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Checa M, Millan-Solsona R, Mares AG, Pujals S, Gomila G. Fast Label-Free Nanoscale Composition Mapping of Eukaryotic Cells Via Scanning Dielectric Force Volume Microscopy and Machine Learning. SMALL METHODS 2021; 5:e2100279. [PMID: 34928004 DOI: 10.1002/smtd.202100279] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Revised: 04/28/2021] [Indexed: 06/14/2023]
Abstract
Mapping the biochemical composition of eukaryotic cells without the use of exogenous labels is a long-sought objective in cell biology. Recently, it has been shown that composition maps on dry single bacterial cells with nanoscale spatial resolution can be inferred from quantitative nanoscale dielectric constant maps obtained with the scanning dielectric microscope. Here, it is shown that this approach can also be applied to the much more challenging case of fixed and dry eukaryotic cells, which are highly heterogeneous and show micrometric topographic variations. More importantly, it is demonstrated that the main bottleneck of the technique (the long computation times required to extract the nanoscale dielectric constant maps) can be shortcut by using supervised neural networks, decreasing them from weeks to seconds in a wokstation computer. This easy-to-use data-driven approach opens the door for in situ and on-the-fly label free nanoscale composition mapping of eukaryotic cells with scanning dielectric microscopy.
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Affiliation(s)
- Martí Checa
- Nanoscale Bioelectrical Characterization Group, Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology (BIST), Carrer Baldiri i Reixac 11-15, Barcelona, 08028, Spain
| | - Ruben Millan-Solsona
- Nanoscale Bioelectrical Characterization Group, Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology (BIST), Carrer Baldiri i Reixac 11-15, Barcelona, 08028, Spain
- Departament d'Enginyeria Electrònica i Biomèdica, Universitat de Barcelona, Carrer Martí i Franquès 1, Barcelona, 08028, Spain
| | - Adrianna Glinkowska Mares
- Nanoscopy for Nanomedicine Group, Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology (BIST), Carrer Baldiri i Reixac 11-15, Barcelona, 08028, Spain
| | - Silvia Pujals
- Departament d'Enginyeria Electrònica i Biomèdica, Universitat de Barcelona, Carrer Martí i Franquès 1, Barcelona, 08028, Spain
- Nanoscopy for Nanomedicine Group, Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology (BIST), Carrer Baldiri i Reixac 11-15, Barcelona, 08028, Spain
| | - Gabriel Gomila
- Nanoscale Bioelectrical Characterization Group, Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology (BIST), Carrer Baldiri i Reixac 11-15, Barcelona, 08028, Spain
- Departament d'Enginyeria Electrònica i Biomèdica, Universitat de Barcelona, Carrer Martí i Franquès 1, Barcelona, 08028, Spain
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2
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Efficient long-range conduction in cable bacteria through nickel protein wires. Nat Commun 2021; 12:3996. [PMID: 34183682 PMCID: PMC8238962 DOI: 10.1038/s41467-021-24312-4] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Accepted: 06/09/2021] [Indexed: 02/06/2023] Open
Abstract
Filamentous cable bacteria display long-range electron transport, generating electrical currents over centimeter distances through a highly ordered network of fibers embedded in their cell envelope. The conductivity of these periplasmic wires is exceptionally high for a biological material, but their chemical structure and underlying electron transport mechanism remain unresolved. Here, we combine high-resolution microscopy, spectroscopy, and chemical imaging on individual cable bacterium filaments to demonstrate that the periplasmic wires consist of a conductive protein core surrounded by an insulating protein shell layer. The core proteins contain a sulfur-ligated nickel cofactor, and conductivity decreases when nickel is oxidized or selectively removed. The involvement of nickel as the active metal in biological conduction is remarkable, and suggests a hitherto unknown form of electron transport that enables efficient conduction in centimeter-long protein structures.
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3
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Di Muzio M, Millan-Solsona R, Dols-Perez A, Borrell JH, Fumagalli L, Gomila G. Dielectric properties and lamellarity of single liposomes measured by in-liquid scanning dielectric microscopy. J Nanobiotechnology 2021; 19:167. [PMID: 34082783 PMCID: PMC8176598 DOI: 10.1186/s12951-021-00912-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Accepted: 05/25/2021] [Indexed: 12/31/2022] Open
Abstract
Liposomes are widely used as drug delivery carriers and as cell model systems. Here, we measure the dielectric properties of individual liposomes adsorbed on a metal electrode by in-liquid scanning dielectric microscopy in force detection mode. From the measurements the lamellarity of the liposomes, the separation between the lamellae and the specific capacitance of the lipid bilayer can be obtained. As application we considered the case of non-extruded DOPC liposomes with radii in the range ~ 100-800 nm. Uni-, bi- and tri-lamellar liposomes have been identified, with the largest population corresponding to bi-lamellar liposomes. The interlamellar separation in the bi-lamellar liposomes is found to be below ~ 10 nm in most instances. The specific capacitance of the DOPC lipid bilayer is found to be ~ 0.75 µF/cm2 in excellent agreement with the value determined on solid supported planar lipid bilayers. The lamellarity of the DOPC liposomes shows the usual correlation with the liposome's size. No correlation is found, instead, with the shape of the adsorbed liposomes. The proposed approach offers a powerful label-free and non-invasive method to determine the lamellarity and dielectric properties of single liposomes.
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Affiliation(s)
- Martina Di Muzio
- Institut de Bioenginyeria de Catalunya (IBEC), The Barcelona Institute of Science and Technology (BIST), c/Baldiri i Reixac 11-15, 08028, Barcelona, Spain
| | - Ruben Millan-Solsona
- Institut de Bioenginyeria de Catalunya (IBEC), The Barcelona Institute of Science and Technology (BIST), c/Baldiri i Reixac 11-15, 08028, Barcelona, Spain.,Departament D'Enginyeria Electrònica I Biomèdica, Universitat de Barcelona, C/Martí i Franqués 1, 08028, Barcelona, Spain
| | - Aurora Dols-Perez
- Institut de Bioenginyeria de Catalunya (IBEC), The Barcelona Institute of Science and Technology (BIST), c/Baldiri i Reixac 11-15, 08028, Barcelona, Spain
| | - Jordi H Borrell
- Secció de Fisicoquímica, Facultat de Farmàcia I Ciències de L'Alimentació, Universitat de Barcelona, Av. Diagonal, 643, 08028, Barcelona, Spain
| | - Laura Fumagalli
- Department of Physics and Astronomy, University of Manchester, Manchester, M13 9PL, UK.,National Graphene Institute, University of Manchester, Manchester, M13 9PL, UK
| | - Gabriel Gomila
- Institut de Bioenginyeria de Catalunya (IBEC), The Barcelona Institute of Science and Technology (BIST), c/Baldiri i Reixac 11-15, 08028, Barcelona, Spain. .,Departament D'Enginyeria Electrònica I Biomèdica, Universitat de Barcelona, C/Martí i Franqués 1, 08028, Barcelona, Spain.
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4
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Valeriano WW, Andrade RR, Vasco JP, Malachias A, Neves BRA, Guimarães PSS, Rodrigues WN. Mapping the local dielectric constant of a biological nanostructured system. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2021; 12:139-150. [PMID: 33564609 PMCID: PMC7849231 DOI: 10.3762/bjnano.12.11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Accepted: 01/04/2021] [Indexed: 06/12/2023]
Abstract
The aim of this work is to determine the varying dielectric constant of a biological nanostructured system via electrostatic force microscopy (EFM) and to show how this method is useful to study natural photonic crystals. We mapped the dielectric constant of the cross section of the posterior wing of the damselfly Chalcopteryx rutilans with nanometric resolution. We obtained structural information on its constitutive nanolayers and the absolute values of their dielectric constant. By relating the measured profile of the static dielectric constant to the profile of the refractive index in the visible range, combined with optical reflectance measurements and simulation, we were able to describe the origin of the strongly iridescent wing colors of this Amazonian rainforest damselfly. The method we demonstrate here should be useful for the study of other biological nanostructured systems.
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Affiliation(s)
- Wescley Walison Valeriano
- Departamento de Física, ICEx, Universidade Federal de Minas Gerais, Av. Antônio Carlos 6627, 31270-901 Belo Horizonte, Minas Gerais, Brazil
| | - Rodrigo Ribeiro Andrade
- Centro de Microscopia, Universidade Federal de Minas Gerais, Av. Antônio Carlos 6627, 31270-901 Belo Horizonte, Minas Gerais, Brazil
| | - Juan Pablo Vasco
- Institute of Theoretical Physics, École Polytechnique Fédérale de Lausanne EPFL, CH-1015 Lausanne, Switzerland
| | - Angelo Malachias
- Departamento de Física, ICEx, Universidade Federal de Minas Gerais, Av. Antônio Carlos 6627, 31270-901 Belo Horizonte, Minas Gerais, Brazil
| | - Bernardo Ruegger Almeida Neves
- Departamento de Física, ICEx, Universidade Federal de Minas Gerais, Av. Antônio Carlos 6627, 31270-901 Belo Horizonte, Minas Gerais, Brazil
- Centro de Microscopia, Universidade Federal de Minas Gerais, Av. Antônio Carlos 6627, 31270-901 Belo Horizonte, Minas Gerais, Brazil
| | - Paulo Sergio Soares Guimarães
- Departamento de Física, ICEx, Universidade Federal de Minas Gerais, Av. Antônio Carlos 6627, 31270-901 Belo Horizonte, Minas Gerais, Brazil
| | - Wagner Nunes Rodrigues
- Departamento de Física, ICEx, Universidade Federal de Minas Gerais, Av. Antônio Carlos 6627, 31270-901 Belo Horizonte, Minas Gerais, Brazil
- Centro de Microscopia, Universidade Federal de Minas Gerais, Av. Antônio Carlos 6627, 31270-901 Belo Horizonte, Minas Gerais, Brazil
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Muzio MD, Millan-Solsona R, Borrell JH, Fumagalli L, Gomila G. Cholesterol Effect on the Specific Capacitance of Submicrometric DOPC Bilayer Patches Measured by in-Liquid Scanning Dielectric Microscopy. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:12963-12972. [PMID: 33084346 DOI: 10.1021/acs.langmuir.0c02251] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The specific capacitance of biological membranes is a key physical parameter in bioelectricity that also provides valuable physicochemical information on composition, phase, or hydration properties. Cholesterol is known to modulate the physicochemical properties of biomembranes, but its effect on the specific capacitance has not been fully established yet. Here we use the high spatial resolution capabilities of in-liquid scanning dielectric microscopy in force detection mode to directly demonstrate that DOPC bilayer patches at 50% cholesterol concentration show a strong reduction of their specific capacitance with respect to pure DOPC bilayer patches. The reduction observed (∼35%) cannot be explained by the small increase in bilayer thickness (∼16%). We suggest that the reduction of the specific capacitance might be due to the dehydration of the polar head groups caused by the insertion of cholesterol molecules in the bilayer. The results reported confirm the potential of in-liquid SDM to study the electrical and physicochemical properties of lipid bilayers at very small scales (down to ∼200 nm here), with implications in fields such as biophysics, bioelectricity, biochemistry, and biosensing.
