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Pangeni R, Meng T, Poudel S, Sharma D, Hutsell H, Ma J, Rubin BK, Longest W, Hindle M, Xu Q. Airway mucus in pulmonary diseases: Muco-adhesive and muco-penetrating particles to overcome the airway mucus barriers. Int J Pharm 2023; 634:122661. [PMID: 36736964 PMCID: PMC9975059 DOI: 10.1016/j.ijpharm.2023.122661] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 01/26/2023] [Accepted: 01/27/2023] [Indexed: 02/04/2023]
Abstract
Airway mucus is a complex viscoelastic gel that provides a defensive physical barrier and shields the airway epithelium by trapping inhaled foreign pathogens and facilitating their removal via mucociliary clearance (MCC). In patients with respiratory diseases, such as chronic obstructive pulmonary disease (COPD), cystic fibrosis (CF), non-CF bronchiectasis, and asthma, an increase in crosslinking and physical entanglement of mucin polymers as well as mucus dehydration often alters and typically reduces mucus mesh network pore size, which reduces neutrophil migration, decreases pathogen capture, sustains bacterial infection, and accelerates lung function decline. Conventional aerosol particles containing hydrophobic drugs are rapidly captured and removed by MCC. Therefore, it is critical to design aerosol delivery systems with the appropriate size and surface chemistry that can improve drug retention and absorption with the goal of increased efficacy. Biodegradable muco-adhesive particles (MAPs) and muco-penetrating particles (MPPs) have been engineered to achieve effective pulmonary delivery and extend drug residence time in the lungs. MAPs can be used to target mucus as they get trapped in airway mucus by steric obstruction and/or adhesion. MPPs avoid muco-adhesion and are designed to have a particle size smaller than the mucus network, enhancing lung retention of particles as well as transport to the respiratory epithelial layer and drug absorption. In this review, we aim to provide insight into the composition of airway mucus, rheological characteristics of airway mucus in healthy and diseased subjects, the most recent techniques to study the flow dynamics and particle diffusion in airway mucus (in particular, multiple particle tracking, MPT), and the advancements in engineering MPPs that have contributed to improved airway mucus penetration, lung distribution, and retention.
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Affiliation(s)
- Rudra Pangeni
- Department of Pharmaceutics, Virginia Commonwealth University, Richmond, VA, USA
| | - Tuo Meng
- Department of Pharmaceutics, Virginia Commonwealth University, Richmond, VA, USA
| | - Sagun Poudel
- Department of Pharmaceutics, Virginia Commonwealth University, Richmond, VA, USA
| | - Divya Sharma
- Department of Physiology and Biophysics, Virginia Commonwealth University, Richmond, VA, USA
| | - Hallie Hutsell
- Department of Pharmaceutics, Virginia Commonwealth University, Richmond, VA, USA
| | - Jonathan Ma
- Department of Pediatrics, Children's Hospital of Richmond, Richmond, VA, USA
| | - Bruce K Rubin
- Department of Physiology and Biophysics, Virginia Commonwealth University, Richmond, VA, USA; Department of Pediatrics, Children's Hospital of Richmond, Richmond, VA, USA
| | - Worth Longest
- Department of Pharmaceutics, Virginia Commonwealth University, Richmond, VA, USA; Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University, Richmond, VA, USA
| | - Michael Hindle
- Department of Pharmaceutics, Virginia Commonwealth University, Richmond, VA, USA
| | - Qingguo Xu
- Department of Pharmaceutics, Virginia Commonwealth University, Richmond, VA, USA; Department of Ophthalmology, Massey Cancer Center, Center for Pharmaceutical Engineering, and Institute for Structural Biology, Drug Discovery & Development (ISB3D), Virginia Commonwealth University, Richmond, VA, USA.
