1
|
Kardashina T, Serrano EE, Dawson JA, Drach B. Mechanical characterization of Xenopus laevis oocytes using atomic force microscopy. J Mech Behav Biomed Mater 2024; 157:106648. [PMID: 38996625 DOI: 10.1016/j.jmbbm.2024.106648] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Revised: 06/25/2024] [Accepted: 06/30/2024] [Indexed: 07/14/2024]
Abstract
Mechanical properties are essential for the biological activities of cells, and they have been shown to be affected by diseases. Therefore, accurate mechanical characterization is important for studying the cell lifecycle, cell-cell interactions, and disease diagnosis. While the cytoskeleton and actin cortex are typically the primary structural stiffness contributors in most live cells, oocytes possess an additional extracellular layer known as the vitelline membrane (VM), or envelope, which can significantly impact their overall mechanical properties. In this study, we utilized nanoindentation via an atomic force microscope to measure the Young's modulus of Xenopus laevis oocytes at different force setpoints and explored the influence of the VM by conducting measurements on oocytes with the membrane removed. The findings revealed that the removal of VM led to a significant decrease in the apparent Young's modulus of the oocytes, highlighting the pivotal role of the VM as the main structural component responsible for the oocyte's shape and stiffness. Furthermore, the mechanical behavior of VM was investigated through finite element (FE) simulations of the nanoindentation process. FE simulations with the VM Young's modulus in the range 20-60 MPa resulted in force-displacement curves that closely resemble experimental in terms of shape and maximum force for a given indentation depth.
Collapse
Affiliation(s)
- Tatiana Kardashina
- Department of Mechanical and Aerospace Engineering, New Mexico State University, Las Cruces NM, USA
| | - Elba E Serrano
- Department of Biology, New Mexico State University, Las Cruces NM, USA
| | - John A Dawson
- Department of Economics, Applied Statistics, and International Business, New Mexico State University, Las Cruces NM, USA
| | - Borys Drach
- Department of Mechanical and Aerospace Engineering, New Mexico State University, Las Cruces NM, USA.
| |
Collapse
|
2
|
Zhurenkov KE, Akbarinejad A, Porritt H, Horrocks MS, Malmström J. Colloidal Probe Technique Optimization for Determination of Young's Modulus of Soft Adhesive Hydrogels. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024. [PMID: 39023221 DOI: 10.1021/acs.langmuir.4c01047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/20/2024]
Abstract
Atomic force microscopy (AFM) is a valuable tool for determining the Young's modulus of a wide range of materials. However, it faces challenges, particularly when assessing adhesive materials like soft poly(N-isopropylacrylamide) (pNIPAM) hydrogels. This study focuses on enhancing the consistency and reliability of AFM measurements by functionally modifying AFM spherical tip cantilevers to address substrate adhesion issues with these hydrogels. Specifically, hydrophobic functionalization with 1H,1H,2H,2H-perfluorooctyltrichlorosilane (PFOCTS) emerged as the most effective approach, yielding consistent and reliable Young's modulus data across various pNIPAM hydrogel samples. This work highlights the importance of optimizing data acquisition in AFM, rather than relying on postprocessing, to reduce inconsistencies in Young's modulus assessment.
Collapse
Affiliation(s)
- Kirill E Zhurenkov
- Department of Chemical and Materials Engineering, The University of Auckland, 1010 Auckland, New Zealand
- MacDiarmid Institute for Advanced Materials and Nanotechnology, 6140 Wellington, New Zealand
| | - Alireza Akbarinejad
- Department of Chemical and Materials Engineering, The University of Auckland, 1010 Auckland, New Zealand
- MacDiarmid Institute for Advanced Materials and Nanotechnology, 6140 Wellington, New Zealand
| | - Harrison Porritt
- Department of Chemical and Materials Engineering, The University of Auckland, 1010 Auckland, New Zealand
- MacDiarmid Institute for Advanced Materials and Nanotechnology, 6140 Wellington, New Zealand
| | - Matthew S Horrocks
- Department of Chemical and Materials Engineering, The University of Auckland, 1010 Auckland, New Zealand
- MacDiarmid Institute for Advanced Materials and Nanotechnology, 6140 Wellington, New Zealand
| | - Jenny Malmström
- Department of Chemical and Materials Engineering, The University of Auckland, 1010 Auckland, New Zealand
- MacDiarmid Institute for Advanced Materials and Nanotechnology, 6140 Wellington, New Zealand
| |
Collapse
|
3
|
Bianchi E, Ruggeri M, Del Favero E, Pisano R, Artusio F, Ricci C, Vigani B, Ferraretto A, Boselli C, Icaro Cornaglia A, Rossi S, Sandri G. Chondroitin sulfate and caseinophosphopeptides doped polyurethane-based highly porous 3D scaffolds for tendon-to-bone regeneration. Int J Pharm 2024; 652:123822. [PMID: 38242257 DOI: 10.1016/j.ijpharm.2024.123822] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Revised: 01/16/2024] [Accepted: 01/16/2024] [Indexed: 01/21/2024]
Abstract
Tendon disorders are common injuries, which can be greatly debilitating as they are often accompanied by great pain and inflammation. Moreover, several problems are also related to the laceration of the tendon-to-bone interface (TBI), a specific region subjected to great mechanical stresses. The techniques used nowadays for the treatment of tendon and TBI injuries often involve surgery. However, one critical aspect of this procedure involves the elevated risk of fail due to the tissues weakening and the postoperative alterations of the normal joint mechanics. Synthetic polymers, such as thermoplastic polyurethane, are of special interest in the tissue engineering field as they allow the production of scaffolds with tunable elastic and mechanical properties, that could guarantee an effective support during the new tissue formation. Based on these premises, the aim of this work was the design and the development of highly porous 3D scaffolds based on thermoplastic polyurethane, and doped with chondroitin sulfate and caseinophosphopeptides, able to mimic the structural, biomechanical, and biochemical functions of the TBI. The obtained scaffolds were characterized by a homogeneous microporous structure, and by a porosity optimal for cell nutrition and migration. They were also characterized by remarkable mechanical properties, reaching values comparable to the ones of the native tendons. The scaffolds promoted the tenocyte adhesion and proliferation when caseinophosphopetides and chondroitin sulfate are present in the 3D structure. In particular, caseinophosphopeptides' optimal concentration for cell proliferation resulted 2.4 mg/mL. Finally, the systems evaluation in vivo demonstrated the scaffolds' safety, since they did not cause any inflammatory effect nor foreign body response, representing interesting platforms for the regeneration of injured TBI.