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Affiliation(s)
- Martina Di Muzio
- Nanoscale Bioelectrical Characterization, Institut de Bioenginyeria de Catalunya, The Barcelona Institute of Science and Technology, 08028 Barcelona, Spain
| | - Ruben Millan-Solsona
- Nanoscale Bioelectrical Characterization, Institut de Bioenginyeria de Catalunya, The Barcelona Institute of Science and Technology, 08028 Barcelona, Spain
| | | | | | - Gabriel Gomila
- Nanoscale Bioelectrical Characterization, Institut de Bioenginyeria de Catalunya, The Barcelona Institute of Science and Technology, 08028 Barcelona, Spain
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6
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Millan-Solsona R, Checa M, Fumagalli L, Gomila G. Mapping the capacitance of self-assembled monolayers at metal/electrolyte interfaces at the nanoscale by in-liquid scanning dielectric microscopy. NANOSCALE 2020; 12:20658-20668. [PMID: 33043923 DOI: 10.1039/d0nr05723a] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Organic self-assembled monolayers (SAMs) at metal/electrolyte interfaces have been thoroughly investigated both from fundamental and applied points of view. A relevant figure of merit of metal/SAM/electrolyte interfaces is the specific capacitance, which determines the charge that can be accumulated at the metal electrode. Here, we show that the specific capacitance of non-uniform alkanethiol SAMs at gold/electrolyte interfaces can be quantitatively measured and mapped at the nanoscale by in-liquid scanning dielectric microscopy in force detection mode. We show that sub-100 nm spatial resolution in ultrathin (<1 nm) SAMs can be achieved, largely improving the performance of current sensing characterization techniques. The present results provide access to study the dielectric properties of metal/SAM/electrolyte interfaces at scales that have remained unexplored until now.
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Affiliation(s)
- Ruben Millan-Solsona
- Institut de Bioenginyeria de Catalunya (IBEC), The Barcelona Institute of Science and Technology, c/Baldiri i Reixac 11-15, 08028, Barcelona, Spain. and Departament d'Enginyeria Electrònica i Biomèdica, Universitat de Barcelona, C/Martí i Franquès 1, 08028, Barcelona, Spain
| | - Martí Checa
- Institut de Bioenginyeria de Catalunya (IBEC), The Barcelona Institute of Science and Technology, c/Baldiri i Reixac 11-15, 08028, Barcelona, Spain.
| | - Laura Fumagalli
- Department of Physics and Astronomy, University of Manchester, Manchester M13 9PL, UK and National Graphene Institute, University of Manchester, Manchester M13 9PL, UK
| | - Gabriel Gomila
- Institut de Bioenginyeria de Catalunya (IBEC), The Barcelona Institute of Science and Technology, c/Baldiri i Reixac 11-15, 08028, Barcelona, Spain. and Departament d'Enginyeria Electrònica i Biomèdica, Universitat de Barcelona, C/Martí i Franquès 1, 08028, Barcelona, Spain
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7
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Ren H, Sun WF. Characterizing Dielectric Permittivity of Nanoscale Dielectric Films by Electrostatic Micro-Probe Technology: Finite Element Simulations. SENSORS (BASEL, SWITZERLAND) 2019; 19:E5405. [PMID: 31817944 PMCID: PMC6960583 DOI: 10.3390/s19245405] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Revised: 11/26/2019] [Accepted: 12/06/2019] [Indexed: 11/16/2022]
Abstract
Finite element simulations for detecting the dielectric permittivity of planar nanoscale dielectrics by electrostatic probe are performed to explore the microprobe technology of characterizing nanomaterials. The electrostatic force produced by the polarization of nanoscale dielectrics is analyzed by a capacitance gradient between the probe and nano-sample in an electrostatic detection system, in which sample thickness is varied in the range of 1 nm-10 μm, the width (diameter) encompasses from 100 nm to 10 μm, the tilt angle of probe alters between 0° and 20°, and the relative dielectric constant covers 2-1000 to represent a majority of dielectric materials. For dielectric thin films with infinite lateral dimension, the critical diameter is determined, not only by the geometric shape and tilt angle of detecting probe, but also by the thickness of the tested nanofilm. Meanwhile, for the thickness greater than 100 nm, the critical diameter is almost independent on the probe geometry while being primarily dominated by the thickness and dielectric permittivity of nanomaterials, which approximately complies a variation as exponential functions. For nanofilms with a plane size which can be regarded as infinite, a pertaining analytical formalism is established and verified for the film thickness in an ultrathin limit of 10-100 nm, with the probe axis being perpendicular and tilt to film plane, respectively. The present research suggests a general testing scheme for characterizing flat, nanoscale, dielectric materials on metal substrates by means of electrostatic microscopy, which can realize an accurate quantitative analysis of dielectric permittivity.
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Affiliation(s)
| | - Wei-Feng Sun
- Key Laboratory of Engineering Dielectrics and Its Application, Ministry of Education, School of Electrical and Electronic Engineering, Harbin University of Science and Technology, Harbin 150080, China;
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8
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Checa M, Millan-Solsona R, Blanco N, Torrents E, Fabregas R, Gomila G. Mapping the dielectric constant of a single bacterial cell at the nanoscale with scanning dielectric force volume microscopy. NANOSCALE 2019; 11:20809-20819. [PMID: 31657419 DOI: 10.1039/c9nr07659j] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Mapping the dielectric constant at the nanoscale of samples showing a complex topography, such as non-planar nanocomposite materials or single cells, poses formidable challenges to existing nanoscale dielectric microscopy techniques. Here we overcome these limitations by introducing Scanning Dielectric Force Volume Microscopy. This scanning probe microscopy technique is based on the acquisition of electrostatic force approach curves at every point of a sample and its post-processing and quantification by using a computational model that incorporates the actual measured sample topography. The technique provides quantitative nanoscale images of the local dielectric constant of the sample with unparalleled accuracy, spatial resolution and statistical significance, irrespectively of the complexity of its topography. We illustrate the potential of the technique by presenting a nanoscale dielectric constant map of a single bacterial cell, including its small-scale appendages. The bacterial cell shows three characteristic equivalent dielectric constant values, namely, εr,bac1 = 2.6 ± 0.2, εr,bac2 = 3.6 ± 0.4 and εr,bac3 = 4.9 ± 0.5, which enable identifying different dielectric properties of the cell wall and of the cytoplasmatic region, as well as, the existence of variations in the dielectric constant along the bacterial cell wall itself. Scanning Dielectric Force Volume Microscopy is expected to have an important impact in Materials and Life Sciences where the mapping of the dielectric properties of samples showing complex nanoscale topographies is often needed.
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Affiliation(s)
- Martí Checa
- Nanoscale Bioelectrical Characterization, Institut de Bioenginyeria de Catalunya (IBEC), The Barcelona Institute of Science and Technology, c/Baldiri i Reixac 11-15, 08028, Barcelona, Spain. and Departament d'Enginyeria Electrònica i Biomèdica, Universitat de Barcelona, c/Martí i Franquès 1, 08028, Barcelona, Spain
| | - Ruben Millan-Solsona
- Nanoscale Bioelectrical Characterization, Institut de Bioenginyeria de Catalunya (IBEC), The Barcelona Institute of Science and Technology, c/Baldiri i Reixac 11-15, 08028, Barcelona, Spain. and Departament d'Enginyeria Electrònica i Biomèdica, Universitat de Barcelona, c/Martí i Franquès 1, 08028, Barcelona, Spain
| | - Nuria Blanco
- Bacterial Infections: Antimicrobial Therapies, Institut de Bioenginyeria de Catalunya (IBEC), The Barcelona Institute of Science and Technology, c/Baldiri i Reixac 11-15, 08028, Barcelona
| | - Eduard Torrents
- Bacterial Infections: Antimicrobial Therapies, Institut de Bioenginyeria de Catalunya (IBEC), The Barcelona Institute of Science and Technology, c/Baldiri i Reixac 11-15, 08028, Barcelona
| | - Rene Fabregas
- Departament d'Enginyeria Electrònica i Biomèdica, Universitat de Barcelona, c/Martí i Franquès 1, 08028, Barcelona, Spain
| | - Gabriel Gomila
- Nanoscale Bioelectrical Characterization, Institut de Bioenginyeria de Catalunya (IBEC), The Barcelona Institute of Science and Technology, c/Baldiri i Reixac 11-15, 08028, Barcelona, Spain. and Departament d'Enginyeria Electrònica i Biomèdica, Universitat de Barcelona, c/Martí i Franquès 1, 08028, Barcelona, Spain
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9
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Cheong LZ, Zhao W, Song S, Shen C. Lab on a tip: Applications of functional atomic force microscopy for the study of electrical properties in biology. Acta Biomater 2019; 99:33-52. [PMID: 31425893 DOI: 10.1016/j.actbio.2019.08.023] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 07/17/2019] [Accepted: 08/13/2019] [Indexed: 12/11/2022]
Abstract
Electrical properties, such as charge propagation, dielectrics, surface potentials, conductivity, and piezoelectricity, play crucial roles in biomolecules, biomembranes, cells, tissues, and other biological samples. However, characterizing these electrical properties in delicate biosamples is challenging. Atomic Force Microscopy (AFM), the so called "Lab on a Tip" is a powerful and multifunctional approach to quantitatively study the electrical properties of biological samples at the nanometer level. Herein, the principles, theories, and achievements of various modes of AFM in this area have been reviewed and summarized. STATEMENT OF SIGNIFICANCE: Electrical properties such as dielectric and piezoelectric forces, charge propagation behaviors play important structural and functional roles in biosystems from the single molecule level, to cells and tissues. Atomic force microscopy (AFM) has emerged as an ideal toolkit to study electrical property of biology. Herein, the basic principles of AFM are described. We then discuss the multiple modes of AFM to study the electrical properties of biological samples, including Electrostatic Force Microscopy (EFM), Kelvin Probe Force Microscopy (KPFM), Conductive Atomic Force Microscopy (CAFM), Piezoresponse Force Microscopy (PFM) and Scanning ElectroChemical Microscopy (SECM). Finally, the outlook, prospects, and challenges of the various AFM modes when studying the electrical behaviour of the samples are discussed.