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2
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Jung H, Geonzon LC, Yoon WB, Matsukawa S. Change of network structure in agarose solution during gelation studied by multiple particle tracking and NMR measurements. Food Hydrocoll 2023. [DOI: 10.1016/j.foodhyd.2023.108740] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/03/2023]
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3
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Liquid to solid transition of elastin condensates. Proc Natl Acad Sci U S A 2022; 119:e2202240119. [PMID: 36067308 PMCID: PMC9477396 DOI: 10.1073/pnas.2202240119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Liquid-liquid phase separation of tropoelastin has long been considered to be an important early step in the complex process of elastin fiber assembly in the body and has inspired the development of elastin-like peptides with a wide range of industrial and biomedical applications. Despite decades of study, the material state of the condensed liquid phase of elastin and its subsequent maturation remain poorly understood. Here, using a model minielastin that mimics the alternating domain structure of full-length tropoelastin, we examine the elastin liquid phase. We combine differential interference contrast (DIC), fluorescence, and scanning electron microscopy with particle-tracking microrheology to resolve the material transition occurring within elastin liquids over time in the absence of exogenous cross-linking. We find that this transition is accompanied by an intermediate stage marked by the coexistence of insoluble solid and dynamic liquid phases giving rise to significant spatial heterogeneities in material properties. We further demonstrate that varying the length of the terminal hydrophobic domains of minielastins can tune the maturation process. This work not only resolves an important step in the hierarchical assembly process of elastogenesis but further contributes mechanistic insight into the diverse repertoire of protein condensate maturation pathways with emerging importance across biology.
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He S, Caggioni M, Lindberg S, Schultz KM. Gelation phase diagrams of colloidal rod systems measured over a large composition space. RSC Adv 2022; 12:12902-12912. [PMID: 35496333 PMCID: PMC9044831 DOI: 10.1039/d2ra00609j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Accepted: 04/18/2022] [Indexed: 11/21/2022] Open
Abstract
Rheological modifiers tune product rheology with a small amount of material. To effectively use rheological modifiers, characterizing the rheology of the system at different compositions is crucial. Two colloidal rod system, hydrogenated castor oil and polyamide, are characterized in a formulation that includes a surfactant (linear alkylbenzene sulfonate) and a depletant (polyethylene oxide). We characterize both rod systems using multiple particle tracking microrheology (MPT) and bulk rheology and build phase diagrams over a large component composition space. In MPT, fluorescent particles are embedded in the sample and their Brownian motion is measured and related to rheological properties. From MPT, we determine that in both systems: (1) microstructure is not changed with increasing colloid concentration, (2) materials undergo a sol–gel transition as depletant concentration increases and (3) the microstructure changes but does not undergo a phase transition as surfactant concentration increases in the absence of depletant. When comparing MPT and bulk rheology results different trends are measured. Using bulk rheology we observe: (1) elasticity of both systems increase as colloid concentration increases and (2) the storage modulus does not change when PEO or LAS concentration is increased. The differences measured with MPT and bulk rheology are likely due to differences in sensitivity and measurement method. This work shows the utility of using both techniques together to fully characterize rheological properties over a large composition space. These gelation phase diagrams will provide a guide to determine the composition needed for desired rheological properties and eliminate trial-and-error experiments during product formulation. Colloidal rod systems used as rheological modifiers are characterized over a large composition space with microrheology and bulk rheology. Phase diagrams are built that enable identification of compositions with desired properties eliminating trial-and-error experiments.![]()
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Affiliation(s)
- Shiqin He
- Department of Chemical and Biomolecular Engineering, Lehigh University Bethlehem PA USA +1-610-758-5057 +1-610-758-2012
| | - Marco Caggioni
- Process and Engineering Development, Procter & Gamble Co. West Chester OH USA
| | - Seth Lindberg
- Process and Engineering Development, Procter & Gamble Co. West Chester OH USA
| | - Kelly M Schultz
- Department of Chemical and Biomolecular Engineering, Lehigh University Bethlehem PA USA +1-610-758-5057 +1-610-758-2012
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5
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Effects of Visfatin on Intracellular Mechanics and Catabolism in Human Primary Chondrocytes through Glycogen Synthase Kinase 3β Inactivation. Int J Mol Sci 2021; 22:ijms22158107. [PMID: 34360874 PMCID: PMC8348639 DOI: 10.3390/ijms22158107] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Revised: 07/23/2021] [Accepted: 07/26/2021] [Indexed: 12/18/2022] Open
Abstract
Osteoarthritis (OA) is still a recalcitrant musculoskeletal disease on account of its complex biochemistry and mechanical stimulations. Apart from stimulation by external mechanical forces, the regulation of intracellular mechanics in chondrocytes has also been linked to OA development. Recently, visfatin has received significant attention because of the clinical finding of the positive correlation between its serum/synovial level and OA progression. However, the precise mechanism involved is still unclear. This study determined the effect of visfatin on intracellular mechanics and catabolism in human primary chondrocytes isolated from patients. The intracellular stiffness of chondrocytes was analyzed by the particle-tracking microrheology method. It was shown that visfatin damages the microtubule and microfilament networks to influence intracellular mechanics to decrease the intracellular elasticity and viscosity via glycogen synthase kinase 3β (GSK3β) inactivation induced by p38 signaling. Further, microtubule network destruction in human primary chondrocytes is predominantly responsible for the catabolic effect of visfatin on the cyclooxygenase 2 upregulation. The present study shows a more comprehensive interpretation of OA development induced by visfatin through biochemical and biophysical perspectives. Finally, the role of GSK3β inactivation, and subsequent regulation of intracellular mechanics, might be considered as theranostic targets for future drug development for OA.
