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Akdeniz B, Wood JA, Lammertink RGH. Diffusiophoresis in Polymer and Nanoparticle Gradients. J Phys Chem B 2024; 128:5874-5887. [PMID: 38837230 PMCID: PMC11194826 DOI: 10.1021/acs.jpcb.4c00985] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2024] [Revised: 05/22/2024] [Accepted: 05/24/2024] [Indexed: 06/07/2024]
Abstract
Diffusiophoresis is the movement of the colloidal particles in response to a concentration gradient and can be observed for both electrolyte (e.g., salt) and nonelectrolyte (e.g., glucose) solutes. Here, we investigated the diffusiophoretic behavior of polystyrene (PS-carboxylate surface) microparticles in nonadsorbing charged and uncharged solute gradients [sodium polystyrenesulfonate (NaPSS), polyethylene glycol (PEG), and nanoscale colloidal silica (SiO2)] using a dead-end channel setup. We compared the diffusiophoretic motion in these gradient types with each other and to the case of using a monovalent salt gradient. In each of the nonadsorbing gradient systems (NaPSS, PEG, and SiO2 nanoparticles), the PS particles migrated toward the lower solute concentration. The exclusion distance values (from the initial position) of particles were recorded within the dead-end channel, and it was found that an increase in solute concentration increases exclusion from the main channel. In the polyelectrolyte case, the motion of PS microparticles was reduced by the addition of a background salt due to reduced electrostatic interaction, whereas it remained constant when using the neutral polymer. Particle diffusiophoresis in gradients of polyelectrolytes (charged macromolecules) is quite similar to the behavior when using a PEG gradient (uncharged macromolecule) in the presence of a background electrolyte. Moreover, we observed PS microparticles under different concentrations and molecular weights of PEG gradients. By combining the simulations, we estimated the exclusion length, which was previously proposed to be the order of the polymer radius. Furthermore, the movement of PS microparticles was analyzed in the gradient of silica nanoparticles. The exclusion distance was higher in silica nanoparticle gradients compared to similar-size PEG gradients because silica nanoparticles are charged. The diffusiophoretic transport of the PS microparticles could be simulated by considering the interaction between the PS microparticles and silica nanoparticles.
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Affiliation(s)
- Burak Akdeniz
- Soft Matter, Fluidics and Interfaces,
MESA+ Institute for Nanotechnology, University
of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Jeffery A. Wood
- Soft Matter, Fluidics and Interfaces,
MESA+ Institute for Nanotechnology, University
of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Rob G. H. Lammertink
- Soft Matter, Fluidics and Interfaces,
MESA+ Institute for Nanotechnology, University
of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
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2
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Kariya Y, Honma M, Tokuda K, Konagaya A, Suzuki H. Utility of constraints reflecting system stability on analyses for biological models. PLoS Comput Biol 2022; 18:e1010441. [PMID: 36084151 PMCID: PMC9491612 DOI: 10.1371/journal.pcbi.1010441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2021] [Revised: 09/21/2022] [Accepted: 07/26/2022] [Indexed: 12/03/2022] Open
Abstract
Simulating complex biological models consisting of multiple ordinary differential equations can aid in the prediction of the pharmacological/biological responses; however, they are often hampered by the availability of reliable kinetic parameters. In the present study, we aimed to discover the properties of behaviors without determining an optimal combination of kinetic parameter values (parameter set). The key idea was to collect as many parameter sets as possible. Given that many systems are biologically stable and resilient (BSR), we focused on the dynamics around the steady state and formulated objective functions for BSR by partial linear approximation of the focused region. Using the objective functions and modified global cluster Newton method, we developed an algorithm for a thorough exploration of the allowable parameter space for biological systems (TEAPS). We first applied TEAPS to the NF-κB signaling model. This system shows a damped oscillation after stimulation and seems to fit the BSR constraint. By applying TEAPS, we found several directions in parameter space which stringently determines the BSR property. In such directions, the experimentally fitted parameter values were included in the range of the obtained parameter sets. The arachidonic acid metabolic pathway model was used as a model related to pharmacological responses. The pharmacological effects of nonsteroidal anti-inflammatory drugs were simulated using the parameter sets obtained by TEAPS. The structural properties of the system were partly extracted by analyzing the distribution of the obtained parameter sets. In addition, the simulations showed inter-drug differences in prostacyclin to thromboxane A2 ratio such that aspirin treatment tends to increase the ratio, while rofecoxib treatment tends to decrease it. These trends are comparable to the clinical observations. These results on real biological models suggest that the parameter sets satisfying the BSR condition can help in finding biologically plausible parameter sets and understanding the properties of biological systems. We propose a new method to analyze the properties of biological dynamic models, which we named TEAPS (Thorough Exploration of Allowable Parameter Space). TEAPS can thoroughly determine combinations of parameter values for ordinary differential equations with which an initial state in a certain range converges to a particular fixed point. This stable and resilient behavior is a characteristic shared with many biological systems, including metabolic systems and intracellular signaling systems. Therefore, this thorough search outlined the possible parameter space as biological systems for target models, which helps to understand the system constraints when the target systems behave dynamically. The obtained parameter space can be used as an initial space for parameter tuning. For models that include a large number of parameters, the parameter space to be searched in the parameter tuning process is too large; therefore, narrowing down the space by TEAPS potentially contributes to the analysis of the dynamics of complicated biological models. Thus, our approach can partly overcome the current problem in parameter tuning and can advance the computational dynamic analyses of biological systems.
