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Heuberger L, Messmer D, dos Santos EC, Scherrer D, Lörtscher E, Schoenenberger C, Palivan CG. Microfluidic Giant Polymer Vesicles Equipped with Biopores for High-Throughput Screening of Bacteria. Adv Sci (Weinh) 2024; 11:e2307103. [PMID: 38158637 PMCID: PMC10953582 DOI: 10.1002/advs.202307103] [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] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Indexed: 01/03/2024]
Abstract
Understanding the mechanisms of antibiotic resistance is critical for the development of new therapeutics. Traditional methods for testing bacteria are often limited in their efficiency and reusability. Single bacterial cells can be studied at high throughput using double emulsions, although the lack of control over the oil shell permeability and limited access to the droplet interior present serious drawbacks. Here, a straightforward strategy for studying bacteria-encapsulating double emulsion-templated giant unilamellar vesicles (GUVs) is introduced. This microfluidic approach serves to simultaneously load bacteria inside synthetic GUVs and to permeabilize their membrane with the pore-forming peptide melittin. This enables antibiotic delivery or the influx of fresh medium into the GUV lumen for highly parallel cultivation and antimicrobial efficacy testing. Polymer-based GUVs proved to be efficient culture and analysis microvessels, as microfluidics allow easy selection and encapsulation of bacteria and rapid modification of culture conditions for antibiotic development. Further, a method for in situ profiling of biofilms within GUVs for high-throughput screening is demonstrated. Conceivably, synthetic GUVs equipped with biopores can serve as a foundation for the high-throughput screening of bacterial colony interactions during biofilm formation and for investigating the effect of antibiotics on biofilms.
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Affiliation(s)
- Lukas Heuberger
- Department of ChemistryUniversity of BaselMattenstrasse 22Basel4002Switzerland
| | - Daniel Messmer
- Department of ChemistryUniversity of BaselMattenstrasse 22Basel4002Switzerland
| | - Elena C. dos Santos
- Department of ChemistryUniversity of BaselMattenstrasse 22Basel4002Switzerland
| | - Dominik Scherrer
- IBM Research Europe–ZürichSäumerstrasse 4Rüschlikon8803Switzerland
| | - Emanuel Lörtscher
- IBM Research Europe–ZürichSäumerstrasse 4Rüschlikon8803Switzerland
- NCCR‐Molecular Systems EngineeringMattenstrasse 24a, BPR 1095Basel4058Switzerland
| | | | - Cornelia G. Palivan
- Department of ChemistryUniversity of BaselMattenstrasse 22Basel4002Switzerland
- NCCR‐Molecular Systems EngineeringMattenstrasse 24a, BPR 1095Basel4058Switzerland
- Swiss Nanoscience Institute (SNI)University of BaselKlingelbergstrasse 82Basel4056Switzerland
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2
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Monserrat Lopez D, Rottmann P, Fussenegger M, Lörtscher E. Silicon-Based 3D Microfluidics for Parallelization of Droplet Generation. Micromachines (Basel) 2023; 14:1289. [PMID: 37512600 PMCID: PMC10386391 DOI: 10.3390/mi14071289] [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] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Revised: 06/20/2023] [Accepted: 06/21/2023] [Indexed: 07/30/2023]
Abstract
Both the diversity and complexity of microfluidic systems have experienced a tremendous progress over the last decades, enabled by new materials, novel device concepts and innovative fabrication routes. In particular the subfield of high-throughput screening, used for biochemical, genetic and pharmacological samples, has extensively emerged from developments in droplet microfluidics. More recently, new 3D device architectures enabled either by stacking layers of PDMS or by direct 3D-printing have gained enormous attention for applications in chemical synthesis or biomedical assays. While the first microfluidic devices were based on silicon and glass structures, those materials have not yet been significantly expanded towards 3D despite their high chemical compatibility, mechanical strength or mass-production potential. In our work, we present a generic fabrication route based on the implementation of vertical vias and a redistribution layer to create glass-silicon-glass 3D microfluidic structures. It is used to build different droplet-generating devices with several flow-focusing junctions in parallel, all fed from a single source. We study the effect of having several of these junctions in parallel by varying the flow conditions of both the continuous and the dispersed phases. We demonstrate that the generic concept enables an upscaling in the production rate by increasing the number of droplet generators per device without sacrificing the monodispersity of the droplets.
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Affiliation(s)
- Diego Monserrat Lopez
- IBM Research Europe-Zurich, Säumerstrasse 4, CH-8803 Rüschlikon, Switzerland
- Department of Biosystems Science and Engineering, ETH Zürich, Mattenstrasse 26, CH-4058 Basel, Switzerland
| | - Philipp Rottmann
- Department of Biosystems Science and Engineering, ETH Zürich, Mattenstrasse 26, CH-4058 Basel, Switzerland
| | - Martin Fussenegger
- Department of Biosystems Science and Engineering, ETH Zürich, Mattenstrasse 26, CH-4058 Basel, Switzerland
- Faculty of Science, University of Basel, Mattenstrasse 26, CH-4058 Basel, Switzerland
| | - Emanuel Lörtscher
- IBM Research Europe-Zurich, Säumerstrasse 4, CH-8803 Rüschlikon, Switzerland
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3
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Monserrat Lopez D, Rottmann P, Puebla-Hellmann G, Drechsler U, Mayor M, Panke S, Fussenegger M, Lörtscher E. Direct electrification of silicon microfluidics for electric field applications. Microsyst Nanoeng 2023; 9:81. [PMID: 37342556 PMCID: PMC10277806 DOI: 10.1038/s41378-023-00552-w] [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] [Figures] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 04/25/2023] [Accepted: 05/10/2023] [Indexed: 06/23/2023]
Abstract
Microfluidic systems are widely used in fundamental research and industrial applications due to their unique behavior, enhanced control, and manipulation opportunities of liquids in constrained geometries. In micrometer-sized channels, electric fields are efficient mechanisms for manipulating liquids, leading to deflection, injection, poration or electrochemical modification of cells and droplets. While PDMS-based microfluidic devices are used due to their inexpensive fabrication, they are limited in terms of electrode integration. Using silicon as the channel material, microfabrication techniques can be used to create nearby electrodes. Despite the advantages that silicon provides, its opacity has prevented its usage in most important microfluidic applications that need optical access. To overcome this barrier, silicon-on-insulator technology in microfluidics is introduced to create optical viewports and channel-interfacing electrodes. More specifically, the microfluidic channel walls are directly electrified via selective, nanoscale etching to introduce insulation segments inside the silicon device layer, thereby achieving the most homogeneous electric field distributions and lowest operation voltages feasible across microfluidic channels. These ideal electrostatic conditions enable a drastic energy reduction, as effectively shown via picoinjection and fluorescence-activated droplet sorting applications at voltages below 6 and 15 V, respectively, facilitating low-voltage electric field applications in next-generation microfluidics.
