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Winkler R, Brugger-Hatzl M, Seewald LM, Kuhness D, Barth S, Mairhofer T, Kothleitner G, Plank H. Additive Manufacturing of Co 3Fe Nano-Probes for Magnetic Force Microscopy. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:1217. [PMID: 37049311 PMCID: PMC10097098 DOI: 10.3390/nano13071217] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Revised: 03/23/2023] [Accepted: 03/27/2023] [Indexed: 06/19/2023]
Abstract
Magnetic force microscopy (MFM) is a powerful extension of atomic force microscopy (AFM), which mostly uses nano-probes with functional coatings for studying magnetic surface features. Although well established, additional layers inherently increase apex radii, which reduce lateral resolution and also contain the risk of delamination, rendering such nano-probes doubtful or even useless. To overcome these limitations, we now introduce the additive direct-write fabrication of magnetic nano-cones via focused electron beam-induced deposition (FEBID) using an HCo3Fe(CO)12 precursor. The study first identifies a proper 3D design, confines the most relevant process parameters by means of primary electron energy and beam currents, and evaluates post-growth procedures as well. That way, highly crystalline nano-tips with minimal surface contamination and apex radii in the sub-15 nm regime are fabricated and benchmarked against commercial products. The results not only reveal a very high performance during MFM operation but in particular demonstrate virtually loss-free behavior after almost 8 h of continuous operation, thanks to the all-metal character. Even after more than 12 months of storage in ambient conditions, no performance loss is observed, which underlines the high overall performance of the here-introduced FEBID-based Co3Fe MFM nano-probes.
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Affiliation(s)
- Robert Winkler
- Christian Doppler Laboratory—DEFINE, Graz University of Technology, 8010 Graz, Austria
| | | | | | - David Kuhness
- Christian Doppler Laboratory—DEFINE, Graz University of Technology, 8010 Graz, Austria
| | - Sven Barth
- Institute of Physics, Goethe University, 60438 Frankfurt, Germany
- Institute for Inorganic and Analytical Chemistry, Goethe University Frankfurt, Max-von-Laue-Str. 7, 60438 Frankfurt, Germany
| | - Thomas Mairhofer
- Institute of Electron Microscopy, Graz University of Technology, 8010 Graz, Austria
| | - Gerald Kothleitner
- Graz Centre for Electron Microscopy, 8010 Graz, Austria
- Institute of Electron Microscopy, Graz University of Technology, 8010 Graz, Austria
| | - Harald Plank
- Christian Doppler Laboratory—DEFINE, Graz University of Technology, 8010 Graz, Austria
- Graz Centre for Electron Microscopy, 8010 Graz, Austria
- Institute of Electron Microscopy, Graz University of Technology, 8010 Graz, Austria
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2
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Lu N, Xiao S, Zhang R, Liu J, Ma L, Wu S. Thin head atomic force microscope for integration with optical microscope. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2022; 93:083702. [PMID: 36050041 DOI: 10.1063/5.0093080] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Accepted: 07/04/2022] [Indexed: 06/15/2023]
Abstract
We present a novel thin head atomic force microscope (AFM) that can be easily integrated with an upright optical microscope (OM). The optical beam detection unit in the AFM used an obliquely incident laser beam onto the cantilever, reducing the AFM head's effective thickness to 7.3 mm. That allows an open space above the cantilever probe to accommodate the objective lens up to 0.6 numerical aperture (N.A.) without obstruction. A multi-function digital controller was developed to control the AFM and reserved interfaces to communicate with the OM. To assess the performance of the developed AFM, we first measured the noise level and bandwidths of the AFM system. Then, the imaging quality of the AFM was evaluated by both calibration grids and two-dimensional materials. Finally, the thin head AFM was integrated into a homemade white light interferometer as a demonstration of combined use with an advanced optical system. The experimental results demonstrated that our developed AFM is suitable for integration under upright OM and brings AFM high-resolution advantages to the existing OM system.