Collapse
Affiliation(s)
- Eleonora Bianchi
- Department of Drug Sciences, University of Pavia, via Taramelli 12, 27100 Pavia, Italy
| | - Marco Ruggeri
- Department of Drug Sciences, University of Pavia, via Taramelli 12, 27100 Pavia, Italy
| | - Elena Del Favero
- Department of Medical Biotechnology and Translational Medicine, Università degli Studi di Milano, Milano, Italy
| | - Roberto Pisano
- Department of Applied Science and Technology (DISAT), Polytechnic of Torino, Torino, Italy
| | - Fiora Artusio
- Department of Applied Science and Technology (DISAT), Polytechnic of Torino, Torino, Italy
| | - Caterina Ricci
- Department of Medical Biotechnology and Translational Medicine, Università degli Studi di Milano, Milano, Italy
| | - Barbara Vigani
- Department of Drug Sciences, University of Pavia, via Taramelli 12, 27100 Pavia, Italy
| | - Anita Ferraretto
- Department of Biomedical Sciences for Health, Università degli Studi di Milano, via Mangiagalli 31, Milan, Italy; Laboratory of Experimental Biochemistry & Molecular Biology, IRCCS Istituto Galeazzi-Sant'Ambrogio, Via Cristina Belgioioso 173, 20157 Milan, Italy
| | - Cinzia Boselli
- Department of Drug Sciences, University of Pavia, via Taramelli 12, 27100 Pavia, Italy
| | - Antonia Icaro Cornaglia
- Department of Public Health, Experimental and Forensic Medicine, University of Pavia, via Forlanini 2, 27100 Pavia, Italy
| | - Silvia Rossi
- Department of Drug Sciences, University of Pavia, via Taramelli 12, 27100 Pavia, Italy
| | - Giuseppina Sandri
- Department of Drug Sciences, University of Pavia, via Taramelli 12, 27100 Pavia, Italy.
| |
Collapse
|
4
|
McCarthy CM, McKevitt KL, Connolly SA, Andersson I, Leahy FC, Egan S, Moloney MA, Kavanagh EG, Peirce C, Cunnane EM, McGourty KD, Walsh MT, Mulvihill JJE. Microindentation of fresh soft biological tissue: A rapid tissue sectioning and mounting protocol. PLoS One 2024; 19:e0297618. [PMID: 38422111 PMCID: PMC10903917 DOI: 10.1371/journal.pone.0297618] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Accepted: 01/03/2024] [Indexed: 03/02/2024] Open
Abstract
Microindentation of fresh biological tissues is necessary for the creation of 3D biomimetic models that accurately represent the native extracellular matrix microenvironment. However, tissue must first be precisely sectioned into slices. Challenges exist in the preparation of fresh tissue slices, as they can tear easily and must be processed rapidly in order to mitigate tissue degradation. In this study, we propose an optimised mounting condition for microindentation and demonstrate that embedding tissue in a mixture of 2.5% agarose and 1.5% gelatin is the most favourable method of tissue slice mounting for microindentation. This protocol allows for rapid processing of fresh biological tissue and is applicable to a variety of tissue types.
Collapse
Affiliation(s)
- Clíona M. McCarthy
- Biomaterials Cluster, Bernal Institute, University of Limerick, Limerick, Ireland
- School of Engineering, University of Limerick, Limerick, Ireland
| | - Kevin L. McKevitt
- Department of Vascular & Endovascular Surgery, University Hospital Limerick, Limerick, Ireland
| | - Sinéad A. Connolly
- Biomaterials Cluster, Bernal Institute, University of Limerick, Limerick, Ireland
- School of Engineering, University of Limerick, Limerick, Ireland
| | - Isabel Andersson
- Biomaterials Cluster, Bernal Institute, University of Limerick, Limerick, Ireland
- School of Engineering, University of Limerick, Limerick, Ireland
| | - Fiona C. Leahy
- Department of Vascular & Endovascular Surgery, University Hospital Limerick, Limerick, Ireland
| | - Siobhan Egan
- Department of Colorectal Surgery, University Hospital Limerick, Limerick, Ireland
| | - Michael A. Moloney
- Department of Vascular & Endovascular Surgery, University Hospital Limerick, Limerick, Ireland
| | - Eamon G. Kavanagh
- Department of Vascular & Endovascular Surgery, University Hospital Limerick, Limerick, Ireland
| | - Colin Peirce
- Department of Colorectal Surgery, University Hospital Limerick, Limerick, Ireland
| | - Eoghan M. Cunnane
- Biomaterials Cluster, Bernal Institute, University of Limerick, Limerick, Ireland
- School of Engineering, University of Limerick, Limerick, Ireland
- Health Research Institute, University of Limerick, Limerick, Ireland
| | - Kieran D. McGourty
- Biomaterials Cluster, Bernal Institute, University of Limerick, Limerick, Ireland
- School of Engineering, University of Limerick, Limerick, Ireland
- School of Chemical Sciences, University of Limerick, Limerick, Ireland
| | - Michael T. Walsh
- Biomaterials Cluster, Bernal Institute, University of Limerick, Limerick, Ireland
- School of Engineering, University of Limerick, Limerick, Ireland
- Health Research Institute, University of Limerick, Limerick, Ireland
| | - John J. E. Mulvihill
- Biomaterials Cluster, Bernal Institute, University of Limerick, Limerick, Ireland
- School of Engineering, University of Limerick, Limerick, Ireland
- Health Research Institute, University of Limerick, Limerick, Ireland
| |
Collapse
|
5
|
Brill-Karniely Y, Tischenko K, Benny O. Analyzing force measurements of multi-cellular clusters comprising indeterminate geometries. Biomech Model Mechanobiol 2024; 23:145-155. [PMID: 37770729 PMCID: PMC10902013 DOI: 10.1007/s10237-023-01764-9] [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: 03/15/2023] [Accepted: 08/09/2023] [Indexed: 09/30/2023]
Abstract
Multi-cellular biomimetic models often comprise heterogenic geometries. Therefore, quantification of their mechanical properties-which is crucial for various biomedical applications-is a challenge. Due to its simplicity, linear fitting is traditionally used in analyzing force-displacement data of parallel compression measurements of multi-cellular clusters, such as tumor spheroids. However, the linear assumption would be artificial when the contact geometry is not planar. We propose here the integrated elasticity (IE) regression, which is based on extrapolation of established elastic theories for well-defined geometries, and is free, extremely simple to apply, and optimal for analyzing coarsely concave multi-cellular clusters. We studied here the quality of the data analysis in force measurements of tumor spheroids comprising different types of melanoma cells, using either the IE or the traditional linear regressions. The IE regression maintained excellent precision also when the contact geometry deviated from planarity (as shown by our image analysis). While the quality of the linear fittings was relatively satisfying, these predicted smaller elastic moduli as compared to the IE regression. This was in accordance with previous studies, in which the elastic moduli predicted by linear fits were smaller compared to those obtained by well-established methods. This suggests that linear regressions underestimate the elastic constants of bio-samples even in cases where the fitting precision seems satisfying, and highlights the need in alternative methods as the IE scheme. For comparison between different types of spheroids we further recommend to increase the soundness by regarding relative moduli, using universal reference samples.