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Affiliation(s)
- Diego Monserrat Lopez
- IBM Research Europe - Zurich, Säumerstrasse 4, CH-8803 Rüschlikon, Switzerland
- ETH Zürich, Department of Biosystems Science and Engineering, Mattenstrasse 26, 4058 Basel, Switzerland
| | - Philipp Rottmann
- ETH Zürich, Department of Biosystems Science and Engineering, Mattenstrasse 26, 4058 Basel, Switzerland
| | - Gabriel Puebla-Hellmann
- IBM Research Europe - Zurich, Säumerstrasse 4, CH-8803 Rüschlikon, Switzerland
- University of Basel, Department of Chemistry, St. Johanns-Ring 19, CH-4056 Basel, Switzerland
| | - Ute Drechsler
- IBM Research Europe - Zurich, Säumerstrasse 4, CH-8803 Rüschlikon, Switzerland
| | - Marcel Mayor
- University of Basel, Department of Chemistry, St. Johanns-Ring 19, CH-4056 Basel, Switzerland
- Institute for Nanotechnology (INT), Karlsruhe Institute of Technology (KIT), P. O. Box 3640, 76021 Karlsruhe, Germany
| | - Sven Panke
- ETH Zürich, Department of Biosystems Science and Engineering, Mattenstrasse 26, 4058 Basel, Switzerland
| | - Martin Fussenegger
- ETH Zürich, Department of Biosystems Science and Engineering, Mattenstrasse 26, 4058 Basel, Switzerland
- University of Basel, Faculty of Life Science, Basel, Switzerland
| | - Emanuel Lörtscher
- IBM Research Europe - Zurich, Säumerstrasse 4, CH-8803 Rüschlikon, Switzerland
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Grimaudo V, Lopez DM, Prone G, Lüthi T, Flisch A, López AC, Grozovski V, Tulej M, Riedo A, Zboray R, Lörtscher E, Broekmann P, Wurz P. Quantitative laser-matter interaction: a 3D study of UV-fs-laser ablation on single crystalline Ru(0001). Opt Express 2023; 31:17964-17986. [PMID: 37381517 DOI: 10.1364/oe.485713] [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: 03/07/2023] [Accepted: 04/28/2023] [Indexed: 06/30/2023]
Abstract
Laser ablation is nowadays an extensively applied technology to probe the chemical composition of solid materials. It allows for precise targeting of micrometer objects on and in samples, and enables chemical depth profiling with nanometer resolution. An in-depth understanding of the 3D geometry of the ablation craters is crucial for precise calibration of the depth scale in chemical depth profiles. Herein we present a comprehensive study on laser ablation processes using a Gaussian-shaped UV-femtosecond irradiation source and present how the combination of three different imaging methods (scanning electron microscopy, interferometric microscopy, and X-ray computed tomography) can provide accurate information on the crater's shapes. Crater analysis by applying X-ray computed tomography is of considerable interest because it allows the imaging of an array of craters in one step with sub-µm accuracy and is not limited to the aspect ratio of the crater. X-ray computed tomography thereby complements the analysis of laser ablation craters. The study investigates the effect of laser pulse energy and laser burst count on a single crystal Ru(0001) sample. Single crystals ensure that there is no dependence on the grain orientations during the laser ablation process. An array of 156 craters of different dimensions ranging from <20 nm to ∼40 µm in depth were created. For each individually applied laser pulse, we measured the number of ions generated in the ablation plume with our laser ablation ionization mass spectrometer. We show to which extent the combination of these four techniques reveals valuable information on the ablation threshold, the ablation rate, and the limiting ablation depth. The latter is expected to be a consequence of decreasing irradiance upon increasing crater surface area. The ion signal generated was found to be proportional to the volume ablated up to the certain depth, which enables in-situ depth calibration during the measurement.
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Monserrat Lopez D, Grimaudo V, Prone G, Flisch A, Riedo A, Zboray R, Lüthi T, Mayor M, Fussenegger M, Broekmann P, Wurz P, Lörtscher E. Automated, 3-D and Sub-Micron Accurate Ablation-Volume Determination by Inverse Molding and X-Ray Computed Tomography. Adv Sci (Weinh) 2022; 9:e2200136. [PMID: 35521972 PMCID: PMC9284130 DOI: 10.1002/advs.202200136] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Revised: 03/25/2022] [Indexed: 06/14/2023]
Abstract
Ablation of materials in combination with element-specific analysis of the matter released is a widely used method to accurately determine a material's chemical composition. Among other methods, repetitive ablation using femto-second pulsed laser systems provides excellent spatial resolution through its incremental removal of nanometer thick layers. The method can be combined with high-resolution mass spectrometry, for example, laser ablation ionization mass spectrometry, to simultaneously analyze chemically the material released. With increasing depth of the volume ablated, however, secondary effects start to play an important role and the ablation geometry deviates substantially from the desired cylindrical shape. Consequently, primarily conical but sometimes even more complex, rather than cylindrical, craters are created. Their dimensions need to be analyzed to enable a direct correlation with the element-specific analytical signals. Here, a post-ablation analysis method is presented that combines generic polydimethylsiloxane-based molding of craters with the volumetric reconstruction of the crater's inverse using X-ray computed tomography. Automated analysis yields the full, sub-micron accurate anatomy of the craters, thereby a scalable and generic method to better understand the fundamentals underlying ablation processes applicable to a wide range of materials. Furthermore, it may serve toward a more accurate determination of heterogeneous material's composition for a variety of applications without requiring time- and labor-intensive analyses of individual craters.
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Affiliation(s)
- Diego Monserrat Lopez
- Science & Technology DepartmentIBM Research Europe ‐ ZurichSäumerstrasse 4RüschlikonCH‐8803Switzerland
- Department of Biosystems Science and EngineeringETH ZürichMattenstrasse 26Basel4058Switzerland
| | - Valentine Grimaudo
- Physics InstituteSpace Research & Planetary SciencesUniversity of BernSidlerstrasse 5BernCH‐3012Switzerland
| | - Giulia Prone
- Science & Technology DepartmentIBM Research Europe ‐ ZurichSäumerstrasse 4RüschlikonCH‐8803Switzerland
- Department of ChemistryUniversity of BaselSt. Johanns‐Ring 19BaselCH‐4056Switzerland
| | - Alexander Flisch
- EMPASwiss Federal Laboratories for Materials Science and TechnologyÜberlandstrasse 129DübendorfCH‐8600Switzerland
| | - Andreas Riedo
- Physics InstituteSpace Research & Planetary SciencesUniversity of BernSidlerstrasse 5BernCH‐3012Switzerland
| | - Robert Zboray
- EMPASwiss Federal Laboratories for Materials Science and TechnologyÜberlandstrasse 129DübendorfCH‐8600Switzerland
| | - Thomas Lüthi
- EMPASwiss Federal Laboratories for Materials Science and TechnologyÜberlandstrasse 129DübendorfCH‐8600Switzerland
| | - Marcel Mayor
- Department of ChemistryUniversity of BaselSt. Johanns‐Ring 19BaselCH‐4056Switzerland
| | - Martin Fussenegger
- Department of Biosystems Science and EngineeringETH ZürichMattenstrasse 26Basel4058Switzerland
| | - Peter Broekmann
- Department of ChemistryBiochemistry and Pharmaceutical ScienceUniversity of BernFreiestrasse 3BernCH‐3012Switzerland
| | - Peter Wurz
- Physics InstituteSpace Research & Planetary SciencesUniversity of BernSidlerstrasse 5BernCH‐3012Switzerland
| | - Emanuel Lörtscher
- Science & Technology DepartmentIBM Research Europe ‐ ZurichSäumerstrasse 4RüschlikonCH‐8803Switzerland
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6
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Wen P, Tiwari P, Scherrer M, Lörtscher E, Gotsmann B, Moselund KE. Thermal Simulation and Experimental Analysis of Optically Pumped InP-on-Si Micro- and Nanocavity Lasers. ACS Photonics 2022; 9:1338-1348. [PMID: 35480495 PMCID: PMC9026276 DOI: 10.1021/acsphotonics.1c01951] [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] [Subscribe] [Scholar Register] [Received: 12/19/2021] [Indexed: 06/14/2023]
Abstract
There is a general trend of downscaling laser cavities, but with high integration and energy densities of nanocavity lasers, significant thermal issues affect their operation. The complexity of geometrical parameters and the various materials involved hinder the extraction of clear design guidelines and operation strategies. Here, we present a systematic thermal analysis of InP-on-Si micro- and nanocavity lasers based on steady-state and transient thermal simulations and experimental analysis. In particular, we investigate the use of metal cavities for improving the thermal properties of InP-on-Si micro- and nanocavity lasers. Heating of lasers is studied by using Raman thermometry and the results agree well with simulation results, both revealing a temperature reduction of hundreds of kelvins for the metal-clad cavity. Transient simulations are carried out to improve our understanding of the dynamic temperature variation under pulsed and continuous wave pumping conditions. The results show that the presence of a metal cladding not only increases the overall efficiency in heat dissipation but also causes a much faster temperature response. Together with optical experimental results under pulsed pumping, we conclude that a pulse width of 10 ns and a repetition rate of 100 kHz is the optimal pumping condition for a 2 μm wide square cavity.