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Vitali V, Nava G, Zanchetta G, Bragheri F, Crespi A, Osellame R, Bellini T, Cristiani I, Minzioni P. Integrated Optofluidic Chip for Oscillatory Microrheology. Sci Rep 2020; 10:5831. [PMID: 32242060 PMCID: PMC7118116 DOI: 10.1038/s41598-020-62628-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Accepted: 03/05/2020] [Indexed: 11/24/2022] Open
Abstract
We propose and demonstrate an on-chip optofluidic device allowing active oscillatory microrheological measurements with sub-μL sample volume, low cost and high flexibility. Thanks to the use of this optofluidic microrheometer it is possible to measure the viscoelastic properties of complex fluids in the frequency range 0.01-10 Hz at different temperatures. The system is based on the optical forces exerted on a microbead by two counterpropagating infrared laser beams. The core elements of the optical part, integrated waveguides and an optical modulator, are fabricated by fs-laser writing on a glass substrate. The system performance is validated by measuring viscoelastic solutions of aqueous worm-like micelles composed by Cetylpyridinium Chloride (CPyCl) and Sodium Salicylate (NaSal).
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Affiliation(s)
- Valerio Vitali
- University of Pavia, Dept. of Electrical, Computer and Biomedical Engineering, Pavia, 27100, Italy
| | - Giovanni Nava
- University of Milano, Dept. of Medical Biotechnology and Translational Medicine, Milano, 20129, Italy
| | - Giuliano Zanchetta
- University of Milano, Dept. of Medical Biotechnology and Translational Medicine, Milano, 20129, Italy
| | - Francesca Bragheri
- Istituto di Fotonica e Nanotecnologie, Consiglio Nazionale delle Ricerche (IFN-CNR), Milano, 20133, Italy
| | - Andrea Crespi
- Istituto di Fotonica e Nanotecnologie, Consiglio Nazionale delle Ricerche (IFN-CNR), Milano, 20133, Italy
- Dipartimento di Fisica, Politecnico di Milano, Milano, 20133, Italy
| | - Roberto Osellame
- Istituto di Fotonica e Nanotecnologie, Consiglio Nazionale delle Ricerche (IFN-CNR), Milano, 20133, Italy
- Dipartimento di Fisica, Politecnico di Milano, Milano, 20133, Italy
| | - Tommaso Bellini
- University of Milano, Dept. of Medical Biotechnology and Translational Medicine, Milano, 20129, Italy
| | - Ilaria Cristiani
- University of Pavia, Dept. of Electrical, Computer and Biomedical Engineering, Pavia, 27100, Italy
| | - Paolo Minzioni
- University of Pavia, Dept. of Electrical, Computer and Biomedical Engineering, Pavia, 27100, Italy.
