research Center for Applied Sciences, Academia Sinica, Taipei 115, Taiwan, Republic of China, Department of Materials Science and Engineering, National Tsing Hua University, Hsin-Chu, Taiwan 300, Republic of China, and Department of Materials Science and Engineering, National Taiwan University, Taipei, Taiwan 106, Republic of China
| |
Collapse
|