Collapse
Affiliation(s)
- Yifat Brill-Karniely
- Institute for Drug Research, The School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, 9112001, Jerusalem, Israel.
- Institute of Animal Science, ARO, The Volcani Center, 50250, Bet-Dagan, Israel.
| | - Katerina Tischenko
- Institute for Drug Research, The School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, 9112001, Jerusalem, Israel
| | - Ofra Benny
- Institute for Drug Research, The School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, 9112001, Jerusalem, Israel.
| |
Collapse
|
6
|
Streltsov DR, Borisov KM, Kalinina AA, Muzafarov AM. Quantitative Elasticity Mapping of Submicron Silica Hollow Particles by PeakForce QNM AFM Mode. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:1916. [PMID: 37446432 DOI: 10.3390/nano13131916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Revised: 06/16/2023] [Accepted: 06/21/2023] [Indexed: 07/15/2023]
Abstract
Silica hollow spheres with a diameter of 100-300 nm and a shell thickness of 8±2 nm were synthesized using a self-templating amphiphilic polymeric precursor, i.e., poly(ethylene glycol)-substituted hyperbranched polyethoxysiloxane. Their elastic properties were addressed with a high-frequency AFM indentation method based on the PeakForce QNM (quantitative nanomechanical mapping) mode enabling simultaneous visualization of the surface morphology and high-resolution mapping of the mechanical properties. The factors affecting the accuracy of the mechanical measurements such as a local slope of the particle surface, deformation of the silica hollow particles by a solid substrate, shell thickness variation, and applied force range were analysed. The Young's modulus of the shell material was evaluated as E=26±7 GPa independent of the applied force in the elastic regime of deformations. Beyond the elastic regime, the buckling instability was observed revealing a non-linear force-deformation response with a hysteresis between the loading and unloading force-distance curves and irreversible deformation of the shell at high applied forces. Thus, it was demonstrated that PeakForce QNM mode can be used for quantitative measurements of the elastic properties of submicon-sized silica hollow particles with nano-size shell thickness, as well as for estimation of the buckling behaviour beyond the elastic regime of shell deformations.
Collapse
Affiliation(s)
- Dmitry R Streltsov
- Enikolopov Institute of Synthetic Polymeric Materials of Russian Academy of Sciences, 117393 Moscow, Russia
| | - Kirill M Borisov
- Enikolopov Institute of Synthetic Polymeric Materials of Russian Academy of Sciences, 117393 Moscow, Russia
| | - Aleksandra A Kalinina
- Enikolopov Institute of Synthetic Polymeric Materials of Russian Academy of Sciences, 117393 Moscow, Russia
| | - Aziz M Muzafarov
- Enikolopov Institute of Synthetic Polymeric Materials of Russian Academy of Sciences, 117393 Moscow, Russia
- A.N. Nesmeyanov Institute of Organoelement Compounds of Russian Academy of Sciences, 119334 Moscow, Russia
| |
Collapse
|
7
|
Hakim Khalili M, Zhang R, Wilson S, Goel S, Impey SA, Aria AI. Additive Manufacturing and Physicomechanical Characteristics of PEGDA Hydrogels: Recent Advances and Perspective for Tissue Engineering. Polymers (Basel) 2023; 15:polym15102341. [PMID: 37242919 DOI: 10.3390/polym15102341] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Revised: 05/11/2023] [Accepted: 05/12/2023] [Indexed: 05/28/2023] Open
Abstract
In this brief review, we discuss the recent advancements in using poly(ethylene glycol) diacrylate (PEGDA) hydrogels for tissue engineering applications. PEGDA hydrogels are highly attractive in biomedical and biotechnology fields due to their soft and hydrated properties that can replicate living tissues. These hydrogels can be manipulated using light, heat, and cross-linkers to achieve desirable functionalities. Unlike previous reviews that focused solely on material design and fabrication of bioactive hydrogels and their cell viability and interactions with the extracellular matrix (ECM), we compare the traditional bulk photo-crosslinking method with the latest three-dimensional (3D) printing of PEGDA hydrogels. We present detailed evidence combining the physical, chemical, bulk, and localized mechanical characteristics, including their composition, fabrication methods, experimental conditions, and reported mechanical properties of bulk and 3D printed PEGDA hydrogels. Furthermore, we highlight the current state of biomedical applications of 3D PEGDA hydrogels in tissue engineering and organ-on-chip devices over the last 20 years. Finally, we delve into the current obstacles and future possibilities in the field of engineering 3D layer-by-layer (LbL) PEGDA hydrogels for tissue engineering and organ-on-chip devices.