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Affiliation(s)
- Yoshiaki Kariya
- Department of Pharmacy, The University of Tokyo Hospital, Faculty of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Masashi Honma
- Department of Pharmacy, The University of Tokyo Hospital, Faculty of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
- * E-mail:
| | - Keita Tokuda
- Department of Computer Science, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Akihiko Konagaya
- Molecular Robotics Research Institute, Limited, Kyowa Create Dai-ichi, Minato-ku, Tokyo, Japan
| | - Hiroshi Suzuki
- Department of Pharmacy, The University of Tokyo Hospital, Faculty of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
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Liu D, Qiu Y, Li Q, Zhang H. Atomistic Simulation of Lysozyme in Solutions Crowded by Tetraethylene Glycol: Force Field Dependence. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27072110. [PMID: 35408509 PMCID: PMC9000840 DOI: 10.3390/molecules27072110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Revised: 03/21/2022] [Accepted: 03/22/2022] [Indexed: 11/16/2022]
Abstract
The behavior of biomolecules in crowded environments remains largely unknown due to the accuracy of simulation models and the limited experimental data for comparison. Here we chose a small crowder of tetraethylene glycol (PEG-4) to investigate the self-crowding of PEG-4 solutions and molecular crowding effects on the structure and diffusion of lysozyme at varied concentrations from dilute water to pure PEG-4 liquid. Two Amber-like force fields of Amber14SB and a99SB-disp were examined with TIP3P (fast diffusivity and low viscosity) and a99SB-disp (slow diffusivity and high viscosity) water models, respectively. Compared to the Amber14SB protein simulations, the a99SB-disp model yields more coordinated water and less PEG-4 molecules, less intramolecular hydrogen bonds (HBs), more protein-water HBs, and less protein-PEG HBs as well as stronger interactions and more hydrophilic and less hydrophobic contacts with solvent molecules. The a99SB-disp model offers comparable protein-solvent interactions in concentrated PEG-4 solutions to that in pure water. The PEG-4 crowding leads to a slow-down in the diffusivity of water, PEG-4, and protein, and the decline in the diffusion from atomistic simulations is close to or faster than the hard sphere model that neglects attractive interactions. Despite these differences, the overall structure of lysozyme appears to be maintained well at different PEG-4 concentrations for both force fields, except a slightly large deviation at 370 K at low concentrations with the a99SB-disp model. This is mainly attributed to the strong intramolecular interactions of the protein in the Amber14SB force field and to the large viscosity of the a99SB-disp water model. The results indicate that the protein force fields and the viscosity of crowder solutions affect the simulation of biomolecules under crowding conditions.
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Shikha, Shandilya E, Priyanka, Maiti S. Directional migration propensity of calf thymus DNA in a gradient of metal ions. Chem Commun (Camb) 2022; 58:9353-9356. [DOI: 10.1039/d2cc03160d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The migration propensity and spatially modulated surface deposition of calf thymus DNA have been reported in response to gradients of different monovalent and divalent ions.
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Affiliation(s)
- Shikha
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Knowledge City, Manauli 140306, India
| | - Ekta Shandilya
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Knowledge City, Manauli 140306, India
| | - Priyanka
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Knowledge City, Manauli 140306, India
| | - Subhabrata Maiti
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Knowledge City, Manauli 140306, India
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Abstract
AbstractSolute transport under single-phase flow conditions in porous micromodels was studied using high-resolution optical imaging. Experiments examined loading (injection of ink-water solution into a clear water-filled micromodel) and unloading (injection of clear water into an ink-water filled micromodel). Statistically homogeneous and fine-coarse porous micromodels patterns were used. It is shown that the transport time scale during unloading is larger than that under loading, even in a micromodel with a homogeneous structure, so that larger values of the dispersion coefficient were obtained for transport during unloading. The difference between the dispersion values for unloading and loading cases decreased with an increase in the flow rate. This implies that diffusion is the key factor controlling the degree of difference between loading and unloading transport time scales, in the cases considered here. Moreover, the patterned heterogeneity micromodel, containing distinct sections of fine and coarse porous media, increased the difference between the transport time scales during loading and unloading processes. These results raise the question of whether this discrepancy in transport time scales for the same hydrodynamic conditions is observable at larger length and time scales.