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Affiliation(s)
- Nianhang Lu
- State Key Laboratory of Precision Measurement Technology and Instruments, Tianjin University, Tianjin 300072, China
| | - Shasha Xiao
- State Key Laboratory of Precision Measurement Technology and Instruments, Tianjin University, Tianjin 300072, China
| | - Rui Zhang
- State Key Laboratory of Precision Measurement Technology and Instruments, Tianjin University, Tianjin 300072, China
| | - Jirui Liu
- State Key Laboratory of Precision Measurement Technology and Instruments, Tianjin University, Tianjin 300072, China
| | - Long Ma
- Sino-European Institute of Aviation Engineering, Civil Aviation University of China, Tianjin 300300, China
| | - Sen Wu
- State Key Laboratory of Precision Measurement Technology and Instruments, Tianjin University, Tianjin 300072, China
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Andany SH, Hlawacek G, Hummel S, Brillard C, Kangül M, Fantner GE. An atomic force microscope integrated with a helium ion microscope for correlative nanoscale characterization. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2020; 11:1272-1279. [PMID: 32953371 PMCID: PMC7476598 DOI: 10.3762/bjnano.11.111] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Accepted: 07/30/2020] [Indexed: 05/26/2023]
Abstract
In this work, we report on the integration of an atomic force microscope (AFM) into a helium ion microscope (HIM). The HIM is a powerful instrument, capable of imaging and machining of nanoscale structures with sub-nanometer resolution, while the AFM is a well-established versatile tool for multiparametric nanoscale characterization. Combining the two techniques opens the way for unprecedented in situ correlative analysis at the nanoscale. Nanomachining and analysis can be performed without contamination of the sample and environmental changes between processing steps. The practicality of the resulting tool lies in the complementarity of the two techniques. The AFM offers not only true 3D topography maps, something the HIM can only provide in an indirect way, but also allows for nanomechanical property mapping, as well as for electrical and magnetic characterization of the sample after focused ion beam materials modification with the HIM. The experimental setup is described and evaluated through a series of correlative experiments, demonstrating the feasibility of the integration.
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Affiliation(s)
- Santiago H Andany
- Laboratory for Bio- and Nano-Instrumentation, Swiss Federal Institute of Technology Lausanne (EPFL), Lausanne CH-1015, Switzerland
| | - Gregor Hlawacek
- Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf, Dresden 01328, Germany
| | | | - Charlène Brillard
- Laboratory for Bio- and Nano-Instrumentation, Swiss Federal Institute of Technology Lausanne (EPFL), Lausanne CH-1015, Switzerland
| | - Mustafa Kangül
- Laboratory for Bio- and Nano-Instrumentation, Swiss Federal Institute of Technology Lausanne (EPFL), Lausanne CH-1015, Switzerland
| | - Georg E Fantner
- Laboratory for Bio- and Nano-Instrumentation, Swiss Federal Institute of Technology Lausanne (EPFL), Lausanne CH-1015, Switzerland
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4
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Atomic Force Microscopy Imaging in Turbid Liquids: A Promising Tool in Nanomedicine. SENSORS 2020; 20:s20133715. [PMID: 32630829 PMCID: PMC7374447 DOI: 10.3390/s20133715] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Revised: 06/25/2020] [Accepted: 06/29/2020] [Indexed: 01/18/2023]
Abstract
Tracking of biological and physiological processes on the nanoscale is a central part of the growing field of nanomedicine. Although atomic force microscopy (AFM) is one of the most appropriate techniques in this area, investigations in non-transparent fluids such as human blood are not possible with conventional AFMs due to limitations caused by the optical readout. Here, we show a promising approach based on self-sensing cantilevers (SSC) as a replacement for optical readout in biological AFM imaging. Piezo-resistors, in the form of a Wheatstone bridge, are embedded into the cantilever, whereas two of them are placed at the bending edge. This enables the deflection of the cantilever to be precisely recorded by measuring the changes in resistance. Furthermore, the conventional acoustic or magnetic vibration excitation in intermittent contact mode can be replaced by a thermal excitation using a heating loop. We show further developments of existing approaches enabling stable measurements in turbid liquids. Different readout and excitation methods are compared under various environmental conditions, ranging from dry state to human blood. To demonstrate the applicability of our laser-free bio-AFM for nanomedical research, we have selected the hemostatic process of blood coagulation as well as ultra-flat red blood cells in different turbid fluids. Furthermore, the effects on noise and scanning speed of different media are compared. The technical realization is shown (1) on a conventional optical beam deflection (OBD)-based AFM, where we replaced the optical part by a new SSC nose cone, and (2) on an all-electric AFM, which we adapted for measurements in turbid liquids.