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7
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Wyss RM, Parzefall M, Schlichting KP, Gruber CM, Busschaert S, Lightner CR, Lörtscher E, Novotny L, Heeg S. Freestanding and Permeable Nanoporous Gold Membranes for Surface-Enhanced Raman Scattering. ACS Appl Mater Interfaces 2022; 14:16558-16567. [PMID: 35353489 DOI: 10.1021/acsami.2c02608] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Surface-enhanced Raman spectroscopy (SERS) demands reliable, high-enhancement substrates in order to be used in different fields of application. Here we introduce freestanding porous gold membranes (PAuM) as easy-to-produce, scalable, mechanically stable, and effective SERS substrates. We fabricate large-scale sub-30 nm thick PAuM that form freestanding membranes with varying morphologies depending on the nominal gold thickness. These PAuM are mechanically stable for pressures up to more than 3 bar and exhibit surface-enhanced Raman scattering with local enhancement factors from 104 to 105, which we demonstrate by wavelength-dependent and spatially resolved Raman measurements using graphene as a local Raman probe. Numerical simulations reveal that the enhancement arises from individual, nanoscale pores in the membrane acting as optical slot antennas. Our PAuM are mechanically stable, provide robust SERS enhancement for excitation power densities up to 106 W cm-2, and may find use as a building block in SERS-based sensing applications.
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Affiliation(s)
- Roman M Wyss
- Soft Materials Department of Materials, ETH Zürich, Zürich CH-8093, Switzerland
| | | | - Karl-Philipp Schlichting
- Laboratory of Thermodynamics in Emerging Technologies Department of Mechanical and Process Engineering, ETH Zürich, Zürich CH-8092, Switzerland
| | | | | | - Carin Rae Lightner
- Optical Materials Engineering Laboratory, Department of Mechanical and Process Engineering, ETH Zürich, Zürich CH-8092, Switzerland
| | | | - Lukas Novotny
- Photonics Laboratory, ETH Zürich, Zürich CH-8093, Switzerland
| | - Sebastian Heeg
- Photonics Laboratory, ETH Zürich, Zürich CH-8093, Switzerland
- Department of Physics, Humboldt Universität zu Berlin, 12489Berlin, Germany
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8
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Scherrer D, Vogel D, Drechsler U, Olziersky A, Sparr C, Mayor M, Lörtscher E. Reaktionsverfolgung von Festphasensynthesen in selbstassemblierenden Monolagen mit oberflächenverstärkter Raman‐Spektroskopie. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202102319] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Dominik Scherrer
- Science and Technology Department, IBM Research Europe Säumerstrasse 4 8803 Rüschlikon Schweiz
- Department of Chemistry University of Basel St. Johanns-Ring 19 4056 Basel Schweiz
| | - David Vogel
- Department of Chemistry University of Basel St. Johanns-Ring 19 4056 Basel Schweiz
| | - Ute Drechsler
- Science and Technology Department, IBM Research Europe Säumerstrasse 4 8803 Rüschlikon Schweiz
| | - Antonis Olziersky
- Science and Technology Department, IBM Research Europe Säumerstrasse 4 8803 Rüschlikon Schweiz
| | - Christof Sparr
- Department of Chemistry University of Basel St. Johanns-Ring 19 4056 Basel Schweiz
| | - Marcel Mayor
- Department of Chemistry University of Basel St. Johanns-Ring 19 4056 Basel Schweiz
- Institute for Nanotechnology (INT) Karlsruhe Institute of Technology (KIT) P. O. Box 3640 76021 Karlsruhe Deutschland
- Lehn Institute of Functional Materials (LIFM) School of Chemistry Sun Yat-Sen University (SYSU) Guangzhou 510275 VR China
| | - Emanuel Lörtscher
- Science and Technology Department, IBM Research Europe Säumerstrasse 4 8803 Rüschlikon Schweiz
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9
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Scherrer D, Vogel D, Drechsler U, Olziersky A, Sparr C, Mayor M, Lörtscher E. Monitoring Solid-Phase Reactions in Self-Assembled Monolayers by Surface-Enhanced Raman Spectroscopy. Angew Chem Int Ed Engl 2021; 60:17981-17988. [PMID: 34048139 PMCID: PMC8456949 DOI: 10.1002/anie.202102319] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [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: 02/15/2021] [Revised: 05/18/2021] [Indexed: 12/27/2022]
Abstract
Nanopatterned surfaces enhance incident electromagnetic radiation and thereby enable the detection and characterization of self-assembled monolayers (SAMs), for instance in surface-enhanced Raman spectroscopy (SERS). Herein, Au nanohole arrays, developed and characterized as SERS substrates, are exemplarily used for monitoring a solid-phase deprotection and a subsequent copper(I)-catalyzed azide-alkyne cycloaddition "click" reaction, performed directly on the corresponding SAMs. The SERS substrate was found to be highly reliable in terms of signal reproducibility and chemical stability. Furthermore, the intermediates and the product of the solid-phase synthesis were identified by SERS. The spectra of the immobilized compounds showed minor differences compared to spectra of the microcrystalline solids. With its uniform SERS signals and the high chemical stability, the platform paves the way for monitoring molecular manipulations in surface functionalization applications.
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Affiliation(s)
- Dominik Scherrer
- Science and Technology Department, IBM Research EuropeSäumerstrasse 48803RüschlikonSwitzerland
- Department of ChemistryUniversity of BaselSt. Johanns-Ring 194056BaselSwitzerland
| | - David Vogel
- Department of ChemistryUniversity of BaselSt. Johanns-Ring 194056BaselSwitzerland
| | - Ute Drechsler
- Science and Technology Department, IBM Research EuropeSäumerstrasse 48803RüschlikonSwitzerland
| | - Antonis Olziersky
- Science and Technology Department, IBM Research EuropeSäumerstrasse 48803RüschlikonSwitzerland
| | - Christof Sparr
- Department of ChemistryUniversity of BaselSt. Johanns-Ring 194056BaselSwitzerland
| | - Marcel Mayor
- Department of ChemistryUniversity of BaselSt. Johanns-Ring 194056BaselSwitzerland
- Institute for Nanotechnology (INT)Karlsruhe Institute of Technology (KIT)P. O. Box 364076021KarlsruheGermany
- Lehn Institute of Functional Materials (LIFM)School of ChemistrySun Yat-Sen University (SYSU)Guangzhou510275P.R. China
| | - Emanuel Lörtscher
- Science and Technology Department, IBM Research EuropeSäumerstrasse 48803RüschlikonSwitzerland
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Dos Santos EC, Belluati A, Necula D, Scherrer D, Meyer CE, Wehr RP, Lörtscher E, Palivan CG, Meier W. Combinatorial Strategy for Studying Biochemical Pathways in Double Emulsion Templated Cell-Sized Compartments. Adv Mater 2020; 32:e2004804. [PMID: 33107187 DOI: 10.1002/adma.202004804] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 09/08/2020] [Indexed: 05/16/2023]
Abstract
Cells rely upon producing enzymes at precise rates and stoichiometry for maximizing functionalities. The reasons for this optimal control are unknown, primarily because of the interconnectivity of the enzymatic cascade effects within multi-step pathways. Here, an elegant strategy for studying such behavior, by controlling segregation/combination of enzymes/metabolites in synthetic cell-sized compartments, while preserving vital cellular elements is presented. Therefore, compartments shaped into polymer GUVs are developed, producing via high-precision double-emulsion microfluidics that enable: i) tight control over the absolute and relative enzymatic contents inside the GUVs, reaching nearly 100% encapsulation and co-encapsulation efficiencies, and ii) functional reconstitution of biopores and membrane proteins in the GUVs polymeric membrane, thus supporting in situ reactions. GUVs equipped with biopores/membrane proteins and loaded with one or more enzymes are arranged in a variety of combinations that allow the study of a three-step cascade in multiple topologies. Due to the spatiotemporal control provided, optimum conditions for decreasing the accumulation of inhibitors are unveiled, and benefited from reactive intermediates to maximize the overall cascade efficiency in compartments. The non-system-specific feature of the novel strategy makes this system an ideal candidate for the development of new synthetic routes as well as for screening natural and more complex pathways.
