1
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Kaspi O, Israelsohn-Azulay O, Yigal Z, Rosengarten H, Krmpotić M, Gouasmia S, Bogdanović Radović I, Jalkanen P, Liski A, Mizohata K, Räisänen J, Kasztovszky Z, Harsányi I, Acharya R, Pujari PK, Mihály M, Braun M, Shabi N, Girshevitz O, Senderowitz H. Toward Developing Techniques─Agnostic Machine Learning Classification Models for Forensically Relevant Glass Fragments. J Chem Inf Model 2023; 63:87-100. [PMID: 36512692 PMCID: PMC9832481 DOI: 10.1021/acs.jcim.2c01362] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Glass fragments found in crime scenes may constitute important forensic evidence when properly analyzed, for example, to determine their origin. This analysis could be greatly helped by having a large and diverse database of glass fragments and by using it for constructing reliable machine learning (ML)-based glass classification models. Ideally, the samples that make up this database should be analyzed by a single accurate and standardized analytical technique. However, due to differences in equipment across laboratories, this is not feasible. With this in mind, in this work, we investigated if and how measurement performed at different laboratories on the same set of glass fragments could be combined in the context of ML. First, we demonstrated that elemental analysis methods such as particle-induced X-ray emission (PIXE), laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), scanning electron microscopy with energy-dispersive X-ray spectrometry (SEM-EDS), particle-induced Gamma-ray emission (PIGE), instrumental neutron activation analysis (INAA), and prompt Gamma-ray neutron activation analysis (PGAA) could each produce lab-specific ML-based classification models. Next, we determined rules for the successful combinations of data from different laboratories and techniques and demonstrated that when followed, they give rise to improved models, and conversely, poor combinations will lead to poor-performing models. Thus, the combination of PIXE and LA-ICP-MS improves the performances by ∼10-15%, while combining PGAA with other techniques provides poorer performances in comparison with the lab-specific models. Finally, we demonstrated that the poor performances of the SEM-EDS technique, still in use by law enforcement agencies, could be greatly improved by replacing SEM-EDS measurements for Fe and Ca by PIXE measurements for these elements. These findings suggest a process whereby forensic laboratories using different elemental analysis techniques could upload their data into a unified database and get reliable classification based on lab-agnostic models. This in turn brings us closer to a more exhaustive extraction of information from glass fragment evidence and furthermore may form the basis for international-wide collaboration between law enforcement agencies.
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Affiliation(s)
- Omer Kaspi
- Department
of Chemistry, Bar-Ilan University, Ramat-Gan5290002, Israel
| | | | - Zidon Yigal
- Toolmarks
and Materials Lab, Israel Police HQ, Jerusalem9720045, Israel
| | - Hila Rosengarten
- Toolmarks
and Materials Lab, Israel Police HQ, Jerusalem9720045, Israel
| | - Matea Krmpotić
- Laboratory
for Ion Beam Interactions, Division of Experimental Physics, Rud̵er Bošković Institute, Bijenička cesta 54, ZagrebHR-10000, Croatia
| | - Sabrina Gouasmia
- Laboratory
for Ion Beam Interactions, Division of Experimental Physics, Rud̵er Bošković Institute, Bijenička cesta 54, ZagrebHR-10000, Croatia
| | - Iva Bogdanović Radović
- Laboratory
for Ion Beam Interactions, Division of Experimental Physics, Rud̵er Bošković Institute, Bijenička cesta 54, ZagrebHR-10000, Croatia
| | - Pasi Jalkanen
- Department
of Physics, University of Helsinki, P.O. Box 43, HelsinkiFI-00014, Finland
| | - Anna Liski
- Department
of Physics, University of Helsinki, P.O. Box 43, HelsinkiFI-00014, Finland
| | - Kenichiro Mizohata
- Department
of Physics, University of Helsinki, P.O. Box 43, HelsinkiFI-00014, Finland
| | - Jyrki Räisänen
- Department
of Physics, University of Helsinki, P.O. Box 43, HelsinkiFI-00014, Finland
| | - Zsolt Kasztovszky
- Centre
for Energy Research, Konkoly-Thege Miklós út 29-33, Budapest1121, Hungary
| | - Ildikó Harsányi
- Centre
for Energy Research, Konkoly-Thege Miklós út 29-33, Budapest1121, Hungary
| | | | | | - Molnár Mihály
- International
Radiocarbon AMS Competence and Training Center, ATOMKI, Debrecen4026, Hungary
| | - Mihaly Braun
- Laboratory
of Climatology and Environmental Physics (ICER), ATOMKI, Debrecen4026, Hungary
| | - Nahum Shabi
- Bar
Ilan Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat-Gan5290002, Israel
| | - Olga Girshevitz
- Bar
Ilan Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat-Gan5290002, Israel,
| | - Hanoch Senderowitz
- Department
of Chemistry, Bar-Ilan University, Ramat-Gan5290002, Israel,
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2
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Shriber P, Avraham ES, Malik B, Teblum E, Girshevitz O, Perelshtein I, Ejgenberg M, Gofer Y, Zubarev Y, Nagler P, Nessim GD. Controlling the morphology while retaining the unique SnS stoichiometry of bulk tin sulfide produced by the rapid method of heating Sn foil in sulfur vapor by vapor phase reaction using two-furnace chemical vapor deposition system. Chem Pap 2022. [DOI: 10.1007/s11696-022-02550-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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3
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Girshevitz O, Cohen-Sinai N, Zahavi A, Vardizer Y, Fixler D, Goldenberg-Cohen N. Trace Elements in Tears: Comparison of Rural and Urban Populations Using Particle Induced X-ray Emission. J Pers Med 2022; 12:jpm12101633. [PMID: 36294772 PMCID: PMC9605629 DOI: 10.3390/jpm12101633] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Revised: 09/22/2022] [Accepted: 09/29/2022] [Indexed: 11/06/2022] Open
Abstract
We aimed to evaluate the types and concentrations of trace elements in tears of individuals living in urban and rural environments using particle induced X-ray emission (PIXE) and the possible association with exposure to air pollution and suggest a novel method for tear-based biomonitoring studies. This cross-sectional pilot study comprised 42 healthy subjects, 28 living in a rural area and 14 in an industrial city. Tears were collected with Schirmer paper and characterized by PIXE. Trace element concentrations from both eyes were averaged together with environmental pollution data. Main outcome measures were between-group differences in types and concentrations of trace elements in tears and comparison to environmental data. The rural group included 12/28 men, mean age 45.2 ± 14.8 years. The urban group consisted of 11/14 men of mean age 27 ± 5.9 years. Six rural and all urban were active smokers. Air pollution data showed more toxic elements in the rural environment. On PIXE analysis, chlorine, sodium, and potassium were found in similar concentrations in all samples. Normalizing to chlorine yielded higher values of aluminum, iron, copper, and titanium in the rural group; aluminum was found only in the rural group. The higher levels of certain trace elements in the rural group may, in part, be a consequence of exposure to specific environmental conditions. No direct association was found with air pollution data. PIXE is useful to analyze trace elements in tears, which might serve as a marker for individual exposure to environmental pollutants in biomonitoring studies.
