1
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Pacheco-Pozo A, Krapf D. Fractional Brownian motion with fluctuating diffusivities. Phys Rev E 2024; 110:014105. [PMID: 39160988 DOI: 10.1103/physreve.110.014105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2024] [Accepted: 06/20/2024] [Indexed: 08/21/2024]
Abstract
Despite the success of fractional Brownian motion (fBm) in modeling systems that exhibit anomalous diffusion due to temporal correlations, recent experimental and theoretical studies highlight the necessity for a more comprehensive approach of a generalization that incorporates heterogeneities in either the tracers or the environment. This work presents a modification of Lévy's representation of fBm for the case in which the generalized diffusion coefficient is a stochastic process. We derive analytical expressions for the autocovariance function and both ensemble- and time-averaged mean squared displacements. Further, we validate the efficacy of the developed framework in two-state systems, comparing analytical asymptotic expressions with numerical simulations.
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2
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Liang Y, Wang W, Metzler R. Aging and confinement in subordinated fractional Brownian motion. Phys Rev E 2024; 109:064144. [PMID: 39020934 DOI: 10.1103/physreve.109.064144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Accepted: 05/29/2024] [Indexed: 07/20/2024]
Abstract
We study the effects of aging properties of subordinated fractional Brownian motion (FBM) with drift and in harmonic confinement, when the measurement of the stochastic process starts a time t_{a}>0 after its original initiation at t=0. Specifically, we consider the aged versions of the ensemble mean-squared displacement (MSD) and the time-averaged MSD (TAMSD), along with the aging factor. Our results are favorably compared with simulations results. The aging subordinated FBM exhibits a disparity between MSD and TAMSD and is thus weakly nonergodic, while strong aging is shown to effect a convergence of the MSD and TAMSD. The information on the aging factor with respect to the lag time exhibits an identical form to the aging behavior of subdiffusive continuous-time random walks (CTRW). The statistical properties of the MSD and TAMSD for the confined subordinated FBM are also derived. At long times, the MSD in the harmonic potential has a stationary value, that depends on the Hurst index of the parental (nonequilibrium) FBM. The TAMSD of confined subordinated FBM does not relax to a stationary value but increases sublinearly with lag time, analogously to confined CTRW. Specifically, short aging times t_{a} in confined subordinated FBM do not affect the aged MSD, while for long aging times the aged MSD has a power-law increase and is identical to the aged TAMSD.
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3
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Rajyaguru A, Metzler R, Dror I, Grolimund D, Berkowitz B. Diffusion in Porous Rock Is Anomalous. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:8946-8954. [PMID: 38736287 PMCID: PMC11112742 DOI: 10.1021/acs.est.4c01386] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2024] [Revised: 04/30/2024] [Accepted: 05/01/2024] [Indexed: 05/14/2024]
Abstract
Molecular diffusion of chemical species in subsurface environments─rock formations, soil sediments, marine, river, and lake sediments─plays a critical role in a variety of dynamic processes, many of which affect water chemistry. We investigate and demonstrate the occurrence of anomalous (non-Fickian) diffusion behavior, distinct from classically assumed Fickian diffusion. We measured molecular diffusion through a series of five chalk and dolomite rock samples over a period of about two months. We demonstrate that in all cases, diffusion behavior is significantly different than Fickian. We then analyze the results using a continuous time random walk framework that can describe anomalous diffusion in heterogeneous porous materials such as rock. This methodology shows extreme long-time tailing of tracer advance as compared to conventional Fickian diffusion processes. The finding that distinct anomalous diffusion occurs ubiquitously implies that diffusion-driven processes in subsurface zones should be analyzed using tools that account for non-Fickian diffusion.
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Affiliation(s)
- Ashish Rajyaguru
- Department
of Earth and Planetary Sciences, Weizmann
Institute of Science, Rehovot 7610001, Israel
| | - Ralf Metzler
- Institute
for Physics and Astronomy, University of
Potsdam, 14476 Potsdam, Germany
- Asia
Pacific Centre for Theoretical Physics, Pohang 37673, Republic of Korea
| | - Ishai Dror
- Department
of Earth and Planetary Sciences, Weizmann
Institute of Science, Rehovot 7610001, Israel
| | | | - Brian Berkowitz
- Department
of Earth and Planetary Sciences, Weizmann
Institute of Science, Rehovot 7610001, Israel
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4
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Tripathy M, Srivastava A. Non-affine deformation analysis and 3D packing defects: A new way to probe membrane heterogeneity in molecular simulations. Methods Enzymol 2024; 701:541-577. [PMID: 39025582 DOI: 10.1016/bs.mie.2024.03.011] [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] [Indexed: 07/20/2024]
Abstract
Here, we discuss a new framework developed over the last 5 years in our group to probe nanoscale membrane heterogeneity. The framework is based on the idea of characterizing lateral heterogeneity through non-affine deformation (NAD) measurements, transverse heterogeneity through three dimensional (3D) lipid packing defects, and using these approaches to formalize the seemingly trivial correlation between lateral organization and lipid packing in biological membranes. We find that measurements from NAD analysis, a prescription which is borrowed from Physics of glasses and granular material, can faithfully distinguish between liquid-ordered and disordered phases in membranes at molecular length scales and, can also be used to identify phase boundaries with high precision. Concomitantly, 3D-packing defects can not only distinguish between the two co-existing fluid phases based on their molecular scale packing (or membrane free volume), but also provide a route to connect the membrane domains to their functionality, such as exploring the molecular origins of inter-leaflet domain registration and peptide partitioning. The correlation between lateral membrane order and transverse packing presents novel molecular design-level features that can explain functions such as protein/peptide partitioning and small-molecule permeation dynamics in complex and heterogeneous membranes with high-fidelity. The framework allows us to explore the nature of lateral organization and molecular packing as a manifestation of intricate molecular interactions among a chemically rich variety of lipids and other molecules in a membrane with complex membrane composition and asymmetry across leaflets.
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Affiliation(s)
- Madhusmita Tripathy
- Department of Chemistry, Technical University of Darmstadt, Darmstadt, Germany.
| | - Anand Srivastava
- Molecular Biophysics Unit, Indian Institute of Science Bangalore, Karnataka, India.
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5
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Yan C, Guan D, Wang Y, Lai PY, Chen HY, Tong P. Avalanches and Extreme Value Statistics of a Mesoscale Moving Contact Line. PHYSICAL REVIEW LETTERS 2024; 132:084003. [PMID: 38457705 DOI: 10.1103/physrevlett.132.084003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Revised: 11/13/2023] [Accepted: 01/16/2024] [Indexed: 03/10/2024]
Abstract
We report direct atomic force microscopy measurements of pinning-depinning dynamics of a circular moving contact line (CL) over the rough surface of a micron-sized vertical hanging glass fiber, which intersects a liquid-air interface. The measured capillary force acting on the CL exhibits sawtoothlike fluctuations, with a linear accumulation of force of slope k (stick) followed by a sharp release of force δf, which is proportional to the CL slip length. From a thorough analysis of a large volume of the stick-slip events, we find that the local maximal force F_{c} needed for CL depinning follows the extreme value statistics and the measured δf follows the avalanche dynamics with a power law distribution in good agreement with the Alessandro-Beatrice-Bertotti-Montorsi (ABBM) model. The experiment provides an accurate statistical description of the CL dynamics at mesoscale, which has important implications to a common class of problems involving stick-slip motion in a random defect or roughness landscape.
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Affiliation(s)
- Caishan Yan
- Department of Physics, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
| | - Dongshi Guan
- State Key Laboratory of Nonlinear Mechanics, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, China
- School of Engineering Science, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yin Wang
- Department of Physics, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
| | - Pik-Yin Lai
- Department of Physics and Center for Complex Systems, National Central University, Taoyuan City 320, Taiwan
- Physics Division, National Center for Theoretical Sciences, Taipei 10617, Taiwan
| | - Hsuan-Yi Chen
- Department of Physics and Center for Complex Systems, National Central University, Taoyuan City 320, Taiwan
- Physics Division, National Center for Theoretical Sciences, Taipei 10617, Taiwan
| | - Penger Tong
- Department of Physics, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
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6
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Großmann R, Bort LS, Moldenhawer T, Stange M, Panah SS, Metzler R, Beta C. Non-Gaussian Displacements in Active Transport on a Carpet of Motile Cells. PHYSICAL REVIEW LETTERS 2024; 132:088301. [PMID: 38457713 DOI: 10.1103/physrevlett.132.088301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Revised: 01/10/2024] [Accepted: 01/24/2024] [Indexed: 03/10/2024]
Abstract
We study the dynamics of micron-sized particles on a layer of motile cells. This cell carpet acts as an active bath that propels passive tracer particles via direct mechanical contact. The resulting nonequilibrium transport shows a crossover from superdiffusive to normal-diffusive dynamics. The particle displacement distribution is distinctly non-Gaussian even at macroscopic timescales exceeding the measurement time. We obtain the distribution of diffusion coefficients from the experimental data and introduce a model for the displacement distribution that matches the experimentally observed non-Gaussian statistics. We argue why similar transport properties are expected for many composite active matter systems.