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10
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Zhao W, Cui W, Xu S, Cheong LZ, Wang D, Shen C. Direct study of the electrical properties of PC12 cells and hippocampal neurons by EFM and KPFM. NANOSCALE ADVANCES 2019; 1:537-545. [PMID: 36132273 PMCID: PMC9473159 DOI: 10.1039/c8na00202a] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Accepted: 11/19/2018] [Indexed: 05/30/2023]
Abstract
Electrical related properties play important roles in biological structures and functions. Herein, the capacitance gradient and local contact potential difference (CPD) of cell bodies and processes of PC12 cells (representative cells of the sympathetic nervous system), hippocampal neurons (representative cells of the central nervous system) and spines were investigated by Electrostatic Force Microscopy (EFM) and Kelvin Probe Force Microscopy (KPFM) at high lateral spatial resolution directly. The results demonstrate that the capacitance gradients of cell bodies, processes and spines of PC12 cells and hippocampal neurons are very close (in the range of 19-23 zF nm-1) and fit well with the theoretical calculation results (21.7 zF nm-1). This indicates that the differences of nerve signal activities and functions of the sympathetic and central nervous systems are not related to the electric polarization properties. The CPD of cell bodies and processes of PC12 cells is smaller than that of hippocampal neurons. The CPD of spines is much more negative than that of the cell bodies and processes. These results reveal that the surface potential is closely related to the neural signal transduction functions, and spines play vital roles in neural signal transmission. This work indicates the similarity (capacitance gradient) and differences (surface potential) of the electrical properties between the sympathetic and central nervous systems for the first time. The methods and results of this work are useful in the further study of the electrical properties in cellular activities and physiological processes.
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Affiliation(s)
- Weidong Zhao
- Ningbo Institute of Materials Technology & Engineering, Chinese Academy of Sciences 1219 Zhongguan Road Ningbo Zhejiang China
| | - Wei Cui
- Ningbo Key Laboratory of Behavioral Neuroscience, Provincial Key Laboratory of Pathophysiology, School of Medicine, Ningbo University Ningbo Zhejiang China
| | - Shujun Xu
- Ningbo Key Laboratory of Behavioral Neuroscience, Provincial Key Laboratory of Pathophysiology, School of Medicine, Ningbo University Ningbo Zhejiang China
| | - Ling-Zhi Cheong
- School of Marine Science, Ningbo University Ningbo 315211 China
| | - Deyu Wang
- Ningbo Institute of Materials Technology & Engineering, Chinese Academy of Sciences 1219 Zhongguan Road Ningbo Zhejiang China
| | - Cai Shen
- Ningbo Institute of Materials Technology & Engineering, Chinese Academy of Sciences 1219 Zhongguan Road Ningbo Zhejiang China
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11
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Choi TS, Han JY, Heo CE, Lee SW, Kim HI. Electrostatic and hydrophobic interactions of lipid-associated α-synuclein: The role of a water-limited interfaces in amyloid fibrillation. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1860:1854-1862. [DOI: 10.1016/j.bbamem.2018.02.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Revised: 02/05/2018] [Accepted: 02/05/2018] [Indexed: 12/22/2022]
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12
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Valavade AV, Date KS, Press MR, Kothari DC. Scanning Dielectric Constant Microscopy for imaging single biological cells. Biomed Phys Eng Express 2018. [DOI: 10.1088/2057-1976/aada1c] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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13
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Fumagalli L, Esfandiar A, Fabregas R, Hu S, Ares P, Janardanan A, Yang Q, Radha B, Taniguchi T, Watanabe K, Gomila G, Novoselov KS, Geim AK. Anomalously low dielectric constant of confined water. Science 2018; 360:1339-1342. [PMID: 29930134 DOI: 10.1126/science.aat4191] [Citation(s) in RCA: 434] [Impact Index Per Article: 72.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2018] [Accepted: 05/03/2018] [Indexed: 01/02/2023]
Abstract
The dielectric constant ε of interfacial water has been predicted to be smaller than that of bulk water (ε ≈ 80) because the rotational freedom of water dipoles is expected to decrease near surfaces, yet experimental evidence is lacking. We report local capacitance measurements for water confined between two atomically flat walls separated by various distances down to 1 nanometer. Our experiments reveal the presence of an interfacial layer with vanishingly small polarization such that its out-of-plane ε is only ~2. The electrically dead layer is found to be two to three molecules thick. These results provide much-needed feedback for theories describing water-mediated surface interactions and the behavior of interfacial water, and show a way to investigate the dielectric properties of other fluids and solids under extreme confinement.
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Affiliation(s)
- L Fumagalli
- School of Physics and Astronomy, University of Manchester, Manchester M13 9PL, UK. .,National Graphene Institute, University of Manchester, Manchester M13 9PL, UK
| | - A Esfandiar
- Department of Physics, Sharif University of Technology, P.O. Box 11155-9161, Tehran, Iran
| | - R Fabregas
- Departament d'Electrònica, Universitat de Barcelona, C/ Martí i Franquès 1, 08028 Barcelona, Spain.,Institut de Bioenginyeria de Catalunya, Barcelona Institute of Science and Technology, C/ Baldiri i Reixac 15-21, 08028 Barcelona, Spain
| | - S Hu
- School of Physics and Astronomy, University of Manchester, Manchester M13 9PL, UK.,National Graphene Institute, University of Manchester, Manchester M13 9PL, UK
| | - P Ares
- School of Physics and Astronomy, University of Manchester, Manchester M13 9PL, UK.,National Graphene Institute, University of Manchester, Manchester M13 9PL, UK
| | - A Janardanan
- School of Physics and Astronomy, University of Manchester, Manchester M13 9PL, UK.,National Graphene Institute, University of Manchester, Manchester M13 9PL, UK
| | - Q Yang
- School of Physics and Astronomy, University of Manchester, Manchester M13 9PL, UK.,National Graphene Institute, University of Manchester, Manchester M13 9PL, UK
| | - B Radha
- School of Physics and Astronomy, University of Manchester, Manchester M13 9PL, UK.,National Graphene Institute, University of Manchester, Manchester M13 9PL, UK
| | - T Taniguchi
- National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - K Watanabe
- National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - G Gomila
- Departament d'Electrònica, Universitat de Barcelona, C/ Martí i Franquès 1, 08028 Barcelona, Spain.,Institut de Bioenginyeria de Catalunya, Barcelona Institute of Science and Technology, C/ Baldiri i Reixac 15-21, 08028 Barcelona, Spain
| | - K S Novoselov
- School of Physics and Astronomy, University of Manchester, Manchester M13 9PL, UK.,National Graphene Institute, University of Manchester, Manchester M13 9PL, UK
| | - A K Geim
- School of Physics and Astronomy, University of Manchester, Manchester M13 9PL, UK. .,National Graphene Institute, University of Manchester, Manchester M13 9PL, UK
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14
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Collins L, Kilpatrick JI, Kalinin SV, Rodriguez BJ. Towards nanoscale electrical measurements in liquid by advanced KPFM techniques: a review. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2018; 81:086101. [PMID: 29990308 DOI: 10.1088/1361-6633/aab560] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Fundamental mechanisms of energy storage, corrosion, sensing, and multiple biological functionalities are directly coupled to electrical processes and ionic dynamics at solid-liquid interfaces. In many cases, these processes are spatially inhomogeneous taking place at grain boundaries, step edges, point defects, ion channels, etc and possess complex time and voltage dependent dynamics. This necessitates time-resolved and real-space probing of these phenomena. In this review, we discuss the applications of force-sensitive voltage modulated scanning probe microscopy (SPM) for probing electrical phenomena at solid-liquid interfaces. We first describe the working principles behind electrostatic and Kelvin probe force microscopies (EFM & KPFM) at the gas-solid interface, review the state of the art in advanced KPFM methods and developments to (i) overcome limitations of classical KPFM, (ii) expand the information accessible from KPFM, and (iii) extend KPFM operation to liquid environments. We briefly discuss the theoretical framework of electrical double layer (EDL) forces and dynamics, the implications and breakdown of classical EDL models for highly charged interfaces or under high ion concentrations, and describe recent modifications of the classical EDL theory relevant for understanding nanoscale electrical measurements at the solid-liquid interface. We further review the latest achievements in mapping surface charge, dielectric constants, and electrodynamic and electrochemical processes in liquids. Finally, we outline the key challenges and opportunities that exist in the field of nanoscale electrical measurements in liquid as well as providing a roadmap for the future development of liquid KPFM.
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Affiliation(s)
- Liam Collins
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831, United States of America. Institute for Functional Imaging of Materials, Oak Ridge National Laboratory, Oak Ridge, TN 37831, United States of America
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15
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Hiranaga Y, Chinone N, Cho Y. Nanoscale linear permittivity imaging based on scanning nonlinear dielectric microscopy. NANOTECHNOLOGY 2018; 29:205709. [PMID: 29578111 DOI: 10.1088/1361-6528/aab3c2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
A nanoscale linear permittivity imaging method based on scanning nonlinear dielectric microscopy (SNDM) was developed. The ∂C/∂z-mode SNDM (∂C/∂z-SNDM) technique described herein employs probe-height modulation to suppress disturbances originating from stray capacitance and to improve measurement stability. This method allows local permittivity distributions to be examined with extremely low noise levels (approximately 0.01 aF) by virtue of the highly sensitive probe. A cross-section of a multilayer oxide film was visualized using ∂C/∂z-SNDM as a demonstration, and numerical simulations of the response signals were conducted to gain additional insights. The experimental signal intensities were found to be in a good agreement with the theoretical values, with the exception of the background components, demonstrating that absolute sample permittivity values could be determined. The signal profiles near the boundaries between different dielectrics were calculated using various vibration amplitudes and the boundary transition widths were obtained. The beneficial aspects of higher-harmonic response imaging are discussed herein, taking into account assessments of spatial resolution and quantitation.