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Affiliation(s)
- Olga Girshevitz
- Faculty of Engineering and Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat Gan 5290002, Israel
| | - Noa Cohen-Sinai
- Department of Ophthalmology, Bnai-Zion Medical Center, Haifa 339419, Israel
| | - Alon Zahavi
- Department of Ophthalmology, Rabin Medical Center—Beilinson Hospital, Petach Tikva 4941492, Israel
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Yoav Vardizer
- Department of Ophthalmology, Bnai-Zion Medical Center, Haifa 339419, Israel
| | - Dror Fixler
- Faculty of Engineering and Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat Gan 5290002, Israel
| | - Nitza Goldenberg-Cohen
- Department of Ophthalmology, Bnai-Zion Medical Center, Haifa 339419, Israel
- The Krieger Eye Research Laboratory, Bruce and Ruth Rapaport Faculty of Medicine, Technion, Israel Institute of Technology, Haifa 3200003, Israel
- Correspondence: ; Tel.: +972-4-8359554
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4
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Hen M, Dokhanian L, Grunwald E, Slook M, Katzman M, Priel M, Girshevitz O, Zadok A. Analysis of thin layers using surface acoustic wave-photonic devices in silicon-on-insulator. Opt Express 2022; 30:6949-6959. [PMID: 35299468 DOI: 10.1364/oe.448865] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Accepted: 01/25/2022] [Indexed: 06/14/2023]
Abstract
The analysis of thin layers deposited on various substrates is widely employed in thickness monitoring, materials research and development and quality control. Measurements are often performed based on changes to acoustic resonance frequencies of quartz micro-balance devices. The technique is extremely sensitive, but it is restricted to hundreds of MHz frequencies and requires electrical connectivity. In this work we propose and demonstrate the analysis of elastic properties of thin layers deposited on surface acoustic wave-photonic devices in standard silicon-on-insulator. The devices operate at 2.4 GHz frequency, and their interfaces are fiber-optic. The radio-frequency transfer functions of the devices are modified by sub-percent level changes to the group velocity of surface acoustic waves following deposition of layers. Layers of aluminum oxide and germanium sulfide of thickness between 10-80 nm are characterized. The analysis provides estimates for Young's modulus of the layers.
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5
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Kaspi O, Israelsohn-Azulay O, Yigal Z, Rosengarten H, Krmpotić M, Gouasmia S, Radović IB, Jalkanen P, Liski A, Mizohata K, Räisänen J, Girshevitz O, Senderowitz H. Inter-laboratory workflow for forensic applications: Classification of car glass fragments. Forensic Sci Int 2022; 333:111216. [DOI: 10.1016/j.forsciint.2022.111216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 01/27/2022] [Accepted: 02/07/2022] [Indexed: 11/04/2022]
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6
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Kaspi O, Girshevitz O, Senderowitz H. PIXE based, Machine-Learning (PIXEL) supported workflow for glass fragments classification. Talanta 2021; 234:122608. [PMID: 34364421 DOI: 10.1016/j.talanta.2021.122608] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 06/08/2021] [Accepted: 06/09/2021] [Indexed: 10/21/2022]
Abstract
This paper presents a structured workflow for glass fragment analysis based on a combination of Elemental Analysis using PIXE and Machine Learning tools, with the ultimate goal of standardizing and helping forensic efforts. The proposed workflow was implemented on glass fragments received from the Israeli DIFS (Israeli Police Force's Division of Identification and Forensic Sciences) that were collected from various vehicles, including glass fragments from different manufacturers and years of production. We demonstrate that this workflow can produce models with high (>80%) accuracy in identifying glass fragment's origins and provide a test-case demonstrating how the model can be applied in real-life forensic events. We provide a standard, reproducible methodology that can be used in many forensic domains beyond glass fragments, for example, Gun Shot Residue, flammable liquids, illegal substances, and more.
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Affiliation(s)
- Omer Kaspi
- Department of Chemistry, Bar-Ilan University, Ramat-Gan, 5290002, Israel
| | - Olga Girshevitz
- Bar Ilan Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat-Gan, 5290002, Israel.
| | - Hanoch Senderowitz
- Department of Chemistry, Bar-Ilan University, Ramat-Gan, 5290002, Israel.