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Affiliation(s)
- Robert Großmann
- Institute of Physics and Astronomy, University of Potsdam, Potsdam 14476, Germany
| | - Lara S Bort
- Institute of Physics and Astronomy, University of Potsdam, Potsdam 14476, Germany
| | - Ted Moldenhawer
- Institute of Physics and Astronomy, University of Potsdam, Potsdam 14476, Germany
| | - Maike Stange
- Institute of Physics and Astronomy, University of Potsdam, Potsdam 14476, Germany
| | | | - Ralf Metzler
- Institute of Physics and Astronomy, University of Potsdam, Potsdam 14476, Germany
- Asia Pacific Center for Theoretical Physics, Pohang 37673, Republic of Korea
| | - Carsten Beta
- Institute of Physics and Astronomy, University of Potsdam, Potsdam 14476, Germany
- Nano Life Science Institute (WPI-NanoLSI), Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan
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7
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Xu R, Zhang W, Jin T, Tu W, Xu C, Wei Y, Han W, Yang K, Yuan B. Cholesterol Depletion and Membrane Deformation by MeβCD and the Resultant Enhanced T Cell Killing. ACS APPLIED MATERIALS & INTERFACES 2024; 16:6813-6824. [PMID: 38290472 DOI: 10.1021/acsami.3c16213] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2024]
Abstract
Recent studies have demonstrated the crucial role of cholesterol (Chol) in regulating the mechanical properties and biological functions of cell membranes. Methyl-β-cyclodextrin (MeβCD) is commonly utilized to modulate the Chol content in cell membranes, but there remains a lack of a comprehensive understanding. In this study, using a range of different techniques, we find that the optimal ratio of MeβCD to Chol for complete removal of Chol from a phosphocholine (PC)/Chol mixed membrane with a 1:1 mol ratio is 4.5:1, while the critical MeβCD-to-Chol ratio for membrane permeation falls within the range between 1.5 and 2.4. MeβCD at elevated concentrations induces the formation of fibrils or tubes from a PC membrane. Single lipid tracking reveals that removing Chol restores the diffusion of lipid molecules in the PC/Chol membrane to levels observed in pure PC membranes. Exposure to 5 mM MeβCD for 30 min effectively eliminates Chol from various cell lines, leading to an up to 8-fold enhancement in melittin cytotoxicity over Hela cells and an up to 3.5-fold augmentation of T cell cytotoxicity against B16F10-OVA cells. This study presents a diagram that delineates the concentration- and time-dependent distribution of MeβCD-induced Chol depletion and membrane deformation, which holds significant potential for modulating the mechanical properties of cellular membranes in prospective biomedical applications.
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Affiliation(s)
- Rong Xu
- Center for Soft Condensed Matter Physics and Interdisciplinary Research & School of Physical Science and Technology, Soochow University, Suzhou 215006, Jiangsu, China
- Songshan Lake Materials Laboratory, Dongguan 523808, Guangdong, China
| | - Wanting Zhang
- Center for Soft Condensed Matter Physics and Interdisciplinary Research & School of Physical Science and Technology, Soochow University, Suzhou 215006, Jiangsu, China
- Songshan Lake Materials Laboratory, Dongguan 523808, Guangdong, China
| | - Taoli Jin
- Songshan Lake Materials Laboratory, Dongguan 523808, Guangdong, China
| | - Wenqiang Tu
- Center for Soft Condensed Matter Physics and Interdisciplinary Research & School of Physical Science and Technology, Soochow University, Suzhou 215006, Jiangsu, China
| | - Cheng Xu
- Songshan Lake Materials Laboratory, Dongguan 523808, Guangdong, China
| | - Yushuang Wei
- Songshan Lake Materials Laboratory, Dongguan 523808, Guangdong, China
| | - Weijing Han
- Songshan Lake Materials Laboratory, Dongguan 523808, Guangdong, China
| | - Kai Yang
- Center for Soft Condensed Matter Physics and Interdisciplinary Research & School of Physical Science and Technology, Soochow University, Suzhou 215006, Jiangsu, China
- Songshan Lake Materials Laboratory, Dongguan 523808, Guangdong, China
| | - Bing Yuan
- Songshan Lake Materials Laboratory, Dongguan 523808, Guangdong, China
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8
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Gong J, Li Q, Zeng S, Wang J. Non-Gaussian anomalous diffusion of optical vortices. Phys Rev E 2024; 109:024111. [PMID: 38491579 DOI: 10.1103/physreve.109.024111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Accepted: 12/15/2023] [Indexed: 03/18/2024]
Abstract
Anomalous diffusion of different particlelike entities, the deviation from typical Brownian motion, is ubiquitous in complex physical and biological systems. While optical vortices move randomly in evolving speckle fields, optical vortices have only been observed to exhibit pure Brownian motion in random speckle fields. Here we present direct experimental evidence of the anomalous diffusion of optical vortices in temporally varying speckle patterns from multiple-scattering viscoelastic media. Moreover, we observe two characteristic features, i.e., the self-similarity and the antipersistent correlation of the optical vortex motion, indicating that the mechanism of the observed subdiffusion of optical vortices can only be attributed to fractional Brownian motion (FBM). We further demonstrate that the vortex displacements exhibit a non-Gaussian heavy-tailed distribution. Additionally, we modulate the extent of subdiffusion, such as diffusive scaling exponents, and the non-Gaussianity of optical vortices by altering the viscoelasticity of samples. The discovery of the complex FBM but non-Gaussian subdiffusion of optical vortices may not only offer insight into certain fundamental physics, including the anomalous diffusion of vortices in fluids and the decoupling between Brownianity and Gaussianity, but also suggest a strong potential for utilizing optical vortices as tracers in microrheology instead of the introduced exogenous probe particles in particle tracking microrheology.
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Affiliation(s)
- Jiaxing Gong
- Department of Biomedical Engineering, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Qi Li
- Department of Biomedical Engineering, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Shaoqun Zeng
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics, MoE Key Laboratory for Biomedical Photonics, School of Engineering Sciences, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Jing Wang
- Department of Biomedical Engineering, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
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9
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Mariya S, Barr JJ, Sunthar P, Prakash JR. Universal scaling of the diffusivity of dendrimers in a semidilute solution of linear polymers. SOFT MATTER 2024; 20:993-1008. [PMID: 38197233 DOI: 10.1039/d3sm01190a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2024]
Abstract
The static and dynamic properties of dendrimers in semidilute solutions of linear chains of comparable size are investigated using Brownian dynamics simulations. The radius of gyration and diffusivity of a wide variety of low generation dendrimers and linear chains in solution follow universal scaling laws independent of their topology. Analysis of the shape functions and internal density of dendrimers shows that they are more spherical than linear chains and have a dense core. At intermediate times, dendrimers become subdiffusive, with an exponent higher than that previously reported for nanoparticles in semidilute polymer solutions. The long-time diffusivity of dendrimers does not follow theoretical predictions for nanoparticles. We propose a new scaling law for the long-time diffusion coefficients of dendrimers which accounts for the fact that, unlike nanoparticles, dendrimers shrink with an increase in background solution concentration. Analysis of the properties of a special case of a higher functionality dendrimer shows a transition from polymer-like to nanoparticle-like behaviour.