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Affiliation(s)
- Yoshiomi Hiranaga
- Research Institute of Electrical Communication, Tohoku University, 2-1-1 Katahira Aoba-ku, Sendai 980-8577, Japan
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16
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Wang Y, Shen Y, Wang X, Shen Z, Li B, Hu J, Zhang Y. Nanoscale mapping of dielectric properties based on surface adhesion force measurements. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2018; 9:900-906. [PMID: 29600151 PMCID: PMC5870145 DOI: 10.3762/bjnano.9.84] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Accepted: 02/16/2018] [Indexed: 06/08/2023]
Abstract
The detection of local dielectric properties is of great importance in a wide variety of scientific studies and applications. Here, we report a novel method for the characterization of local dielectric distributions based on surface adhesion mapping by atomic force microscopy (AFM). The two-dimensional (2D) materials graphene oxide (GO), and partially reduced graphene oxide (RGO), which have similar thicknesses but large differences in their dielectric properties, were studied as model systems. Through direct imaging of the samples with a biased AFM tip in PeakForce Quantitative Nano-Mechanics (PF-QNM) mode, the local dielectric properties of GO and RGO were revealed by mapping their surface adhesion forces. Thus, GO and RGO could be conveniently differentiated. This method provides a simple and general approach for the fast characterization of the local dielectric properties of graphene-based materials and will further facilitate their applications in energy generation and storage devices.
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Affiliation(s)
- Ying Wang
- Key Laboratory of Interfacial Physics and Technology and Laboratory of Physical Biology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
| | - Yue Shen
- Key Laboratory of Salt Lake Resources Chemistry of Qinghai Province, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining, Qinghai 810008, China
| | - Xingya Wang
- Key Laboratory of Interfacial Physics and Technology and Laboratory of Physical Biology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhiwei Shen
- Key Laboratory of Interfacial Physics and Technology and Laboratory of Physical Biology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Bin Li
- Key Laboratory of Interfacial Physics and Technology and Laboratory of Physical Biology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
| | - Jun Hu
- Key Laboratory of Interfacial Physics and Technology and Laboratory of Physical Biology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
| | - Yi Zhang
- Key Laboratory of Interfacial Physics and Technology and Laboratory of Physical Biology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
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17
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Biagi MC, Badino G, Fabregas R, Gramse G, Fumagalli L, Gomila G. Direct mapping of the electric permittivity of heterogeneous non-planar thin films at gigahertz frequencies by scanning microwave microscopy. Phys Chem Chem Phys 2018; 19:3884-3893. [PMID: 28106185 DOI: 10.1039/c6cp08215g] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We obtained maps of electric permittivity at ∼19 GHz frequencies on non-planar thin film heterogeneous samples by means of combined atomic force-scanning microwave microscopy (AFM-SMM). We show that the electric permittivity maps can be obtained directly from the capacitance images acquired in contact mode, after removing the topographic cross-talk effects. This result demonstrates the possibility of identifying the electric permittivity of different materials in a thin film sample irrespectively of their thickness by just direct imaging and processing. We show, in addition, that quantitative maps of the electric permittivity can be obtained with no need for any theoretical calculation or complex quantification procedures when the electric permittivity of one of the materials is known. To achieve these results the use of contact mode imaging is a key factor. For non-contact imaging modes the effects of local sample thickness and of the imaging distance make the interpretation of the capacitance images in terms of the electric permittivity properties of the materials much more complex. The present results represent a substantial contribution to the field of nanoscale microwave dielectric characterization of thin film materials with important implications for the characterization of novel 3D electronic devices and 3D nanomaterials.
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Affiliation(s)
- Maria Chiara Biagi
- Institut de Bioenginyeria de Catalunya (IBEC), c/Baldiri i Reixac 11-15, 08028, Barcelona, Spain.
| | - Giorgio Badino
- Keysight Technologies Austria GmbH, Keysight Lab, Gruberst. 40, 4020-Linz, Austria
| | - Rene Fabregas
- Institut de Bioenginyeria de Catalunya (IBEC), c/Baldiri i Reixac 11-15, 08028, Barcelona, Spain. and Departament d'Enginyeries: Electrònica, Universitat de Barcelona, C/Martí i Franqués 1, 08028, Barcelona, Spain
| | - Georg Gramse
- Johannes Kepler University Linz, Institute for Biophysics, Gruberst. 40, 4020-Linz, Austria
| | - Laura Fumagalli
- School of Physics and Astronomy, University of Manchester, Oxford Road, Manchester, M13 9PL, UK
| | - Gabriel Gomila
- Institut de Bioenginyeria de Catalunya (IBEC), c/Baldiri i Reixac 11-15, 08028, Barcelona, Spain. and Departament d'Enginyeries: Electrònica, Universitat de Barcelona, C/Martí i Franqués 1, 08028, Barcelona, Spain
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18
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Microwave measurement of giant unilamellar vesicles in aqueous solution. Sci Rep 2018; 8:497. [PMID: 29323157 PMCID: PMC5764977 DOI: 10.1038/s41598-017-18806-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Accepted: 12/18/2017] [Indexed: 11/26/2022] Open
Abstract
A microwave technique is demonstrated to measure floating giant unilamellar vesicle (GUV) membranes in a 25 μm wide and 18.8 μm high microfluidic channel. The measurement is conducted at 2.7 and 7.9 GHz, at which a split-ring resonator (SRR) operates at odd modes. A 500 nm wide and 100 μm long SRR split gap is used to scan GUVs that are slightly larger than 25 μm in diameter. The smaller fluidic channel induces flattened GUV membrane sections, which make close contact with the SRR gap surface. The used GUVs are synthesized with POPC (16:0–18:1 PC 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine), SM (16:0 Egg Sphingomyelin) and cholesterol at different molecular compositions. It is shown that SM and POPC bilayers have different dielectric permittivity values, which also change with measurement frequencies. The obtained membrane permittivity values, e.g. 73.64-j6.13 for POPC at 2.7 GHz, are more than 10 times larger than previously reported results. The discrepancy is likely due to the measurement of dielectric polarization parallel with, other than perpendicular to, the membrane surface. POPC and SM-rich GUV surface sections are also clearly identified. Further work is needed to verify the obtained large permittivity values and enable accurate analysis of membrane composition.
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19
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Collins L, Ahmadi M, Wu T, Hu B, Kalinin SV, Jesse S. Breaking the Time Barrier in Kelvin Probe Force Microscopy: Fast Free Force Reconstruction Using the G-Mode Platform. ACS NANO 2017; 11:8717-8729. [PMID: 28780850 DOI: 10.1021/acsnano.7b02114] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Atomic force microscopy (AFM) offers unparalleled insight into structure and material functionality across nanometer length scales. However, the spatial resolution afforded by the AFM tip is counterpoised by slow detection speeds compared to other common microscopy techniques (e.g., optical, scanning electron microscopy, etc.). In this work, we develop an ultrafast AFM imaging approach allowing direct reconstruction of the tip-sample forces with ∼3 order of magnitude higher time resolution than is achievable using standard AFM detection methods. Fast free force recovery (F3R) overcomes the widely viewed temporal bottleneck in AFM, that is, the mechanical bandwidth of the cantilever, enabling time-resolved imaging at sub-bandwidth speeds. We demonstrate quantitative recovery of electrostatic forces with ∼10 μs temporal resolution, free from influences of the cantilever ring-down. We further apply the F3R method to Kelvin probe force microscopy (KPFM) measurements. F3R-KPFM is an open loop imaging approach (i.e., no bias feedback), allowing ultrafast surface potential measurements (e.g., <20 μs) to be performed at regular KPFM scan speeds. F3R-KPFM is demonstrated for exploration of ion migration in organometallic halide perovskite materials and shown to allow spatiotemporal imaging of positively charged ion migration under applied electric field, as well as subsequent formation of accumulated charges at the perovskite/electrode interface. In this work, we demonstrate quantitative F3R-KPFM measurements-however, we fully expect the F3R approach to be valid for all modes of noncontact AFM operation, including noninvasive probing of ultrafast electrical and magnetic dynamics.
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Affiliation(s)
| | - Mahshid Ahmadi
- Joint Institute for Advanced Materials, Department of Materials Science and Engineering, University of Tennessee , Knoxville 37996, United States
| | - Ting Wu
- Joint Institute for Advanced Materials, Department of Materials Science and Engineering, University of Tennessee , Knoxville 37996, United States
| | - Bin Hu
- Joint Institute for Advanced Materials, Department of Materials Science and Engineering, University of Tennessee , Knoxville 37996, United States
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20
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Martínez-Tong DE, Miccio LA, Alegria A. Ionic transport in the amorphous phase of semicrystalline polyethylene oxide thin films. SOFT MATTER 2017; 13:5597-5603. [PMID: 28730197 DOI: 10.1039/c7sm00651a] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We present a detailed study on the ionic transport properties of polyethylene oxide (PEO) thin films prepared under different conditions. Using a state-of-the-art Atomic Force Microscopy (AFM) methodology, we simultaneously acquired the nanostructured topography of these semicrystalline polymer films as well as the corresponding dielectric function; in the latter case by probing the frequency-dependent tip-sample electrical interactions. By means of this AFM protocol, we studied the ionic conductivity in the PEO amorphous phase and its dependence on film preparation conditions. In general, for any preparation method, we found a distribution of conductivities ranging from 10-14 to 10-6 S cm-1. Specifically, PEO thin films crystallized from the melt presented relatively high conductivity values, which decreased in the PEO films prepared from solutions at room temperature depending on solvent polarity. We discuss our results by considering the molecular arrangement of the polymer segments in the complex amorphous phase, which is strongly influenced by the PEO crystallization route.
