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Rheinlaender J, Schäffer TE. Measuring the Shape, Stiffness, and Interface Tension of Droplets with the Scanning Ion Conductance Microscope. ACS NANO 2024; 18:16257-16264. [PMID: 38868865 DOI: 10.1021/acsnano.4c02743] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2024]
Abstract
Imaging and probing liquid-liquid interfaces at the micro- and nanoscale are of high relevance, for example, in materials science, surface chemistry, and microfluidics. However, existing imaging techniques are limited in resolution, average over large sample areas, or interact with the sample. Here, we present a method to quantify the shape, stiffness, and interface tension of liquid droplets with the scanning ion conductance microscope (SICM), providing submicrometer resolution and the ability to perform noncontact mechanical measurements. We show that we can accurately image the three-dimensional shape of micrometer-sized liquid droplets made of, for example, decane, hexane, or different oils. We then introduce numerical models to quantitatively obtain their stiffness and interface tension from SICM data. We verified our method by measuring the interface tension of decane droplets changing under the influence of surfactants at different concentrations. Finally, we use SICM to resolve the dissolution dynamics of decane droplets, showing that droplet shape exhibits different dissolution modes and stiffness continuously increases while the interface tension remains constant. We thereby demonstrate that SICM is a useful method to investigate liquid-liquid interfaces on the microscale with applications in materials or life sciences.
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Affiliation(s)
- Johannes Rheinlaender
- Institute of Applied Physics, University of Tübingen, Auf der Morgenstelle 10, Tübingen, Tübingen 72076, Germany
| | - Tilman E Schäffer
- Institute of Applied Physics, University of Tübingen, Auf der Morgenstelle 10, Tübingen, Tübingen 72076, Germany
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2
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Siboni H, Ruseska I, Zimmer A. Atomic Force Microscopy for the Study of Cell Mechanics in Pharmaceutics. Pharmaceutics 2024; 16:733. [PMID: 38931854 PMCID: PMC11207904 DOI: 10.3390/pharmaceutics16060733] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2024] [Revised: 05/15/2024] [Accepted: 05/17/2024] [Indexed: 06/28/2024] Open
Abstract
Cell mechanics is gaining attraction in drug screening, but the applicable methods have not yet become part of the standardized norm. This review presents the current state of the art for atomic force microscopy, which is the most widely available method. The field is first motivated as a new way of tracking pharmaceutical effects, followed by a basic introduction targeted at pharmacists on how to measure cellular stiffness. The review then moves on to the current state of the knowledge in terms of experimental results and supplementary methods such as fluorescence microscopy that can give relevant additional information. Finally, rheological approaches as well as the theoretical interpretations are presented before ending on additional methods and outlooks.
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Affiliation(s)
- Henrik Siboni
- Pharmaceutical Technology & Biopharmacy, Institute of Pharmaceutical Sciences, University of Graz, 8010 Graz, Austria; (H.S.); (I.R.)
- Single Molecule Chemistry, Institute of Chemistry, University of Graz, 8010 Graz, Austria
| | - Ivana Ruseska
- Pharmaceutical Technology & Biopharmacy, Institute of Pharmaceutical Sciences, University of Graz, 8010 Graz, Austria; (H.S.); (I.R.)
| | - Andreas Zimmer
- Pharmaceutical Technology & Biopharmacy, Institute of Pharmaceutical Sciences, University of Graz, 8010 Graz, Austria; (H.S.); (I.R.)