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7
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Edri E, Armon N, Greenberg E, Moshe-Tsurel S, Lubotzky D, Salzillo T, Perelshtein I, Tkachev M, Girshevitz O, Shpaisman H. Laser Printing of Multilayered Alternately Conducting and Insulating Microstructures. ACS Appl Mater Interfaces 2021; 13:36416-36425. [PMID: 34296861 PMCID: PMC8397236 DOI: 10.1021/acsami.1c06204] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2021] [Accepted: 07/12/2021] [Indexed: 05/19/2023]
Abstract
Production of multilayered microstructures composed of conducting and insulating materials is of great interest as they can be utilized as microelectronic components. Current proposed fabrication methods of these microstructures include top-down and bottom-up methods, each having their own set of drawbacks. Laser-based methods were shown to pattern various materials with micron/sub-micron resolution; however, multilayered structures demonstrating conducting/insulating/conducting properties were not yet realized. Here, we demonstrate laser printing of multilayered microstructures consisting of conducting platinum and insulating silicon oxide layers by a combination of thermally driven reactions with microbubble-assisted printing. PtCl2 dissolved in N-methyl-2-pyrrolidone (NMP) was used as a precursor to form conducting Pt layers, while tetraethyl orthosilicate dissolved in NMP formed insulating silicon oxide layers identified by Raman spectroscopy. We demonstrate control over the height of the insulating layer between ∼50 and 250 nm by varying the laser power and number of iterations. The resistivity of the silicon oxide layer at 0.5 V was 1.5 × 1011 Ωm. Other materials that we studied were found to be porous and prone to cracking, rendering them irrelevant as insulators. Finally, we show how microfluidics can enhance multilayered laser microprinting by quickly switching between precursors. The concepts presented here could provide new opportunities for simple fabrication of multilayered microelectronic devices.
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Affiliation(s)
- Eitan Edri
- Department
of Chemistry, Bar-Ilan University, Ramat Gan 5290002, Israel
- Institute
of Nanotechnology and Advanced Materials (BINA), Bar-Ilan University, Ramat
Gan 5290002, Israel
| | - Nina Armon
- Department
of Chemistry, Bar-Ilan University, Ramat Gan 5290002, Israel
- Institute
of Nanotechnology and Advanced Materials (BINA), Bar-Ilan University, Ramat
Gan 5290002, Israel
| | - Ehud Greenberg
- Department
of Chemistry, Bar-Ilan University, Ramat Gan 5290002, Israel
- Institute
of Nanotechnology and Advanced Materials (BINA), Bar-Ilan University, Ramat
Gan 5290002, Israel
| | - Shlomit Moshe-Tsurel
- Department
of Chemistry, Bar-Ilan University, Ramat Gan 5290002, Israel
- Institute
of Nanotechnology and Advanced Materials (BINA), Bar-Ilan University, Ramat
Gan 5290002, Israel
| | - Danielle Lubotzky
- Department
of Chemistry, Bar-Ilan University, Ramat Gan 5290002, Israel
- Institute
of Nanotechnology and Advanced Materials (BINA), Bar-Ilan University, Ramat
Gan 5290002, Israel
| | - Tommaso Salzillo
- Department
of Chemical and Biological Physics, Weizmann
Institute of Science, Rehovot 76100, Israel
| | - Ilana Perelshtein
- Institute
of Nanotechnology and Advanced Materials (BINA), Bar-Ilan University, Ramat
Gan 5290002, Israel
| | - Maria Tkachev
- Institute
of Nanotechnology and Advanced Materials (BINA), Bar-Ilan University, Ramat
Gan 5290002, Israel
| | - Olga Girshevitz
- Institute
of Nanotechnology and Advanced Materials (BINA), Bar-Ilan University, Ramat
Gan 5290002, Israel
| | - Hagay Shpaisman
- Department
of Chemistry, Bar-Ilan University, Ramat Gan 5290002, Israel
- Institute
of Nanotechnology and Advanced Materials (BINA), Bar-Ilan University, Ramat
Gan 5290002, Israel
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8
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Telkhozhayeva M, Teblum E, Konar R, Girshevitz O, Perelshtein I, Aviv H, Tischler YR, Nessim GD. Higher Ultrasonic Frequency Liquid Phase Exfoliation Leads to Larger and Monolayer to Few-Layer Flakes of 2D Layered Materials. Langmuir 2021; 37:4504-4514. [PMID: 33724843 DOI: 10.1021/acs.langmuir.0c03668] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Among the most reliable techniques for exfoliation of two-dimensional (2D) layered materials, sonication-assisted liquid-phase exfoliation (LPE) is considered as a cost-effective and straightforward method for preparing graphene and its 2D inorganic counterparts at reasonable sizes and acceptable levels of defects. Although there were rapid advances in this field, the effect and outcome of the sonication frequency are poorly understood and often ignored, resulting in a low exfoliation efficiency. Here, we demonstrate that simple mild bath sonication at a higher frequency and low power positively contributes to the thickness, size, and quality of the final exfoliated products. We show that monolayer graphene flakes can be directly exfoliated from graphite using ethanol as a solvent by increasing the frequency of the bath sonication from 37 to 80 kHz. The statistical analysis shows that ∼77% of the measured graphene flakes have a thickness below three layers with an average lateral size of 13 μm. We demonstrate that this approach works for digenite (Cu9S5) and silver sulfide (Ag2S), thus indicating that this exfoliation technique can be applied to other inorganic 2D materials to obtain high-quality few-layered flakes. This simple and effective method facilitates the formation of monolayer/few layers of graphene and transition metal chalcogenides for a wide range of applications.