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Affiliation(s)
- Silpa Mariya
- IITB-Monash Research Academy, Indian Institute of Technology Bombay, Mumbai, 400076, India
| | - Jeremy J Barr
- School of Biological Sciences, Monash University, Clayton, VIC 3800, Australia
| | - P Sunthar
- Department of Chemical Engineering, Indian Institute of Technology Bombay, Mumbai, 400076, India
| | - J Ravi Prakash
- Department of Chemical and Biological Engineering, Monash University, Clayton, VIC 3800, Australia.
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10
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Ye Z, Zhang C, Yuan J, Xiao L. Ligand-Receptor Interaction Triggers Hopping and Sliding Motions on Living Cell Membranes. J Am Chem Soc 2023; 145:25177-25185. [PMID: 37947087 DOI: 10.1021/jacs.3c06925] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2023]
Abstract
Exploring the surface-capturing and releasing processes of nanocargo on the living cell membrane is critical for understanding the membrane translocation process. In this work, we achieve total internal reflection scattering (TIRS) illumination on a commercial dark-field optical microscope without the introduction of any additional optical components. By gradually reducing the diaphragm size in the excitation light path, the angle of the incident beam can be well manipulated. Under optimal conditions, the excitation light can be totally reflected at the glass/water interface, resulting in a thin layer of evanescent field for TIRS illumination. Due to the exponential decay feature of the evanescent field, the displacement of the nanocargo along the vertical direction can be directly resolved in the intensity track. With this method, we selectively monitor the dynamics of the transferrin-modified nanocargo on the living cell membrane. Transition between confined diffusion and long-range searching is involved in the binding site recognition process, which exhibits non-Gaussian and nonergodic-like behavior. More interestingly, 2D fast sliding and 3D hopping motions are also distinguished on the fluidic cell membrane, which is essentially modulated by the strength of ligand-receptor interactions, as revealed by the free-energy profiles. These heterogeneous and dynamic interactions together control the diffusion mode of the nanocargo on the lipid membrane and, thus, determine the cellular translocation efficiency.
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Affiliation(s)
- Zhongju Ye
- Department of Chemistry, Zhengzhou University, Zhengzhou 450001, China
| | - Chen Zhang
- Department of Chemistry, Zhengzhou University, Zhengzhou 450001, China
| | - Jie Yuan
- School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang 453007, China
| | - Lehui Xiao
- College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China
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11
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Hu M, Chen H, Wang H, Burov S, Barkai E, Wang D. Triggering Gaussian-to-Exponential Transition of Displacement Distribution in Polymer Nanocomposites via Adsorption-Induced Trapping. ACS NANO 2023; 17:21708-21718. [PMID: 37879044 DOI: 10.1021/acsnano.3c06897] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2023]
Abstract
In many disordered systems, the diffusion of classical particles is described by a displacement distribution P(x, t) that displays exponential tails instead of Gaussian statistics expected for Brownian motion. However, the experimental demonstration of control of this behavior by increasing the disorder strength has remained challenging. In this work, we explore the Gaussian-to-exponential transition by using diffusion of poly(ethylene glycol) (PEG) in attractive nanoparticle-polymer mixtures and controlling the volume fraction of the nanoparticles. In this work, we find "knobs", namely nanoparticle concentration and interaction, which enable the change in the shape of P(x,t) in a well-defined way. The Gaussian-to-exponential transition is consistent with a modified large deviation approach for a continuous time random walk and also with Monte Carlo simulations involving a microscopic model of polymer trapping via reversible adsorption to the nanoparticle surface. Our work bears significance in unraveling the fundamental physics behind the exponential decay of the displacement distribution at the tails, which is commonly observed in soft materials and nanomaterials.
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Affiliation(s)
- Ming Hu
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin 130022, People's Republic of China
- University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
| | - Hongbo Chen
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin 130022, People's Republic of China
| | - Hongru Wang
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin 130022, People's Republic of China
- University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
| | - Stanislav Burov
- Department of Physics, Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat-Gan 52900, Israel
| | - Eli Barkai
- Department of Physics, Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat-Gan 52900, Israel
| | - Dapeng Wang
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin 130022, People's Republic of China
- University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
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12
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Waigh TA, Korabel N. Heterogeneous anomalous transport in cellular and molecular biology. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2023; 86:126601. [PMID: 37863075 DOI: 10.1088/1361-6633/ad058f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Accepted: 10/20/2023] [Indexed: 10/22/2023]
Abstract
It is well established that a wide variety of phenomena in cellular and molecular biology involve anomalous transport e.g. the statistics for the motility of cells and molecules are fractional and do not conform to the archetypes of simple diffusion or ballistic transport. Recent research demonstrates that anomalous transport is in many cases heterogeneous in both time and space. Thus single anomalous exponents and single generalised diffusion coefficients are unable to satisfactorily describe many crucial phenomena in cellular and molecular biology. We consider advances in the field ofheterogeneous anomalous transport(HAT) highlighting: experimental techniques (single molecule methods, microscopy, image analysis, fluorescence correlation spectroscopy, inelastic neutron scattering, and nuclear magnetic resonance), theoretical tools for data analysis (robust statistical methods such as first passage probabilities, survival analysis, different varieties of mean square displacements, etc), analytic theory and generative theoretical models based on simulations. Special emphasis is made on high throughput analysis techniques based on machine learning and neural networks. Furthermore, we consider anomalous transport in the context of microrheology and the heterogeneous viscoelasticity of complex fluids. HAT in the wavefronts of reaction-diffusion systems is also considered since it plays an important role in morphogenesis and signalling. In addition, we present specific examples from cellular biology including embryonic cells, leucocytes, cancer cells, bacterial cells, bacterial biofilms, and eukaryotic microorganisms. Case studies from molecular biology include DNA, membranes, endosomal transport, endoplasmic reticula, mucins, globular proteins, and amyloids.
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Affiliation(s)
- Thomas Andrew Waigh
- Biological Physics, School of Physics and Astronomy, University of Manchester, Manchester M13 9PL, United Kingdom
| | - Nickolay Korabel
- Department of Mathematics, The University of Manchester, Manchester M13 9PL, United Kingdom
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13
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Sun H, Qi H, Hu W, Guan L, Xue J, Ai Y, Wang Y, Ding M, Liang Q. Single Nanovesicles Tracking Reveals Their Heterogeneous Extracellular Adsorptions. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2023; 19:e2301888. [PMID: 37467296 DOI: 10.1002/smll.202301888] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2023] [Revised: 06/07/2023] [Indexed: 07/21/2023]
Abstract
The vigorous nanomedicine offers significant possibilities for effective therapeutics of various diseases, and nanovesicles (NVs) represented by artificial liposomes and natural exosomes and cytomembranes especially show great potential. However, their complex interactions with cells, particularly the heterogeneous extracellular adsorptions, are difficult to analyze spatiotemporally due to the transient dynamics. In this study, by single NVs tracking, the extracellular NVs adsorptions are directly observed and their heterogeneous characteristics are revealed. Briefly, plenty of NVs adsorbed on HCT116 cells are tracked and classified, and it is discovered that they exhibit various diffusion properties from different extracellular regions: stable adsorptions on the rear surface and restricted adsorptions on the front protrusion. After the hydrolysis of hyaluronic acid in the extracellular matrix by hyaluronidase, the restricted adsorptions are further weakened and manifested as dissociative adsorptions, which demonstrated reduced total NVs adsorptions from a single-cell and single-particle perspective. Compared with traditional static analysis, the spatiotemporal tracking and heterogeneous results not only reveal the extracellular NVs-cell interactions but also inspire a wide variety of nanomedicine and their nano-investigations.