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Deshwal A, Maiti S. Macromolecular Crowding Effect on the Activity of Liposome-Bound Alkaline Phosphatase: A Paradoxical Inhibitory Action. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:7273-7284. [PMID: 34086469 DOI: 10.1021/acs.langmuir.1c01177] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The cytoplasm of a cell is extremely crowded, with 20-30% being large biomolecules. This crowding enforces a significant amount of the physical and chemical barrier around biomolecules, so understanding any biomolecular event within the cellular system is challenging. Unsurprisingly, enzymes show a diverse kind of catalytic behavior inside a crowded environment and thus have remained an area of active interest in the last few decades. The situation can become even more complex and exciting in the case of understanding the behavior of a membrane-bound enzyme (almost 25-30% of enzymes are membrane-bound) in such a crowded environment that until now has remained unexplored. Herein, we have particularly investigated how a membrane-bound enzyme (using liposome-bound alkaline phosphatase) can behave in a crowded environment comprising polymer molecule-like poly(ethylene glycol) (PEG) of different weights (PEG400, PEG4000, and PEG9000) and Ficoll 400. We have compared the activity using a polymer microbead conjugated enzyme and have found that liposome-bound alkaline phosphatase had much higher activity in crowded environments, showing the importance and superiority of soft-deformable particles (i.e., vesicles) over hard spheres in macro-molecularly crowded media. Interstingly, we have found a paradoxical behavior of inhibitors in terms of both their extent and pathway of inhibitory action. For instance, phosphates, known as competitive inhibitors in buffer, behave as uncompetitive inhibitors in liposome-bound enzymes in crowded media with an ∼5-fold less inhibitory effect, whereas phenyl alanine (an uncompetitive inhibitor in buffer) did not show any inhibitory potential when the enzyme was membrane-bound and in crowded media containing PEG9000 (30 wt %). Overall, this demonstration elucidates aspects of membrane-bound enzymes in crowded media in terms of both catalytic behavior and inhibitory actions and can lead to further studies of the understanding of enzymatic behavior in such complex crowded environments having a dampening effect in regular diffusive transport.
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Affiliation(s)
- Akshi Deshwal
- Indian Institute of Science Education and Research (IISER) Mohali, Department of Chemical Sciences, Knowledge City, Manauli 140306, India
| | - Subhabrata Maiti
- Indian Institute of Science Education and Research (IISER) Mohali, Department of Chemical Sciences, Knowledge City, Manauli 140306, India
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It is time to crowd your cell culture media - Physicochemical considerations with biological consequences. Biomaterials 2021; 275:120943. [PMID: 34139505 DOI: 10.1016/j.biomaterials.2021.120943] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2020] [Revised: 05/24/2021] [Accepted: 05/29/2021] [Indexed: 12/12/2022]
Abstract
In vivo, the interior and exterior of cells is populated by various macromolecules that create an extremely crowded milieu. Yet again, in vitro eukaryotic cell culture is conducted in dilute culture media that hardly imitate the native tissue density. Herein, the concept of macromolecular crowding is discussed in both intracellular and extracellular context. Particular emphasis is given on how the physicochemical properties of the crowding molecules govern and determine kinetics, equilibria and mechanism of action of biochemical and biological reactions, processes and functions. It is evidenced that we are still at the beginning of appreciating, let alone effectively implementing, the potential of macromolecular crowding in permanently differentiated and stem cell culture systems.