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Affiliation(s)
- Elena C Dos Santos
- Department of Chemistry, University of Basel, Mattenstrasse 24a, BPR 1096, 4002, Basel, Switzerland
| | - Andrea Belluati
- Department of Chemistry, University of Basel, Mattenstrasse 24a, BPR 1096, 4002, Basel, Switzerland
| | - Danut Necula
- Department of Chemistry, University of Basel, Mattenstrasse 24a, BPR 1096, 4002, Basel, Switzerland
| | - Dominik Scherrer
- Department of Chemistry, University of Basel, Mattenstrasse 24a, BPR 1096, 4002, Basel, Switzerland
- IBM Research Europe, Saeumerstrasse 4, 8803, Rueschlikon, Switzerland
| | - Claire E Meyer
- Department of Chemistry, University of Basel, Mattenstrasse 24a, BPR 1096, 4002, Basel, Switzerland
| | - Riccardo P Wehr
- Department of Chemistry, University of Basel, Mattenstrasse 24a, BPR 1096, 4002, Basel, Switzerland
| | - Emanuel Lörtscher
- IBM Research Europe, Saeumerstrasse 4, 8803, Rueschlikon, Switzerland
| | - Cornelia G Palivan
- Department of Chemistry, University of Basel, Mattenstrasse 24a, BPR 1096, 4002, Basel, Switzerland
| | - Wolfgang Meier
- Department of Chemistry, University of Basel, Mattenstrasse 24a, BPR 1096, 4002, Basel, Switzerland
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11
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Gruber CM, Herrmann L, Bellido EP, Dössegger J, Olziersky A, Drechsler U, Puebla-Hellmann G, Botton GA, Novotny L, Lörtscher E. Resonant Optical Antennas with Atomic-Sized Tips and Tunable Gaps Achieved by Mechanical Actuation and Electrical Control. Nano Lett 2020; 20:4346-4353. [PMID: 32369701 DOI: 10.1021/acs.nanolett.0c01072] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Enhanced electromagnetic fields in nanometer gaps of plasmonic structures increase the optical interaction with matter, including Raman scattering and optical absorption. Quantum electron tunneling across sub-1 nm gaps, however, lowers these effects again. Understanding these phenomena requires controlled variation of gap sizes. Mechanically actuated plasmonic antennas enable repeatable tuning of gap sizes from the weak-coupling over the quantum-electron-tunneling to the direct-electrical-contact regime. Gap sizes are controlled electrically via leads that only weakly disturb plasmonic modes. Conductance signals show a near-continuous transition from electron tunneling to metallic contact. As the antenna's absorption cross-section is reduced, thermal expansion effects are negligible, in contrast to conventional break-junctions. Optical scattering spectra reveal first continuous red shifts for decreasing gap sizes and then blue shifts below gaps of 0.3 nm. The approach provides pathways to study opto- and electromolecular processes at the limit of plasmonic sensing.
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Affiliation(s)
- Cynthia M Gruber
- IBM Research - Zurich, Säumerstrasse 4, CH-8803 Rüschlikon, Switzerland
- ETH Zürich, Photonics Laboratory, Hönggerbergring 64, CH-8093 Zürich, Switzerland
| | - Lars Herrmann
- IBM Research - Zurich, Säumerstrasse 4, CH-8803 Rüschlikon, Switzerland
- ETH Zürich, Photonics Laboratory, Hönggerbergring 64, CH-8093 Zürich, Switzerland
| | - Edson P Bellido
- McMaster University, 1280 Main Street West, Hamilton, ON L8S4M1, Canada
| | - Janine Dössegger
- IBM Research - Zurich, Säumerstrasse 4, CH-8803 Rüschlikon, Switzerland
- ETH Zürich, Photonics Laboratory, Hönggerbergring 64, CH-8093 Zürich, Switzerland
| | - Antonis Olziersky
- IBM Research - Zurich, Säumerstrasse 4, CH-8803 Rüschlikon, Switzerland
| | - Ute Drechsler
- IBM Research - Zurich, Säumerstrasse 4, CH-8803 Rüschlikon, Switzerland
| | - Gabriel Puebla-Hellmann
- IBM Research - Zurich, Säumerstrasse 4, CH-8803 Rüschlikon, Switzerland
- University of Basel, St. Johanns-Ring 19, CH-4056 Basel, Switzerland
| | | | - Lukas Novotny
- ETH Zürich, Photonics Laboratory, Hönggerbergring 64, CH-8093 Zürich, Switzerland
| | - Emanuel Lörtscher
- IBM Research - Zurich, Säumerstrasse 4, CH-8803 Rüschlikon, Switzerland
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12
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Cedeño López A, Grimaudo V, Riedo A, Tulej M, Wiesendanger R, Lukmanov R, Moreno-García P, Lörtscher E, Wurz P, Broekmann P. Three-Dimensional Composition Analysis of SnAg Solder Bumps Using Ultraviolet Femtosecond Laser Ablation Ionization Mass Spectrometry. Anal Chem 2019; 92:1355-1362. [DOI: 10.1021/acs.analchem.9b04530] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Affiliation(s)
- A. Cedeño López
- Department of Chemistry and Biochemistry, Interfacial Electrochemistry Group, University of Bern, Freiestrasse 3, 3012 Bern, Switzerland
| | - V. Grimaudo
- Physics Institute, Space Research and Planetary Sciences, University of Bern, Sidlerstrasse 5, 3012 Bern, Switzerland
| | - A. Riedo
- Laboratory for Astrophysics, Leiden Observatory, Leiden University, Niels Bohrweg 2, 2333 CA Leiden, The Netherlands
| | - M. Tulej
- Physics Institute, Space Research and Planetary Sciences, University of Bern, Sidlerstrasse 5, 3012 Bern, Switzerland
| | - R. Wiesendanger
- Physics Institute, Space Research and Planetary Sciences, University of Bern, Sidlerstrasse 5, 3012 Bern, Switzerland
| | - R. Lukmanov
- Physics Institute, Space Research and Planetary Sciences, University of Bern, Sidlerstrasse 5, 3012 Bern, Switzerland
| | - P. Moreno-García
- Department of Chemistry and Biochemistry, Interfacial Electrochemistry Group, University of Bern, Freiestrasse 3, 3012 Bern, Switzerland
| | - E. Lörtscher
- IBM Research Zurich, Säumerstrasse 4, 8803 Rüschlikon, Switzerland
| | - P. Wurz
- Physics Institute, Space Research and Planetary Sciences, University of Bern, Sidlerstrasse 5, 3012 Bern, Switzerland
| | - P. Broekmann
- Department of Chemistry and Biochemistry, Interfacial Electrochemistry Group, University of Bern, Freiestrasse 3, 3012 Bern, Switzerland
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13
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Puebla-Hellmann G, Venkatesan K, Mayor M, Lörtscher E. Metallic nanoparticle contacts for high-yield, ambient-stable molecular-monolayer devices. Nature 2018; 559:232-235. [DOI: 10.1038/s41586-018-0275-z] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Accepted: 05/04/2018] [Indexed: 11/09/2022]
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14
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Moreno-García P, Grimaudo V, Riedo A, Cedeño López A, Wiesendanger R, Tulej M, Gruber C, Lörtscher E, Wurz P, Broekmann P. Insights into Laser Ablation Processes of Heterogeneous Samples: Toward Analysis of Through-Silicon-Vias. Anal Chem 2018; 90:6666-6674. [DOI: 10.1021/acs.analchem.8b00492] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Pavel Moreno-García
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, CH-3012 Bern, Switzerland
| | - Valentine Grimaudo
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, CH-3012 Bern, Switzerland
| | - Andreas Riedo
- Physics Institute, Space Research and Planetary Sciences, University of Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland
- Sackler Laboratory for Astrophysics, Leiden Observatory, Leiden University, Niels Bohrweg 2, 2333 CA Leiden, The Netherlands
| | - Alena Cedeño López
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, CH-3012 Bern, Switzerland
| | - Reto Wiesendanger
- Physics Institute, Space Research and Planetary Sciences, University of Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland
| | - Marek Tulej
- Physics Institute, Space Research and Planetary Sciences, University of Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland
| | - Cynthia Gruber
- IBM Research−Zurich, Science and Technology Department, Säumerstrasse 4, CH-8803 Rüschlikon, Switzerland
| | - Emanuel Lörtscher
- IBM Research−Zurich, Science and Technology Department, Säumerstrasse 4, CH-8803 Rüschlikon, Switzerland
| | - Peter Wurz
- Physics Institute, Space Research and Planetary Sciences, University of Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland
| | - Peter Broekmann
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, CH-3012 Bern, Switzerland
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15