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3
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Brás MM, Sousa A, Cruz TB, Michalewski J, Leite M, Sousa SR, Granja PL, Radmacher M. Microrheological comparison of melanoma cells by atomic force microscopy. J Biol Phys 2024; 50:55-69. [PMID: 38240860 PMCID: PMC10864228 DOI: 10.1007/s10867-023-09648-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2023] [Accepted: 11/21/2023] [Indexed: 02/15/2024] Open
Abstract
Melanoma is one of the most severe cancers due to its great potential to form metastasis. Recent studies showed the importance of mechanical property assessment in metastasis formation which depends on the cytoskeleton dynamics and cell migration. Although cells are considered purely elastic, they are viscoelastic entities. Microrheology atomic force microscopy (AFM) enables the assessment of elasticity and viscous properties, which are relevant to cell behavior regulation. The current work compares the mechanical properties of human neonatal primary melanocytes (HNPMs) with two melanoma cell lines (WM793B and 1205LU cells), using microrheology AFM. Immunocytochemistry of F-actin filaments and phosphorylated focal adhesion kinase (p-FAK) and cell migration assays were performed to understand the differences found in microrheology AFM regarding the tumor cell lines tested. AFM revealed that HNPMs and tumor cell lines had distinct mechanical properties. HNPMs were softer, less viscous, presenting a higher power-law than melanoma cells. Immunostaining showed that metastatic 1205LU cells expressed more p-FAK than WM793B cells. Melanoma cell migration assays showed that WM73B did not close the gap, in contrast to 1205LU cells, which closed the gap at the end of 23 h. These data seem to corroborate the high migratory behavior of 1205LU cells. Microrheology AFM applied to HNPMs and melanoma cells allowed the quantification of elasticity, viscous properties, glassy phase, and power-law properties, which have an impact in cell migration and metastasis formation. AFM study is important since it can be used as a biomarker of the different stages of the disease in melanoma.
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Affiliation(s)
- M Manuela Brás
- Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, Porto, 4200-135, Portugal
- Faculdade de Engenharia da Universidade do Porto (FEUP), Porto, 4200-465, Portugal
| | - Aureliana Sousa
- Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, Porto, 4200-135, Portugal
| | - Tânia B Cruz
- Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, Porto, 4200-135, Portugal
| | - Jonas Michalewski
- Institute of Biophysics, University of Bremen, Bremen, 28334, Germany
| | - Marina Leite
- Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, Porto, 4200-135, Portugal
| | - Susana R Sousa
- Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, Porto, 4200-135, Portugal
- Instituto Superior de Engenharia do Porto (ISEP), Instituto Politécnico do Porto, Porto, 4200-072, Portugal
| | - Pedro L Granja
- Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, Porto, 4200-135, Portugal
| | - Manfred Radmacher
- Institute of Biophysics, University of Bremen, Bremen, 28334, Germany.
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Dubkov S, Overchenko A, Novikov D, Kolmogorov V, Volkova L, Gorelkin P, Erofeev A, Parkhomenko Y. Single-Cell Analysis with Silver-Coated Pipette by Combined SERS and SICM. Cells 2023; 12:2521. [PMID: 37947599 PMCID: PMC10650894 DOI: 10.3390/cells12212521] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 10/13/2023] [Accepted: 10/17/2023] [Indexed: 11/12/2023] Open
Abstract
The study of individual cell processes that occur both on their surface and inside is highly interesting for the development of new medical drugs, cytology and cell technologies. This work presents an original technique for fabricating the silver-coated pipette and its use for the cell analysis by combination with surface-enhanced Raman spectroscopy (SERS) and scanning ion-conducting microscopy (SICM). Unlike the majority of other designs, the pipette opening in our case remains uncovered, which is important for SICM. SERS-active Ag nanoparticles on the pipette surface are formed by vacuum-thermal evaporation followed by annealing. An array of nanoparticles had a diameter on the order of 36 nm and spacing of 12 nm. A two-particle model based on Laplace equations is used to calculate a theoretical enhancement factor (EF). The surface morphology of the samples is investigated by scanning electron microscopy while SICM is used to reveal the surface topography, to evaluate Young's modulus of living cells and to control an injection of the SERS-active pipettes into them. A Raman microscope-spectrometer was used to collect characteristic SERS spectra of cells and cell components. Local Raman spectra were obtained from the cytoplasm and nucleus of the same HEK-293 cancer cell. The EF of the SERS-active pipette was 7 × 105. As a result, we demonstrate utilizing the silver-coated pipette for both the SICM study and the molecular composition analysis of cytoplasm and the nucleus of living cells by SERS. The probe localization in cells is successfully achieved.