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5
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Kreith J, Strunz T, Fantner EJ, Fantner GE, Cordill MJ. A versatile atomic force microscope integrated with a scanning electron microscope. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2017; 88:053704. [PMID: 28571420 DOI: 10.1063/1.4983317] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
A versatile atomic force microscope (AFM), which can be installed in a scanning electron microscope (SEM), is introduced. The flexible design of the instrument enables correlated analysis for different experimental configurations, such as AFM imaging directly after nanoindentation in vacuum. In order to demonstrate the capabilities of the specially designed AFM installed inside a SEM, slip steps emanating around nanoindents in single crystalline brass were examined. This example showcases how the combination of AFM and SEM imaging can be utilized for quantitative dislocation analysis through the measurement of the slip step heights without the hindrance of oxide formation. Finally, an in situ nanoindentation technique is introduced, illustrating the use of AFM imaging during indentation experiments to examine plastic deformation occurring under the indenter tip. The mechanical indentation data are correlated to the SEM and AFM images to estimate the number of dislocations emitted to the surface.
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Affiliation(s)
- J Kreith
- Department of Material Physics, Montanuniversität Leoben, Jahnstrasse 12, 8700 Leoben, Austria
| | - T Strunz
- GETec Microscopy GmbH, Vienna, Austria
| | | | - G E Fantner
- Laboratoray for Bio- and Nano-Instrumentation, EPFL, Lausanne, Switzerland
| | - M J Cordill
- Erich Schmid Institute of Materials Science, Austrian Academy of Sciences, Jahnstrasse 12, Leoben 8700, Austria
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Dukic M, Adams JD, Fantner GE. Piezoresistive AFM cantilevers surpassing standard optical beam deflection in low noise topography imaging. Sci Rep 2015; 5:16393. [PMID: 26574164 PMCID: PMC4647226 DOI: 10.1038/srep16393] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Accepted: 09/25/2015] [Indexed: 11/08/2022] Open
Abstract
Optical beam deflection (OBD) is the most prevalent method for measuring cantilever deflections in atomic force microscopy (AFM), mainly due to its excellent noise performance. In contrast, piezoresistive strain-sensing techniques provide benefits over OBD in readout size and the ability to image in light-sensitive or opaque environments, but traditionally have worse noise performance. Miniaturisation of cantilevers, however, brings much greater benefit to the noise performance of piezoresistive sensing than to OBD. In this paper, we show both theoretically and experimentally that by using small-sized piezoresistive cantilevers, the AFM imaging noise equal or lower than the OBD readout noise is feasible, at standard scanning speeds and power dissipation. We demonstrate that with both readouts we achieve a system noise of ≈0.3 Å at 20 kHz measurement bandwidth. Finally, we show that small-sized piezoresistive cantilevers are well suited for piezoresistive nanoscale imaging of biological and solid state samples in air.
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Affiliation(s)
- Maja Dukic
- Laboratory for Bio- and Nano-Instrumentation, École Polytechnique Fédérale de Lausanne, Batiment BM 3109 Station 17, 1015 Lausanne, Switzerland
| | - Jonathan D. Adams
- Laboratory for Bio- and Nano-Instrumentation, École Polytechnique Fédérale de Lausanne, Batiment BM 3109 Station 17, 1015 Lausanne, Switzerland
| | - Georg E. Fantner
- Laboratory for Bio- and Nano-Instrumentation, École Polytechnique Fédérale de Lausanne, Batiment BM 3109 Station 17, 1015 Lausanne, Switzerland
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7
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Meier T, Förste A, Tavassolizadeh A, Rott K, Meyners D, Gröger R, Reiss G, Quandt E, Schimmel T, Hölscher H. A scanning probe microscope for magnetoresistive cantilevers utilizing a nested scanner design for large-area scans. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2015; 6:451-461. [PMID: 25821686 PMCID: PMC4362309 DOI: 10.3762/bjnano.6.46] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Accepted: 01/06/2015] [Indexed: 06/04/2023]
Abstract
We describe an atomic force microscope (AFM) for the characterization of self-sensing tunneling magnetoresistive (TMR) cantilevers. Furthermore, we achieve a large scan-range with a nested scanner design of two independent piezo scanners: a small high resolution scanner with a scan range of 5 × 5 × 5 μm(3) is mounted on a large-area scanner with a scan range of 800 × 800 × 35 μm(3). In order to characterize TMR sensors on AFM cantilevers as deflection sensors, the AFM is equipped with a laser beam deflection setup to measure the deflection of the cantilevers independently. The instrument is based on a commercial AFM controller and capable to perform large-area scanning directly without stitching of images. Images obtained on different samples such as calibration standard, optical grating, EPROM chip, self-assembled monolayers and atomic step-edges of gold demonstrate the high stability of the nested scanner design and the performance of self-sensing TMR cantilevers.