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21
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Li D, Wang Y, Du H, Xu S, Li Z, Yang Y, Wang C. Nanoscale Electric Characteristics and Oriented Assembly of Halobacterium salinarum Membrane Revealed by Electric Force Microscopy. NANOMATERIALS 2016; 6:nano6110197. [PMID: 28335325 PMCID: PMC5245739 DOI: 10.3390/nano6110197] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Revised: 09/28/2016] [Accepted: 10/08/2016] [Indexed: 11/25/2022]
Abstract
Purple membranes (PM) of the bacteria Halobacterium salinarum are a unique natural membrane where bacteriorhodopsin (BR) can convert photon energy and pump protons. Elucidating the electronic properties of biomembranes is critical for revealing biological mechanisms and developing new devices. We report here the electric properties of PMs studied by using multi-functional electric force microscopy (EFM) at the nanoscale. The topography, surface potential, and dielectric capacity of PMs were imaged and quantitatively measured in parallel. Two orientations of PMs were identified by EFM because of its high resolution in differentiating electrical characteristics. The extracellular (EC) sides were more negative than the cytoplasmic (CP) side by 8 mV. The direction of potential difference may facilitate movement of protons across the membrane and thus play important roles in proton pumping. Unlike the side-dependent surface potentials observed in PM, the EFM capacitive response was independent of the side and was measured to be at a dC/dz value of ~5.25 nF/m. Furthermore, by modification of PM with de novo peptides based on peptide-protein interaction, directional oriented PM assembly on silicon substrate was obtained for technical devices. This work develops a new method for studying membrane nanoelectronics and exploring the bioelectric application at the nanoscale.
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Affiliation(s)
- Denghua Li
- Agricultural Information Institute, Chinese Academy of Agricultural Sciences/Key Laboratory of Agricultural Information Service Technology of Ministry of Agriculture, Beijing 100081, China.
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, China.
| | - Yibing Wang
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, China.
| | - Huiwen Du
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, China.
| | - Shiwei Xu
- Agricultural Information Institute, Chinese Academy of Agricultural Sciences/Key Laboratory of Agricultural Information Service Technology of Ministry of Agriculture, Beijing 100081, China.
| | - Zhemin Li
- Agricultural Information Institute, Chinese Academy of Agricultural Sciences/Key Laboratory of Agricultural Information Service Technology of Ministry of Agriculture, Beijing 100081, China.
| | - Yanlian Yang
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, China.
| | - Chen Wang
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, China.
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22
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Hansen KV, Norrman K, Jacobsen T. High temperature conductance mapping for correlation of electrical properties with micron-sized chemical and microstructural features. Ultramicroscopy 2016; 170:69-76. [PMID: 27552435 DOI: 10.1016/j.ultramic.2016.07.019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2016] [Revised: 07/11/2016] [Accepted: 07/25/2016] [Indexed: 11/28/2022]
Abstract
High temperature AC conductance mapping is a scanning probe technique for resolving local electrical properties in microscopic areas. It is especially suited for detecting poorly conducting phases and for ionically conducting materials such as those used in solid oxide electrochemical cells. Secondary silicate phases formed at the edge of lanthanum strontium manganite microelectrodes are used as an example for correlation of chemical, microstructural and electrical properties with a spatial resolution of 1-2µm to demonstrate the technique. The measurements are performed in situ in a controlled atmosphere high temperature scanning probe microscope at 650°C in air.
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Affiliation(s)
- Karin Vels Hansen
- Department of Energy Conversion and Storage, Technical University of Denmark, Frederiksborgvej 399, DK-4000 Roskilde, Denmark.
| | - Kion Norrman
- Department of Energy Conversion and Storage, Technical University of Denmark, Frederiksborgvej 399, DK-4000 Roskilde, Denmark
| | - Torben Jacobsen
- Department of Chemistry, Technical University of Denmark, Kemitorvet Building 207, DK-2800 Lyngby, Denmark
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23
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Van Der Hofstadt M, Fabregas R, Biagi MC, Fumagalli L, Gomila G. Nanoscale dielectric microscopy of non-planar samples by lift-mode electrostatic force microscopy. NANOTECHNOLOGY 2016; 27:405706. [PMID: 27597315 DOI: 10.1088/0957-4484/27/40/405706] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Lift-mode electrostatic force microscopy (EFM) is one of the most convenient imaging modes to study the local dielectric properties of non-planar samples. Here we present the quantitative analysis of this imaging mode. We introduce a method to quantify and subtract the topographic crosstalk from the lift-mode EFM images, and a 3D numerical approach that allows for extracting the local dielectric constant with nanoscale spatial resolution free from topographic artifacts. We demonstrate this procedure by measuring the dielectric properties of micropatterned SiO2 pillars and of single bacteria cells, thus illustrating the wide applicability of our approach from materials science to biology.
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Affiliation(s)
- M Van Der Hofstadt
- Institut de Bioenginyeria de Catalunya (IBEC), C/Baldiri i Reixac 11-15, E-08028, Barcelona, Spain. Departament d'Enginyeries: Electrònica, Universitat de Barcelona, C/Martí i Franqués 1, E-08028, Barcelona, Spain
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24
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Botaya L, Coromina X, Samitier J, Puig-Vidal M, Otero J. Visualized Multiprobe Electrical Impedance Measurements with STM Tips Using Shear Force Feedback Control. SENSORS (BASEL, SWITZERLAND) 2016; 16:s16060757. [PMID: 27231911 PMCID: PMC4934183 DOI: 10.3390/s16060757] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Revised: 05/17/2016] [Accepted: 05/21/2016] [Indexed: 06/05/2023]
Abstract
Here we devise a multiprobe electrical measurement system based on quartz tuning forks (QTFs) and metallic tips capable of having full 3D control over the position of the probes. The system is based on the use of bent tungsten tips that are placed in mechanical contact (glue-free solution) with a QTF sensor. Shear forces acting in the probe are measured to control the tip-sample distance in the Z direction. Moreover, the tilting of the tip allows the visualization of the experiment under the optical microscope, allowing the coordination of the probes in X and Y directions. Meanwhile, the metallic tips are connected to a current-voltage amplifier circuit to measure the currents and thus the impedance of the studied samples. We discuss here the different aspects that must be addressed when conducting these multiprobe experiments, such as the amplitude of oscillation, shear force distance control, and wire tilting. Different results obtained in the measurement of calibration samples and microparticles are presented. They demonstrate the feasibility of the system to measure the impedance of the samples with a full 3D control on the position of the nanotips.
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Affiliation(s)
- Luis Botaya
- Department of Electronics, Universitat de Barcelona, Barcelona 08028, Spain.
| | - Xavier Coromina
- Department of Electronics, Universitat de Barcelona, Barcelona 08028, Spain.
| | - Josep Samitier
- Department of Electronics, Universitat de Barcelona, Barcelona 08028, Spain.
| | - Manel Puig-Vidal
- Department of Electronics, Universitat de Barcelona, Barcelona 08028, Spain.
| | - Jorge Otero
- Department of Electronics, Universitat de Barcelona, Barcelona 08028, Spain.
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25
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Biagi MC, Fabregas R, Gramse G, Van Der Hofstadt M, Juárez A, Kienberger F, Fumagalli L, Gomila G. Nanoscale Electric Permittivity of Single Bacterial Cells at Gigahertz Frequencies by Scanning Microwave Microscopy. ACS NANO 2016; 10:280-8. [PMID: 26643251 DOI: 10.1021/acsnano.5b04279] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
We quantified the electric permittivity of single bacterial cells at microwave frequencies and nanoscale spatial resolution by means of near-field scanning microwave microscopy. To this end, calibrated complex admittance images have been obtained at ∼19 GHz and analyzed with a methodology that removes the nonlocal topographic cross-talk contributions and thus provides quantifiable intrinsic dielectric images of the bacterial cells. Results for single Escherichia coli cells provide a relative electric permittivity of ∼4 in dry conditions and ∼20 in humid conditions, with no significant loss contributions. Present findings, together with the ability of microwaves to penetrate the cell membrane, open an important avenue in the microwave label-free imaging of single cells with nanoscale spatial resolution.
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Affiliation(s)
- Maria Chiara Biagi
- Institut de Bioenginyeria de Catalunya (IBEC), c/Baldiri i Reixac 11-15, 08028 Barcelona, Spain
| | - Rene Fabregas
- Institut de Bioenginyeria de Catalunya (IBEC), c/Baldiri i Reixac 11-15, 08028 Barcelona, Spain
| | - Georg Gramse
- Institute for Biophysics, Johannes Kepler University Linz , Gruberst. 40, 4020 Linz, Austria
| | - Marc Van Der Hofstadt
- Institut de Bioenginyeria de Catalunya (IBEC), c/Baldiri i Reixac 11-15, 08028 Barcelona, Spain
| | - Antonio Juárez
- Institut de Bioenginyeria de Catalunya (IBEC), c/Baldiri i Reixac 11-15, 08028 Barcelona, Spain
- Departament de Microbiologia, Universitat de Barcelona , Av. Diagonal 643, 08028 Barcelona, Spain
| | - Ferry Kienberger
- Keysight Lab, Keysight Technologies Austria GmbH , Gruberst. 40, 4020 Linz, Austria
| | - Laura Fumagalli
- School of Physics and Astronomy, University of Manchester , Oxford Road, Manchester M13 9PL, United Kingdom
| | - Gabriel Gomila
- Institut de Bioenginyeria de Catalunya (IBEC), c/Baldiri i Reixac 11-15, 08028 Barcelona, Spain
- Departament d'Electrònica, Universitat de Barcelona , C/Martí i Franqués 1, 08028 Barcelona, Spain
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26
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Carminati M, Ferrari G, Vergani M, Sampietro M. The role of micro-scale current sensing in biomedicine: A unifying view and design guidelines. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2016; 2015:3201-4. [PMID: 26736973 DOI: 10.1109/embc.2015.7319073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The electrical activity of cells is regulated by ion fluxes and chemical signaling between them is sustained by redox-reactive molecules. Consequently, current sensing represents a straightforward way to interface electronics with biology and a common detection tool in several applications spanning from patch-clamp and nanopores to micro-scale impedance tracking. Reaching pA resolution at the ms timescale represents a challenge for the readout circuit and here all the criticalities involved in the optimal design of the sensing electrode are reviewed. Advantages vs. drawbacks and risks of the use of silicon as active vs. passive substrate respectively are illustrated by means of experimental examples.
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27
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Dols-Perez A, Gramse G, Calò A, Gomila G, Fumagalli L. Nanoscale electric polarizability of ultrathin biolayers on insulating substrates by electrostatic force microscopy. NANOSCALE 2015; 7:18327-18336. [PMID: 26488226 DOI: 10.1039/c5nr04983k] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We measured and quantified the local electric polarization properties of ultrathin (∼5 nm) biolayers on mm-thick mica substrates. We achieved it by scanning a sharp conductive tip (<10 nm radius) of an electrostatic force microscope over the biolayers and quantifying sub-picoNewton electric polarization forces with a sharp-tip model implemented using finite-element numerical calculations. We obtained relative dielectric constants εr = 3.3, 2.4 and 1.9 for bacteriorhodopsin, dioleoylphosphatidylcholine (DOPC) and cholesterol layers, chosen as representative of the main cell membrane components, with an error below 10% and a spatial resolution down to ∼50 nm. The ability of using insulating substrates common in biophysics research, such as mica or glass, instead of metallic substrates, offers both a general platform to determine the dielectric properties of biolayers and a wider compatibility with other characterization techniques, such as optical microscopy. This opens up new possibilities for biolayer research at the nanoscale, including nanoscale label-free composition mapping.