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Affiliation(s)
- Sergey Dubkov
- Institute of Advanced Materials and Technologies, National Research University of Electronic Technology, 124498 Moscow, Russia
| | - Aleksei Overchenko
- Research Laboratory of Biophysics, National University of Science and Technology “MISIS” (MISIS), 119049 Moscow, Russia (P.G.); (A.E.)
- Molecular Nanophotonics Group, Peter Debye Institute for Soft Matter Physics, Leipzig University, 04109 Leipzig, Germany
| | - Denis Novikov
- Institute of Advanced Materials and Technologies, National Research University of Electronic Technology, 124498 Moscow, Russia
| | - Vasilii Kolmogorov
- Research Laboratory of Biophysics, National University of Science and Technology “MISIS” (MISIS), 119049 Moscow, Russia (P.G.); (A.E.)
- Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia
| | - Lidiya Volkova
- Institute of Nanotechnology of Microelectronics RAS, 115487 Moscow, Russia
| | - Petr Gorelkin
- Research Laboratory of Biophysics, National University of Science and Technology “MISIS” (MISIS), 119049 Moscow, Russia (P.G.); (A.E.)
| | - Alexander Erofeev
- Research Laboratory of Biophysics, National University of Science and Technology “MISIS” (MISIS), 119049 Moscow, Russia (P.G.); (A.E.)
| | - Yuri Parkhomenko
- Research Laboratory of Biophysics, National University of Science and Technology “MISIS” (MISIS), 119049 Moscow, Russia (P.G.); (A.E.)
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Rajendran AK, Sankar D, Amirthalingam S, Kim HD, Rangasamy J, Hwang NS. Trends in mechanobiology guided tissue engineering and tools to study cell-substrate interactions: a brief review. Biomater Res 2023; 27:55. [PMID: 37264479 DOI: 10.1186/s40824-023-00393-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Accepted: 05/09/2023] [Indexed: 06/03/2023] Open
Abstract
Sensing the mechanical properties of the substrates or the matrix by the cells and the tissues, the subsequent downstream responses at the cellular, nuclear and epigenetic levels and the outcomes are beginning to get unraveled more recently. There have been various instances where researchers have established the underlying connection between the cellular mechanosignalling pathways and cellular physiology, cellular differentiation, and also tissue pathology. It has been now accepted that mechanosignalling, alone or in combination with classical pathways, could play a significant role in fate determination, development, and organization of cells and tissues. Furthermore, as mechanobiology is gaining traction, so do the various techniques to ponder and gain insights into the still unraveled pathways. This review would briefly discuss some of the interesting works wherein it has been shown that specific alteration of the mechanical properties of the substrates would lead to fate determination of stem cells into various differentiated cells such as osteoblasts, adipocytes, tenocytes, cardiomyocytes, and neurons, and how these properties are being utilized for the development of organoids. This review would also cover various techniques that have been developed and employed to explore the effects of mechanosignalling, including imaging of mechanosensing proteins, atomic force microscopy (AFM), quartz crystal microbalance with dissipation measurements (QCMD), traction force microscopy (TFM), microdevice arrays, Spatio-temporal image analysis, optical tweezer force measurements, mechanoscanning ion conductance microscopy (mSICM), acoustofluidic interferometric device (AID) and so forth. This review would provide insights to the researchers who work on exploiting various mechanical properties of substrates to control the cellular and tissue functions for tissue engineering and regenerative applications, and also will shed light on the advancements of various techniques that could be utilized to unravel the unknown in the field of cellular mechanobiology.