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Affiliation(s)
- Madina Telkhozhayeva
- Department of Chemistry and Institute of Nanotechnology, Bar-Ilan University, Ramat Gan 52900, Israel
| | - Eti Teblum
- Department of Chemistry and Institute of Nanotechnology, Bar-Ilan University, Ramat Gan 52900, Israel
| | - Rajashree Konar
- Department of Chemistry and Institute of Nanotechnology, Bar-Ilan University, Ramat Gan 52900, Israel
| | - Olga Girshevitz
- Institute of Nanotechnology & Advanced Materials, Bar-Ilan University, Ramat Gan 52900, Israel
| | - Ilana Perelshtein
- Institute of Nanotechnology & Advanced Materials, Bar-Ilan University, Ramat Gan 52900, Israel
| | - Hagit Aviv
- Department of Chemistry and Institute of Nanotechnology, Bar-Ilan University, Ramat Gan 52900, Israel
| | - Yaakov R Tischler
- Department of Chemistry and Institute of Nanotechnology, Bar-Ilan University, Ramat Gan 52900, Israel
| | - Gilbert Daniel Nessim
- Department of Chemistry and Institute of Nanotechnology, Bar-Ilan University, Ramat Gan 52900, Israel
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9
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Ceratti DR, Zohar A, Kozlov R, Dong H, Uraltsev G, Girshevitz O, Pinkas I, Avram L, Hodes G, Cahen D. Eppur si Muove: Proton Diffusion in Halide Perovskite Single Crystals. Adv Mater 2020; 32:e2002467. [PMID: 33048452 DOI: 10.1002/adma.202002467] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Revised: 07/24/2020] [Indexed: 05/19/2023]
Abstract
Ion diffusion affects the optoelectronic properties of halide-perovskites (HaPs). Until now, the fastest diffusion has been attributed to the movement of the halides, largely neglecting the contribution of protons, on the basis of computed density estimates. Here, the process of proton diffusion inside HaPs, following deuterium-hydrogen exchange and migration in MAPbI3 , MAPbBr3 , and FAPbBr3 single crystals, is proven through D/H NMR quantification, Raman spectroscopy, and elastic recoil detection analysis, challenging the original assumption of halide-dominated diffusion. The results are confirmed by impedance spectroscopy, where MAPbBr3 - and CsPbBr3 -based solar cells respond at very different frequencies. Water plays a key role in allowing the migration of protons as deuteration is not detected in its absence. The water contribution is modeled to explain and forecast its effect as a function of its concentration in the perovskite structure. These findings are of great importance as they evidence how unexpected, water-dependent proton diffusion can be at the basis of the ≈7 orders of magnitude spread of diffusion (attributed to I- and Br- ) coefficient values, reported in the literature. The reported enhancement of the optoelectronic properties of HaP when exposed to small amounts of water may be related to the finding.
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Affiliation(s)
- Davide Raffaele Ceratti
- Department of Materials and Interfaces, Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Arava Zohar
- Department of Materials and Interfaces, Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Roman Kozlov
- Department of Materials and Interfaces, Weizmann Institute of Science, Rehovot, 7610001, Israel
- Department of Functional Inorganic Materials, Academician Semenov, Chernogolovka, Moscow, 142432, Russia
| | - Hao Dong
- Department of Materials and Interfaces, Weizmann Institute of Science, Rehovot, 7610001, Israel
- School of Physics, Nanjing University, Nanjing, Jiangsu Province, 210093, China
| | - Gennady Uraltsev
- Department of Mathematics, Cornell University, Ithaca, NY, 14853, USA
| | - Olga Girshevitz
- Institute of Nanotechnology and Advanced Materials, Department of Chemistry, Bar-Ilan University, Ramat Gan, 5290002, Israel
| | - Iddo Pinkas
- Department of Chemical Research Support, Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Liat Avram
- Department of Chemical Research Support, Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Gary Hodes
- Department of Materials and Interfaces, Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - David Cahen
- Department of Materials and Interfaces, Weizmann Institute of Science, Rehovot, 7610001, Israel
- Institute of Nanotechnology and Advanced Materials, Department of Chemistry, Bar-Ilan University, Ramat Gan, 5290002, Israel
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10
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Shpigel N, Sigalov S, Malchik F, Levi MD, Girshevitz O, Khalfin RL, Aurbach D. Quantification of porosity in extensively nanoporous thin films in contact with gases and liquids. Nat Commun 2019; 10:4394. [PMID: 31562308 PMCID: PMC6765025 DOI: 10.1038/s41467-019-12277-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Accepted: 08/29/2019] [Indexed: 11/27/2022] Open
Abstract
Nanoporous layers are widely spread in nature and among artificial devices. However, complex characterization of extensively nanoporous thin films showing porosity-dependent softening lacks consistency and reliability when using different analytical techniques. We introduce herein, a facile and precise method of such complex characterization by multi-harmonic QCM-D (Quartz Crystal Microbalance with Dissipation Monitoring) measurements performed both in the air and liquids (Au-Zn alloy was used as a typical example). The porosity values determined by QCM-D in air and different liquids are entirely consistent with that obtained from parallel RBS (Rutherford Backscattering Spectroscopy) and GISAXS (Grazing-Incidence Small-Angle Scattering) characterizations. This ensures precise quantification of the nanolayer porosity simultaneously with tracking their viscoelastic properties in liquids, significantly increasing sensitivity of the viscoelastic detection (viscoelastic contrast principle). Our approach is in high demand for quantifying potential-induced changes in nanoporous layers of complex architectures fabricated for various electrocatalytic energy storage and analytical devices. Thin porous layers are largely used, but a reliable method to quantify their porosity is missing. Here the authors demonstrate a method, based on quartz crystal microbalance measurements with dissipation monitoring, for accurate assessment of porosity and mechanical properties in thin porous films.
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Affiliation(s)
- Netanel Shpigel
- Department of Chemistry, Bar Ilan Institute for Nanotechnology and Advanced Materials (BINA), Bar-Ilan University, 52900, Ramat-Gan, Israel
| | - Sergey Sigalov
- Department of Chemistry, Bar Ilan Institute for Nanotechnology and Advanced Materials (BINA), Bar-Ilan University, 52900, Ramat-Gan, Israel
| | - Fyodor Malchik
- Department of Chemistry, Bar Ilan Institute for Nanotechnology and Advanced Materials (BINA), Bar-Ilan University, 52900, Ramat-Gan, Israel
| | - Mikhael D Levi
- Department of Chemistry, Bar Ilan Institute for Nanotechnology and Advanced Materials (BINA), Bar-Ilan University, 52900, Ramat-Gan, Israel
| | - Olga Girshevitz
- Department of Chemistry, Bar Ilan Institute for Nanotechnology and Advanced Materials (BINA), Bar-Ilan University, 52900, Ramat-Gan, Israel
| | - Rafail L Khalfin
- Departments of Mechanical Engineering and Chemical Engineering, Technion - Israel Institute of Technology, 32000, Haifa, Israel
| | - Doron Aurbach
- Department of Chemistry, Bar Ilan Institute for Nanotechnology and Advanced Materials (BINA), Bar-Ilan University, 52900, Ramat-Gan, Israel.