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Affiliation(s)
- A Dols-Perez
- Institut de Química Avançada de Catalunya (IQAC-CSIC), C/Jordi Girona 18-26, 08034, Barcelona, Spain and CIBER of Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Barcelona, Spain
| | - G Gramse
- Johannes Kepler University Linz, Institute for Biophysics, Gruberst. 40, 4020-Linz, Austria
| | - A Calò
- CIC NanoGUNE Consolider, E-20018 Donostia San Sebastian, Spain
| | - G Gomila
- Nanobioelec group, Institut de Bioenginyeria de Catalunya (IBEC), Baldiri i Reixac 15-21, 08028-Barcelona, Spain and Departament d'Electrònica, Universitat de Barcelona, C/Martí i Franquès 1, 08028 Barcelona, Spain
| | - L Fumagalli
- School of Physics and Astronomy, University of Manchester, Oxford Road, Manchester, M13 9PL, UK.
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Zhang J, Lu W, Li YS, Cai J, Chen L. Dielectric force microscopy: imaging charge carriers in nanomaterials without electrical contacts. Acc Chem Res 2015; 48:1788-96. [PMID: 26061707 DOI: 10.1021/acs.accounts.5b00046] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Nanomaterials are increasingly used in electronic, optoelectronic, bioelectronic, sensing, and energy nanodevices. Characterization of electrical properties at nanometer scales thus becomes not only a pursuit in basic science but also of widespread practical need. The conventional field-effect transistor (FET) approach involves making electrical contacts to individual nanomaterials. This approach faces serious challenges in routine characterization due to the small size and the intrinsic heterogeneity of nanomaterials, as well as the difficulties in forming Ohmic contact with nanomaterials. Since the charge carrier polarization in semiconducting and metallic materials dominates their dielectric response to external fields, detecting dielectric polarization is an alternative approach in probing the carrier properties and electrical conductivity in nanomaterials. This Account reviews the challenges in the electrical conductivity characterization of nanomaterials and demonstrates that dielectric force microscopy (DFM) is a powerful tool to address the challenges. DFM measures the dielectric polarization via its force interaction with charges on the DFM tip and thus eliminates the need to make electrical contacts with nanomaterials. Furthermore, DFM imaging provides nanometer-scaled spatial resolution. Single-walled carbon nanotubes (SWNTs) and ZnO nanowires are used as model systems. The transverse dielectric permittivity of SWNTs is quantitatively measured to be ∼10, and the differences in longitudinal dielectric polarization are exploited to distinguish metallic SWNTs from semiconducting SWNTs. By application of a gate voltage at the DFM tip, the local carrier concentration underneath the tip can be accumulated or depleted, depending on charge carrier type and the density of states near the Fermi level. This effect is exploited to identify the conductivity type and carrier type in nanomaterials. By making comparison between DFM and FET measurements on the exact same SWNTs, it is found that the DFM gate modulation ratio, which is the ratio of DFM signal strengths at different gate voltage, is linearly proportional to the logarithm of FET device on/off ratio. A Drude-level model is established to explain the semilogarithmic correlation between DFM gate modulation ration and FET device on/off ratio and simulate the dependence of DFM force on charge carrier concentration and mobility. Future developments towards DFM imaging of charge carrier concentration or mobility in nanomaterials and nanodevices can thus be expected.
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Affiliation(s)
- Jie Zhang
- i-Lab, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, Jiangsu 215123, China
| | - Wei Lu
- i-Lab, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, Jiangsu 215123, China
| | - Yize Stephanie Li
- i-Lab, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, Jiangsu 215123, China
| | - Jinhua Cai
- i-Lab, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, Jiangsu 215123, China
| | - Liwei Chen
- i-Lab, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, Jiangsu 215123, China
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29
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New tools for elucidating the environmental origins of single molecule photoluminescence intermittency. Chem Phys Lett 2015. [DOI: 10.1016/j.cplett.2015.04.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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30
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Fumagalli L, Edwards MA, Gomila G. Quantitative electrostatic force microscopy with sharp silicon tips. NANOTECHNOLOGY 2014; 25:495701. [PMID: 25407683 DOI: 10.1088/0957-4484/25/49/495701] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Electrostatic force microscopy (EFM) probes are typically coated in either metal (radius ∼ 30 nm) or highly-doped diamond (radius ∼ 100 nm). Highly-doped silicon probes, which offer a sharpened and stable tip apex (radius ∼ 1-10 nm) and are usually used only in standard atomic force microscopy, have been recently shown to allow enhanced lateral resolution in quantitative EFM and its application for dielectric constant measurement. Here we present the theoretical modelling required to quantitatively interpret the electrostatic force between these sharpened tips and samples. In contrast to a sphere-capped cone geometry used to describe metal/diamond-coated tips, modelling a sharpened silicon tip requires a geometry comprised of a cone with two different angles. Theoretical results are supported by experimental measurements of metallic substrates and ∼10 nm radius dielectric nanoparticles. This work is equally applicable to EFM and other electrical scanned probe techniques, where it allows quantifying electrical properties of nanomaterials and 3D nano-objects with higher resolution.
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Affiliation(s)
- L Fumagalli
- Nanobioelec Group, Institut de Bioenginyeria de Catalunya (IBEC), Universitat de Barcelona, C/Martí i Franquès 1, E-08028 Barcelona, Spain. Departament d'Electrònica, Universitat de Barcelona, C/Martí i Franquès 1, E-08028 Barcelona, Spain.
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31
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Miccio LA, Kummali MM, Schwartz GA, Alegría Á, Colmenero J. AFM based dielectric spectroscopy: Extended frequency range through excitation of cantilever higher eigenmodes. Ultramicroscopy 2014; 146:55-61. [DOI: 10.1016/j.ultramic.2014.06.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2013] [Revised: 06/21/2014] [Accepted: 06/23/2014] [Indexed: 11/25/2022]
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32
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Gomila G, Gramse G, Fumagalli L. Finite-size effects and analytical modeling of electrostatic force microscopy applied to dielectric films. NANOTECHNOLOGY 2014; 25:255702. [PMID: 24897410 DOI: 10.1088/0957-4484/25/25/255702] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
A numerical analysis of the polarization force between a sharp conducting probe and a dielectric film of finite lateral dimensions on a metallic substrate is presented with the double objective of (i) determining the conditions under which the film can be approximated by a laterally infinite film and (ii) proposing an analytical model valid in this limit. We show that, for a given dielectric film, the critical diameter above which the film can be modeled as laterally infinite depends not only on the probe geometry, as expected, but mainly on the film thickness. In particular, for films with intermediate to large thicknesses (>100 nm), the critical diameter is nearly independent from the probe geometry and essentially depends on the film thickness and dielectric constant following a relatively simple phenomenological expression. For films that can be considered as laterally infinite, we propose a generalized analytical model valid in the thin-ultrathin limit (<20-50 nm) that reproduces the numerical calculations and the experimental data. Present results provide a general framework under which accurate quantification of electrostatic force microscopy measurements on dielectric films on metallic substrates can be achieved.
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Affiliation(s)
- G Gomila
- Institut de Bioenginyeria de Catalunya (IBEC), C/Balidiri i Reixac 15-21, 08028 Barcelona, Spain. Departament d'Electrònica, Universitat de Barcelona, C/Martí i Franquès 1, 08028 Barcelona, Spain
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33
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Gramse G, Kasper M, Fumagalli L, Gomila G, Hinterdorfer P, Kienberger F. Calibrated complex impedance and permittivity measurements with scanning microwave microscopy. NANOTECHNOLOGY 2014; 25:145703. [PMID: 24633347 DOI: 10.1088/0957-4484/25/14/145703] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We present a procedure for calibrated complex impedance measurements and dielectric quantification with scanning microwave microscopy. The calibration procedure works in situ directly on the substrate with the specimen of interest and does not require any specific calibration sample. In the workflow tip-sample approach curves are used to extract calibrated complex impedance values and to convert measured S11 reflection signals into sample capacitance and resistance images. The dielectric constant of thin dielectric SiO2 films were determined from the capacitance images and approach curves using appropriate electrical tip-sample models and the εr value extracted at f = 19.81 GHz is in good agreement with the nominal value of εr ∼ 4. The capacitive and resistive material properties of a doped Si semiconductor sample were studied at different doping densities and tip-sample bias voltages. Following a simple serial model the capacitance-voltage spectroscopy curves are clearly related to the semiconductor depletion zone while the resistivity is rising with falling dopant density from 20 Ω to 20 kΩ. The proposed procedure of calibrated complex impedance measurements is simple and fast and the accuracy of the results is not affected by varying stray capacitances. It works for nanoscale samples on either fully dielectric or highly conductive substrates at frequencies between 1 and 20 GHz.
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Affiliation(s)
- G Gramse
- Johannes Kepler University of Linz, Institute for Biophysics, Gruberstrasse 40, A-4020 Linz, Austria
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34
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Gomila G, Esteban-Ferrer D, Fumagalli L. Quantification of the dielectric constant of single non-spherical nanoparticles from polarization forces: eccentricity effects. NANOTECHNOLOGY 2013; 24:505713. [PMID: 24284953 DOI: 10.1088/0957-4484/24/50/505713] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
We analyze by means of finite-element numerical calculations the polarization force between a sharp conducting tip and a non-spherical uncharged dielectric nanoparticle with the objective of quantifying its dielectric constant from electrostatic force microscopy (EFM) measurements. We show that for an oblate spheroid nanoparticle of given height the strength of the polarization force acting on the tip depends linearly on the eccentricity, e, of the nanoparticle in the small eccentricity and low dielectric constant regimes (1 < e < 2 and 1 < ε(r) < 10), while for higher eccentricities (e > 2) the dependence is sub-linear and finally becomes independent of e for very large eccentricities (e > 30). These results imply that a precise account of the nanoparticle shape is required to quantify EFM data and obtain the dielectric constants of non-spherical dielectric nanoparticles. Experimental results obtained on polystyrene, silicon dioxide and aluminum oxide nanoparticles and on single viruses are used to illustrate the main findings.