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Affiliation(s)
- Arun Kumar Rajendran
- School of Chemical and Biological Engineering, Institute of Chemical Processes, Seoul National University, Seoul, 08826, Republic of Korea
| | - Deepthi Sankar
- Polymeric Biomaterials Lab, School of Nanosciences and Molecular Medicine, Amrita Vishwa Vidyapeetham, Kochi, 682041, India
| | - Sivashanmugam Amirthalingam
- School of Chemical and Biological Engineering, Institute of Chemical Processes, Seoul National University, Seoul, 08826, Republic of Korea
- Institute of Engineering Research, Seoul National University, Seoul, 08826, Republic of Korea
| | - Hwan D Kim
- Department of Polymer Science and Engineering, Korea National University of Transportation, Chungju, 27469, Republic of Korea
- Department of Biomedical Engineering, Korea National University of Transportation, Chungju, 27469, Republic of Korea
| | - Jayakumar Rangasamy
- Polymeric Biomaterials Lab, School of Nanosciences and Molecular Medicine, Amrita Vishwa Vidyapeetham, Kochi, 682041, India.
| | - Nathaniel S Hwang
- School of Chemical and Biological Engineering, Institute of Chemical Processes, Seoul National University, Seoul, 08826, Republic of Korea.
- Institute of Engineering Research, Seoul National University, Seoul, 08826, Republic of Korea.
- Interdisciplinary Program in Bioengineering, Seoul National University, Seoul, 08826, Republic of Korea.
- Bio-MAX/N-Bio Institute, Institute of Bio-Engineering, Seoul National University, Seoul, 08826, Republic of Korea.
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6
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Chen F, He J, Manandhar P, Yang Y, Liu P, Gu N. Gauging surface charge distribution of live cell membrane by ionic current change using scanning ion conductance microscopy. NANOSCALE 2021; 13:19973-19984. [PMID: 34825684 DOI: 10.1039/d1nr05230f] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The distribution of surface charge and potential of cell membrane plays an indispensable role in cellular activities. However, probing surface charge of live cells under physiological conditions, until recently, remains an arduous challenge owing to the lack of effective methods. Scanning ion conductance microscopy (SICM) is an emerging imaging technique for imaging a live cell membrane in its native state. Here, we introduce a simple SICM based imaging technique to effectively map the surface charge contrast distribution of soft substrates including cell membranes by utilizing the higher surface charge sensitivity of the ionic current when the nanopipette tip is close to the substrate with a relatively high current change. This technique was assessed on charged model substrates made of polydimethylsiloxane, and the surface charge sensitivity of ionic current change was supported by finite element method simulations. With this method, we can distinguish the surface charge difference between the cell membrane and the supporting collagen matrix. We also observed the surface charge change induced by the small membrane damage after 1% dimethyl sulfoxide (DMSO) treatment. This new SICM technique provides opportunities to study interfacial and cell membrane processes with high spatial resolution.
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Affiliation(s)
- Feng Chen
- School of Biomedical Engineering and Informatics, Nanjing Medical University, Nanjing 211166, People's Republic of China
- Physics Department, Biomolecular Science Institute, Florida International University, Miami, FL 33199, USA.
| | - Jin He
- Physics Department, Biomolecular Science Institute, Florida International University, Miami, FL 33199, USA.
| | - Prakash Manandhar
- Department of Chemistry and Biochemistry, Florida International University, Miami, FL 33199, USA
| | - Yizi Yang
- School of Biomedical Engineering and Informatics, Nanjing Medical University, Nanjing 211166, People's Republic of China
| | - Peidang Liu
- Jiangsu Key Laboratory for Biomaterials and Devices, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210009, China.
| | - Ning Gu
- School of Biomedical Engineering and Informatics, Nanjing Medical University, Nanjing 211166, People's Republic of China
- Jiangsu Key Laboratory for Biomaterials and Devices, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210009, China.