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7
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Viscoelasticity in natural tissues and engineered scaffolds for tissue reconstruction. Acta Biomater 2019; 97:74-92. [PMID: 31400521 DOI: 10.1016/j.actbio.2019.08.013] [Citation(s) in RCA: 64] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Revised: 07/23/2019] [Accepted: 08/06/2019] [Indexed: 02/05/2023]
Abstract
Viscoelasticity of living tissues plays a critical role in tissue homeostasis and regeneration, and its implication in disease development and progression is being recognized recently. In this review, we first explored the state of knowledge regarding the potential application of tissue viscoelasticity in disease diagnosis. In order to better characterize viscoelasticity with local resolution and non-invasiveness, emerging characterization methods have been developed with the potential to be supplemented to existing facilities. To understand cellular responses to matrix viscoelastic behaviors in vitro, hydrogels made of natural polymers have been developed and the relationships between their molecular structure and viscoelastic behaviors, are elucidated. Moreover, how cells perceive the viscoelastic microenvironment and cellular responses including cell attachment, spreading, proliferation, differentiation and matrix production, have been discussed. Finally, some future perspective on an integrated mechanobiological comprehension of the viscoelastic behaviors involved in tissue homeostasis, cellular responses and biomaterial design are highlighted. STATEMENT OF SIGNIFICANCE: Tissue- or organ-scale viscoelastic behavior is critical for homeostasis, and the molecular basis and cellular responses of viscoelastic materials at micro- or nano-scale are being recognized recently. We summarized the potential applications of viscoelasticity in disease diagnosis enabled by emerging non-invasive characterization technologies, and discussed the underlying mechanism of viscoelasticity of hydrogels and current understandings of cell regulatory functions of them. With a growing understanding of the molecular basis of hydrogel viscoelasticity and recognition of its regulatory functions on cell behaviors, it is important to bring the clinical insights on how these characterization technologies and engineered materials may contribute to disease diagnosis and treatment. This review explains the basics in characterizing viscoelasticity with our hope to bridge the gap between basic research and clinical applications.
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8
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Carotenuto R, Tussellino M. Xenopus laevis oocyte as a model for the study of the cytoskeleton. C R Biol 2018; 341:219-227. [PMID: 29705198 DOI: 10.1016/j.crvi.2018.04.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Accepted: 04/06/2018] [Indexed: 11/28/2022]
Abstract
At the beginning of diplotene, the oocyte of Xenopus laevis is a cell of about 10-20 microns destined to increase 10,000-fold its size when the oocyte becomes filled with yolk platelets and has accumulated a great number of pigment granules in a half of its periphery. Its internal architecture is gradually accomplished during growth because of several factors, especially because of cytoskeletal changes. In the fully-grown oocyte, the cytoskeleton appears to sustain the eccentrically located germinal vesicle through arms radiating from the cortex to the germinal vesicle, a unique organization not to be found in other Amphibians. In this report, we summarized and analysed steps of cytoskeletal proteins and related mRNAs organization and function throughout diplotene stage, highlighting our studies in this animal model. The cytoskeletal proteins appear to exploit their activity with respect to ribosomal 60S subunit maturation and during translation. Most importantly, the polarity of the oocyte is achieved through a sophisticated and highly organized localization of mRNAs and cytoskeletal proteins in one side of the cell. This asymmetry will start the construction of the oocyte polarity that is instrumental for determining the characteristic of this cell, which will become an embryo. Moreover, in the same time membrane composition, conditioned by the underlying cytoskeletal organization, will acquire the prerequisites for sperm binding and fusion.
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Affiliation(s)
- Rosa Carotenuto
- Department of Biology, University of Naples Federico II, Napoli, Italy.