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Affiliation(s)
- Tobias Meier
- Institute of Microstructure Technology, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - Alexander Förste
- Institute of Nanotechnology, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - Ali Tavassolizadeh
- Institute for Materials Science, Christian-Albrechts-Universität zu Kiel, Kaiserstraße 2, 24143 Kiel, Germany
| | - Karsten Rott
- Department of Physics, Bielefeld University, Universitässtraße 25, 33615 Bielefeld, Germany
| | - Dirk Meyners
- Institute for Materials Science, Christian-Albrechts-Universität zu Kiel, Kaiserstraße 2, 24143 Kiel, Germany
| | - Roland Gröger
- Institute of Nanotechnology, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - Günter Reiss
- Department of Physics, Bielefeld University, Universitässtraße 25, 33615 Bielefeld, Germany
| | - Eckhard Quandt
- Institute for Materials Science, Christian-Albrechts-Universität zu Kiel, Kaiserstraße 2, 24143 Kiel, Germany
| | - Thomas Schimmel
- Institute of Nanotechnology, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
- Institute of Applied Physics, Karlsruhe Institute of Technology (KIT), Wolfgang-Gaede-Straße 1, 76131 Karlsruhe, Germany
| | - Hendrik Hölscher
- Institute of Microstructure Technology, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
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8
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Ruppert MG, Moheimani SOR. A novel self-sensing technique for tapping-mode atomic force microscopy. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2013; 84:125006. [PMID: 24387461 DOI: 10.1063/1.4841855] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
This work proposes a novel self-sensing tapping-mode atomic force microscopy operation utilizing charge measurement. A microcantilever coated with a single piezoelectric layer is simultaneously used for actuation and deflection sensing. The cantilever can be batch fabricated with existing micro electro mechanical system processes. The setup enables the omission of the optical beam deflection technique which is commonly used to measure the cantilever oscillation amplitude. Due to the high amount of capacitive feedthrough in the measured charge signal, a feedforward control technique is employed to increase the dynamic range from less than 1 dB to approximately 35 dB. Experiments show that the conditioned charge signal achieves excellent signal-to-noise ratio and can therefore be used as a feedback signal for atomic force microscopy imaging.
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Affiliation(s)
- Michael G Ruppert
- The University of Newcastle, University Drive, Callaghan NSW 2308, Australia
| | - S O Reza Moheimani
- The University of Newcastle, University Drive, Callaghan NSW 2308, Australia
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9
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Lee AK, Lewis DM, Ashman PJ. Force and energy requirement for microalgal cell disruption: an atomic force microscope evaluation. BIORESOURCE TECHNOLOGY 2013. [PMID: 23196239 DOI: 10.1016/j.biortech.2012.10.032] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Cell disruption is an essential step in the release of cellular contents but mechanical cell disruption processes are highly energy intensive. This energy requirement may become a critical issue for the sustainability of low valued commodities such as microalgal biofuels derived from extracted lipids. By the use of an atomic force microscope (AFM), this study evaluated the force and energy required to indent and disrupt individual cells of the marine microalga, Tetraselmis suecica. It was found that the force and energy required for the indentation and disruption varies according to the location of the cell with the average being 17.43 pJ. This amount is the equivalent of 673 J kg(-1) of the dry microalgal biomass. In comparison, the most energy efficient mechanical cell disruption process, hydrodynamic cavitation, has specific energy requirement that is approx. 5 orders of magnitude greater than that measured by AFM. The result clearly shows that existing mechanical cell disruption processes are highly energy inefficient and further research and innovation is required for sustainable microalgal biofuels production.
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Affiliation(s)
- Andrew K Lee
- Microalgal Engineering and Research Group, Centre for Energy Technology, School of Chemical Engineering, University of Adelaide, SA, Australia.
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Doll JC, Peng AW, Ricci AJ, Pruitt BL. Faster than the speed of hearing: nanomechanical force probes enable the electromechanical observation of cochlear hair cells. NANO LETTERS 2012; 12:6107-11. [PMID: 23181721 PMCID: PMC3549426 DOI: 10.1021/nl3036349] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Understanding the mechanisms responsible for our sense of hearing requires new tools for unprecedented stimulation and monitoring of sensory cell mechanotransduction at frequencies yet to be explored. We describe nanomechanical force probes designed to evoke mechanotransduction currents at up to 100 kHz in living cells. High-speed force and displacement metrology is enabled by integrating piezoresistive sensors and piezoelectric actuators onto nanoscale cantilevers. The design, fabrication process, actuator performance, and actuator-sensor crosstalk compensation results are presented. We demonstrate the measurement of mammalian cochlear hair cell mechanotransduction with simultaneous patch clamp recordings at unprecedented speeds. The probes can deliver mechanical stimuli with sub-10 μs rise times in water and are compatible with standard upright and inverted microscopes.