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7
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Abstract
Scanning ion conductance microscopy (SICM) has emerged as a versatile tool for studies of interfaces in biology and materials science with notable utility in biophysical and electrochemical measurements. The heart of the SICM is a nanometer-scale electrolyte filled glass pipette that serves as a scanning probe. In the initial conception, manipulations of ion currents through the tip of the pipette and appropriate positioning hardware provided a route to recording micro- and nanoscopic mapping of the topography of surfaces. Subsequent advances in instrumentation, probe design, and methods significantly increased opportunities for SICM beyond recording topography. Hybridization of SICM with coincident characterization techniques such as optical microscopy and faradaic electrodes have brought SICM to the forefront as a tool for nanoscale chemical measurement for a wide range of applications. Modern approaches to SICM realize an important tool in analytical, bioanalytical, biophysical, and materials measurements, where significant opportunities remain for further exploration. In this review, we chronicle the development of SICM from the perspective of both the development of instrumentation and methods and the breadth of measurements performed.
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Affiliation(s)
- Cheng Zhu
- Department of Chemistry, Indiana University, 800 E. Kirkwood Avenue, Bloomington, Indiana 47405, United States
| | - Kaixiang Huang
- Department of Chemistry, Indiana University, 800 E. Kirkwood Avenue, Bloomington, Indiana 47405, United States
| | - Natasha P Siepser
- Department of Chemistry, Indiana University, 800 E. Kirkwood Avenue, Bloomington, Indiana 47405, United States
| | - Lane A Baker
- Department of Chemistry, Indiana University, 800 E. Kirkwood Avenue, Bloomington, Indiana 47405, United States
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Kolmogorov VS, Erofeev AS, Woodcock E, Efremov YM, Iakovlev AP, Savin NA, Alova AV, Lavrushkina SV, Kireev II, Prelovskaya AO, Sviderskaya EV, Scaini D, Klyachko NL, Timashev PS, Takahashi Y, Salikhov SV, Parkhomenko YN, Majouga AG, Edwards CRW, Novak P, Korchev YE, Gorelkin PV. Mapping mechanical properties of living cells at nanoscale using intrinsic nanopipette-sample force interactions. NANOSCALE 2021; 13:6558-6568. [PMID: 33885535 DOI: 10.1039/d0nr08349f] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Mechanical properties of living cells determined by cytoskeletal elements play a crucial role in a wide range of biological functions. However, low-stress mapping of mechanical properties with nanoscale resolution but with a minimal effect on the fragile structure of cells remains difficult. Scanning Ion-Conductance Microscopy (SICM) for quantitative nanomechanical mapping (QNM) is based on intrinsic force interactions between nanopipettes and samples and has been previously suggested as a promising alternative to conventional techniques. In this work, we have provided an alternative estimation of intrinsic force and stress and demonstrated the possibility to perform qualitative and quantitative analysis of cell nanomechanical properties of a variety of living cells. Force estimation on decane droplets with well-known elastic properties, similar to living cells, revealed that the forces applied using a nanopipette are much smaller than in the case using atomic force microscopy. We have shown that we can perform nanoscale topography and QNM using a scanning procedure with no detectable effect on live cells, allowing long-term QNM as well as detection of nanomechanical properties under drug-induced alterations of actin filaments and microtubulin.
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Affiliation(s)
- Vasilii S Kolmogorov
- National University of Science and Technology "MISiS", 4 Leninskiy prospekt, Moscow, 119049, Russian Federation.