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9
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Rodell CB, Highley CB, Chen MH, Dusaj NN, Wang C, Han L, Burdick JA. Evolution of hierarchical porous structures in supramolecular guest-host hydrogels. SOFT MATTER 2016; 12:7839-7847. [PMID: 27714343 PMCID: PMC5074696 DOI: 10.1039/c6sm01395c] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Macromolecular interactions are used to form supramolecular assemblies, including through the interaction of guest-host chemical pairs. Microstructural heterogeneity has been observed within such physical hydrogels; yet, systematic investigation of the microstructure and its determining inputs are lacking. Herein, we investigated the hierarchical self-assembly of hyaluronic acid (HA) modified by the guest-host pair adamantane (Ad-HA, guest) and β-cyclodextrin (CD-HA, host), as well as with methacrylate groups to both tether fluorescent agents and to covalently stabilize the material structure. We observed microporous materials in the hydrated state, which temporally arose from initially homogenous hydrogels composed of the two polymers. Independent fluorescent labeling of Ad-HA and CD-HA demonstrated spatiotemporal co-localization, indicative of guest-host polymer condensation on the microscale. The hydrogel void fractions and pore diameters were independently tuned through incubation time (0-7 days), polymer concentration (1.25-10 wt%), and polymer modification (25-50% Ad-HA modification). Void fractions as great as 93.3 ± 2.4% were achieved and pore diameters ranged from 2.1 ± 0.5 to 1025.4 ± 209.4 μm. The segregation of discrete solid and solute phases was measured with both atomic force microscopy and diffusive microparticle tracking analysis, where the solute phase contained only dilute polymer. The study represents a systematic investigation of hierarchical self-assembly in binary associating hydrogels, and provides insights on mechanisms that control microstructure within supramolecular hydrogels.
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Affiliation(s)
| | | | - Minna H. Chen
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA
| | - Neville N. Dusaj
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA
| | - Chao Wang
- School of Biomedical Engineering Science and Health Systems, Drexel University, Philadelphia, PA
| | - Lin Han
- School of Biomedical Engineering Science and Health Systems, Drexel University, Philadelphia, PA
| | - Jason A. Burdick
- Corresponding Author Jason A. Burdick, PhD, Department of Bioengineering, University of Pennsylvania, 240 Skirkanich Hall, 210 S. 33 Street, Philadelphia, PA 19104 (USA),
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10
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Yang H, Kang W, Wu H, Li Z, Yu Y, Lu Y, Zhang L, Wang M, He Y. Passive microrheology for measurement of gelation behavior of a kind of polymer gel P(AM-AA-AMPS). J Appl Polym Sci 2016. [DOI: 10.1002/app.43364] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Affiliation(s)
- Hongbin Yang
- Enhanced Oil Recovery Research Institute, China University of Petroleum (Beijing); Changping District Beijing 102249 China
| | - Wanli Kang
- Enhanced Oil Recovery Research Institute, China University of Petroleum (Beijing); Changping District Beijing 102249 China
- School of Petroleum Engineering; China University of Petroleum (East China) Qingdao, Shandong 266580 China
| | - Hairong Wu
- Enhanced Oil Recovery Research Institute, China University of Petroleum (Beijing); Changping District Beijing 102249 China
| | - Zhe Li
- Enhanced Oil Recovery Research Institute, China University of Petroleum (Beijing); Changping District Beijing 102249 China
| | - Yang Yu
- Enhanced Oil Recovery Research Institute, China University of Petroleum (Beijing); Changping District Beijing 102249 China
| | - Yao Lu
- Enhanced Oil Recovery Research Institute, China University of Petroleum (Beijing); Changping District Beijing 102249 China
| | - Liming Zhang
- Enhanced Oil Recovery Research Institute, China University of Petroleum (Beijing); Changping District Beijing 102249 China
| | - Manying Wang
- Enhanced Oil Recovery Research Institute, China University of Petroleum (Beijing); Changping District Beijing 102249 China
| | - Yuwei He
- Beijing LDS Technology Co. Ltd; Chaoyang District Beijing 100101 China
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11
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Leake MC. Analytical tools for single-molecule fluorescence imaging in cellulo. Phys Chem Chem Phys 2015; 16:12635-47. [PMID: 24626744 DOI: 10.1039/c4cp00219a] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Recent technological advances in cutting-edge ultrasensitive fluorescence microscopy have allowed single-molecule imaging experiments in living cells across all three domains of life to become commonplace. Single-molecule live-cell data is typically obtained in a low signal-to-noise ratio (SNR) regime sometimes only marginally in excess of 1, in which a combination of detector shot noise, sub-optimal probe photophysics, native cell autofluorescence and intrinsically underlying stochasticity of molecules result in highly noisy datasets for which underlying true molecular behaviour is non-trivial to discern. The ability to elucidate real molecular phenomena is essential in relating experimental single-molecule observations to both the biological system under study as well as offering insight into the fine details of the physical and chemical environments of the living cell. To confront this problem of faithful signal extraction and analysis in a noise-dominated regime, the 'needle in a haystack' challenge, such experiments benefit enormously from a suite of objective, automated, high-throughput analysis tools that can home in on the underlying 'molecular signature' and generate meaningful statistics across a large population of individual cells and molecules. Here, I discuss the development and application of several analytical methods applied to real case studies, including objective methods of segmenting cellular images from light microscopy data, tools to robustly localize and track single fluorescently-labelled molecules, algorithms to objectively interpret molecular mobility, analysis protocols to reliably estimate molecular stoichiometry and turnover, and methods to objectively render distributions of molecular parameters.