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Affiliation(s)
- Hua Sun
- MOE Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology, Laboratory of Flexible Electronics Technology, Center for Synthetic and Systems Biology, Department of Chemistry, Tsinghua University, Beijing, 100084, China
| | - Huibo Qi
- MOE Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology, Laboratory of Flexible Electronics Technology, Center for Synthetic and Systems Biology, Department of Chemistry, Tsinghua University, Beijing, 100084, China
| | - Wanting Hu
- MOE Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology, Laboratory of Flexible Electronics Technology, Center for Synthetic and Systems Biology, Department of Chemistry, Tsinghua University, Beijing, 100084, China
| | - Liandi Guan
- MOE Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology, Laboratory of Flexible Electronics Technology, Center for Synthetic and Systems Biology, Department of Chemistry, Tsinghua University, Beijing, 100084, China
| | - Jianfeng Xue
- MOE Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology, Laboratory of Flexible Electronics Technology, Center for Synthetic and Systems Biology, Department of Chemistry, Tsinghua University, Beijing, 100084, China
| | - Yongjian Ai
- MOE Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology, Laboratory of Flexible Electronics Technology, Center for Synthetic and Systems Biology, Department of Chemistry, Tsinghua University, Beijing, 100084, China
| | - Yu Wang
- MOE Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology, Laboratory of Flexible Electronics Technology, Center for Synthetic and Systems Biology, Department of Chemistry, Tsinghua University, Beijing, 100084, China
| | - Mingyu Ding
- MOE Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology, Laboratory of Flexible Electronics Technology, Center for Synthetic and Systems Biology, Department of Chemistry, Tsinghua University, Beijing, 100084, China
| | - Qionglin Liang
- MOE Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology, Laboratory of Flexible Electronics Technology, Center for Synthetic and Systems Biology, Department of Chemistry, Tsinghua University, Beijing, 100084, China
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14
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Valdés Gómez A, Sevilla FJ. Fractional and scaled Brownian motion on the sphere: The effects of long-time correlations on navigation strategies. Phys Rev E 2023; 108:054117. [PMID: 38115432 DOI: 10.1103/physreve.108.054117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Accepted: 10/04/2023] [Indexed: 12/21/2023]
Abstract
We analyze fractional Brownian motion and scaled Brownian motion on the two-dimensional sphere S^{2}. We find that the intrinsic long-time correlations that characterize fractional Brownian motion collude with the specific dynamics (navigation strategies) carried out on the surface giving rise to rich transport properties. We focus our study on two classes of navigation strategies: one induced by a specific set of coordinates chosen for S^{2} (we have chosen the spherical ones in the present analysis), for which we find that contrary to what occurs in the absence of such long-time correlations, nonequilibrium stationary distributions are attained. These results resemble those reported in confined flat spaces in one and two dimensions [Guggenberger et al. New J. Phys. 21, 022002 (2019)1367-263010.1088/1367-2630/ab075f; Vojta et al. Phys. Rev. E 102, 032108 (2020)2470-004510.1103/PhysRevE.102.032108]; however, in the case analyzed here, there are no boundaries that affect the motion on the sphere. In contrast, when the navigation strategy chosen corresponds to a frame of reference moving with the particle (a Frenet-Serret reference system), then the equilibrium distribution on the sphere is recovered in the long-time limit. For both navigation strategies, the relaxation times toward the stationary distribution depend on the particular value of the Hurst parameter. We also show that on S^{2}, scaled Brownian motion, distinguished by a time-dependent diffusion coefficient with a power-scaling, is independent of the navigation strategy finding a good agreement between the analytical calculations obtained from the solution of a time-dependent diffusion equation on S^{2}, and the numerical results obtained from our numerical method to generate ensemble of trajectories.
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Affiliation(s)
- Adriano Valdés Gómez
- Facultad de Ciencias, Universidad Nacional Autónoma de México, Alcaldía Coyoacán, C.P. 04510 Ciudad Universitaria, Ciudad de México, México
- BBVA AI Factory México
| | - Francisco J Sevilla
- Instituto de Física, Universidad Nacional Autónoma de México, Apdo. Postal 20-364, 01000, Ciudad de México, México
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15
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Yan C, Chen HY, Lai PY, Tong P. Statistical laws of stick-slip friction at mesoscale. Nat Commun 2023; 14:6221. [PMID: 37798284 PMCID: PMC10556047 DOI: 10.1038/s41467-023-41850-1] [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: 11/03/2022] [Accepted: 09/20/2023] [Indexed: 10/07/2023] Open
Abstract
Friction between two rough solid surfaces often involves local stick-slip events occurring at different locations of the contact interface. If the apparent contact area is large, multiple local slips may take place simultaneously and the total frictional force is a sum of the pinning forces imposed by many asperities on the interface. Here, we report a systematic study of stick-slip friction over a mesoscale contact area using a hanging-beam lateral atomic-force-microscope, which is capable of resolving frictional force fluctuations generated by individual slip events and measuring their statistical properties at the single-slip resolution. The measured probability density functions (PDFs) of the slip length δxs, the maximal force Fc needed to trigger the local slips, and the local force gradient [Formula: see text] of the asperity-induced pinning force field provide a comprehensive statistical description of stick-slip friction that is often associated with the avalanche dynamics at a critical state. In particular, the measured PDF of δxs obeys a power law distribution and the power-law exponent is explained by a new theoretical model for the under-damped spring-block motion under a Brownian-correlated pinning force field. This model provides a long-sought physical mechanism for the avalanche dynamics in stick-slip friction at mesoscale.
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Affiliation(s)
- Caishan Yan
- Department of Physics, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
| | - Hsuan-Yi Chen
- Department of Physics and Center for Complex Systems, National Central University, Taoyuan City, 320, Taiwan
- Physics Division, National Center for Theoretical Sciences, Taipei, 10617, Taiwan
| | - Pik-Yin Lai
- Department of Physics and Center for Complex Systems, National Central University, Taoyuan City, 320, Taiwan
- Physics Division, National Center for Theoretical Sciences, Taipei, 10617, Taiwan
| | - Penger Tong
- Department of Physics, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong.
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16
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Nakai F, Uneyama T. Brownian yet non-Gaussian diffusion of a light particle in heavy gas: Lorentz-gas-based analysis. Phys Rev E 2023; 108:044129. [PMID: 37978684 DOI: 10.1103/physreve.108.044129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2023] [Accepted: 09/21/2023] [Indexed: 11/19/2023]
Abstract
Non-Gaussian diffusion was recently observed in a gas mixture with mass and fraction contrast [F. Nakai et al., Phys. Rev. E 107, 014605 (2023)2470-004510.1103/PhysRevE.107.014605]. The mean-square displacement of a minor gas particle with a small mass is linear in time, while the displacement distribution deviates from the Gaussian distribution, which is called the Brownian yet non-Gaussian diffusion. In this work, we theoretically analyze this case where the mass contrast is sufficiently large. Major heavy particles can be interpreted as immobile obstacles, and a minor light particle behaves like a Lorentz gas particle within an intermediate timescale. Despite the similarity between the gas mixture and the conventional Lorentz gas system, the Lorentz gas description cannot fully describe the Brownian yet non-Gaussian diffusion. A successful description can be achieved through a canonical ensemble average of the statistical quantities of the Lorentz gas over the initial speed. Furhter, we show that the van Hove correlation function has a nonexponential tail, which is contrary to the exponential tail observed in various systems.
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Affiliation(s)
- Fumiaki Nakai
- Department of Materials Physics, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa, Nagoya 464-8603, Japan
| | - Takashi Uneyama
- Department of Materials Physics, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa, Nagoya 464-8603, Japan
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17
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Luo MB, Hua DY. Simulation Study on the Mechanism of Intermediate Subdiffusion of Diffusive Particles in Crowded Systems. ACS OMEGA 2023; 8:34188-34195. [PMID: 37744832 PMCID: PMC10515404 DOI: 10.1021/acsomega.3c05945] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/12/2023] [Accepted: 08/29/2023] [Indexed: 09/26/2023]
Abstract
The intermediate subdiffusion of diffusive particles in crowded systems is studied for two model systems: the continuous time random walk (CTRW) model and the obstruction-binding model. For the CTRW model with an arbitrarily given longest waiting time τmax, we find that the diffusive particle exhibits subdiffusion below τmax and recovers normal diffusion above τmax. For the obstruction-binding model with randomly distributed attractive obstacles, the diffusion of the diffusive particle is dependent on the binding energy and the density of obstacles. Interestingly, diffusion curves for different binding strengths can be overlapped by rescaling the simulation time, indicating that the diffusive particle in the obstruction-binding model can change from the intermediate subdiffusion to the normal diffusion at a long-term simulation scale. The results of the two model systems show that the diffusive particles only exhibit intermediate subdiffusion below the longest waiting time. Therefore, long timescale subdiffusion would only be observed in the CTRW model with an infinitely long waiting time and in the obstruction-binding model with an infinitely large binding strength.