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Grimaudo V, Moreno-García P, Cedeño López A, Riedo A, Wiesendanger R, Tulej M, Gruber C, Lörtscher E, Wurz P, Broekmann P. Depth Profiling and Cross-Sectional Laser Ablation Ionization Mass Spectrometry Studies of Through-Silicon-Vias. Anal Chem 2018; 90:5179-5186. [DOI: 10.1021/acs.analchem.7b05313] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Affiliation(s)
- Valentine Grimaudo
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, 3012 Bern, Switzerland
| | - Pavel Moreno-García
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, 3012 Bern, Switzerland
| | - Alena Cedeño López
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, 3012 Bern, Switzerland
| | - Andreas Riedo
- Sackler Laboratory for Astrophysics, Leiden University, Niels Bohrweg 2, 2333 CA Leiden, The Netherlands
| | - Reto Wiesendanger
- Physics Institute, Space Research and Planetary Sciences, University of Bern, Sidlerstrasse 5, 3012 Bern, Switzerland
| | - Marek Tulej
- Physics Institute, Space Research and Planetary Sciences, University of Bern, Sidlerstrasse 5, 3012 Bern, Switzerland
| | - Cynthia Gruber
- IBM Research - Zürich, Science and Technology Department, Säumerstrasse 4, 8803 Rüschlikon, Switzerland
| | - Emanuel Lörtscher
- IBM Research - Zürich, Science and Technology Department, Säumerstrasse 4, 8803 Rüschlikon, Switzerland
| | - Peter Wurz
- Physics Institute, Space Research and Planetary Sciences, University of Bern, Sidlerstrasse 5, 3012 Bern, Switzerland
| | - Peter Broekmann
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, 3012 Bern, Switzerland
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16
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Koren E, Leven I, Lörtscher E, Knoll A, Hod O, Duerig U. Coherent commensurate electronic states at the interface between misoriented graphene layers. Nat Nanotechnol 2016; 11:752-7. [PMID: 27271963 DOI: 10.1038/nnano.2016.85] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Accepted: 04/26/2016] [Indexed: 05/13/2023]
Abstract
Graphene and layered materials in general exhibit rich physics and application potential owing to their exceptional electronic properties, which arise from the intricate π-orbital coupling and the symmetry breaking in twisted bilayer systems. Here, we report room-temperature experiments to study electrical transport across a bilayer graphene interface with a well-defined rotation angle between the layers that is controllable in situ. This twisted interface is artificially created in mesoscopic pillars made of highly oriented pyrolytic graphite by mechanical actuation. The overall measured angular dependence of the conductivity is consistent with a phonon-assisted transport mechanism that preserves the electron momentum of conduction electrons passing the interface. The most intriguing observations are sharp conductivity peaks at interlayer rotation angles of 21.8° and 38.2°. These angles correspond to a commensurate crystalline superstructure leading to a coherent two-dimensional (2D) electronic interface state. Such states, predicted by theory, form the basis for a new class of 2D weakly coupled bilayer systems with hitherto unexplored properties and applications.
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Affiliation(s)
- Elad Koren
- IBM Research - Zurich, Rueschlikon 8803, Switzerland
| | - Itai Leven
- Department of Physical Chemistry, School of Chemistry, The Raymond and Beverly Sackler Faculty of Exact Sciences and The Sackler Center for Computational Molecular and Materials Science, Tel Aviv University, Tel Aviv 6997801, Israel
| | | | - Armin Knoll
- IBM Research - Zurich, Rueschlikon 8803, Switzerland
| | - Oded Hod
- Department of Physical Chemistry, School of Chemistry, The Raymond and Beverly Sackler Faculty of Exact Sciences and The Sackler Center for Computational Molecular and Materials Science, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Urs Duerig
- IBM Research - Zurich, Rueschlikon 8803, Switzerland
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17
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Schwarz F, Koch M, Kastlunger G, Berke H, Stadler R, Venkatesan K, Lörtscher E. Charge Transport and Conductance Switching of Redox-Active Azulene Derivatives. Angew Chem Int Ed Engl 2016; 55:11781-6. [DOI: 10.1002/anie.201605559] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Indexed: 11/10/2022]
Affiliation(s)
- Florian Schwarz
- Science and Technology Department; IBM Research - Zürich; Säumerstrasse 4 8803 Rüschlikon Switzerland
| | - Michael Koch
- Chemie Departement; University of Zurich; Winterthurerstrasse 190 8057 Zürich Switzerland
| | - Georg Kastlunger
- Institut für Theoretische Physik; TU Wien - Vienna University of Technology; Wiedner Haupstrasse 8-10 Vienna 1040 Austria
| | - Heinz Berke
- Chemie Departement; University of Zurich; Winterthurerstrasse 190 8057 Zürich Switzerland
| | - Robert Stadler
- Institut für Theoretische Physik; TU Wien - Vienna University of Technology; Wiedner Haupstrasse 8-10 Vienna 1040 Austria
| | - Koushik Venkatesan
- Chemie Departement; University of Zurich; Winterthurerstrasse 190 8057 Zürich Switzerland
| | - Emanuel Lörtscher
- Science and Technology Department; IBM Research - Zürich; Säumerstrasse 4 8803 Rüschlikon Switzerland
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18
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Schwarz F, Koch M, Kastlunger G, Berke H, Stadler R, Venkatesan K, Lörtscher E. Ladungstransport und Leitfähigkeitsschalten von redoxaktiven Azulen-Derivaten. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201605559] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Florian Schwarz
- Science and Technology Department; IBM Research - Zürich; Säumerstrasse 4 8803 Rüschlikon Schweiz
| | - Michael Koch
- Chemie Departement; University of Zurich; Winterthurerstrasse 190 8057 Zürich Schweiz
| | - Georg Kastlunger
- Institut für Theoretische Physik; TU Wien - Vienna University of Technology; Wiedner Haupstrasse 8-10 Wien 1040 Österreich
| | - Heinz Berke
- Chemie Departement; University of Zurich; Winterthurerstrasse 190 8057 Zürich Schweiz
| | - Robert Stadler
- Institut für Theoretische Physik; TU Wien - Vienna University of Technology; Wiedner Haupstrasse 8-10 Wien 1040 Österreich
| | - Koushik Venkatesan
- Chemie Departement; University of Zurich; Winterthurerstrasse 190 8057 Zürich Schweiz
| | - Emanuel Lörtscher
- Science and Technology Department; IBM Research - Zürich; Säumerstrasse 4 8803 Rüschlikon Schweiz
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19
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Puebla-Hellmann G, Mayor M, Lörtscher E. Functional Nanopores: A Solid-state Concept for Artificial Reaction Compartments and Molecular Factories. Chimia (Aarau) 2016; 70:432-8. [PMID: 27363373 DOI: 10.2533/chimia.2016.432] [Citation(s) in RCA: 1] [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: 11/19/2022] Open
Abstract
On the road towards the long-term goal of the NCCR Molecular Systems Engineering to create artificial molecular factories, we aim at introducing a compartmentalization strategy based on solid-state silicon technology targeting zeptoliter reaction volumes and simultaneous electrical contact to ensembles of well-oriented molecules. This approach allows the probing of molecular building blocks under a controlled environment prior to their use in a complex molecular factory. Furthermore, these ultra-sensitive electrical conductance measurements allow molecular responses to a variety of external triggers to be used as sensing and feedback mechanisms. So far, we demonstrate the proof-of-concept by electrically contacting self-assembled mono-layers of alkane-dithiols as an established test system. Here, the molecular films are laterally constrained by a circular dielectric confinement, forming a so-called 'nanopore'. Device yields above 85% are consistently achieved down to sub-50 nm nanopore diameters. This generic platform will be extended to create distributed, cascaded reactors with individually addressable reaction sites, including interconnecting micro-fluidic channels for electrochemical communication among nanopores and sensing sites for reaction control and feedback. In this scientific outlook, we will sketch how such a solid-state nanopore concept can be used to study various aspects of molecular compounds tailored for operation in a molecular factory.