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Affiliation(s)
- M C Leake
- Biological Physical Sciences Institute (BPSI), Departments of Physics and Biology, University of York, York, YO10 5DD, UK.
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12
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Wong LH, Kurniawan NA, Too HP, Rajagopalan R. Spatially resolved microrheology of heterogeneous biopolymer hydrogels using covalently bound microspheres. Biomech Model Mechanobiol 2013; 13:839-49. [PMID: 24158353 DOI: 10.1007/s10237-013-0538-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2013] [Accepted: 10/15/2013] [Indexed: 11/28/2022]
Abstract
Characterization of the rheological properties of heterogeneous biopolymers is important not only to understand the effect of substrate elasticity on cell behaviors, but also to provide insights into mechanical changes during cellular remodeling of the environment. Conventional particle-tracking microrheology (PTM) techniques are compromised by probe-network slippage and cage-hopping problems, and require a priori knowledge of network mesh size in order to determine a suitable probe size. We demonstrated here the usefulness of covalently bound probes for PTM of biopolymers to overcome the above limitations. We showed that, in a well-defined system like polyacrylamide gels, surface-modified probe particles using a zero-length crosslinker provided more reliable measurements of network mechanics as compared to standard carboxylated probes. We further demonstrated that appropriate surface modification of microspheres for PTM circumvented the requirement of using microspheres larger than the network mesh, an approach typically considered to be ideal. Using the method presented in this study, we found the local network at the leading edge of a typical C6 glioma cell to be stiffer as compared to the side. Our findings established that permanent interaction between the probe and network is crucial to reliably measure the local network mechanics in reconstituted, heterogeneous networks using PTM.
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Affiliation(s)
- Long Hui Wong
- Chemical and Pharmaceutical Engineering, Singapore-MIT Alliance, National University of Singapore, Singapore, 117576, Singapore
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El Kaffas A, Bekah D, Rui M, Kumaradas JC, Kolios MC. Investigating longitudinal changes in the mechanical properties of MCF-7 cells exposed to paclitaxol using particle tracking microrheology. Phys Med Biol 2013; 58:923-36. [PMID: 23340402 DOI: 10.1088/0031-9155/58/4/923] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Evidence suggests that compression and shear wave elastography are sensitive to the mechanical property changes occuring in dying cells following chemotherapy, and can hence be used to monitor cancer treatment response. A qualitative and quantitative understanding of the mechanical changes at the cellular level would allow to better infer how these changes affect macroscopic tissue mechanical properties and therefore allow the optimization of elastographic techniques (such as shear wave elastography) for the monitoring of cancer therapy. We used intracellular particle tracking microrheology (PTM) to investigate the mechanical property changes of cells exposed to paclitaxol, a mitotic inhibitor used in cancer chemotherapy. The average elastic and viscous moduli of the cytoplasm of treated MCF-7 breast cancer cells were calculated for frequency ranges between 0.2 and 100 rad s(-1) (corresponding to 0.03 and 15.92 Hz, respectively). A significant increase in the complex shear modulus of the cell cytoplasm was detected at 12 h post treatment. At 24 h after drug exposure, the elastic and viscous moduli increased by a total of 191.3 Pa (>8000×) and 9 Pa (∼9×), respectively for low frequency shear modulus measurements (at 1 rad s(-1)). At higher frequencies (10 rad s(-1)), the elastic and viscous moduli increased by 188.5 Pa (∼60×) and 1.7 Pa (∼1.1×), respectively. Our work demonstrates that PTM can be used to measure changes in the mechanical properties of treated cells and that cell elasticity significantly increases by 24 h after chemotherapy exposure.