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Affiliation(s)
- G Gomila
- Institut de Bioenginyeria de Catalunya (IBEC) , C/Balidiri i Reixac 15-21, E-08028 Barcelona, Spain. Departament d'Electrònica, Universitat de Barcelona, C/Martí i Franquès 1, E-08028 Barcelona, Spain
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35
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Collins L, Kilpatrick JI, Weber SAL, Tselev A, Vlassiouk IV, Ivanov IN, Jesse S, Kalinin SV, Rodriguez BJ. Open loop Kelvin probe force microscopy with single and multi-frequency excitation. NANOTECHNOLOGY 2013; 24:475702. [PMID: 24176878 DOI: 10.1088/0957-4484/24/47/475702] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Conventional Kelvin probe force microscopy (KPFM) relies on closed loop (CL) bias feedback for the determination of surface potential (SP). However, SP measured by CL-KPFM has been shown to be strongly influenced by the choice of measurement parameters due to non-electrostatic contributions to the input signal of the bias feedback loop. This often leads to systematic errors of several hundred mV and can also result in topographical crosstalk. Here, open loop (OL)-KPFM modes are investigated as a means of obtaining a quantitative, crosstalk free measurement of the SP of graphene grown on Cu foil, and are directly contrasted with CL-KPFM. OL-KPFM operation is demonstrated in both single and multi-frequency excitation regimes, yielding quantitative SP measurements. The SP difference between single and multilayer graphene structures using OL-KPFM was found to be 63 ± 11 mV, consistent with values previously reported by CL-KPFM. Furthermore, the same relative potential difference between Al2O3-coated graphene and Al2O3-coated Cu was observed using both CL and OL techniques. We observed an offset of 55 mV between absolute SP values obtained by OL and CL techniques, which is attributed to the influence of non-electrostatic contributions to the input of the bias feedback used in CL-KPFM.
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Affiliation(s)
- L Collins
- School of Physics, University College Dublin, Belfield, Dublin 4, Ireland. Conway Institute of Biomedical and Biomolecular Research, University College Dublin, Belfield, Dublin 4, Ireland
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36
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Gramse G, Edwards MA, Fumagalli L, Gomila G. Theory of amplitude modulated electrostatic force microscopy for dielectric measurements in liquids at MHz frequencies. NANOTECHNOLOGY 2013; 24:415709. [PMID: 24061045 DOI: 10.1088/0957-4484/24/41/415709] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
A theoretical analysis of amplitude modulated electrostatic force microscopy (AM-EFM) in liquid media at MHz frequencies, based on a simple tip-sample parallel plate model, is presented. The model qualitatively explains the main features of AM-EFM in liquid media and provides a simple explanation of how the measured electric forces are affected by: the frequency of the applied voltage, the tip-sample distance, the ionic concentration, the relative dielectric constant of the solution, and the relative dielectric constant and thickness of the sample. These results provide a simple framework for the design of AM-EFM measurements for localized dielectric characterization in liquid media.
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Affiliation(s)
- G Gramse
- Institut de Bioenginyeria de Catalunya (IBEC), C/Baldiri i Reixac 15-21, E-08028 Barcelona, Spain. Departament d'Electrònica, Universitat de Barcelona, C/Martí i Franquès 1, E-08028 Barcelona, Spain
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37
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Corrales TP, Laroze D, Zardalidis G, Floudas G, Butt HJ, Kappl M. Dynamic Heterogeneity and Phase Separation Kinetics in Miscible Poly(vinyl acetate)/Poly(ethylene oxide) Blends by Local Dielectric Spectroscopy. Macromolecules 2013. [DOI: 10.1021/ma4007158] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
| | - David Laroze
- Max Planck Institute for Polymer Research, D-55128 Mainz, Germany
- Instituto
de Alta Investigación, Universidad de Tarapacá, Casilla 7-D Arica, Chile
| | - George Zardalidis
- Department
of Physics, University of Ioannina, 45110 Ioannina, Greece
| | - George Floudas
- Max Planck Institute for Polymer Research, D-55128 Mainz, Germany
- Department
of Physics, University of Ioannina, 45110 Ioannina, Greece
| | - Hans-Jürgen Butt
- Max Planck Institute for Polymer Research, D-55128 Mainz, Germany
| | - Michael Kappl
- Max Planck Institute for Polymer Research, D-55128 Mainz, Germany
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38
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Signore G, Abbandonato G, Storti B, Stöckl M, Subramaniam V, Bizzarri R. Imaging the static dielectric constant in vitro and in living cells by a bioconjugable GFP chromophore analog. Chem Commun (Camb) 2013; 49:1723-5. [PMID: 23340669 DOI: 10.1039/c3cc38071h] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
A fluorescent probe structurally similar to the GFP chromophore is demonstrated to report the local static dielectric constant. This probe can be chemically functionalized for selective targeting at the intracellular level.
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Affiliation(s)
- Giovanni Signore
- Center for Nanotechnology Innovation @ NEST, Istituto Italiano di Tecnologia, Pisa, Italy
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39
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Hess CM, Riley EA, Palos-Chávez J, Reid PJ. Measuring the spatial distribution of dielectric constants in polymers through quasi-single molecule microscopy. J Phys Chem B 2013; 117:7106-12. [PMID: 23735049 PMCID: PMC4091822 DOI: 10.1021/jp4008398] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The variation in dielectric constant is measured for thin films of poly(methyl methacrylate) (PMMA) and poly(vinylidene fluoride) (PVDF) using confocal fluorescence microscopy. Spatial variation in the local dielectric constant of the polymer films on the ~250 nm length scale is measured using the solvochromatic emission from incorporated nile red (NR) at "quasi-single molecule" (10(-7) M) and true single molecule (SM) concentrations (10(-9) M). Correlation of the NR fluorescence wavelength maximum with dielectric constant is used to transform images of NR's emission maxima to spatial variation in local dielectric constant. We demonstrate that the distributions of dielectric environments measured in the quasi- and true SM approaches are equivalent; however, the enhanced signal rates present in the quasi-SM approach result in this technique being more efficient. In addition, the quasi-SM technique reports directly on the continuous spatial variation in dielectric constant, information that is difficult to obtain in true SM studies. With regards to the polymers of interest, the results presented here demonstrate that a limited distribution of dielectric environments is present in PMMA; however, a broad distribution of environments exists in PVDF consistent with this polymer existing as a distribution of structural phases.
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Affiliation(s)
- Chelsea M. Hess
- Box 351700, Dept. of Chemistry, University of Washington, Seattle, WA 98195
| | - Erin A. Riley
- Box 351700, Dept. of Chemistry, University of Washington, Seattle, WA 98195
| | - Jorge Palos-Chávez
- Box 351700, Dept. of Chemistry, University of Washington, Seattle, WA 98195
| | - Philip J. Reid
- Box 351700, Dept. of Chemistry, University of Washington, Seattle, WA 98195
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40
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Nanoscale measurement of the dielectric constant of supported lipid bilayers in aqueous solutions with electrostatic force microscopy. Biophys J 2013; 104:1257-62. [PMID: 23528085 DOI: 10.1016/j.bpj.2013.02.011] [Citation(s) in RCA: 114] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2012] [Revised: 01/23/2013] [Accepted: 02/11/2013] [Indexed: 12/31/2022] Open
Abstract
We present what is, to our knowledge, the first experimental demonstration of dielectric constant measurement and quantification of supported lipid bilayers in electrolyte solutions with nanoscale spatial resolution. The dielectric constant was quantitatively reconstructed with finite element calculations by combining thickness information and local polarization forces which were measured using an electrostatic force microscope adapted to work in a liquid environment. Measurements of submicrometric dipalmitoylphosphatidylcholine lipid bilayer patches gave dielectric constants of ε(r) ~ 3, which are higher than the values typically reported for the hydrophobic part of lipid membranes (ε(r) ~ 2) and suggest a large contribution of the polar headgroup region to the dielectric response of the lipid bilayer. This work opens apparently new possibilities in the study of biomembrane electrostatics and other bioelectric phenomena.
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41
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Otero J, Baños R, González L, Torrents E, Juárez A, Puig-Vidal M. Quartz tuning fork studies on the surface properties of Pseudomonas aeruginosa during early stages of biofilm formation. Colloids Surf B Biointerfaces 2013; 102:117-23. [DOI: 10.1016/j.colsurfb.2012.08.013] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2012] [Revised: 07/19/2012] [Accepted: 08/07/2012] [Indexed: 11/29/2022]
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Gómez-Navarro C, Guzmán-Vázquez FJ, Gómez-Herrero J, Saenz JJ, Sacha GM. Fast and non-invasive conductivity determination by the dielectric response of reduced graphene oxide: an electrostatic force microscopy study. NANOSCALE 2012; 4:7231-7236. [PMID: 23073187 DOI: 10.1039/c2nr32640j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The high dispersion found in the literature for the conductivity of Reduced Graphene Oxide (RGO) layers makes it highly desirable to develop fast and non-invasive methods for their characterization. Here we show that Electrostatic Force Microscopy (EFM) is an in situ, fast, and contactless technique to evaluate the conductivity of chemically derived graphene layers. The dielectric response of RGO flakes is observed to depend on their conductivity in the range of 0-3 S m(-1). Interestingly, we also find that for electrostatic purposes, a graphene layer is equivalent to an extremely thin dielectric layer with an effective permittivity (ε(eff)) that depends on the conductivity of the layers and spans from 5 for the insulating layers, to 2000 for the more conductive ones. We discuss how these high values of ε(eff) are a consequence of the incomplete screening of electric fields through graphene layers.
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Affiliation(s)
- Cristina Gómez-Navarro
- Departamento de Física de la Materia Condensada and Centro de Investigación en Física de la Materia Condensada (IFIMAC), Universidad Autónoma de Madrid, 28049, Madrid, Spain.