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Williams I, Lee S, Apriceno A, Sear RP, Battaglia G. Diffusioosmotic and convective flows induced by a nonelectrolyte concentration gradient. Proc Natl Acad Sci U S A 2020; 117:25263-25271. [PMID: 32989158 PMCID: PMC7568292 DOI: 10.1073/pnas.2009072117] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Glucose is an important energy source in our bodies, and its consumption results in gradients over length scales ranging from the subcellular to entire organs. Concentration gradients can drive material transport through both diffusioosmosis and convection. Convection arises because concentration gradients are mass density gradients. Diffusioosmosis is fluid flow induced by the interaction between a solute and a solid surface. A concentration gradient parallel to a surface creates an osmotic pressure gradient near the surface, resulting in flow. Diffusioosmosis is well understood for electrolyte solutes, but is more poorly characterized for nonelectrolytes such as glucose. We measure fluid flow in glucose gradients formed in a millimeter-long thin channel and find that increasing the gradient causes a crossover from diffusioosmosis-dominated to convection-dominated flow. We cannot explain this with established theories of these phenomena which predict that both scale linearly. In our system, the convection speed is linear in the gradient, but the diffusioosmotic speed has a much weaker concentration dependence and is large even for dilute solutions. We develop existing models and show that a strong surface-solute interaction, a heterogeneous surface, and accounting for a concentration-dependent solution viscosity can explain our data. This demonstrates how sensitive nonelectrolyte diffusioosmosis is to surface and solution properties and to surface-solute interactions. A comprehensive understanding of this sensitivity is required to understand transport in biological systems on length scales from micrometers to millimeters where surfaces are invariably complex and heterogeneous.
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Affiliation(s)
- Ian Williams
- Institute for Bioengineering of Catalonia, The Barcelona Institute of Science and Technology, 08028 Barcelona, Spain;
- Department of Chemistry, University College London, London WC1H 0AJ, United Kingdom
| | - Sangyoon Lee
- Department of Chemistry, University College London, London WC1H 0AJ, United Kingdom
- Department of Chemistry, Seoul National University, Seoul 08826, Republic of Korea
| | - Azzurra Apriceno
- Institute for Bioengineering of Catalonia, The Barcelona Institute of Science and Technology, 08028 Barcelona, Spain
- Department of Chemistry, University College London, London WC1H 0AJ, United Kingdom
| | - Richard P Sear
- Department of Physics, University of Surrey, Guildford GU2 7XH, United Kingdom
| | - Giuseppe Battaglia
- Institute for Bioengineering of Catalonia, The Barcelona Institute of Science and Technology, 08028 Barcelona, Spain
- Department of Chemistry, University College London, London WC1H 0AJ, United Kingdom
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Skóra T, Vaghefikia F, Fitter J, Kondrat S. Macromolecular Crowding: How Shape and Interactions Affect Diffusion. J Phys Chem B 2020; 124:7537-7543. [PMID: 32790396 DOI: 10.1021/acs.jpcb.0c04846] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
A significant fraction of the cell volume is occupied by various proteins, polysaccharides, nucleic acids, etc., which considerably reduces the mobility of macromolecules. Theoretical and experimental work so far have mainly focused on the dependence of the mobility on the occupied volume, while the effect of a macromolecular shape received less attention. Herein, using fluorescence correlation spectroscopy (FCS) and Brownian dynamics (BD) simulations, we report on a dramatic slowdown of tracer diffusion by cylindrically shaped double-stranded (ds) DNAs (16 nm in length). We find, for instance, that the translational diffusion coefficient of a streptavidin tracer is reduced by about 60% for a volume fraction of dsDNA as low as just 5%. For comparison, for a spherical crowder (Ficoll70) the slowdown is only 10% at the same volume fraction and 60% reduction occurs at a volume fraction as high as 35%. BD simulations reveal that this reduction can be attributed to a larger volume excluded to a tracer by dsDNA particles, as compared with spherical Ficoll70 at the same volume fraction, and to the differences in the tracer-crowder attractive interactions. In addition, we find using BD simulations that rotational diffusion of dsDNA is less affected by the crowder shape than its translational motion. Our results show that diffusion in crowded systems is determined not merely by the occupied volume fraction, but that the shape and interactions can determine diffusion, which is relevant to the diverse intracellular environments inside living cells.