Collapse
Affiliation(s)
- Mohammad Hakim Khalili
- Surface Engineering and Precision Centre, School of Aerospace, Transport and Manufacturing, Cranfield University, Bedford MK43 0AL, UK
| | - Rujing Zhang
- Sophion Bioscience A/S, Baltorpvej 154, 2750 Copenhagen, Denmark
| | - Sandra Wilson
- Sophion Bioscience A/S, Baltorpvej 154, 2750 Copenhagen, Denmark
| | - Saurav Goel
- School of Engineering, London South Bank University, 103 Borough Road, London SE1 0AA, UK
- Department of Mechanical Engineering, University of Petroleum and Energy Studies, Dehradun 248007, India
| | - Susan A Impey
- Surface Engineering and Precision Centre, School of Aerospace, Transport and Manufacturing, Cranfield University, Bedford MK43 0AL, UK
| | - Adrianus Indrat Aria
- Surface Engineering and Precision Centre, School of Aerospace, Transport and Manufacturing, Cranfield University, Bedford MK43 0AL, UK
| |
Collapse
|
8
|
Kontomaris SV, Stylianou A, Chliveros G, Malamou A. Determining Spatial Variability of Elastic Properties for Biological Samples Using AFM. MICROMACHINES 2023; 14:mi14010182. [PMID: 36677243 PMCID: PMC9862197 DOI: 10.3390/mi14010182] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 12/26/2022] [Accepted: 01/09/2023] [Indexed: 05/29/2023]
Abstract
Measuring the mechanical properties (i.e., elasticity in terms of Young's modulus) of biological samples using Atomic Force Microscopy (AFM) indentation at the nanoscale has opened new horizons in studying and detecting various pathological conditions at early stages, including cancer and osteoarthritis. It is expected that AFM techniques will play a key role in the future in disease diagnosis and modeling using rigorous mathematical criteria (i.e., automated user-independent diagnosis). In this review, AFM techniques and mathematical models for determining the spatial variability of elastic properties of biological materials at the nanoscale are presented and discussed. Significant issues concerning the rationality of the elastic half-space assumption, the possibility of monitoring the depth-dependent mechanical properties, and the construction of 3D Young's modulus maps are also presented.
Collapse
Affiliation(s)
- Stylianos Vasileios Kontomaris
- BioNanoTec Ltd., Nicosia 2043, Cyprus
- Faculty of Engineering and Architecture, Metropolitan College, 15125 Athens, Greece
| | - Andreas Stylianou
- School of Sciences, European University Cyprus, Nicosia 2404, Cyprus
| | - Georgios Chliveros
- Faculty of Engineering and Architecture, Metropolitan College, 15125 Athens, Greece
| | - Anna Malamou
- School of Electrical and Computer Engineering, National Technical University of Athens, 15780 Athens, Greece
| |
Collapse
|
9
|
Elasticity regulates nanomaterial transport as delivery vehicles: Design, characterization, mechanisms and state of the art. Biomaterials 2022; 291:121879. [DOI: 10.1016/j.biomaterials.2022.121879] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 10/14/2022] [Accepted: 10/23/2022] [Indexed: 11/22/2022]
|
10
|
Mishra VS, Ochalski TJ, McCarthy NA, Brodkorb A, Rodriguez BJ, Hogan SA. Topographical changes in high-protein, milk powders as a function of moisture sorption using amplitude-modulation atomic force microscopy. Food Hydrocoll 2022. [DOI: 10.1016/j.foodhyd.2022.107504] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
|
11
|
Shi Y, Sivarajan S, Crocker JC, Reich DH. Measuring Cytoskeletal Mechanical Fluctuations and Rheology with Active Micropost Arrays. Curr Protoc 2022; 2:e433. [PMID: 35612274 PMCID: PMC9321978 DOI: 10.1002/cpz1.433] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The dynamics of the cellular actomyosin cytoskeleton are crucial to many aspects of cellular function. Here, we describe techniques that employ active micropost array detectors (AMPADs) to measure cytoskeletal rheology and mechanical force fluctuations. The AMPADS are arrays of flexible poly(dimethylsiloxane) (PDMS) microposts with magnetic nanowires embedded in a subset of microposts to enable actuation of those posts via an externally applied magnetic field. Techniques are described to track the magnetic microposts' motion with nanometer precision at up to 100 video frames per second to measure the local cellular rheology at well-defined positions. Application of these high-precision tracking techniques to the full array of microposts in contact with a cell also enables mapping of the cytoskeletal mechanical fluctuation dynamics with high spatial and temporal resolution. This article describes (1) the fabrication of magnetic micropost arrays, (2) measurement protocols for both local rheology and cytoskeletal force fluctuation mapping, and (3) special-purpose software routines to reduce and analyze these data. © 2022 The Authors. Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: Fabrication of magnetic micropost arrays Basic Protocol 2: Data acquisition for cellular force fluctuations on non-magnetic micropost arrays Basic Protocol 3: Data acquisition for local cellular rheology measurements with magnetic microposts Basic Protocol 4: Data reduction: determining microposts' motion Basic Protocol 5: Data analysis: determining local rheology from magnetic microposts Basic Protocol 6: Data analysis for force fluctuation measurements Support Protocol 1: Fabrication of magnetic Ni nanowires by electrodeposition Support Protocol 2: Configuring Streampix for magnetic rheology measurements.
Collapse
Affiliation(s)
- Yu Shi
- Department of Physics and Astronomy, Johns Hopkins University, Baltimore, Maryland.,Current address: Department of Biomedical Engineering, University of North Carolina, Chapel Hill, North Carolina
| | - Shankar Sivarajan
- Department of Physics and Astronomy, Johns Hopkins University, Baltimore, Maryland
| | - John C Crocker
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Daniel H Reich
- Department of Physics and Astronomy, Johns Hopkins University, Baltimore, Maryland
| |
Collapse
|
12
|
Molaei M, Kandy SK, Graber ZT, Baumgart T, Radhakrishnan R, Crocker JC. Probing lipid membrane bending mechanics using gold nanorod tracking. PHYSICAL REVIEW RESEARCH 2022; 4:L012027. [PMID: 35373142 PMCID: PMC8975244 DOI: 10.1103/physrevresearch.4.l012027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Lipid bilayer membranes undergo rapid bending undulations with wavelengths from tens of nanometers to tens of microns due to thermal fluctuations. Here, we probe such undulations and the membranes' mechanics by measuring the time-varying orientation of single gold nanorods (GNRs) adhered to the membrane, using high-speed dark field microscopy. In a lipid vesicle, such measurements allow the determination of the membrane's viscosity, bending rigidity, and tension as well as the friction coefficient for sliding of the monolayers over one another. The in-plane rotation of the GNR is hindered by undulations in a tension dependent manner, consistent with simulations. The motion of single GNRs adhered to the plasma membrane of living cultured cells similarly reveals the membrane's complex physics and coupling to the cell's actomyosin cortex.