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11
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Garini Y, Roth E, Bitler A, Girshevitz O. Measuring the Conformation of Single Stranded DNA using a DNA Origami Nano-Structure. Biophys J 2019. [DOI: 10.1016/j.bpj.2018.11.218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
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12
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Shawat Avraham E, Westover AS, Girshevitz O, Pint CL, Nessim GD. Modulating the height of carbon nanotube forests by controlling the molybdenum thin film reservoir thickness. Nanoscale 2019; 11:1929-1936. [PMID: 30644490 DOI: 10.1039/c8nr08197b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Many catalyst materials have been tried to synthesize ultra-long carbon nanotubes (CNTs) by extending catalyst lifetime and delaying growth termination. We propose a time-controlled, variable composition iron-molybdenum catalyst system, where the diffusion of molybdenum (as a thin layer reservoir) is mediated by the alumina underlayer, to reach and to slowly alloy with the Fe catalyst on the surface during the thermal process. This technique enhanced both the catalytic activity and the catalytic lifetime to grow CNT carpets with heights up 5 mm, compared to a maximum of approximately 1.5 mm for a regular sample (without Mo reservoir). Moreover, the CNT height increased with the thickness of the Mo thin layer reservoir for thicknesses from 10 nm to 30 nm. We discuss this new growth mechanism using high resolution transmission microscopy (HRTEM) images of cross-section lamellas and Rutherford Back Scattering (RBS) analysis to show the increasing alloying of Mo with Fe. Overall, the proposed technique of mediated diffusion of Mo to the surface with subsequent progressive alloying with the Fe catalyst, besides enhancing CNT height, could allow the one-step synthesis of CNT carpets with regions of different heights based on patterning these regions with different thicknesses of the Mo reservoir during sample preparation.
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Affiliation(s)
- E Shawat Avraham
- Department of Chemistry, Bar Ilan Institute for Nanotechnology and Advanced materials (BINA), Bar Ilan University, Ramat Gan, 52900, Israel.
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13
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Roth E, Glick Azaria A, Girshevitz O, Bitler A, Garini Y. Measuring the Conformation and Persistence Length of Single-Stranded DNA Using a DNA Origami Structure. Nano Lett 2018; 18:6703-6709. [PMID: 30352164 DOI: 10.1021/acs.nanolett.8b02093] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Measuring the mechanical properties of single-stranded DNA (ssDNA) is a challenge that has been addressed by different methods lately. The short persistence length, fragile structure, and the appearance of stem loops complicate the measurement, and this leads to a large variability in the measured values. Here we describe an innovative method based on DNA origami for studying the biophysical properties of ssDNA. By synthesizing a DNA origami structure that consists of two rigid rods with an ssDNA segment between them, we developed a method to characterize the effective persistence length of a random-sequence ssDNA while allowing the formation of stem loops. We imaged the structure with an atomic force microscope (AFM); the rigid rods provide a means for the exact identification of the ssDNA ends. This leads to an accurate determination of the end-to-end distance of each ssDNA segment, and by fitting the measured distribution to the ideal chain polymer model we measured an effective persistence length of 1.98 ± 0.72 nm. This method enables one to measure short or long strands of ssDNA, and it can cope with the formation of stem loops that are often formed along ssDNA. We envision that this method can be used for measuring stem loops for determining the effect of repetitive nucleotide sequences and environmental conditions on the mechanical properties of ssDNA and the effect of interacting proteins with ssDNA. We further noted that the method can be extended to nanoprobes for measuring the interactions of specific DNA sequences, because the DNA origami rods (or similar structures) can hold multiple fluorescent probes that can be easily detected.
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Affiliation(s)
- Efrat Roth
- Physics Department and Institute for Nanotechnology , Bar Ilan University , Ramat Gan 5290002 , Israel
| | - Alex Glick Azaria
- Physics Department and Institute for Nanotechnology , Bar Ilan University , Ramat Gan 5290002 , Israel
| | - Olga Girshevitz
- Physics Department and Institute for Nanotechnology , Bar Ilan University , Ramat Gan 5290002 , Israel
| | - Arkady Bitler
- Physics Department and Institute for Nanotechnology , Bar Ilan University , Ramat Gan 5290002 , Israel
| | - Yuval Garini
- Physics Department and Institute for Nanotechnology , Bar Ilan University , Ramat Gan 5290002 , Israel
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14
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Shpigel N, Levi MD, Sigalov S, Girshevitz O, Aurbach D, Daikhin L, Pikma P, Marandi M, Jänes A, Lust E, Jäckel N, Presser V. In situ hydrodynamic spectroscopy for structure characterization of porous energy storage electrodes. Nat Mater 2016; 15:570-575. [PMID: 26928637 DOI: 10.1038/nmat4577] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Accepted: 01/14/2016] [Indexed: 06/05/2023]
Abstract
A primary atomic-scale effect accompanying Li-ion insertion into rechargeable battery electrodes is a significant intercalation-induced change of the unit cell volume of the crystalline material. This generates a variety of secondary multiscale dimensional changes and causes a deterioration in the energy storage performance stability. Although traditional in situ height-sensing techniques (atomic force microscopy or electrochemical dilatometry) are able to sense electrode thickness changes at a nanometre scale, they are much less informative concerning intercalation-induced changes of the porous electrode structure at a mesoscopic scale. Based on a electrochemical quartz-crystal microbalance with dissipation monitoring on multiple overtone orders, herein we introduce an in situ hydrodynamic spectroscopic method for porous electrode structure characterization. This new method will enable future developments and applications in the fields of battery and supercapacitor research, especially for diagnostics of viscoelastic properties of binders for composite electrodes and probing the micromechanical stability of their internal electrode porous structure and interfaces.