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Affiliation(s)
- Meng-Bo Luo
- School of Physics, Zhejiang University, Hangzhou 310027, China
| | - Dao-Yang Hua
- School of Physics, Zhejiang University, Hangzhou 310027, China
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18
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Wu J, Xu C, Ye Z, Chen H, Wang Y, Yang K, Yuan B. Transition between Different Diffusion Modes of Individual Lipids during the Membrane-Specific Action of As-CATH4 Peptides. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2023; 19:e2301713. [PMID: 37093200 DOI: 10.1002/smll.202301713] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 04/02/2023] [Indexed: 05/03/2023]
Abstract
The cell membrane permeabilization ability of immune defense antimicrobial peptides (AMPs) is widely applied in biomedicine. Although the mechanisms of peptide-membrane interactions have been widely investigated, analyses at the molecular level are still lacking. Herein, the membrane-specific action of a native AMP, As-CATH4, is investigated using a single-lipid tracking method in combination with live cell and model membrane assays conducted at different scales. The peptide-membrane interaction process is characterized by analyzing single-lipid diffusion behaviors. As-CATH4 exhibits potent antimicrobial activity through bacterial membrane permeabilization, with moderate cytotoxicity against mammalian cells. In-plane diffusion analyses of individual lipids show that the lipid molecules exhibit non-Gaussian and heterogeneous diffusion behaviors in both pristine and peptide-treated membranes, which can be decomposed into two Gaussian subgroups corresponding to normal- and slow-diffusive lipids. Assessment of the temporal evolution of these two diffusion modes of lipids reveal that the peptide action states of As-CATH4 include surface binding, transmembrane defect formation, and dynamic equilibrium. The action mechanisms of As-CATH4 at varying concentrations and against different membranes are distinguished. This work resolves the simultaneous mixed diffusion mechanisms of single lipids in biomimetic cell membranes, especially during dynamic membrane permeabilization by AMPs.
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Affiliation(s)
- Jinfeng Wu
- Center for Soft Condensed Matter Physics and Interdisciplinary Research & School of Physical Science and Technology, Soochow University, Suzhou, Jiangsu, 215006, P. R. China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, P. R. China
| | - Cheng Xu
- Center for Soft Condensed Matter Physics and Interdisciplinary Research & School of Physical Science and Technology, Soochow University, Suzhou, Jiangsu, 215006, P. R. China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, P. R. China
| | - Zifan Ye
- Department of Biopharmaceutical Sciences, College of Pharmaceutical Sciences, Soochow University, Suzhou, 215123, P. R. China
| | - Haibo Chen
- Center for Soft Condensed Matter Physics and Interdisciplinary Research & School of Physical Science and Technology, Soochow University, Suzhou, Jiangsu, 215006, P. R. China
| | - Yipeng Wang
- Department of Biopharmaceutical Sciences, College of Pharmaceutical Sciences, Soochow University, Suzhou, 215123, P. R. China
| | - Kai Yang
- Center for Soft Condensed Matter Physics and Interdisciplinary Research & School of Physical Science and Technology, Soochow University, Suzhou, Jiangsu, 215006, P. R. China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, P. R. China
| | - Bing Yuan
- Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, P. R. China
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19
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Sakamoto K, Akimoto T, Muramatsu M, Sansom MSP, Metzler R, Yamamoto E. Heterogeneous biological membranes regulate protein partitioning via fluctuating diffusivity. PNAS NEXUS 2023; 2:pgad258. [PMID: 37593200 PMCID: PMC10427746 DOI: 10.1093/pnasnexus/pgad258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 06/22/2023] [Accepted: 07/27/2023] [Indexed: 08/19/2023]
Abstract
Cell membranes phase separate into ordered L o and disordered L d domains depending on their compositions. This membrane compartmentalization is heterogeneous and regulates the localization of specific proteins related to cell signaling and trafficking. However, it is unclear how the heterogeneity of the membranes affects the diffusion and localization of proteins in L o and L d domains. Here, using Langevin dynamics simulations coupled with the phase-field (LDPF) method, we investigate several tens of milliseconds-scale diffusion and localization of proteins in heterogeneous biological membrane models showing phase separation into L o and L d domains. The diffusivity of proteins exhibits temporal fluctuations depending on the field composition. Increases in molecular concentrations and domain preference of the molecule induce subdiffusive behavior due to molecular collisions by crowding and confinement effects, respectively. Moreover, we quantitatively demonstrate that the protein partitioning into the L o domain is determined by the difference in molecular diffusivity between domains, molecular preference of domain, and molecular concentration. These results pave the way for understanding how biological reactions caused by molecular partitioning may be controlled in heterogeneous media. Moreover, the methodology proposed here is applicable not only to biological membrane systems but also to the study of diffusion and localization phenomena of molecules in various heterogeneous systems.
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Affiliation(s)
- Ken Sakamoto
- Department of System Design Engineering, Keio University, Yokohama, Kanagawa 223-8522, Japan
| | - Takuma Akimoto
- Department of Physics, Tokyo University of Science, Noda, Chiba 278-8510, Japan
| | - Mayu Muramatsu
- Department of Mechanical Engineering, Keio University, Yokohama, Kanagawa 223-8522, Japan
| | - Mark S P Sansom
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Ralf Metzler
- Institute of Physics & Astronomy, University of Potsdam, Potsdam-Golm 14476, Germany
- Asia Pacific Centre for Theoretical Physics, Pohang 37673, Republic of Korea
| | - Eiji Yamamoto
- Department of System Design Engineering, Keio University, Yokohama, Kanagawa 223-8522, Japan
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20
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Tripathy M, Srivastava A. Lipid packing in biological membranes governs protein localization and membrane permeability. Biophys J 2023; 122:2727-2743. [PMID: 37254482 PMCID: PMC10397809 DOI: 10.1016/j.bpj.2023.05.028] [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: 12/16/2022] [Revised: 04/18/2023] [Accepted: 05/25/2023] [Indexed: 06/01/2023] Open
Abstract
Plasma membrane (PM) heterogeneity has long been implicated in various cellular functions. However, mechanistic principles governing functional regulations of lipid environment are not well understood due to the inherent complexities associated with the relevant length and timescales that limit both direct experimental measurements and their interpretation. In this context, computer simulations hold immense potential to investigate molecular-level interactions and mechanisms that lead to PM heterogeneity and its functions. Herein, we investigate spatial and dynamic heterogeneity in model membranes with coexisting liquid ordered and liquid disordered phases and characterize the membrane order in terms of the local topological changes in lipid environment using the nonaffine deformation framework. Furthermore, we probe the packing defects in these membranes, which can be considered as the conjugate of membrane order assessed in terms of the nonaffine parameter. In doing so, we formalize the connection between membrane packing and local membrane order and use that to explore the mechanistic principles behind their functions. Our observations suggest that heterogeneity in mixed phase membranes is a consequence of local lipid topology and its temporal evolution, which give rise to disparate lipid packing in ordered and disordered domains. This in turn governs the distinct nature of packing defects in these domains that can play a crucial role in preferential localization of proteins in mixed phase membranes. Furthermore, we observe that lipid packing also leads to contrasting distribution of free volume in the membrane core region in ordered and disordered membranes, which can lead to distinctive membrane permeability of small molecules. Our results, thus, indicate that heterogeneity in mixed phase membranes closely governs the membrane functions that may emerge from packing-related basic design principles.
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Affiliation(s)
- Madhusmita Tripathy
- Molecular Biophysics Unit, Indian Institute of Science Bangalore, Bangalore, Karnataka, India.
| | - Anand Srivastava
- Molecular Biophysics Unit, Indian Institute of Science Bangalore, Bangalore, Karnataka, India.
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21
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Ciarlo A, Pastore R, Greco F, Sasso A, Pesce G. Fickian yet non-Gaussian diffusion of a quasi-2D colloidal system in an optical speckle field: experiment and simulations. Sci Rep 2023; 13:7408. [PMID: 37149715 PMCID: PMC10164168 DOI: 10.1038/s41598-023-34433-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Accepted: 04/29/2023] [Indexed: 05/08/2023] Open
Abstract
We investigate a quasi-2D suspension of Brownian particles in an optical speckle field produced by holographic manipulation of a laser wavefront. This system was developed to study, in a systematic and controllable way, a distinctive instance of diffusion, called Fickian yet Non Gaussian diffusion (FnGD), observed, during the last decade, for colloidal particles in a variety of complex and biological fluids. Our setup generates an optical speckle field that behaves like a disordered set of optical traps. First, we describe the experimental setup and the dynamics of the particles, focusing on mean square displacements, displacement distributions and kurtosis. Then, we present Brownian Dynamics simulations of point-like particles in a complex energy landscape, mimicking that generated by the optical speckle field. We show that our simulations can capture the salient features of the experimental results, including the emergence of FnGD, also covering times longer than the ones so far achieved in experiments. Some deviations are observed at long time only, with the Gaussian restoring being slower in simulations than in experiments. Overall, the introduced numerical model might be exploited to guide the design of upcoming experiments targeted, for example, to fully monitor the recovery of Gaussianity.