Collapse
Affiliation(s)
- Mehdi Molaei
- Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Sreeja Kutti Kandy
- Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Zachary T. Graber
- Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Tobias Baumgart
- Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Ravi Radhakrishnan
- Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
- Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - John C. Crocker
- Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
- Corresponding author:
| |
Collapse
|
13
|
Brill-Karniely Y. Mechanical Measurements of Cells Using AFM: 3D or 2D Physics? Front Bioeng Biotechnol 2020; 8:605153. [PMID: 33330437 PMCID: PMC7731794 DOI: 10.3389/fbioe.2020.605153] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Accepted: 10/08/2020] [Indexed: 12/28/2022] Open
Affiliation(s)
- Yifat Brill-Karniely
- Faculty of Medicine, The School of Pharmacy, Institute for Drug Research, The Hebrew University of Jerusalem, Jerusalem, Israel
| |
Collapse
|
14
|
Ganjian M, Angeloni L, Mirzaali MJ, Modaresifar K, Hagen CW, Ghatkesar MK, Hagedoorn PL, Fratila-Apachitei LE, Zadpoor AA. Quantitative mechanics of 3D printed nanopillars interacting with bacterial cells. NANOSCALE 2020; 12:21988-22001. [PMID: 32914826 DOI: 10.1039/d0nr05984f] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
One of the methods to create sub-10 nm resolution metal-composed 3D nanopillars is electron beam-induced deposition (EBID). Surface nanotopographies (e.g., nanopillars) could play an important role in the design and fabrication of implantable medical devices by preventing the infections that are caused by the bacterial colonization of the implant surface. The mechanical properties of such nanoscale structures can influence their bactericidal efficiency. In addition, these properties are key factors in determining the fate of stem cells. In this study, we quantified the relevant mechanical properties of EBID nanopillars interacting with Staphylococcus aureus (S. aureus) using atomic force microscopy (AFM). We first determined the elastic modulus (17.7 GPa) and the fracture stress (3.0 ± 0.3 GPa) of the nanopillars using the quantitative imaging (QI) mode and contact mode (CM) of AFM. The displacement of the nanopillars interacting with the bacteria cells was measured by scanning electron microscopy (50.3 ± 9.0 nm). Finite element method based simulations were then applied to obtain the force-displacement curve of the nanopillars (considering the specified dimensions and the measured value of the elastic modulus) based on which an interaction force of 88.7 ± 36.1 nN was determined. The maximum von Mises stress of the nanopillars subjected to these forces was also determined (3.2 ± 0.3 GPa). These values were close to the maximum (i.e., fracture) stress of the pillars as measured by AFM, indicating that the nanopillars were close to their breaking point while interacting with S. aureus. These findings reveal unique quantitative data regarding the mechanical properties of nanopillars interacting with bacterial cells and highlight the possibilities of enhancing the bactericidal activity of the investigated EBID nanopillars by adjusting both their geometry and mechanical properties.
Collapse
Affiliation(s)
- Mahya Ganjian
- Department of Biomechanical Engineering, Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology, Mekelweg 2, 2628CD, Delft, The Netherlands.
| | | | | | | | | | | | | | | | | |
Collapse
|
15
|
Zemła J, Bobrowska J, Kubiak A, Zieliński T, Pabijan J, Pogoda K, Bobrowski P, Lekka M. Indenting soft samples (hydrogels and cells) with cantilevers possessing various shapes of probing tip. EUROPEAN BIOPHYSICS JOURNAL : EBJ 2020; 49:485-495. [PMID: 32803311 PMCID: PMC7456413 DOI: 10.1007/s00249-020-01456-7] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Revised: 05/06/2020] [Accepted: 08/11/2020] [Indexed: 12/20/2022]
Abstract
The identification of cancer-related changes in cells and tissues based on the measurements of elastic properties using atomic force microscopy (AFM) seems to be approaching clinical application. Several limiting aspects have already been discussed; however, still, no data have shown how specific AFM probe geometries are related to the biomechanical evaluation of cancer cells. Here, we analyze and compare the nanomechanical results of mechanically homogenous polyacrylamide gels and heterogeneous bladder cancer cells measured using AFM probes of various tip geometry, including symmetric and non-symmetric pyramids and a sphere. Our observations show large modulus variability aligned with both types of AFM probes used and with the internal structure of the cells. Altogether, these results demonstrate that it is possible to differentiate between compliant and rigid samples of kPa elasticity; however, simultaneously, they highlight the strong need for standardized protocols for AFM-based elasticity measurements if applied in clinical practice including the use of a single type of AFM cantilever.
Collapse
Affiliation(s)
- Joanna Zemła
- Institute of Nuclear Physics Polish Academy of Sciences, PL-31342, Kraków, Poland.
| | - Justyna Bobrowska
- Institute of Nuclear Physics Polish Academy of Sciences, PL-31342, Kraków, Poland
| | - Andrzej Kubiak
- Institute of Nuclear Physics Polish Academy of Sciences, PL-31342, Kraków, Poland
| | - Tomasz Zieliński
- Institute of Nuclear Physics Polish Academy of Sciences, PL-31342, Kraków, Poland
| | - Joanna Pabijan
- Institute of Nuclear Physics Polish Academy of Sciences, PL-31342, Kraków, Poland
| | - Katarzyna Pogoda
- Institute of Nuclear Physics Polish Academy of Sciences, PL-31342, Kraków, Poland
| | - Piotr Bobrowski
- Institute of Metallurgy and Materials Science Polish Academy of Sciences, PL-30059, Kraków, Poland
| | - Małgorzata Lekka
- Institute of Nuclear Physics Polish Academy of Sciences, PL-31342, Kraków, Poland.
| |
Collapse
|
16
|
Tiwari S, Kazemi-Moridani A, Zheng Y, Barney CW, McLeod KR, Dougan CE, Crosby AJ, Tew GN, Peyton SR, Cai S, Lee JH. Seeded laser-induced cavitation for studying high-strain-rate irreversible deformation of soft materials. SOFT MATTER 2020; 16:9006-9013. [PMID: 33021618 DOI: 10.1039/d0sm00710b] [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
Characterizing the high-strain-rate and high-strain mechanics of soft materials is critical to understanding the complex behavior of polymers and various dynamic injury mechanisms, including traumatic brain injury. However, their dynamic mechanical deformation under extreme conditions is technically difficult to quantify and often includes irreversible damage. To address such challenges, we investigate an experimental method, which allows quantification of the extreme mechanical properties of soft materials using ultrafast stroboscopic imaging of highly reproducible laser-induced cavitation events. As a reference material, we characterize variably cross-linked polydimethylsiloxane specimens using this method. The consistency of the laser-induced cavitation is achieved through the introduction of laser absorbing seed microspheres. Based on a simplified viscoelastic model, representative high-strain-rate shear moduli and viscosities of the soft specimens are quantified across different degrees of crosslinking. The quantified rheological parameters align well with the time-temperature superposition prediction of dynamic mechanical analysis. The presented method offers significant advantages with regard to quantifying high-strain rate, irreversible mechanical properties of soft materials and tissues, compared to other methods that rely upon the cyclic dynamics of cavitation. These advances are anticipated to aid in the understanding of how damage and injury develop in soft materials and tissues.