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Affiliation(s)
- Gabriel Puebla-Hellmann
- Department of Chemistry, University of Basel, St. Johanns-Ring 19, CH-4056 Basel, IBM Research - Zurich Säumerstrasse 4, CH-8803 Rüschlikon, Switzerland.
| | - Marcel Mayor
- Department of Chemistry, University of Basel, St. Johanns-Ring 19, CH-4056 Basel, Switzerland
| | - Emanuel Lörtscher
- IBM Research - Zurich, Säumerstrasse 4, CH-8803 Rüschlikon, Switzerland
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20
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Schwarz F, Kastlunger G, Lissel F, Egler-Lucas C, Semenov SN, Venkatesan K, Berke H, Stadler R, Lörtscher E. Field-induced conductance switching by charge-state alternation in organometallic single-molecule junctions. Nat Nanotechnol 2016; 11:170-6. [PMID: 26571004 DOI: 10.1038/nnano.2015.255] [Citation(s) in RCA: 99] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2015] [Accepted: 10/05/2015] [Indexed: 05/23/2023]
Abstract
Charge transport through single molecules can be influenced by the charge and spin states of redox-active metal centres placed in the transport pathway. These intrinsic properties are usually manipulated by varying the molecule's electrochemical and magnetic environment, a procedure that requires complex setups with multiple terminals. Here we show that oxidation and reduction of organometallic compounds containing either Fe, Ru or Mo centres can solely be triggered by the electric field applied to a two-terminal molecular junction. Whereas all compounds exhibit bias-dependent hysteresis, the Mo-containing compound additionally shows an abrupt voltage-induced conductance switching, yielding high-to-low current ratios exceeding 1,000 at bias voltages of less than 1.0 V. Density functional theory calculations identify a localized, redox-active molecular orbital that is weakly coupled to the electrodes and closely aligned with the Fermi energy of the leads because of the spin-polarized ground state unique to the Mo centre. This situation provides an additional slow and incoherent hopping channel for transport, triggering a transient charging effect in the entire molecule with a strong hysteresis and large high-to-low current ratios.
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Affiliation(s)
- Florian Schwarz
- IBM Research - Zurich, Säumerstrasse 4, Rüschlikon 8803, Switzerland
| | - Georg Kastlunger
- Department of Physical Chemistry, University of Vienna, Sensengasse 8/7, Vienna 1090, Austria
- Institute for Theoretical Physics, TU Wien - Vienna University of Technology, Wiedner Hauptstrasse 8-10, Vienna 1040, Austria
| | - Franziska Lissel
- Department of Chemistry, University of Zürich, Winterthurerstrasse 190, Zürich 8057, Switzerland
| | - Carolina Egler-Lucas
- Department of Chemistry, University of Zürich, Winterthurerstrasse 190, Zürich 8057, Switzerland
| | - Sergey N Semenov
- Department of Chemistry, University of Zürich, Winterthurerstrasse 190, Zürich 8057, Switzerland
| | - Koushik Venkatesan
- Department of Chemistry, University of Zürich, Winterthurerstrasse 190, Zürich 8057, Switzerland
| | - Heinz Berke
- Department of Chemistry, University of Zürich, Winterthurerstrasse 190, Zürich 8057, Switzerland
| | - Robert Stadler
- Department of Physical Chemistry, University of Vienna, Sensengasse 8/7, Vienna 1090, Austria
- Institute for Theoretical Physics, TU Wien - Vienna University of Technology, Wiedner Hauptstrasse 8-10, Vienna 1040, Austria
| | - Emanuel Lörtscher
- IBM Research - Zurich, Säumerstrasse 4, Rüschlikon 8803, Switzerland
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21
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Koren E, Knoll AW, Lörtscher E, Duerig U. Direct experimental observation of stacking fault scattering in highly oriented pyrolytic graphite meso-structures. Nat Commun 2014; 5:5837. [PMID: 25510583 DOI: 10.1038/ncomms6837] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2014] [Accepted: 11/11/2014] [Indexed: 11/09/2022] Open
Abstract
Stacking fault defects are thought to be the root cause for many of the anomalous transport phenomena seen in high-quality graphite samples. In stark contrast to their importance, direct observation of stacking faults by diffractive techniques has remained elusive due to fundamental experimental difficulties. Here we show that the stacking fault density and resistance can be measured by analyzing the non-Gaussian scatter observed in the c-axis resistivity of mesoscopic graphite structures. We also show that the deviation from Ohmic conduction seen at high electrical field strength can be fit to a thermally activated transport model, which accurately reproduces the stacking fault density inferred from the statistical analysis. From our measurements, we conclude that the c-axis resistivity is entirely determined by the stacking fault resistance, which is orders of magnitude larger than the inter-layer resistance expected from a Drude model.
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Affiliation(s)
- E Koren
- IBM Research-Zurich, Säumerstrasse 4, 8803 Rüschlikon, Switzerland
| | - A W Knoll
- IBM Research-Zurich, Säumerstrasse 4, 8803 Rüschlikon, Switzerland
| | - E Lörtscher
- IBM Research-Zurich, Säumerstrasse 4, 8803 Rüschlikon, Switzerland
| | - U Duerig
- IBM Research-Zurich, Säumerstrasse 4, 8803 Rüschlikon, Switzerland
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22
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Abstract
Break-junctions (BJs) enable a pair of atomic-sized electrodes to be created and the relative position between them to be controlled with sub-nanometer accuracy by mechanical means-a level of microscopic control that is not yet achievable by top-down fabrication. Locally, a BJ consists of a single-atom contact, an arrangement that is ideal not only to study various types of quantum point contacts, but also to investigate transport through an individual molecule that can bridge such a junction. In this topical review, we will provide a broad overview on the field of single-molecule electronics, in which BJs serve as the main tool of investigation. To correlate the molecular structure and transport properties to gain a fundamental understanding of the underlying transport mechanisms at the molecular scale, basic experiments that systematically cover all aspects of transport by rational chemical design and tailored experiments are needed. The variety of fascinating transport mechanisms and intrinsic molecular functionalities discovered in the past range from nonlinear transport over conductance switching to quantum interference effects observable even at room temperature. Beside discussing these results, we also look at novel directions and the most recent advances in molecular electronics investigating simultaneously electronic transport and also the mechanical and thermal properties of single-molecule junctions as well as the interaction between molecules and light. Finally, we will describe the requirements for a stepwise transition from fundamental BJ experiments towards technology-relevant architectures for future nanoelectronics applications based on ultimately-scaled molecular building blocks.