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Affiliation(s)
- Antonio Ciarlo
- Department of Physics E. Pancini, University of Naples Federico II, Complesso Universitario Monte Sant'Angelo, Via Cintia, 80126, Naples, Italy.
| | - Raffaele Pastore
- Department of Chemical, Materials and Production Engineering, University of Naples Federico II, P.le Tecchio 80, 80125, Naples, Italy
| | - Francesco Greco
- Department of Chemical, Materials and Production Engineering, University of Naples Federico II, P.le Tecchio 80, 80125, Naples, Italy
| | - Antonio Sasso
- Department of Physics E. Pancini, University of Naples Federico II, Complesso Universitario Monte Sant'Angelo, Via Cintia, 80126, Naples, Italy
| | - Giuseppe Pesce
- Department of Physics E. Pancini, University of Naples Federico II, Complesso Universitario Monte Sant'Angelo, Via Cintia, 80126, Naples, Italy
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22
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Rusciano F, Pastore R, Greco F. Universal Evolution of Fickian Non-Gaussian Diffusion in Two- and Three-Dimensional Glass-Forming Liquids. Int J Mol Sci 2023; 24:ijms24097871. [PMID: 37175578 PMCID: PMC10177888 DOI: 10.3390/ijms24097871] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Revised: 04/09/2023] [Accepted: 04/10/2023] [Indexed: 05/15/2023] Open
Abstract
Recent works show that glass-forming liquids display Fickian non-Gaussian Diffusion, with non-Gaussian displacement distributions persisting even at very long times, when linearity in the mean square displacement (Fickianity) has already been attained. Such non-Gaussian deviations temporarily exhibit distinctive exponential tails, with a decay length λ growing in time as a power-law. We herein carefully examine data from four different glass-forming systems with isotropic interactions, both in two and three dimensions, namely, three numerical models of molecular liquids and one experimentally investigated colloidal suspension. Drawing on the identification of a proper time range for reliable exponential fits, we find that a scaling law λ(t)∝tα, with α≃1/3, holds for all considered systems, independently from dimensionality. We further show that, for each system, data at different temperatures/concentration can be collapsed onto a master-curve, identifying a characteristic time for the disappearance of exponential tails and the recovery of Gaussianity. We find that such characteristic time is always related through a power-law to the onset time of Fickianity. The present findings suggest that FnGD in glass-formers may be characterized by a "universal" evolution of the distribution tails, independent from system dimensionality, at least for liquids with isotropic potential.
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Affiliation(s)
- Francesco Rusciano
- Department of Chemical, Materials and Production Engineering, University of Naples Federico II, P.le Tecchio 80, 80125 Napoli, Italy
| | - Raffaele Pastore
- Department of Chemical, Materials and Production Engineering, University of Naples Federico II, P.le Tecchio 80, 80125 Napoli, Italy
| | - Francesco Greco
- Department of Chemical, Materials and Production Engineering, University of Naples Federico II, P.le Tecchio 80, 80125 Napoli, Italy
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23
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Du Y, Lyu Y, Li S, Ding D, Chen J, Yang C, Sun Y, Qu F, Xiao Z, Jiang J, Tan W. Ligand Dilution Analysis Facilitates Aptamer Binding Characterization at the Single-Molecule Level. Angew Chem Int Ed Engl 2023; 62:e202215387. [PMID: 36479802 DOI: 10.1002/anie.202215387] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Revised: 11/29/2022] [Accepted: 12/06/2022] [Indexed: 12/12/2022]
Abstract
Cell-specific aptamers offer a powerful tool to study membrane receptors at the single-molecule level. Most target receptors of aptamers are highly expressed on the cell surface, but difficult to analyze in situ because of dense distribution and fast velocity. Therefore, we herein propose a random sampling-based analysis strategy termed ligand dilution analysis (LDA) for easily implemented aptamer-based receptor study. Receptor density on the cell surface can be calculated based on a regression model. By using a synergistic ligand dilution design, colocalization and differentiation of aptamer and monoclonal antibody (mAb) binding on a single receptor can be realized. Once this is accomplished, precise binding site and detailed aptamer-receptor binding mode can be further determined using molecular docking and molecular dynamics simulation. The ligand dilution strategy also sets the stage for an aptamer-based dynamics analysis of two- and three-dimensional motion and fluctuation of highly expressed receptors on the live cell membrane.
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Affiliation(s)
- Yulin Du
- Molecular Science and Biomedicine Laboratory (MBL), State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, College of Biology, Aptamer Engineering Center of Hunan Province, Hunan University, Changsha, Hunan 410082, China
| | - Yifan Lyu
- Molecular Science and Biomedicine Laboratory (MBL), State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, College of Biology, Aptamer Engineering Center of Hunan Province, Hunan University, Changsha, Hunan 410082, China.,Shenzhen Research Institute, Hunan University, Shenzhen, Guangdong 518000, China.,Institute of Molecular Medicine (IMM), Renji Hospital, Shanghai Jiao Tong University School of Medicine, and College of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Shiquan Li
- Molecular Science and Biomedicine Laboratory (MBL), State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, College of Biology, Aptamer Engineering Center of Hunan Province, Hunan University, Changsha, Hunan 410082, China
| | - Ding Ding
- Institute of Molecular Medicine (IMM), Renji Hospital, Shanghai Jiao Tong University School of Medicine, and College of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Jianghuai Chen
- Molecular Science and Biomedicine Laboratory (MBL), State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, College of Biology, Aptamer Engineering Center of Hunan Province, Hunan University, Changsha, Hunan 410082, China.,Institute of Molecular Medicine (IMM), Renji Hospital, Shanghai Jiao Tong University School of Medicine, and College of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Cai Yang
- Molecular Science and Biomedicine Laboratory (MBL), State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, College of Biology, Aptamer Engineering Center of Hunan Province, Hunan University, Changsha, Hunan 410082, China.,Institute of Molecular Medicine (IMM), Renji Hospital, Shanghai Jiao Tong University School of Medicine, and College of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China.,Zhejiang Cancer Hospital, Hangzhou Institute of Medicine (HIM), Chinese Academy of Sciences, Hangzhou, Zhejiang 310022, China
| | - Yang Sun
- Institute of Molecular Medicine (IMM), Renji Hospital, Shanghai Jiao Tong University School of Medicine, and College of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Fengli Qu
- Zhejiang Cancer Hospital, Hangzhou Institute of Medicine (HIM), Chinese Academy of Sciences, Hangzhou, Zhejiang 310022, China
| | - Zeyu Xiao
- Institute of Molecular Medicine (IMM), Renji Hospital, Shanghai Jiao Tong University School of Medicine, and College of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Jianhui Jiang
- Molecular Science and Biomedicine Laboratory (MBL), State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, College of Biology, Aptamer Engineering Center of Hunan Province, Hunan University, Changsha, Hunan 410082, China
| | - Weihong Tan
- Molecular Science and Biomedicine Laboratory (MBL), State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, College of Biology, Aptamer Engineering Center of Hunan Province, Hunan University, Changsha, Hunan 410082, China.,Institute of Molecular Medicine (IMM), Renji Hospital, Shanghai Jiao Tong University School of Medicine, and College of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China.,Zhejiang Cancer Hospital, Hangzhou Institute of Medicine (HIM), Chinese Academy of Sciences, Hangzhou, Zhejiang 310022, China
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24
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Xu C, Yang K, Yuan B. Non-Gaussian Diffusion of Individual Lipids Unveils the Unique Peptide-Membrane Interaction Dynamics. J Phys Chem Lett 2023; 14:854-862. [PMID: 36656807 DOI: 10.1021/acs.jpclett.2c03467] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
The dynamics of protein (or peptide)-membrane interactions plays a central role in cellular functions; however, the underlying mechanisms remain unclear. Herein, through analyzing the diffusion of individual lipids in a bilayer membrane during the membrane actions of typical peptides (e.g., pore-forming peptide melittin and cell-penetrating peptide TAT) at varying concentrations, the spatial heterogeneity as well as temporal dynamics of lipid motions were investigated which showed close correlation with the peptide action mechanism. Specifically, the spatial heterogeneity of lipid diffusion was characterized by the non-Gaussianity of lipid trajectories, which was further decomposed into two basic diffusion modes; moreover, the temporal evolution of the Gaussian fitting parameters provided quantitative information on the varying metastable interaction states between peptides and the membrane (e.g., peptide landing, membrane insertion, and equilibrium). Generally, this work gives an insight into the correlation between single-lipid diffusion and function-realization of membrane-active peptides.