Collapse
Affiliation(s)
- Sacchita Tiwari
- Department of Mechanical and Industrial Engineering, University of Massachusetts, Amherst, MA 01003, USA.
| | - Amir Kazemi-Moridani
- Department of Mechanical and Industrial Engineering, University of Massachusetts, Amherst, MA 01003, USA.
| | - Yue Zheng
- Department of Mechanical and Aerospace Engineering, University of California at San Diego, La Jolla, CA 9209, USA
| | - Christopher W Barney
- Polymer Science and Engineering Department, University of Massachusetts, Amherst, MA 01003, USA
| | - Kelly R McLeod
- Polymer Science and Engineering Department, University of Massachusetts, Amherst, MA 01003, USA
| | - Carey E Dougan
- Department of Chemical Engineering, University of Massachusetts, Amherst, MA 01003, USA
| | - Alfred J Crosby
- Polymer Science and Engineering Department, University of Massachusetts, Amherst, MA 01003, USA
| | - Gregory N Tew
- Polymer Science and Engineering Department, University of Massachusetts, Amherst, MA 01003, USA
| | - Shelly R Peyton
- Department of Chemical Engineering, University of Massachusetts, Amherst, MA 01003, USA
| | - Shengqiang Cai
- Department of Mechanical and Aerospace Engineering, University of California at San Diego, La Jolla, CA 9209, USA
| | - Jae-Hwang Lee
- Department of Mechanical and Industrial Engineering, University of Massachusetts, Amherst, MA 01003, USA.
| |
Collapse
|
17
|
Zmerli I, Michel JP, Makky A. Bioinspired polydopamine nanoparticles: synthesis, nanomechanical properties, and efficient PEGylation strategy. J Mater Chem B 2020; 8:4489-4504. [PMID: 32365146 DOI: 10.1039/c9tb02769f] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Polydopamine (PDA) is a bioinspired fascinating polymer which is considered nowadays as a material of choice for designing drug delivery nanosystems. Indeed, PDA exhibits multiple interesting features including simple preparation protocols, biocompatibility, simple functionalization procedures, free radicals scavenging and photothermal/photoacoustic properties. However, because of its heterogeneous structure, clear procedures about PDA nanoparticles synthesis and PEGylation with well-defined and reproducible physicochemical properties such as size, shape and nanomechanics are still needed. In this work, we established tightly controlled experimental conditions to synthesize PDA nanoparticles with well-defined size and yield. This allowed us to identify the factors that affect the most these two parameters and to construct surface response plots with accurate predictive values of size and yield. The nanomechanical properties of PDA NPs exhibiting different sizes have been studied with AFM nanoindentation experiments. Our results demonstrated for the first time that the elasticity of PDA NPs was decreasing with their size. This could be explained by the higher geometric packing order of the stacked oligomeric fractions inside the core of the biggest PDA NPs. Next, in order to determine the best PEGylation experimental conditions of PDA NPs using thiol-terminated PEG that allow grafting the highest polymer density with proteins repelling properties, we have first optimized the PEGylation strategy on PDA films. By using a combination of QCM-D and AFM experiments, we could demonstrate that efficient PEGylation of PDA films could be done even at low PEG concentration but in the presence of NaCl which exerts a salting out effect on PEG chains improving thus the grafting density. Finally, we transposed these experimental conditions to PDA NPs and we could synthesize PEGylated PDA NPs exhibiting high stability in physiological conditions as revealed by FTIR and DLS experiments respectively.
Collapse
Affiliation(s)
- Islam Zmerli
- Université Paris-Saclay, CNRS, Institut Galien Paris Sud, 92296, Châtenay-Malabry, France.
| | - Jean-Philippe Michel
- Université Paris-Saclay, CNRS, Institut Galien Paris Sud, 92296, Châtenay-Malabry, France.
| | - Ali Makky
- Université Paris-Saclay, CNRS, Institut Galien Paris Sud, 92296, Châtenay-Malabry, France.
| |
Collapse
|
18
|
Shi Y, Porter CL, Crocker JC, Reich DH. Dissecting fat-tailed fluctuations in the cytoskeleton with active micropost arrays. Proc Natl Acad Sci U S A 2019; 116:13839-13846. [PMID: 31239336 PMCID: PMC6628664 DOI: 10.1073/pnas.1900963116] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The ability of animal cells to crawl, change their shape, and respond to applied force is due to their cytoskeleton: A dynamic, cross-linked network of actin protein filaments and myosin motors. How these building blocks assemble to give rise to cells' mechanics and behavior remains poorly understood. Using active micropost array detectors containing magnetic actuators, we have characterized the mechanics and fluctuations of cells' actomyosin cortex and stress fiber network in detail. Here, we find that both structures display remarkably consistent power law viscoelastic behavior along with highly intermittent fluctuations with fat-tailed distributions of amplitudes. Notably, this motion in the cortex is dominated by occasional large, step-like displacement events, with a spatial extent of several micrometers. Overall, our findings for the cortex appear contrary to the predictions of a recent active gel model, while suggesting that different actomyosin contractile units act in a highly collective and cooperative manner. We hypothesize that cells' actomyosin components robustly self-organize into marginally stable, plastic networks that give cells' their unique biomechanical properties.
Collapse
Affiliation(s)
- Yu Shi
- Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218
| | - Christopher L Porter
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, PA 19104
| | - John C Crocker
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, PA 19104
| | - Daniel H Reich
- Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218;
| |
Collapse
|
19
|
Singaraju AB, Bahl D, Stevens LL. Brillouin Light Scattering: Development of a Near Century-Old Technique for Characterizing the Mechanical Properties of Materials. AAPS PharmSciTech 2019; 20:109. [PMID: 30746575 DOI: 10.1208/s12249-019-1311-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Accepted: 01/15/2019] [Indexed: 11/30/2022] Open
Abstract
Brillouin light scattering (BLS), a technique theoretically described nearly a century back by the French physicist Léon Brillouin in 1922, is a light-scattering method for determining the mechanical properties of materials. This inelastic scattering method is described by the Bragg diffraction of light from a propagating fluctuation in the local dielectric. These fluctuations arise spontaneously from thermally populated sound waves intrinsic to all materials, and thus BLS may be broadly applied to transparent samples of any phase. This review begins with a brief historical overview of the development of BLS, from its theoretical prediction to the current state of the art, and notes specific technological advancements that enabled the development of BLS. Despite the broad utility of BLS, no commercial spectrometer is currently available for purchase, but rather individual components are assembled to suit a specific application. Central to any BLS spectrometer is the interferometer, and its performance characteristics-scanning or non-scanning, multi-passing, and stabilization-are critical considerations for spectrometer design. Consistent with any light-scattering method, the frequency shift is a key observable in BLS, and we summarize the connection of this measurement to evaluate the mechanical properties of materials. With emphasis toward pharmaceutical materials analysis, we introduce the traditional BLS approach for single-crystal elasticity, and this is followed by a discussion of more recent developments in powder BLS. We conclude our review with a perspective on future developments in BLS that may enable BLS as a novel addition to the current catalog of process analytical technologies.