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Affiliation(s)
- Ahmed El Kaffas
- Department of Physics, Ryerson University, 350 Victoria Street, Toronto, Ontario M5B 2K3, Canada.
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14
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Shen MY, Michaelson J, Huang H. Rheological responses of cardiac fibroblasts to mechanical stretch. Biochem Biophys Res Commun 2012; 430:1028-33. [PMID: 23261449 DOI: 10.1016/j.bbrc.2012.12.044] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2012] [Accepted: 12/10/2012] [Indexed: 10/27/2022]
Abstract
Rheological characterization of cells using passive particle tracking techniques can yield substantial information regarding local cellular material properties. However, limited work has been done to establish the changes in material properties of mechanically-responsive cells that experience external stimuli. In this study, cardiac fibroblasts plated on either fibronectin or collagen were treated with cytochalasin, mechanically stretched, or both, and their trajectories and complex moduli were extracted. Results demonstrate that both solid and fluid components were altered by such treatments in a receptor-dependent manner, and that, interestingly, cells treated with cytochalasin were still capable of stiffening in response to mechanical stimuli despite gross stress fiber disruption. These results suggest that the material properties of cells are dependent on a variety of environmental cues and can provide insight into physiological and disease processes.
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Affiliation(s)
- Min Ye Shen
- Columbia University, New York, NY 10027, USA
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15
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Abstract
High-throughput ballistic injection nanorheology is a method for the quantitative study of cell mechanics. Cell mechanics are measured by ballistic injection of submicron particles into the cytoplasm of living cells and tracking the spontaneous displacement of the particles at high spatial resolution. The trajectories of the cytoplasm-embedded particles are transformed into mean-squared displacements, which are subsequently transformed into frequency-dependent viscoelastic moduli and time-dependent creep compliance of the cytoplasm. This method allows for the study of a wide range of cellular conditions, including cells inside a 3D matrix, cell subjected to shear flows and biochemical stimuli, and cells in a live animal. Ballistic injection lasts <1 min and is followed by overnight incubation. Multiple particle tracking for one cell lasts <1 min. Forty cells can be examined in <1 h.
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16
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Viscoelastic gel-strip model for the simulation of migrating cells. Ann Biomed Eng 2011; 39:2735-49. [PMID: 21800204 DOI: 10.1007/s10439-011-0360-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2011] [Accepted: 07/13/2011] [Indexed: 10/17/2022]
Abstract
Migrating tumor cells can exhibit both mesenchymal- and amoeboid-type behaviors. Recent studies have shown that both cellular and extracellular structural and mechanical variables control the transition of tumor cells from one mode to the other and provide them with morphological plasticity. The mesenchymal-mode migration is characterized by strong adhesion and proteolytic machinery to navigate through complex extracellular matrices. The amoeboid-mode migration is characterized by little or no adhesion and strong actomyosin contraction to squeeze through the matrices. While adhesion dependent migration has been computationally and experimentally studied in both 2D and 3D environments, quantitative models of amoeboid motion in native environments are lacking. In order to address this major gap in our understanding and to probe the mesenchymal to amoeboid transitions quantitatively and comprehensively, we have developed an axisymmetric viscoelastic gel-strip model of a single cell to investigate a cell migrating in native-like environments. In this model, cell migration and morphology are governed by internal stresses as well as external forces. The internal stresses are controlled by F-actin density distribution, protrusion strength, and contraction strength. The external forces are controlled by adhesion strength and steric resistance from the extracellular matrix. Our model predicts that the transition of the cell migration mode from mesenchymal- to amoeboid-type, and vice versa, is closely related to the loss of adhesion as well as increased contraction strength of the cells. Our results indicate that amoeboid migration is more suited for low-resistance environment while mesenchymal migration is preferred in high-resistance environment, which would explain the versatile behaviors of tumor cells in complex environments.
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Applications of particle-tracking analysis to the determination of size distributions and concentrations of nanoparticles in environmental, biological and food samples. Trends Analyt Chem 2011. [DOI: 10.1016/j.trac.2011.01.005] [Citation(s) in RCA: 161] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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