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Doll JC, Pruitt BL. High bandwidth piezoresistive force probes with integrated thermal actuation. JOURNAL OF MICROMECHANICS AND MICROENGINEERING : STRUCTURES, DEVICES, AND SYSTEMS 2012; 22:095012. [PMID: 23175616 PMCID: PMC3500968 DOI: 10.1088/0960-1317/22/9/095012] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
We present high-speed force probes with on-chip actuation and sensing for the measurement of pN-scale forces at the microsecond time scale. We achieve a high resonant frequency in water (1-100 kHz) with requisite low spring constants (0.3-40 pN/nm) and low integrated force noise (1-100 pN) by targeting probe dimensions on the order of 300 nm thick, 1-2 μm wide and 30-200 μm long. Forces are measured using silicon piezoresistors while the probes are actuated thermally with an aluminum unimorph and silicon heater. The piezoresistive sensors are designed using open source numerical optimization code that incorporates constraints on operating temperature. Parylene passivation enables operation in ionic media and we demonstrate simultaneous actuation and sensing. The improved design and fabrication techniques that we describe enable a 10-20 fold improvement in force resolution or measurement bandwidth over prior piezoresistive cantilevers of comparable thickness.
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Affiliation(s)
- Joseph C Doll
- Department of Mechanical Engineering, Stanford University, Stanford, CA
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12
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Wright CJ, Shah MK, Powell LC, Armstrong I. Application of AFM from microbial cell to biofilm. SCANNING 2010; 32:134-49. [PMID: 20648545 DOI: 10.1002/sca.20193] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Atomic Force Microscopy (AFM) has proven itself over recent years as an essential tool for the analysis of microbial systems. This article will review how AFM has been used to study microbial systems to provide unique insight into their behavior and relationship with their environment. Immobilization of live cells has enabled AFM imaging and force measurement to provide understanding of the structure and function of numerous microbial cells. At the macromolecular level AFM investigation into the properties of surface macromolecules and the energies associated with their mechanical conformation and functionality has helped unravel the complex interactions of microbial cells. At the level of the whole cell AFM has provided an integrated analysis of how the microbial cell exploits its environment through its selective, adaptable interface, the cell surface. In addition to these areas of study the AFM investigation of microbial biofilms has been vital for industrial and medical process analysis. There exists a tremendous potential for the future application of AFM to microbial systems and this has been strengthened by the trend to use AFM in combination with other characterization methods, such as confocal microscopy and Raman spectroscopy, to elucidate dynamic cellular processes.
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Affiliation(s)
- Chris J Wright
- Multidisciplinary Nanotechnology Centre, School of Engineering, Swansea University, Swansea, United Kingdom.
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13
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Shin C, Jeon I, Khim ZG, Hong JW, Nam H. Study of sensitivity and noise in the piezoelectric self-sensing and self-actuating cantilever with an integrated Wheatstone bridge circuit. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2010; 81:035109. [PMID: 20370215 DOI: 10.1063/1.3327822] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
A detection method using a self-sensing cantilever is more desirable than other detection methods (optical fiber and laser beam bounce detection) that are bulky and require alignment. The advantage of the self-sensing cantilever is its simplicity, particularly its simple structure. It can be used for the construction of an atomic force microscopy system with a vacuum, fluids, and a low temperature chamber. Additionally, the self-actuating cantilever can be used for a high speed scanning system because the bandwidth is larger than the bulk scanner. Frequently, ZnO film has been used as an actuator in a self-actuating cantilever. In this paper, we studied the characteristics of the self-sensing and self-actuating cantilever with an integrated Wheatstone bridge circuit substituting the ZnO film with a lead zirconate titanate (PZT) film as the actuator. We can reduce the leakage current (to less than 10(-4) A/cm(2)) in the PZT cantilever and improve sensor sensitivity through a reduction of noise level from the external sensor circuit using the Wheatstone bridge circuit embedded into the cantilever. The self-sensing and actuating cantilever with an integrated Wheatstone bridge circuit was compared with a commercial self-sensing cantilever or self-sensing and actuating cantilever without an integrated Wheatstone bridge circuit. The measurement results have shown that sensing the signal to noise level and the minimum detectable deflection improved to 4.78 mV and 1.18 nm, respectively. We believe that this cantilever allows for easier system integration and miniaturization, provides better controllability and higher scan speeds, and offers the potential for full automation.
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Affiliation(s)
- ChaeHo Shin
- Interdisciplinary Program of Nano-Science and Technology, Seoul National University, Seoul 151-742, Korea
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