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Affiliation(s)
- Netanel Shpigel
- Department of Chemistry, Bar-Ilan University, Ramat-Gan 52900, Israel
| | - Mikhael D Levi
- Department of Chemistry, Bar-Ilan University, Ramat-Gan 52900, Israel
| | - Sergey Sigalov
- Department of Chemistry, Bar-Ilan University, Ramat-Gan 52900, Israel
| | - Olga Girshevitz
- Department of Chemistry, Bar-Ilan University, Ramat-Gan 52900, Israel
| | - Doron Aurbach
- Department of Chemistry, Bar-Ilan University, Ramat-Gan 52900, Israel
| | - Leonid Daikhin
- School of Chemistry, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel-Aviv University, Ramat Aviv 69978, Israel
| | - Piret Pikma
- Institute of Chemistry, University of Tartu, Ravila 14A, 50411 Tartu, Estonia
| | - Margus Marandi
- Institute of Chemistry, University of Tartu, Ravila 14A, 50411 Tartu, Estonia
- Institute of Physics, University of Tartu, Ravila 14C, 50411 Tartu, Estonia
| | - Alar Jänes
- Institute of Chemistry, University of Tartu, Ravila 14A, 50411 Tartu, Estonia
| | - Enn Lust
- Institute of Chemistry, University of Tartu, Ravila 14A, 50411 Tartu, Estonia
| | - Nicolas Jäckel
- INM - Leibniz Institute for New Materials, 66123 Saarbrücken, Germany
- Department of Materials Science and Engineering, Saarland University, 66123 Saarbrücken, Germany
| | - Volker Presser
- INM - Leibniz Institute for New Materials, 66123 Saarbrücken, Germany
- Department of Materials Science and Engineering, Saarland University, 66123 Saarbrücken, Germany
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15
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Shapiro A, Hozeh A, Girshevitz O, Abu-Horowitz A, Bachelet I. Cooperativity-based modeling of heterotypic DNA nanostructure assembly. Nucleic Acids Res 2015; 43:6587-95. [PMID: 26071955 PMCID: PMC4513873 DOI: 10.1093/nar/gkv602] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Accepted: 05/28/2015] [Indexed: 01/28/2023] Open
Abstract
DNA origami is a robust method for the fabrication of nanoscale 2D and 3D objects with complex features and geometries. The process of DNA origami folding has been recently studied, however quantitative understanding of it is still elusive. Here, we describe a systematic quantification of the assembly process of DNA nanostructures, focusing on the heterotypic DNA junction—in which arms are unequal—as their basic building block. Using bulk fluorescence studies we tracked this process and identified multiple levels of cooperativity from the arms in a single junction to neighboring junctions in a large DNA origami object, demonstrating that cooperativity is a central underlying mechanism in the process of DNA nanostructure assembly. We show that the assembly of junctions in which the arms are consecutively ordered is more efficient than junctions with randomly-ordered components, with the latter showing assembly through several alternative trajectories as a potential mechanism explaining the lower efficiency. This highlights consecutiveness as a new design consideration that could be implemented in DNA nanotechnology CAD tools to produce more efficient and high-yield designs. Altogether, our experimental findings allowed us to devise a quantitative, cooperativity-based heuristic model for the assembly of DNA nanostructures, which is highly consistent with experimental observations.
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Affiliation(s)
- Anastasia Shapiro
- Faculty of Life Sciences and Institute of Nanotechnology & Advanced Materials, Bar-Ilan University, Ramat Gan 52900, Israel
| | - Avital Hozeh
- Faculty of Life Sciences and Institute of Nanotechnology & Advanced Materials, Bar-Ilan University, Ramat Gan 52900, Israel
| | - Olga Girshevitz
- Faculty of Life Sciences and Institute of Nanotechnology & Advanced Materials, Bar-Ilan University, Ramat Gan 52900, Israel
| | - Almogit Abu-Horowitz
- Faculty of Life Sciences and Institute of Nanotechnology & Advanced Materials, Bar-Ilan University, Ramat Gan 52900, Israel
| | - Ido Bachelet
- Faculty of Life Sciences and Institute of Nanotechnology & Advanced Materials, Bar-Ilan University, Ramat Gan 52900, Israel
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16
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Shpigel N, Levi MD, Sigalov S, Girshevitz O, Aurbach D, Daikhin L, Jäckel N, Presser V. Non-Invasive In Situ Dynamic Monitoring of Elastic Properties of Composite Battery Electrodes by EQCM-D. Angew Chem Int Ed Engl 2015; 54:12353-6. [DOI: 10.1002/anie.201501787] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Indexed: 11/09/2022]
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17
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Shpigel N, Levi MD, Sigalov S, Girshevitz O, Aurbach D, Daikhin L, Jäckel N, Presser V. Non-Invasive In Situ Dynamic Monitoring of Elastic Properties of Composite Battery Electrodes by EQCM-D. Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201501787] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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18
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Gotlib-Vainstein K, Gouzman I, Girshevitz O, Bolker A, Atar N, Grossman E, Sukenik CN. Liquid phase deposition of a space-durable, antistatic SnO₂ coating on Kapton. ACS Appl Mater Interfaces 2015; 7:3539-3546. [PMID: 25607925 DOI: 10.1021/am5072817] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Polyimides are widely used in thermal blankets covering the external surfaces of spacecrafts due to their space durability and their thermo-optical properties. However, they are susceptible to atomic oxygen (AO) erosion, the main hazard of low Earth orbit (LEO), and to electrical charging. This work demonstrates that liquid phase deposition (LPD) of 100 nm of tin oxide creates a protective coating on Kapton polyimide that has good adherence and is effective in preventing AO-induced surface erosion and in reducing electrical charging. The as-deposited tin oxide induces no significant changes in the original thermo-optical properties of the polymer and is effective in preventing electrostatic discharge (ESD). The durability of the oxide coating under AO attack was studied using oxygen RF plasma. The AO exposure did not result in any significant changes in surface morphology, thermo-optical, mechanical, and electrical properties of the tin oxide-coated Kapton. The erosion yield of tin oxide-coated Kapton was negligible after exposure to 6.4 × 10(20) O atoms·cm(-2) of LEO equivalent AO fluence, indicating a complete protection of Kapton by the LPD deposited coating. Moreover, the tin oxide coating is flexible enough so that its electrical conductivity stays within the desired range of antistatic materials despite mechanical manipulations. The advantages of liquid phase deposited oxides in terms of their not being line of site limited are well established. We now extend these advantages to coatings that reduce electrostatic discharge while still providing a high level of protection from AO erosion.