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Affiliation(s)
- Florian Schwarz
- IBM Research-Zurich, Department of Science and Technology, Säumerstrasse 4, CH-8803 Rüschlikon, Switzerland
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23
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Schwarz F, Kastlunger G, Lissel F, Riel H, Venkatesan K, Berke H, Stadler R, Lörtscher E. High-conductive organometallic molecular wires with delocalized electron systems strongly coupled to metal electrodes. Nano Lett 2014; 14:5932-5940. [PMID: 25233125 DOI: 10.1021/nl5029045] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Besides active, functional molecular building blocks such as diodes or switches, passive components, for example, molecular wires, are required to realize molecular-scale electronics. Incorporating metal centers in the molecular backbone enables the molecular energy levels to be tuned in respect to the Fermi energy of the electrodes. Furthermore, by using more than one metal center and sp-bridging ligands, a strongly delocalized electron system is formed between these metallic "dopants", facilitating transport along the molecular backbone. Here, we study the influence of molecule-metal coupling on charge transport of dinuclear X(PP)2FeC4Fe(PP)2X molecular wires (PP = Et2PCH2CH2PEt2); X = CN (1), NCS (2), NCSe (3), C4SnMe3 (4), and C2SnMe3 (5) under ultrahigh vacuum and variable temperature conditions. In contrast to 1, which showed unstable junctions at very low conductance (8.1 × 10(-7) G0), 4 formed a Au-C4FeC4FeC4-Au junction 4' after SnMe3 extrusion, which revealed a conductance of 8.9 × 10(-3) G0, 3 orders of magnitude higher than for 2 (7.9 × 10(-6) G0) and 2 orders of magnitude higher than for 3 (3.8 × 10(-4) G0). Density functional theory (DFT) confirmed the experimental trend in the conductance for the various anchoring motifs. The strong hybridization of molecular and metal states found in the C-Au coupling case enables the delocalized electronic system of the organometallic Fe2 backbone to be extended over the molecule-metal interfaces to the metal electrodes to establish high-conductive molecular wires.
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Affiliation(s)
- Florian Schwarz
- IBM Research-Zurich , Säumerstrasse 4, CH-8803 Rüschlikon, Switzerland
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24
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Lissel F, Schwarz F, Blacque O, Riel H, Lörtscher E, Venkatesan K, Berke H. Organometallic Single-Molecule Electronics: Tuning Electron Transport through X(diphosphine)2FeC4Fe(diphosphine)2X Building Blocks by Varying the Fe–X–Au Anchoring Scheme from Coordinative to Covalent. J Am Chem Soc 2014; 136:14560-9. [DOI: 10.1021/ja507672g] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Affiliation(s)
- Franziska Lissel
- Department
of Chemistry, University of Zurich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
| | - Florian Schwarz
- Science & Technology Department, IBM Research - Zurich, Säumerstrasse 4, CH-8803 Rüschlikon, Switzerland
| | - Olivier Blacque
- Department
of Chemistry, University of Zurich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
| | - Heike Riel
- Science & Technology Department, IBM Research - Zurich, Säumerstrasse 4, CH-8803 Rüschlikon, Switzerland
| | - Emanuel Lörtscher
- Science & Technology Department, IBM Research - Zurich, Säumerstrasse 4, CH-8803 Rüschlikon, Switzerland
| | - Koushik Venkatesan
- Department
of Chemistry, University of Zurich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
| | - Heinz Berke
- Department
of Chemistry, University of Zurich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
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25
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Lörtscher E, Widmer D, Gotsmann B. Next-generation nanotechnology laboratories with simultaneous reduction of all relevant disturbances. Nanoscale 2013; 5:10542-10549. [PMID: 24056900 DOI: 10.1039/c3nr03373b] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The tremendous variety of nanotechnology experiments and tools to fabricate and characterize ever-smaller structures down to molecular or even atomic scales leads to stringent demands for appropriate, so-called "silent", premises that allow such susceptible experiments to be conducted. Reducing dimensions means smaller absolute optical and electrical signal levels, and consequently reduced signal-to-noise ratios. Hence, in addition to short-range disturbances inside the laboratory, remote long-range noise sources have to be considered for next-generation laboratories that aim at screening the disturbances and keeping the remaining values at utmost constancy. We present a novel laboratory concept that addresses simultaneously all the disturbances relevant for nanotechnology, namely, vibrations, electro-magnetic fields, temperature, humidity, and sound. Particular attention was paid to tackling the mutual derogation of the various measures to enable unprecedented performance of the novel research platform.
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Affiliation(s)
- Emanuel Lörtscher
- IBM Research - Zurich, Säumerstrasse 4, CH-8803 Rüschlikon, Switzerland.
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26
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Rey A, Billardon G, Lörtscher E, Moth-Poulsen K, Stuhr-Hansen N, Wolf H, Bjørnholm T, Stemmer A, Riel H. Deterministic assembly of linear gold nanorod chains as a platform for nanoscale applications. Nanoscale 2013; 5:8680-8688. [PMID: 23900232 DOI: 10.1039/c3nr02358c] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
We demonstrate a method to assemble gold nanorods highly deterministically into a chain formation by means of directed capillary assembly. This way we achieved straight chains consisting of end-to-end aligned gold nanorods assembled in one specific direction with well-controlled gaps of ∼6 nm between the individual constituents. We determined the conditions for optimum quality and yield of nanorod chain assembly by investigating the influence of template dimensions and assembly temperature. In addition, we transferred the gold nanorod chains from the assembly template onto a Si/SiO2 target substrate, thus establishing a platform for a variety of nanoscale electronic and optical applications ranging from molecular electronics to optical and plasmonic devices. As a first example, electrical measurements are performed on contacted gold nanorod chains before and after their immersion in a solution of thiol end-capped oligophenylenevinylene molecules showing an increase in the conductance by three orders of magnitude, indicating molecular-mediated transport.
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Affiliation(s)
- Antje Rey
- IBM Research-Zurich, Säumerstrasse 4, 8803 Rüschlikon, Switzerland.
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27
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Affiliation(s)
- Emanuel Lörtscher
- IBM Research-Zurich Laboratory, Science & Technology Department, Säumerstrasse 4, CH-8803 Rüschlikon, Switzerland.
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28
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Lörtscher E, Geskin V, Gotsmann B, Fock J, Sørensen JK, Bjørnholm T, Cornil J, van der Zant HSJ, Riel H. Bonding and electronic transport properties of fullerene and fullerene derivatives in break-junction geometries. Small 2013; 9:209-214. [PMID: 23008229 DOI: 10.1002/smll.201201688] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2012] [Indexed: 06/01/2023]
Abstract
Fullerenes are considered anchoring groups for molecular electronics due to a large contact area and their affinity for noble metals. The conductances of fullerene-terminated molecules, however, are found to be even lower than for thiol termination. The effects of weak molecule-metal coupling and symmetry breaking are studied by transport measurements of C(60) and functionalized C(60). The results demonstrate highy efficient contacts between Au and C(60), despite of deposition from solution.
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Affiliation(s)
- Emanuel Lörtscher
- IBM Research-Zurich, Säumerstrasse 4, CH-8803 Rüschlikon, Switzerland.
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Abstract
Charge transport through single diblock dipyrimidinyl diphenyl molecules consisting of a donor and acceptor moiety was measured in the low-bias regime and as a function of bias at different temperatures using the mechanically controllable break-junction technique. Conductance histograms acquired at 10 mV reveal two distinct peaks, separated by a factor of 1.5, representing the two orientations of the single molecule with respect to the applied bias. The current-voltage characteristics exhibit a temperature-independent rectification of up to a factor of 10 in the temperature range between 300 and 50 K with single-molecule currents of 45-70 nA at ±1.5 V. The current-voltage characteristics are discussed using a semiempirical model assuming a variable coupling of the molecular energy levels as well as a nonsymmetric voltage drop across the molecular junction, thus shifting the energy levels accordingly. The excellent agreement of the data with the proposed model suggests that the rectification originates from an asymmetric Coulomb blockade in combination with an electric-field-induced level shifting.