Collapse
|
20
|
Non-invasive electromechanical cell-based biosensors for improved investigation of 3D cardiac models. Biosens Bioelectron 2019; 124-125:129-135. [DOI: 10.1016/j.bios.2018.10.021] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2018] [Revised: 10/11/2018] [Accepted: 10/11/2018] [Indexed: 12/26/2022]
|
21
|
Qian L, Zhao H. Nanoindentation of Soft Biological Materials. MICROMACHINES 2018; 9:E654. [PMID: 30544918 PMCID: PMC6316095 DOI: 10.3390/mi9120654] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Revised: 11/27/2018] [Accepted: 12/05/2018] [Indexed: 01/01/2023]
Abstract
Nanoindentation techniques, with high spatial resolution and force sensitivity, have recently been moved into the center of the spotlight for measuring the mechanical properties of biomaterials, especially bridging the scales from the molecular via the cellular and tissue all the way to the organ level, whereas characterizing soft biomaterials, especially down to biomolecules, is fraught with more pitfalls compared with the hard biomaterials. In this review we detail the constitutive behavior of soft biomaterials under nanoindentation (including AFM) and present the characteristics of experimental aspects in detail, such as the adaption of instrumentation and indentation response of soft biomaterials. We further show some applications, and discuss the challenges and perspectives related to nanoindentation of soft biomaterials, a technique that can pinpoint the mechanical properties of soft biomaterials for the scale-span is far-reaching for understanding biomechanics and mechanobiology.
Collapse
Affiliation(s)
- Long Qian
- School of Mechanical and Aerospace Engineering, Jilin University, Changchun 130025, China.
| | - Hongwei Zhao
- School of Mechanical and Aerospace Engineering, Jilin University, Changchun 130025, China.
| |
Collapse
|
22
|
Characterizing Inner Pressure and Stiffness of Trophoblast and Inner Cell Mass of Blastocysts. Biophys J 2018; 115:2443-2450. [PMID: 30509858 DOI: 10.1016/j.bpj.2018.11.008] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Revised: 10/23/2018] [Accepted: 11/05/2018] [Indexed: 12/14/2022] Open
Abstract
It has long been recognized that mechanical forces underlie mammalian embryonic shape changes. Before gastrulation, the blastocyst embryo undergoes significant shape changes, namely, the blastocyst cavity emerges and expands, and the inner cell mass (ICM) forms and changes in shape. The embryo's inner pressure has been hypothesized to be the driving mechanical input that causes the expansion of the blastocyst cavity and the shape changes of the ICM. However, how the inner pressure and the mechanics of the trophoblast and the ICM change during development is unknown because of the lack of a suitable tool for quantitative characterization. This work presents a laser-assisted magnetic tweezer technique for measuring the inner pressure and Young's modulus of the trophoblast and ICM of the blastocyst-stage mouse embryo. The results quantitatively showed that the inner pressure and Young's modulus of the trophoblast and ICM all increase during progression of mouse blastocysts, providing useful data for understanding how mechanical factors are physiologically integrated with other cues to direct embryo development.
Collapse
|
23
|
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.
Collapse
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
| | | | | | | |
Collapse
|
24
|
Controlling the mechanoelasticity of model biomembranes with room-temperature ionic liquids. Biophys Rev 2018; 10:751-756. [PMID: 29754282 DOI: 10.1007/s12551-018-0424-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Accepted: 04/16/2018] [Indexed: 10/16/2022] Open
Abstract
Room-temperature ionic liquids (RTILs) are a vast class of organic non-aqueous electrolytes whose interaction with biomolecules is receiving great attention for potential applications in bio-nano-technology. Recently, it has been shown that RTILs dispersed at low concentrations at the water-biomembrane interface diffuse into the lipid region of the biomembrane, without disrupting the integrity of the bilayer structure. In this letter, we present the first exploratory study on the effect of absorbed RTILs on the mechanoelasticity of a model biomembrane. Using atomic force microscopy, we found that both the rupture force and the elastic modulus increase upon the insertion of RTILs into the biomembrane. This preliminary result points to the potential use of RTILs to control the mechanoelasticity of cell membranes, opening new avenues for applications in bio-medicine and, more generally, bio-nano-technology. The variety of RTILs offers a vast playground for future studies and potential applications.
Collapse
|
25
|
Nunes-Alves A, Arantes GM. Mechanical Unfolding of Macromolecules Coupled to Bond Dissociation. J Chem Theory Comput 2017; 14:282-290. [DOI: 10.1021/acs.jctc.7b00805] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Ariane Nunes-Alves
- Department of Biochemistry,
Instituto de Quı́mica, Universidade de São Paulo, Av. Prof. Lineu Prestes 748, 05508-900 São Paulo, SP, Brazil
| | - Guilherme Menegon Arantes
- Department of Biochemistry,
Instituto de Quı́mica, Universidade de São Paulo, Av. Prof. Lineu Prestes 748, 05508-900 São Paulo, SP, Brazil
| |
Collapse
|
26
|
Li A, Chen J, Liang ZH, Cai J, Cai HH, Chen M. Comparison of ultrastructural and nanomechanical signature of platelets from acute myocardial infarction and platelet activation. Biochem Biophys Res Commun 2017; 486:245-251. [PMID: 28274875 DOI: 10.1016/j.bbrc.2017.03.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Accepted: 03/03/2017] [Indexed: 12/12/2022]
Abstract
Acute myocardial infarction (AMI) initiation and progression follow complex molecular and structural changes in the nanoarchitecture of platelets. However, it remains poorly understood how the transformation from health to AMI alters the ultrastructural and biomechanical properties of platelets within the platelet activation microenvironment. Here, we show using an atomic force microscope (AFM) that platelet samples, including living human platelets from the healthy and AMI patient, activated platelets from collagen-stimulated model, show distinct ultrastructural imaging and stiffness profiles. Correlative morphology obtained on AMI platelets and collagen-activated platelets display distinct pseudopodia structure and nanoclusters on membrane. In contrast to normal platelets, AMI platelets have a stiffer distribution resulting from complicated pathogenesis, with a prominent high-stiffness peak representative of platelet activation using AFM-based force spectroscopy. Similar findings are seen in specific stages of platelet activation in collagen-stimulated model. Further evidence obtained from different force measurement region with activated platelets shows that platelet migration is correlated to the more elasticity of pseudopodia while high stiffness at the center region. Overall, ultrastructural and nanomechanical profiling by AFM provides quantitative indicators in the clinical diagnostics of AMI with mechanobiological significance.