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Affiliation(s)
- Tomasz Skóra
- Department of Complex Systems, Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
| | - Farzaneh Vaghefikia
- I. Physikalisches Institut (IA), AG Biophysik, RWTH Aachen University, 52074 Aachen, Germany
| | - Jörg Fitter
- I. Physikalisches Institut (IA), AG Biophysik, RWTH Aachen University, 52074 Aachen, Germany.,Institut für Biologische Informationsprozesse (IBI-6), Forschungszentrum Jülich, 52425 Jülich, Germany
| | - Svyatoslav Kondrat
- Department of Complex Systems, Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland.,Max-Planck-Institut für Intelligente Systeme, Heisenbergstraße 3, 70569 Stuttgart, Germany.,Institut für Theoretische Physik IV, Universität Stuttgart, Pfaffenwaldring 57, 70569 Stuttgart, Germany
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10
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Butler PJ. Mechanobiology of dynamic enzyme systems. APL Bioeng 2020; 4:010907. [PMID: 32161834 PMCID: PMC7054122 DOI: 10.1063/1.5133645] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Accepted: 01/28/2020] [Indexed: 12/29/2022] Open
Abstract
This Perspective paper advances a hypothesis of mechanosensation by endothelial cells in which the cell is a dynamic crowded system, driven by continuous enzyme activity, that can be shifted from one non-equilibrium state to another by external force. The nature of the shift will depend on the direction, rate of change, and magnitude of the force. Whether force induces a pathophysiological or physiological change in cell biology will be determined by whether the dynamics of a cellular system can accommodate the dynamics and magnitude of the force application. The complex interplay of non-static cytoskeletal structures governs internal cellular rheology, dynamic spatial reorganization, and chemical kinetics of proteins such as integrins, and a flaccid membrane that is dynamically supported; each may constitute the necessary dynamic properties able to sense external fluid shear stress and reorganize in two and three dimensions. The resulting reorganization of enzyme systems in the cell membrane and cytoplasm may drive the cell to a new physiological state. This review focuses on endothelial cell mechanotransduction of shear stress, but may lead to new avenues of investigation of mechanobiology in general requiring new tools for interrogation of mechanobiological systems, tools that will enable the synthesis of large amounts of spatial and temporal data at the molecular, cellular, and system levels.
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Affiliation(s)
- Peter J. Butler
- Department of Biomedical Engineering The Pennsylvania State University University Park, Pennsylvania 16802, USA
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11
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Wang H, Pemberton JE. Direct Nanoscopic Measurement of Laminar Slip Flow Penetration of Deformable Polymer Brush Surfaces: Synergistic Effect of Grafting Density and Solvent Quality. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:13646-13655. [PMID: 31558025 DOI: 10.1021/acs.langmuir.9b02357] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
A detailed quantitative nanoscopic description of soft surfaces under dynamic flow is lacking, despite its importance. To better understand the role of surface texture in nanoscopic mass transport in complex media, we used Förster resonance energy transfer in combination with total internal reflectance fluorescence microscopy (FRET-TIRFM) to directly measure laminar slip flow penetration depth (slip length) on poly(N-isopropylacrylamide) (pNIPAM) thin films (50-110 nm) of different grafting densities (0.60, 0.38, and 0.27 chain/nm2) in solvents of different qualities created via cononsolvency in situ. Nontrivial synergistic interplay of grafting density and solvent quality on slip length was observed. Slip lengths are typically tens of nm (40-100 nm), increasing and then reaching a plateau with applied linear flow velocity (192-2,952 μm/s) regardless of experimental system. Slip length was systematically larger for lower density films, but the effect of grafting density was more significant in a good solvent than a poor solvent. Interestingly, however, the stagnant film thickness (polymer swollen thickness minus the slip length) collapsed to almost a singular value for a given grafting density regardless of solvent quality, likely suggesting a large gradient of segmental mobility at nonequilibrium. Moreover, we found that slip flow penetrates into soft pNIPAM surfaces more deeply in a good solvent than in a poor solvent and that this behavior was general and independent of grafting density. This behavior is counter to the notion that less interaction between a fluid (probe) and a solid surface promotes slip.
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Affiliation(s)
- Huan Wang
- Department of Chemistry and Biochemistry University of Arizona , Tucson , Arizona 85721 , United States
| | - Jeanne E Pemberton
- Department of Chemistry and Biochemistry University of Arizona , Tucson , Arizona 85721 , United States
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Ghosh S, Mohajerani F, Son S, Velegol D, Butler PJ, Sen A. Motility of Enzyme-Powered Vesicles. NANO LETTERS 2019; 19:6019-6026. [PMID: 31429577 DOI: 10.1021/acs.nanolett.9b01830] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Autonomous nanovehicles powered by energy derived from chemical catalysis have potential applications as active delivery agents. For in vivo applications, it is necessary that the engine and its fuel, as well as the chassis itself, be biocompatible. Enzyme molecules have been shown to display enhanced motility through substrate turnover and are attractive candidates as engines; phospholipid vesicles are biocompatible and can serve as cargo containers. Herein, we describe the autonomous movement of vesicles with membrane-bound enzymes in the presence of the substrate. We find that the motility of the vesicles increases with increasing enzymatic turnover rate. The enhanced diffusion of these enzyme-powered systems was further substantiated in real time by tracking the motion of the vesicles using optical microscopy. The membrane-bound protocells that move by transducing chemical energy into mechanical motion serve as models for motile living cells and are key to the elucidation of the fundamental mechanisms governing active membrane dynamics and cellular movement.
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