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Lörtscher E, Cho CJ, Mayor M, Tschudy M, Rettner C, Riel H. Influence of the anchor group on charge transport through single-molecule junctions. Chemphyschem 2011; 12:1677-82. [PMID: 21633997 DOI: 10.1002/cphc.201000960] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2010] [Revised: 04/04/2011] [Indexed: 11/11/2022]
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Fock J, Sørensen JK, Lörtscher E, Vosch T, Martin CA, Riel H, Kilså K, Bjørnholm T, van der Zant H. A statistical approach to inelastic electron tunneling spectroscopy on fullerene-terminated molecules. Phys Chem Chem Phys 2011; 13:14325-32. [DOI: 10.1039/c1cp20861f] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Moselund KE, Ghoneim H, Schmid H, Björk MT, Lörtscher E, Karg S, Signorello G, Webb D, Tschudy M, Beyeler R, Riel H. Solid-state diffusion as an efficient doping method for silicon nanowires and nanowire field effect transistors. Nanotechnology 2010; 21:435202. [PMID: 20890021 DOI: 10.1088/0957-4484/21/43/435202] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
In this work we investigate doping by solid-state diffusion from a doped oxide layer, obtained by plasma-enhanced chemical vapor deposition (PECVD), as a means for selectively doping silicon nanowires (NWs). We demonstrate both n-type (phosphorous) and p-type (boron) doping up to concentrations of 10(20) cm(-3), and find that this doping mechanism is more efficient for NWs as opposed to planar substrates. We observe no diameter dependence in the range of 25 to 80 nm, which signifies that the NWs are uniformly doped. The drive-in temperature (800-950 °C) can be used to adjust the actual doping concentration in the range 2 × 10(18) to 10(20) cm(-3). Furthermore, we have fabricated NMOS and PMOS devices to show the versatility of this approach and the possibility of achieving segmented doping of NWs. The devices show high I(on)/I(off) ratios of around 10(7) and, especially for the PMOS, good saturation behavior and low hysteresis.
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Kuemin C, Cathrein Huckstadt K, Lörtscher E, Rey A, Decker A, Spencer ND, Wolf H. Selective assembly of sub-micrometer polymer particles. Adv Mater 2010; 22:2804-2808. [PMID: 20432224 DOI: 10.1002/adma.201000396] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Affiliation(s)
- Cyrill Kuemin
- IBM Research - Zurich, Säumerstrasse 4, 8803 Rüschlikon, Switzerland
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Ruben M, Landa A, Lörtscher E, Riel H, Mayor M, Görls H, Weber HB, Arnold A, Evers F. Charge transport through a cardan-joint molecule. Small 2008; 4:2229-2235. [PMID: 19016500 DOI: 10.1002/smll.200800390] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The charge transport through a single ruthenium atom clamped by two terpyridine hinges is investigated, both experimentally and theoretically. The metal-bis(terpyridyl) core is equipped with rigid, conjugated linkers of para-acetyl-mercapto phenylacetylene to establish electrical contact in a two-terminal configuration using Au electrodes. The structure of the [Ru(II)(L)(2)](PF(6))(2) molecule is determined using single-crystal X-ray crystallography, which yields good agreement with calculations based on density functional theory (DFT). By means of the mechanically controllable break-junction technique, current-voltage (I-V), characteristics of [Ru(II)(L)(2)](PF(6))(2) are acquired on a single-molecule level under ultra-high vacuum (UHV) conditions at various temperatures. These results are compared to ab initio transport calculations based on DFT. The simulations show that the cardan-joint structural element of the molecule controls the magnitude of the current. Moreover, the fluctuations in the cardan angle leave the positions of steps in the I-V curve largely invariant. As a consequence, the experimental I-V characteristics exhibit lowest-unoccupied-molecular-orbit-based conductance peaks at particular voltages, which are also found to be temperature independent.
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Affiliation(s)
- Mario Ruben
- Institute of Nanotechnology, Karlsruhe Institute of Technology, PF 3640, 76021 Karlsruhe, Germany.
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Lörtscher E, Elbing M, Tschudy M, von Hänisch C, Weber HB, Mayor M, Riel H. Charge Transport through Molecular Rods with Reduced π-Conjugation. Chemphyschem 2008; 9:2252-8. [DOI: 10.1002/cphc.200800388] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [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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Röösli M, Lörtscher M, Egger M, Pfluger D, Schreier N, Lörtscher E, Locher P, Spoerri A, Minder C. Mortality from Neurodegenerative Disease and Exposure to Extremely Low-Frequency Magnetic Fields: 31 Years of Observations on Swiss Railway Employees. Neuroepidemiology 2007; 28:197-206. [PMID: 17851258 DOI: 10.1159/000108111] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
AIMS The objective of the present study was to investigate the relationship between extremely low-frequency magnetic field (ELF-MF) exposure and mortality from several neurodegenerative conditions in Swiss railway employees. METHODS We studied a cohort of 20,141 Swiss railway employees with 464,129 person-years of follow-up between 1972 and 2002. For each individual, cumulative exposure was calculated from on-site measurements and modelling of past exposure. We compared cause-specific mortality in highly exposed train drivers (mean exposure: 21 microT) with less exposed occupational groups (for example station masters: 1 microT). RESULTS The hazard ratio for train drivers compared to station masters was 1.96 [95% confidence interval (CI) = 0.98-3.92] for senile dementia and 3.15 (95% CI = 0.90-11.04) for Alzheimer's disease. For every 10 microT years of cumulative exposure senile dementia mortality increased by 5.7% (95% CI = 1.3-10.4), Alzheimer's disease by 9.4% (95% CI = 2.7-16.4) and amyotrophic lateral sclerosis by 2.1% (95% CI = -6.8 to 11.7). There was no evidence for an increase in mortality from Parkinson's disease and multiple sclerosis. CONCLUSIONS This study suggests a link between exposure to ELF-MF and Alzheimer's disease and indicates that ELF-MF might act in later stages of the disease process.
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Affiliation(s)
- Martin Röösli
- Department of Social and Preventive Medicine, University of Berne, Berne, Switzerland.
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Röösli M, Lörtscher M, Egger M, Pfluger D, Schreier N, Lörtscher E, Locher P, Spoerri A, Minder C. Leukaemia, brain tumours and exposure to extremely low frequency magnetic fields: cohort study of Swiss railway employees. Occup Environ Med 2007; 64:553-9. [PMID: 17525094 PMCID: PMC2078497 DOI: 10.1136/oem.2006.030270] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
AIMS To investigate the relationship between extremely low frequency magnetic field (ELF-MF) exposure and mortality from leukaemia and brain tumour in a cohort of Swiss railway workers. METHODS 20,141 Swiss railway employees with 464,129 person-years of follow-up between 1972 and 2002 were studied. Mortality rates for leukaemia and brain tumour of highly exposed train drivers (21 muT average annual exposure) were compared with medium and low exposed occupational groups (i.e. station masters with an average exposure of 1 muT). In addition, individual cumulative exposure was calculated from on-site measurements and modelling of past exposures. RESULTS The hazard ratio (HR) for leukaemia mortality of train drivers was 1.43 (95% CI 0.74 to 2.77) compared with station masters. For myeloid leukaemia the HR of train drivers was 4.74 (95% CI 1.04 to 21.60) and for Hodgkin's disease 3.29 (95% CI 0.69 to 15.63). Lymphoid leukaemia, non-Hodgkin's disease and brain tumour mortality were not associated with magnetic field exposure. Concordant results were obtained from analyses based on individual cumulative exposure. CONCLUSIONS Some evidence of an exposure-response association was found for myeloid leukaemia and Hodgkin's disease, but not for other haematopoietic and lymphatic malignancies and brain tumours.
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Affiliation(s)
- Martin Röösli
- Department of Social and Preventive Medicine, University of Berne, Switzerland.
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Abstract
We present a statistical approach that combines comprehensive current-voltage data acquisition during the controlled manipulation of a molecular junction with subsequent statistical analysis. Thereby the most probable transport characteristics can be determined. The excellent sensitivity of this impartial approach to even subnanometer-long molecules is illustrated by benzene-1,4-dithiol and 4,4"-bis(acetylthiol)-2,2',5',2"-tetramethyl-[1,1';4',1"] terphenyl results.
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Hayden O, Björk MT, Schmid H, Riel H, Drechsler U, Karg SF, Lörtscher E, Riess W. Fully depleted nanowire field-effect transistor in inversion mode. Small 2007; 3:230-4. [PMID: 17199244 DOI: 10.1002/smll.200600325] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Affiliation(s)
- Oliver Hayden
- IBM Research GmbH, Zurich Research Laboratory, Rüschlikon, Switzerland.
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Affiliation(s)
- Emanuel Lörtscher
- IBM Zurich Research Laboratory, Säumerstrasse 4, 8803 Rüschlikon, Switzerland
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