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43
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Fumagalli L, Esteban-Ferrer D, Cuervo A, Carrascosa JL, Gomila G. Label-free identification of single dielectric nanoparticles and viruses with ultraweak polarization forces. NATURE MATERIALS 2012; 11:808-16. [PMID: 22772654 DOI: 10.1038/nmat3369] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2012] [Accepted: 05/28/2012] [Indexed: 05/26/2023]
Abstract
Label-free detection of the material composition of nanoparticles could be enabled by the quantification of the nanoparticles' inherent dielectric response to an applied electric field. However, the sensitivity of dielectric nanoscale objects to geometric and non-local effects makes the dielectric response extremely weak. Here we show that electrostatic force microscopy with sub-piconewton resolution can resolve the dielectric constants of single dielectric nanoparticles without the need for any reference material, as well as distinguish nanoparticles that have an identical surface but different inner composition. We unambiguously identified unlabelled ~10 nm nanoparticles of similar morphology but different low-polarizable materials, and discriminated empty from DNA-containing virus capsids. Our approach should make the in situ characterization of nanoscale dielectrics and biological macromolecules possible.
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Affiliation(s)
- Laura Fumagalli
- Institut de Bioenginyeria de Catalunya, c/ Baldiri i Reixac 15-21, 08028 Barcelona, Spain.
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44
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Gramse G, Gomila G, Fumagalli L. Quantifying the dielectric constant of thick insulators by electrostatic force microscopy: effects of the microscopic parts of the probe. NANOTECHNOLOGY 2012; 23:205703. [PMID: 22543516 DOI: 10.1088/0957-4484/23/20/205703] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We present a systematic analysis of the effects that the microscopic parts of electrostatic force microscopy probes (the cone and cantilever) have on the electrostatic interaction between the tip apex and thick insulating substrates (thickness > 100 μm). We discuss how these effects can influence the measurement and quantification of the local dielectric constant of the substrates. We propose and experimentally validate a general methodology that takes into account the influence of the cone and the cantilever, thus enabling us to obtain very accurate values of the dielectric constants of thick insulators.
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Affiliation(s)
- G Gramse
- Institut de Bioenginyeria de Catalunya, C/ Balidiri i Reixac 15-21, 08028 Barcelona, Spain.
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45
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Wang S, Wang R, Wang X, Zhang D, Qiu X. Nanoscale charge distribution and energy band modification in defect-patterned graphene. NANOSCALE 2012; 4:2651-7. [PMID: 22421987 DOI: 10.1039/c2nr00055e] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Defects were introduced precisely to exfoliated graphene (G) sheets on a SiO(2)/n(+) Si substrate to modulate the local energy band structure and the electron pathway using solution-phase oxidation followed by thermal reduction. The resulting nanoscale charge distribution and band gap modification were investigated by electrostatic force microscopy and spectroscopy. A transition phase with coexisting submicron-sized metallic and insulating regions in the moderately oxidized monolayer graphene were visualized and measured directly. It was determined that the delocalization of electrons/holes in a graphene "island" is confined by the surrounding defective C-O matrix, which acts as an energy barrier for mobile charge carriers. In contrast to the irreversible structural variations caused by the oxidation process, the electrical properties of graphene can be restored by annealing. The defect-patterned graphene and graphene oxide heterojunctions were further characterized by electrical transport measurement.
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Affiliation(s)
- Shengnan Wang
- National Center for Nanoscience and Technology, No.11 Zhong Guan Cun Bei Yi Tiao, Beijing, China
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46
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Otero J, Guerrero H, Gonzalez L, Puig-Vidal M. A feedfordward adaptive controller to reduce the imaging time of large-sized biological samples with a SPM-based multiprobe station. SENSORS (BASEL, SWITZERLAND) 2012; 12:686-703. [PMID: 22368491 PMCID: PMC3279235 DOI: 10.3390/s120100686] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/18/2011] [Revised: 01/05/2012] [Accepted: 01/06/2012] [Indexed: 05/31/2023]
Abstract
The time required to image large samples is an important limiting factor in SPM-based systems. In multiprobe setups, especially when working with biological samples, this drawback can make impossible to conduct certain experiments. In this work, we present a feedfordward controller based on bang-bang and adaptive controls. The controls are based in the difference between the maximum speeds that can be used for imaging depending on the flatness of the sample zone. Topographic images of Escherichia coli bacteria samples were acquired using the implemented controllers. Results show that to go faster in the flat zones, rather than using a constant scanning speed for the whole image, speeds up the imaging process of large samples by up to a 4× factor.
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Affiliation(s)
- Jorge Otero
- SIC-BIO, Bioelectronics and Nanobioengineering Group, Department of Electronics, University of Barcelona, Marti i Franques, 1, 08028, Barcelona, Spain; E-Mails: (H.G.); (L.G.); (M.P.-V.)
| | - Hector Guerrero
- SIC-BIO, Bioelectronics and Nanobioengineering Group, Department of Electronics, University of Barcelona, Marti i Franques, 1, 08028, Barcelona, Spain; E-Mails: (H.G.); (L.G.); (M.P.-V.)
| | - Laura Gonzalez
- SIC-BIO, Bioelectronics and Nanobioengineering Group, Department of Electronics, University of Barcelona, Marti i Franques, 1, 08028, Barcelona, Spain; E-Mails: (H.G.); (L.G.); (M.P.-V.)
| | - Manel Puig-Vidal
- SIC-BIO, Bioelectronics and Nanobioengineering Group, Department of Electronics, University of Barcelona, Marti i Franques, 1, 08028, Barcelona, Spain; E-Mails: (H.G.); (L.G.); (M.P.-V.)
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47
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Dols-Perez A, Fumagalli L, Simonsen AC, Gomila G. Ultrathin spin-coated dioleoylphosphatidylcholine lipid layers in dry conditions: a combined atomic force microscopy and nanomechanical study. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2011; 27:13165-13172. [PMID: 21936555 DOI: 10.1021/la202942j] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Atomic force microscopy (AFM) has been used to study the structural and mechanical properties of low concentrated spin-coated dioleoylphosphatidylcholine (DOPC) layers in dry environment (RH ≈ 0%) at the nanoscale. It is shown that for concentrations in the 0.1-1 mM range the structure of the DOPC spin-coated samples consists of an homogeneous lipid monolayer ∼1.3 nm thick covering the whole substrate on top of which lipid bilayer (or multilayer) micro- and nanometric patches and rims are formed. The thickness of the bilayer structures is found to be ∼4.5 nm (or multiples of this value for multilayer structures), while the lateral dimensions range from micrometers to tens of nanometer depending on the lipid concentration. The force required to break a bilayer (breakthrough force) is found to be ∼0.24 nN. No dependence of the mechanical values on the lateral dimensions of the bilayer structures is evidenced. Remarkably, the thickness and breakthrough force values of the bilayers measured in dry environment are very similar to values reported in the literature for supported DOPC bilayers in pure water.
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Affiliation(s)
- Aurora Dols-Perez
- Nanobioelec group, Institut de Bioenginyeria de Catalunya (IBEC), Baldiri i Reixac 15-21, 08028 Barcelona, Spain.
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48
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Nguyen HK, Prevosto D, Labardi M, Capaccioli S, Lucchesi M, Rolla P. Effect of Confinement on Structural Relaxation in Ultrathin Polymer Films Investigated by Local Dielectric Spectroscopy. Macromolecules 2011. [DOI: 10.1021/ma200440z] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Hung K. Nguyen
- Dipartimento di Fisica “Enrico Fermi”, Università di Pisa, Largo Pontecorvo 3, 56127 Pisa, Italy
| | - Daniele Prevosto
- Consiglio Nazionale delle Ricerche, Istituto per i Processi Chimico-Fisici, CNR-IPCF, c/o Dip. Fisica Largo Pontecorvo 3, 56127 Pisa, Italy
| | - Massimiliano Labardi
- Consiglio Nazionale delle Ricerche, Istituto per i Processi Chimico-Fisici, CNR-IPCF, c/o Dip. Fisica Largo Pontecorvo 3, 56127 Pisa, Italy
| | - Simone Capaccioli
- Dipartimento di Fisica “Enrico Fermi”, Università di Pisa, Largo Pontecorvo 3, 56127 Pisa, Italy
- Consiglio Nazionale delle Ricerche, Istituto per i Processi Chimico-Fisici, CNR-IPCF, c/o Dip. Fisica Largo Pontecorvo 3, 56127 Pisa, Italy
| | - Mauro Lucchesi
- Dipartimento di Fisica “Enrico Fermi”, Università di Pisa, Largo Pontecorvo 3, 56127 Pisa, Italy
- Consiglio Nazionale delle Ricerche, Istituto per i Processi Chimico-Fisici, CNR-IPCF, c/o Dip. Fisica Largo Pontecorvo 3, 56127 Pisa, Italy
| | - Pierangelo Rolla
- Dipartimento di Fisica “Enrico Fermi”, Università di Pisa, Largo Pontecorvo 3, 56127 Pisa, Italy
- Consiglio Nazionale delle Ricerche, Istituto per i Processi Chimico-Fisici, CNR-IPCF, c/o Dip. Fisica Largo Pontecorvo 3, 56127 Pisa, Italy
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49
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Kathan-Galipeau K, Nanayakkara S, O'Brian PA, Nikiforov M, Discher BM, Bonnell DA. Direct probe of molecular polarization in de novo protein-electrode interfaces. ACS NANO 2011; 5:4835-4842. [PMID: 21612231 DOI: 10.1021/nn200887n] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
A novel approach to energy harvesting and biosensing devices would exploit optoelectronic processes found in proteins that occur in nature. However, in order to design such systems, the proteins need to be attached to electrodes and the optoelectronic properties in nonliquid (ambient) environments must be understood at a fundamental level. Here we report the simultaneous detection of electron transport and the effect of optical absorption on dielectric polarizability in oriented peptide single molecular layers. This characterization requires a peptide design strategy to control protein/electrode interface interactions, to allow peptide patterning on a substrate, and to induce optical activity. In addition, a new method to probe electronic, dielectric, and optical properties at the single molecular layer level is demonstrated. The combination enables a quantitative comparison of the change in polarization volume between the ground state and excited state in a single molecular layer in a manner that allows spatial mapping relevant to ultimate device design.
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Affiliation(s)
- Kendra Kathan-Galipeau
- Department of Materials Science and Biophysics, The University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
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50
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Sampietro M, Bottani CE, Carminati M, Casari CS, Castoldi A, Ferrari G, Fusi M, Guazzoni C, Rottigni A, Vergani M. Biosensors and Molecular Imaging. IEEE Pulse 2011; 2:35-40. [DOI: 10.1109/mpul.2011.941521] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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