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Affiliation(s)
- Katya Gotlib-Vainstein
- Department of Chemistry and Institute for Nanotechnology and Advanced Materials, Bar-Ilan University , Ramat Gan, Israel 52900
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19
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Yeroslavsky G, Girshevitz O, Foster-Frey J, Donovan DM, Rahimipour S. Antibacterial and antibiofilm surfaces through polydopamine-assisted immobilization of lysostaphin as an antibacterial enzyme. Langmuir 2015; 31:1064-1073. [PMID: 25547537 DOI: 10.1021/la503911m] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Antibiotic resistance and the colonization of bacteria on surfaces, often as biofilms, prolong hospitalization periods, increase mortality, and are thus major concerns for health care providers. There is an urgent need for antimicrobial and antibiofilm surface treatments that are permanent, can eradicate both biofilms and planktonic pathogens over long periods of time, and do not select for resistant strains. In this study, we have demonstrated a simple, robust, and biocompatible method that utilizes the adhesive property of polydopamine (PDA) to covalently attach the antimicrobial enzyme lysostaphin (Lst) to a variety of surfaces to generate antibacterial and antibiofilm interfaces. The immobilization of the recombinant Lst onto PDA-coated surfaces was carried out under physiological conditions, most probably through the C-terminal His6-tag fragment of the enzyme, minimizing the losses of bioagent activity. The modified surfaces were extensively characterized by X-ray photoelectron spectroscopy and peak force quantitative nanomechanical mapping (PeakForce QNM) AFM-based method, and the presence of Lst on the surfaces was further confirmed immunochemically using anti-Lst antibody. We also found that, in contrast to the physically adsorbed Lst, the covalently attached Lst does not leach from the surfaces and maintains its endopeptidase activity to degrade the staphylococcal cell wall, avoiding most intracellular bacterial resistance mechanisms. Moreover, the Lst-coated surfaces kill hospital strains of Staphylococcus aureus in less than 15 min and prevent biofilm formation. This immobilization method should be applicable also to other proteins and enzymes that are recombinantly expressed to include the His6-tag fragment.
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Affiliation(s)
- Gil Yeroslavsky
- Department of Chemistry, Bar-Ilan University , Ramat-Gan 5290002, Israel
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20
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Gotlib-Vainshtein K, Girshevitz O, Sukenik CN, Barlam D, Cohen SR. A nanometric cushion for enhancing scratch and wear resistance of hard films. Beilstein J Nanotechnol 2014; 5:1005-15. [PMID: 25161836 PMCID: PMC4143114 DOI: 10.3762/bjnano.5.114] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/02/2014] [Accepted: 06/18/2014] [Indexed: 06/03/2023]
Abstract
Scratch resistance and friction are core properties which define the tribological characteristics of materials. Attempts to optimize these quantities at solid surfaces are the subject of intense technological interest. The capability to modulate these surface properties while preserving both the bulk properties of the materials and a well-defined, constant chemical composition of the surface is particularly attractive. We report herein the use of a soft, flexible underlayer to control the scratch resistance of oxide surfaces. Titania films of several nm thickness are coated onto substrates of silicon, kapton, polycarbonate, and polydimethylsiloxane (PDMS). The scratch resistance measured by scanning force microscopy is found to be substrate dependent, diminishing in the order PDMS, kapton/polycarbonate, Si/SiO2. Furthermore, when PDMS is applied as an intermediate layer between a harder substrate and titania, marked improvement in the scratch resistance is achieved. This is shown by quantitative wear tests for silicon or kapton, by coating these substrates with PDMS which is subsequently capped by a titania layer, resulting in enhanced scratch/wear resistance. The physical basis of this effect is explored by means of Finite Element Analysis, and we suggest a model for friction reduction based on the "cushioning effect" of a soft intermediate layer.
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Affiliation(s)
- Katya Gotlib-Vainshtein
- Department of Chemistry and Institute of Nanotechnology & Advanced Materials, Bar Ilan University, Ramat-Gan 52900, Israel
| | - Olga Girshevitz
- Department of Chemistry and Institute of Nanotechnology & Advanced Materials, Bar Ilan University, Ramat-Gan 52900, Israel
| | - Chaim N Sukenik
- Department of Chemistry and Institute of Nanotechnology & Advanced Materials, Bar Ilan University, Ramat-Gan 52900, Israel
| | - David Barlam
- Department of Mechanical Engineering, Ben Gurion University, Beer Sheva, Israel
| | - Sidney R Cohen
- Department of Chemical Research Support, Weizmann Institute of Science, Rehovot 76100, Israel
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21
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Nir G, Lindner M, Dietrich HRC, Girshevitz O, Vorgias CE, Garini Y. HU protein induces incoherent DNA persistence length. Biophys J 2011; 100:784-790. [PMID: 21281594 DOI: 10.1016/j.bpj.2010.12.3687] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2010] [Revised: 11/24/2010] [Accepted: 12/02/2010] [Indexed: 11/29/2022] Open
Abstract
HU is a highly conserved protein that is believed to play an important role in the architecture and dynamic compaction of bacterial DNA. Its ability to control DNA bending is crucial for functions such as transcription and replication. The effects of HU on the DNA structure have been studied so far mainly by single molecule methods that require us to apply stretching forces on the DNA and therefore may perturb the DNA-protein interaction. To overcome this hurdle, we study the effect of HU on the DNA structure without applying external forces by using an improved tethered particle motion method. By combining the results with DNA curvature analysis from atomic force microscopy measurements we find that the DNA consists of two different curvature distributions and the measured persistence length is determined by their interplay. As a result, the effective persistence length adopts a bimodal property that depends primarily on the HU concentration. The results can be explained according to a recently suggested model that distinguishes single protein binding from cooperative protein binding.