Collapse
Affiliation(s)
- Aiqun Li
- Department of Chemistry, College of Chemistry and Materials Science, Jinan University, Guangzhou 510632, China
| | - Jianwei Chen
- Department of Cardiology, The First Affiliated Hospital of Jinan University, Guangzhou 510630, China
| | - Zhi-Hong Liang
- Analytical and Testing Center, Jinan University, Guangzhou 510632, China
| | - Jiye Cai
- Department of Chemistry, College of Chemistry and Materials Science, Jinan University, Guangzhou 510632, China; State Key Laboratory of Quality Research in Chinese Medicines, Macau University of Science and Technology, Macau 999078, China
| | - Huai-Hong Cai
- Department of Chemistry, College of Chemistry and Materials Science, Jinan University, Guangzhou 510632, China.
| | - Min Chen
- Department of Respiratory Medicine, Affiliated Hospital of Guangdong Medical University, Zhanjiang 524001, China; Department of Respiratory Medicine, The First Affiliated Hospital of Jinan University, Guangzhou 510630, China.
| |
Collapse
|
27
|
Sahai S, Wilkerson M, Zaske AM, Olson SD, Cox CS, Triolo F. A cost-effective method to immobilize hydrated soft-tissue samples for atomic force microscopy. Biotechniques 2016; 61:206-209. [PMID: 27712584 DOI: 10.2144/000114461] [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: 03/23/2016] [Accepted: 07/08/2016] [Indexed: 11/23/2022] Open
Abstract
Immobilizing hydrated soft tissue specimens for atomic force microscopy (AFM) is a challenge. Here, we describe a simple and very cost-effective immobilization method, based on the use of transglutaminase in an aqueous environment, and successfully apply it to AFM characterization of human native Wharton's Jelly (nWJ), the gelatinous connective tissue matrix of the umbilical cord. A side-by-side comparison with a widely used polyphenolic protein-based tissue adhesive (Corning Cell-Tak), which is known to bind strongly to virtually all inorganic and organic surfaces in aqueous environments, shows that both adhesives successfully immobilize nWJ in its physological hydrated state. The cost of transglutaminase, however, is over 3000-fold lower than that of Cell-Tak, making it a very attractive method for immobilizing soft tissues for AFM characterization.
Collapse
Affiliation(s)
- Suchit Sahai
- Department of Pediatric Surgery, McGovern Medical School, UTHealth - The University of Texas Health Science Center at Houston, Houston, TX
| | - Marysuna Wilkerson
- Department of Pediatric Surgery, McGovern Medical School, UTHealth - The University of Texas Health Science Center at Houston, Houston, TX
| | - Ana Maria Zaske
- Department of Internal Medicine, Division of Cardiology, UTHealth - The University of Texas Health Science Center at Houston, Houston, TX
| | - Scott D Olson
- Department of Pediatric Surgery, McGovern Medical School, UTHealth - The University of Texas Health Science Center at Houston, Houston, TX
| | - Charles S Cox
- Department of Pediatric Surgery, McGovern Medical School, UTHealth - The University of Texas Health Science Center at Houston, Houston, TX
| | - Fabio Triolo
- Department of Pediatric Surgery, McGovern Medical School, UTHealth - The University of Texas Health Science Center at Houston, Houston, TX
| |
Collapse
|
28
|
Panwar A, Tan LP. Current Status of Bioinks for Micro-Extrusion-Based 3D Bioprinting. Molecules 2016; 21:E685. [PMID: 27231892 PMCID: PMC6273655 DOI: 10.3390/molecules21060685] [Citation(s) in RCA: 226] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Revised: 05/16/2016] [Accepted: 05/19/2016] [Indexed: 12/31/2022] Open
Abstract
Recent developments in 3D printing technologies and design have been nothing short of spectacular. Parallel to this, development of bioinks has also emerged as an active research area with almost unlimited possibilities. Many bioinks have been developed for various cells types, but bioinks currently used for 3D printing still have challenges and limitations. Bioink development is significant due to two major objectives. The first objective is to provide growth- and function-supportive bioinks to the cells for their proper organization and eventual function and the second objective is to minimize the effect of printing on cell viability, without compromising the resolution shape and stability of the construct. Here, we will address the current status and challenges of bioinks for 3D printing of tissue constructs for in vitro and in vivo applications.
Collapse
Affiliation(s)
- Amit Panwar
- School of Materials Science and Engineering, Nanyang Technological University, Block N4.1, 50 Nanyang Avenue, Singapore 639798, Singapore.
| | - Lay Poh Tan
- School of Materials Science and Engineering, Nanyang Technological University, Block N4.1, 50 Nanyang Avenue, Singapore 639798, Singapore.
| |
Collapse
|
29
|
Abstract
Polysialic acid (polySia) is an important carbohydrate bio-polymer that is commonly over-expressed on tumours of neuroendocrine origin and plays a key role in tumour progression. polySia exclusively decorates the neural cell adhesion molecule (NCAM) on tumour cell membranes, modulating cell-cell interactions, motility and invasion. In this preliminary study, we examine the nano-mechanical properties of isogenic C6 rat glioma cells-transfected cells engineered to express the enzyme polysialyltransferase ST8SiaII, which synthesises polySia (C6-STX cells) and wild-type cells (C6-WT). We demonstrate that polySia expression leads to reduced elastic and adhesive properties but also more viscoelastic compared to non-expressing wild-type cells. Whilst differences in cell elasticity between healthy and cancer cells are regularly assigned to changes in the cytoskeleton, we show that in this model system, the change in properties at the nano-level is due to the polySia on the transfected cell membrane surface.
Collapse
|