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Swiatlowska P, Sanchez-Alonso JL, Mansfield C, Scaini D, Korchev Y, Novak P, Gorelik J. Short-term angiotensin II treatment regulates cardiac nanomechanics via microtubule modifications. NANOSCALE 2020; 12:16315-16329. [PMID: 32720664 DOI: 10.1039/d0nr02474k] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Mechanical properties of single myocytes contribute to the whole heart performance, but the measurement of mechanics in living cells at high resolution with minimal force interaction remains challenging. Angiotensin II (AngII) is a peptide hormone that regulates a number of physiological functions, including heart performance. It has also been shown to contribute to cell mechanics by inducing cell stiffening. Using non-contact high-resolution Scanning Ion Conductance Microscopy (SICM), we determine simultaneously cell topography and membrane transverse Young's modulus (YM) by a constant pressure application through a nanopipette. While applying pressure, the vertical position is recorded and a deformation map is generated from which YM can be calculated and corrected for the uneven geometry. High resolution of this method also allows studying specific membrane subdomains, such as Z-grooves and crests. We found that short-term AngII treatment reduces the transversal YM in isolated adult rat cardiomyocytes acting via an AT1 receptor. Blocking either a TGF-β1 receptor or Rho kinase abolishes this effect. Analysis of the cytoskeleton showed that AngII depletes microtubules by decreasing long-lived detyrosinated and acetylated microtubule populations. Interestingly, in the failing cardiomyocytes, which are stiffer than controls, the short-term AngII treatment also reduces the YM, thus normalizing the mechanical state of cells. This suggests that the short-term softening effect of AngII on cardiac cells is opposite to the well-characterized long-term hypertrophic effect. In conclusion, we generate a precise nanoscale indication map of location-specific transverse cortical YM within the cell and this can substantially advance our understanding of cellular mechanics in a physiological environment, for example in isolated cardiac myocytes.
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Affiliation(s)
- Pamela Swiatlowska
- Department of Cardiovascular Sciences, National Heart and Lung Institute, Faculty of Medicine, Imperial College London, London, UK.
| | - Jose L Sanchez-Alonso
- Department of Cardiovascular Sciences, National Heart and Lung Institute, Faculty of Medicine, Imperial College London, London, UK.
| | - Catherine Mansfield
- Department of Cardiovascular Sciences, National Heart and Lung Institute, Faculty of Medicine, Imperial College London, London, UK.
| | - Denis Scaini
- Department of Medicine, Imperial College London, London, UK and International School for Advanced Studies, Trieste, Italy
| | - Yuri Korchev
- Department of Medicine, Imperial College London, London, UK and Nano Life Science Institute (WPI-NanoLSI), Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan
| | - Pavel Novak
- Department of Medicine, Imperial College London, London, UK and National University of Science and Technology, MISiS, Leninskiy prospect 4, Moscow, 119991, Russia
| | - Julia Gorelik
- Department of Cardiovascular Sciences, National Heart and Lung Institute, Faculty of Medicine, Imperial College London, London, UK.
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Jiao Y, Zhuang J, Zheng Q, Liao X. A High Accuracy Ion Conductance Imaging Method Based on the Approach Curve Spectrum. Ultramicroscopy 2020; 215:113025. [PMID: 32485394 DOI: 10.1016/j.ultramic.2020.113025] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Revised: 04/28/2020] [Accepted: 05/16/2020] [Indexed: 01/13/2023]
Abstract
Scanning ion conductance microscopy (SICM), as an emerging non-contact in situ topography measurement tool with nano resolution, has been increasingly used in recent years in biomedicine, electrochemistry and materials science. In the conventional measurement method of SICM, the sample topography is constructed according to the position of the probe at the feedback threshold of the ion current. Nevertheless, for different structures, a constant threshold cannot maintain a constant probe-sample distance. This phenomenon makes the measurement topography inconsistent with the real sample surface. In order to solve this problem and improve the measurement accuracy of SICM, a new ion conductance imaging method based on the approach curve spectrum is proposed in this work. In the new method, the local feature around the measurement point is firstly evaluated according to the change rate of ion current. Secondly, based on the local feature, the corresponding approach curve is searched from the prior approach curve spectrum to accurately evaluate the distance between the probe and the sample. Finally, the sample topography is constructed by the probe position subtracting the probe-sample distance. In this paper, we verify the feasibility of the new imaging method by combining finite element theory and experiments. To examine the measurement accuracy, the standard strip silicon and cylindrical polydimethylsiloxane (PDMS) samples are tested, and the improved imaging method can obtain the topography closer to the real samples and reduce the volumetric measurement error by 5.4%. The implementation of the new imaging method will further promote SICM application in related research fields.