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Affiliation(s)
- Guy Nir
- Physics Department, Bar Ilan University, Ramat-Gan, Israel; Institute for Nanotechnology, Bar Ilan University, Ramat-Gan, Israel
| | - Moshe Lindner
- Physics Department, Bar Ilan University, Ramat-Gan, Israel; Institute for Nanotechnology, Bar Ilan University, Ramat-Gan, Israel
| | - Heidelinde R C Dietrich
- Department of Imaging Science and Technology, Delft University of Technology, Delft, The Netherlands
| | - Olga Girshevitz
- Institute for Nanotechnology, Bar Ilan University, Ramat-Gan, Israel
| | - Constantinos E Vorgias
- Department of Biochemistry and Molecular Biology, Faculty of Biology, National and Kapodistrian University of Athens, Athens, Greece
| | - Yuval Garini
- Physics Department, Bar Ilan University, Ramat-Gan, Israel; Institute for Nanotechnology, Bar Ilan University, Ramat-Gan, Israel.
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22
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Shahmoon A, Limon O, Girshevitz O, Zalevsky Z. Self assembly of nano metric metallic particles for realization of photonic and electronic nano transistors. Int J Mol Sci 2010; 11:2241-52. [PMID: 20559513 PMCID: PMC2885105 DOI: 10.3390/ijms11052242] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2010] [Revised: 04/19/2010] [Accepted: 05/07/2010] [Indexed: 11/24/2022] Open
Abstract
In this paper, we present the self assembly procedure as well as experimental results of a novel method for constructing well defined arrangements of self assembly metallic nano particles into sophisticated nano structures. The self assembly concept is based on focused ion beam (FIB) technology, where metallic nano particles are self assembled due to implantation of positive gallium ions into the insulating material (e.g., silica as in silicon on insulator wafers) that acts as intermediary layer between the substrate and the negatively charge metallic nanoparticles.
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Affiliation(s)
- Asaf Shahmoon
- School of Engineering, Bar-Ilan University, Ramat-Gan 52900, Israel; E-Mail:
(A.S.)
| | - Ofer Limon
- School of Engineering, Bar-Ilan University, Ramat-Gan 52900, Israel; E-Mail:
(A.S.)
| | - Olga Girshevitz
- Nanotechnology Center, Bar-Ilan University, Ramat-Gan 52900, Israel
| | - Zeev Zalevsky
- School of Engineering, Bar-Ilan University, Ramat-Gan 52900, Israel; E-Mail:
(A.S.)
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23
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Jin Y, Girshevitz O, Friedman N, Ron I, Cahen D, Sheves M. Covalent attachment of bacteriorhodopsin monolayer to bromo-terminated solid supports: preparation, characterization, and protein stability. Chem Asian J 2008; 3:1146-55. [PMID: 18484563 DOI: 10.1002/asia.200700403] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The interfacing of functional proteins with solid supports and the study of related protein-adsorption behavior are promising and important for potential device applications. In this study, we describe the preparation of bacteriorhodopsin (bR) monolayers on Br-terminated solid supports through covalent attachment. The bonding, by chemical reaction of the exposed free amine groups of bR with the pendant Br group of the chemically modified solid surface, was confirmed both by negative AFM results obtained when acetylated bR (instead of native bR) was used as a control and by weak bands observed at around 1610 cm(-1) in the FTIR spectrum. The coverage of the resultant bR monolayer was significantly increased by changing the pH of the purple-membrane suspension from 9.2 to 6.8. Although bR, which is an exceptionally stable protein, showed a pronounced loss of its photoactivity in these bR monolayers, it retained full photoactivity after covalent binding to Br-terminated alkyls in solution. Several characterization methods, including atomic force microscopy (AFM), contact potential difference (CPD) measurements, and UV/Vis and Fourier transform infrared (FTIR) spectroscopy, verified that these bR monolayers behaved significantly different from native bR. Current-voltage (I-V) measurements (and optical absorption spectroscopy) suggest that the retinal chromophore is probably still present in the protein, whereas the UV/Vis spectrum suggests that it lacks the characteristic covalent protonated Schiff base linkage. This finding sheds light on the unique interactions of biomolecules with solid surfaces and may be significant for the design of protein-containing device structures.
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Affiliation(s)
- Yongdong Jin
- Department of Organic Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel.
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24
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Salomon A, Boecking T, Chan CK, Amy F, Girshevitz O, Cahen D, Kahn A. How do electronic carriers cross Si-bound alkyl monolayers? Phys Rev Lett 2005; 95:266807. [PMID: 16486388 DOI: 10.1103/physrevlett.95.266807] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2005] [Indexed: 05/06/2023]
Abstract
Electron transport through Si-C bound alkyl chains, sandwiched between and Hg, is characterized by two distinct types of barriers, each dominating in a different voltage range. At low voltage, the current depends strongly on temperature but not on molecular length, suggesting transport by thermionic emission over a barrier in the Si. At higher voltage, the current decreases exponentially with molecular length, suggesting transport limited by tunneling through the molecules. The tunnel barrier is estimated, from transport and photoemission data, to be approximately 1.5 eV with a 0.25m(e) effective mass.
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Affiliation(s)
- Adi Salomon
- Department of Materials and Interfaces, Weizmann Institute of Science, Rehovot, Israel
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