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Affiliation(s)
- Cheng Xu
- Center for Soft Condensed Matter Physics and Interdisciplinary Research & School of Physical Science and Technology, Soochow University, Suzhou215006, Jiangsu, China
- Songshan Lake Materials Laboratory, Dongguan523808, Guangdong, China
| | - Kai Yang
- Center for Soft Condensed Matter Physics and Interdisciplinary Research & School of Physical Science and Technology, Soochow University, Suzhou215006, Jiangsu, China
| | - Bing Yuan
- Songshan Lake Materials Laboratory, Dongguan523808, Guangdong, China
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25
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Scott S, Weiss M, Selhuber-Unkel C, Barooji YF, Sabri A, Erler JT, Metzler R, Oddershede LB. Extracting, quantifying, and comparing dynamical and biomechanical properties of living matter through single particle tracking. Phys Chem Chem Phys 2023; 25:1513-1537. [PMID: 36546878 DOI: 10.1039/d2cp01384c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
A panoply of new tools for tracking single particles and molecules has led to an explosion of experimental data, leading to novel insights into physical properties of living matter governing cellular development and function, health and disease. In this Perspective, we present tools to investigate the dynamics and mechanics of living systems from the molecular to cellular scale via single-particle techniques. In particular, we focus on methods to measure, interpret, and analyse complex data sets that are associated with forces, materials properties, transport, and emergent organisation phenomena within biological and soft-matter systems. Current approaches, challenges, and existing solutions in the associated fields are outlined in order to support the growing community of researchers at the interface of physics and the life sciences. Each section focuses not only on the general physical principles and the potential for understanding living matter, but also on details of practical data extraction and analysis, discussing limitations, interpretation, and comparison across different experimental realisations and theoretical frameworks. Particularly relevant results are introduced as examples. While this Perspective describes living matter from a physical perspective, highlighting experimental and theoretical physics techniques relevant for such systems, it is also meant to serve as a solid starting point for researchers in the life sciences interested in the implementation of biophysical methods.
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Affiliation(s)
- Shane Scott
- Institute of Physiology, Kiel University, Hermann-Rodewald-Straße 5, 24118 Kiel, Germany
| | - Matthias Weiss
- Experimental Physics I, University of Bayreuth, Universitätsstr. 30, D-95447 Bayreuth, Germany
| | - Christine Selhuber-Unkel
- Institute for Molecular Systems Engineering, Heidelberg University, D-69120 Heidelberg, Germany.,Max Planck School Matter to Life, Jahnstraße 29, D-69120 Heidelberg, Germany
| | - Younes F Barooji
- Niels Bohr Institute, Blegdamsvej 17, DK-2100 Copenhagen, Denmark.
| | - Adal Sabri
- Experimental Physics I, University of Bayreuth, Universitätsstr. 30, D-95447 Bayreuth, Germany
| | - Janine T Erler
- BRIC, University of Copenhagen, Ole Maaløes Vej 5, DK-2200 Copenhagen, Denmark.
| | - Ralf Metzler
- Institute of Physics and Astronomy, University of Potsdam, Karl-Liebknecht Str. 24/25, D-14476 Potsdam, Germany.,Asia Pacific Center for Theoretical Physics, Pohang 37673, Republic of Korea
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26
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Nakai F, Masubuchi Y, Doi Y, Ishida T, Uneyama T. Fluctuating diffusivity emerges even in binary gas mixtures. Phys Rev E 2023; 107:014605. [PMID: 36797902 DOI: 10.1103/physreve.107.014605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Accepted: 12/22/2022] [Indexed: 01/19/2023]
Abstract
Diffusivity in some soft matter and biological systems changes with time, called the fluctuating diffusivity. In this work, we propose a novel origin for fluctuating diffusivity based on stochastic simulations of binary gas mixtures. In this system, the fraction of one component is significantly small, and the mass of the minor component molecule is different from that of the major component. The minor component exhibits fluctuating diffusivity when its mass is sufficiently smaller than that of the major component. We elucidate that this fluctuating diffusivity is caused by the time scale separation between the relaxation of the velocity direction and the speed of the minor component molecule.
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Affiliation(s)
- Fumiaki Nakai
- Department of Materials Physics, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa, Nagoya 464-8603, Japan
| | - Yuichi Masubuchi
- Department of Materials Physics, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa, Nagoya 464-8603, Japan
| | - Yuya Doi
- Department of Materials Physics, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa, Nagoya 464-8603, Japan
| | - Takato Ishida
- Department of Materials Physics, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa, Nagoya 464-8603, Japan
| | - Takashi Uneyama
- Department of Materials Physics, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa, Nagoya 464-8603, Japan
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27
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Safi Samghabadi F, Slim AH, Smith MW, Chabi M, Conrad JC. Dynamics of Filamentous Viruses in Polyelectrolyte Solutions. Macromolecules 2022. [DOI: 10.1021/acs.macromol.2c01641] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Affiliation(s)
- Farshad Safi Samghabadi
- Department of Chemical and Biomolecular Engineering, University of Houston, Houston, Texas77204, United States
| | - Ali H. Slim
- Department of Chemical and Biomolecular Engineering, University of Houston, Houston, Texas77204, United States
| | - Maxwell W. Smith
- Department of Chemical and Biomolecular Engineering, University of Houston, Houston, Texas77204, United States
| | - Maede Chabi
- Department of Biomedical Engineering, University of Houston, Houston, Texas77204, United States
| | - Jacinta C. Conrad
- Department of Chemical and Biomolecular Engineering, University of Houston, Houston, Texas77204, United States
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28
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Bustos NA, Saad-Roy CM, Cherstvy AG, Wagner CE. Distributed medium viscosity yields quasi-exponential step-size probability distributions in heterogeneous media. SOFT MATTER 2022; 18:8572-8581. [PMID: 36373713 DOI: 10.1039/d2sm00952h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
The analysis of the statistics of random walks undertaken by passive particles in complex media has important implications in a number of areas including pathogen transport and drug delivery. In several systems in which heterogeneity is important, the distribution of particle step-sizes has been found to be exponential in nature, as opposed to the Gaussian distribution associated with Brownian motion. Here, we first develop a theoretical framework to study a simplified version of this problem: the motion of passive tracers in a range of sub-environments with different viscosity. We show that in the limit of a large number of equi-distributed sub-environments spanning a broad viscosity range, an exact analytical expression for the underlying particle step-size distribution can be derived, which approaches an exponential distribution when step sizes are small. We then validate this using a simple experimental system of glycerol-water mixtures, in which the volume fraction of glycerol is systematically varied. Overall, the assumption of exponentially distributed step sizes may substantially over-estimate the incidence of large steps in heterogeneous systems, with important implications in the analysis of various biophysical processes.
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Affiliation(s)
- Nicole A Bustos
- Department of Mechanical Engineering, MIT, Cambridge, MA 02139, USA
| | - Chadi M Saad-Roy
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08540, USA
- Miller Institute for Basic Research in Science, University of California, Berkeley, Berkeley, CA 94720, USA
- Department of Integrative Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Andrey G Cherstvy
- Institute for Physics and Astronomy, University of Potsdam, 14476 Potsdam-Golm, Germany
| | - Caroline E Wagner
- Department of Bioengineering, McGill University, Montreal, QC H3A 0E9, Canada.