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Affiliation(s)
- Yangbohan Jiao
- Key Laboratory of Education Ministry for Modern Design Rotor-Bearing System, Xi'an Jiaotong University, Xi'an 710049, China; School of Mechanical Engineering, Xi'an Jiaotong University, Xi'an 710049, China
| | - Jian Zhuang
- Key Laboratory of Education Ministry for Modern Design Rotor-Bearing System, Xi'an Jiaotong University, Xi'an 710049, China; School of Mechanical Engineering, Xi'an Jiaotong University, Xi'an 710049, China.
| | - Qiangqiang Zheng
- Key Laboratory of Education Ministry for Modern Design Rotor-Bearing System, Xi'an Jiaotong University, Xi'an 710049, China; School of Mechanical Engineering, Xi'an Jiaotong University, Xi'an 710049, China
| | - Xiaobo Liao
- Key Laboratory of Education Ministry for Modern Design Rotor-Bearing System, Xi'an Jiaotong University, Xi'an 710049, China; School of Mechanical Engineering, Xi'an Jiaotong University, Xi'an 710049, China; School of Manufacturing Science and Engineering, Key Laboratory of Testing Technology for Manufacturing Process, Ministry of Education, Southwest University of Science and Technology, Mianyang 621010, China
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11
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Liang W, Yang X, Wang J, Wang Y, Yang W, Liu L. Determination of Dielectric Properties of Cells using AC Electrokinetic-based Microfluidic Platform: A Review of Recent Advances. MICROMACHINES 2020; 11:E513. [PMID: 32438680 PMCID: PMC7281274 DOI: 10.3390/mi11050513] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 05/16/2020] [Accepted: 05/18/2020] [Indexed: 12/18/2022]
Abstract
Cell dielectric properties, a type of intrinsic property of cells, can be used as electrophysiological biomarkers that offer a label-free way to characterize cell phenotypes and states, purify clinical samples, and identify target cancer cells. Here, we present a review of the determination of cell dielectric properties using alternating current (AC) electrokinetic-based microfluidic mechanisms, including electro-rotation (ROT) and dielectrophoresis (DEP). The review covers theoretically how ROT and DEP work to extract cell dielectric properties. We also dive into the details of differently structured ROT chips, followed by a discussion on the determination of cell dielectric properties and the use of these properties in bio-related applications. Additionally, the review offers a look at the future challenges facing the AC electrokinetic-based microfluidic platform in terms of acquiring cell dielectric parameters. Our conclusion is that this platform will bring biomedical and bioengineering sciences to the next level and ultimately achieve the shift from lab-oriented research to real-world applications.
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Affiliation(s)
- Wenfeng Liang
- School of Mechanical Engineering, Shenyang Jianzhu University, Shenyang 110168, China; (X.Y.); (J.W.)
| | - Xieliu Yang
- School of Mechanical Engineering, Shenyang Jianzhu University, Shenyang 110168, China; (X.Y.); (J.W.)
| | - Junhai Wang
- School of Mechanical Engineering, Shenyang Jianzhu University, Shenyang 110168, China; (X.Y.); (J.W.)
| | - Yuechao Wang
- State Key Laboratory of Robotics, Shenyang Institute of Automation, Chinese Academy of Sciences, Shenyang 110016, China;
| | - Wenguang Yang
- School of Electromechanical and Automotive Engineering, Yantai University, Yantai 264005, China;
| | - Lianqing Liu
- State Key Laboratory of Robotics, Shenyang Institute of Automation, Chinese Academy of Sciences, Shenyang 110016, China;
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