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29
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Xue C, Huang Y, Zheng X, Hu G. Hopping Behavior Mediates the Anomalous Confined Diffusion of Nanoparticles in Porous Hydrogels. J Phys Chem Lett 2022; 13:10612-10620. [PMID: 36350083 DOI: 10.1021/acs.jpclett.2c02733] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Diffusion is an essential means of mass transport in porous materials such as hydrogels, which are appealing in various biomedical applications. Herein, we investigate the diffusive motion of nanoparticles (NPs) in porous hydrogels to provide a microscopic view of confined diffusion. Based on the mean square displacement from particle tracking experiments, we elucidate the anomalous diffusion dynamics of the embedded NPs and reveal the heterogeneous pore structures in hydrogels. The results demonstrate that diffusive NPs can intermittently escape from single pores through void connective pathways and exhibit non-Gaussian displacement probability distribution. We simulate this scenario using the Monte Carlo method and clarify the existence of hopping events in porous diffusion. The resultant anomalous diffusion can be fully depicted by combining the hopping mechanism and the hydrodynamic effect. Our results highlight the hopping behavior through the connective pathways and establish a hybrid model to predict NP transport in porous environments.
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Affiliation(s)
- Chundong Xue
- State Key Laboratory of Nonlinear Mechanics, Beijing Key Laboratory of Engineered Construction and Mechanobiology, Institute of Mechanics, Chinese Academy of Sciences, Beijing100190, China
- School of Optoelectronic Engineering and Instrumentation Science, Dalian University of Technology, Dalian116024, China
| | - Yirong Huang
- State Key Laboratory of Nonlinear Mechanics, Beijing Key Laboratory of Engineered Construction and Mechanobiology, Institute of Mechanics, Chinese Academy of Sciences, Beijing100190, China
| | - Xu Zheng
- State Key Laboratory of Nonlinear Mechanics, Beijing Key Laboratory of Engineered Construction and Mechanobiology, Institute of Mechanics, Chinese Academy of Sciences, Beijing100190, China
| | - Guoqing Hu
- Department of Engineering Mechanics, Zhejiang University, Hangzhou310027, China
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30
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Liu Y, Zheng X, Guan D, Jiang X, Hu G. Heterogeneous Nanostructures Cause Anomalous Diffusion in Lipid Monolayers. ACS NANO 2022; 16:16054-16066. [PMID: 36149751 DOI: 10.1021/acsnano.2c04089] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
The diffusion and mobility in biomembranes are crucial for various cell functions; however, the mechanisms involved in such processes remain ambiguous due to the complex membrane structures. Herein, we investigate how the heterogeneous nanostructures cause anomalous diffusion in dipalmitoylphosphatidylcholine (DPPC) monolayers. By identifying the existence of condensed nanodomains and clarifying their impact, our findings renew the understanding of the hydrodynamic description and the statistical feature of the diffusion in the monolayers. We find a universal characteristic of the multistage mean square displacement (MSD) with an intermediate crossover, signifying two membrane viscosities at different scales: the short-time scale describes the local fluidity and is independent of the nominal DPPC density, and the long-time scale represents the global continuous phase taking into account nanodomains and increases with DPPC density. The constant short-time viscosity reflects a dynamic equilibrium between the continuous fluid phase and the condensed nanodomains in the molecular scale. Notably, we observe an "anomalous yet Brownian" phenomenon exhibiting an unusual double-peaked displacement probability distribution (DPD), which is attributed to the net dipolar repulsive force from the heterogeneous nanodomains around the microdomains. The findings provide physical insights into the transport of membrane inclusions that underpin various biological functions and drug deliveries.
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Affiliation(s)
- Yang Liu
- State Key Laboratory of Nonlinear Mechanics (LNM), Beijing Key Laboratory of Engineered Construction and Mechanobiology, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- Frontier Scientific Research Centre for Fluidized Mining of Deep Underground Resources, China University of Mining & Technology, Xuzhou 221116, People's Republic of China
| | - Xu Zheng
- State Key Laboratory of Nonlinear Mechanics (LNM), Beijing Key Laboratory of Engineered Construction and Mechanobiology, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
| | - Dongshi Guan
- State Key Laboratory of Nonlinear Mechanics (LNM), Beijing Key Laboratory of Engineered Construction and Mechanobiology, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
| | - Xikai Jiang
- State Key Laboratory of Nonlinear Mechanics (LNM), Beijing Key Laboratory of Engineered Construction and Mechanobiology, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
| | - Guoqing Hu
- Department of Engineering Mechanics, State Key Laboratory of Fluid Power and Mechatronic Systems, Zhejiang University, Hangzhou 310027, People's Republic of China
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31
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Cheng CH, Lai PY. Efficient reconstruction of directed networks from noisy dynamics using stochastic force inference. Phys Rev E 2022; 106:034302. [PMID: 36266821 DOI: 10.1103/physreve.106.034302] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Accepted: 08/19/2022] [Indexed: 06/16/2023]
Abstract
We consider coupled network dynamics under uncorrelated noises that fluctuate about the noise-free long-time asymptotic state. Our goal is to reconstruct the directed network only from the time-series data of the dynamics of the nodes. By using the stochastic force inference method with a simple natural choice of linear polynomial basis, we derive a reconstruction scheme of the connection weights and the noise strength of each node. Explicit simulations for directed and undirected random networks with various node dynamics are carried out to demonstrate the good accuracy and high efficiency of the reconstruction scheme. We further consider the case when only a subset of the network and its node dynamics can be observed, and it is demonstrated that the directed weighted connections among the observed nodes can be easily and faithfully reconstructed. In addition, we propose a scheme to infer the number of hidden nodes and their effects on each observed node. The accuracy of these results is illustrated by simulations.
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Affiliation(s)
- Chi-Ho Cheng
- Department of Physics, National Changhua University of Education, Changhua 500, Taiwan, Republic of China and Department of Physics and Center for Complex Systems, National Central University, Chung-Li District, Taoyuan City 320, Taiwan, Republic of China
| | - Pik-Yin Lai
- Department of Physics, National Changhua University of Education, Changhua 500, Taiwan, Republic of China and Department of Physics and Center for Complex Systems, National Central University, Chung-Li District, Taoyuan City 320, Taiwan, Republic of China
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32
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Lu Y, Liu XY, Hu GH. Double-Spring Model for Nanoparticle Diffusion in a Polymer Network. Macromolecules 2022. [DOI: 10.1021/acs.macromol.2c00257] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Yu Lu
- School of Mechanics and Engineering Science, Shanghai Institute of Applied Mathematics and Mechanics, Shanghai Key Laboratory of Mechanics in Energy Engineering, Shanghai University, Shanghai 200444, P. R. China
| | - Xin-Yue Liu
- School of Mechanics and Engineering Science, Shanghai Institute of Applied Mathematics and Mechanics, Shanghai Key Laboratory of Mechanics in Energy Engineering, Shanghai University, Shanghai 200444, P. R. China
| | - Guo-Hui Hu
- School of Mechanics and Engineering Science, Shanghai Institute of Applied Mathematics and Mechanics, Shanghai Key Laboratory of Mechanics in Energy Engineering, Shanghai University, Shanghai 200444, P. R. China
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33
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Alcázar-Cano N, Delgado-Buscalioni R. Hydrodynamics induce superdiffusive jumps of passive tracers along critical paths of random networks and colloidal gels. SOFT MATTER 2022; 18:1941-1954. [PMID: 35191454 DOI: 10.1039/d1sm01713f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
We present a numerical study on the effect of hydrodynamic interactions (HI) on the diffusion of inert point tracer particles in several fixed random structures. As expected, the diffusion is hampered by the extra hydrodynamic friction introduced by the obstacle network. However, a non-trivial effect due to HI appears in the analysis of the van-Hove displacement probability close to the percolation threshold, where tracers diffuse through critical fractal paths. We show that the tracer dynamics can be split up into short and long jumps, the latter being ruled by either exponential or Gaussian van Hove distribution tails. While at short time HI slow down the tracer diffusion, at long times, hydrodynamic interactions with the obstacles increase the probability of longer jumps, which circumvent the traps of the labyrinth more easily. Notably, the relation between the anomalous diffusion exponent and the fractal dimension of the critical (intricate) paths is greater than one, which implies that the long-time (long-jump) diffusion is mildly superdiffuse. A possible reason for such a hastening of the diffusion along the network corridors is the hydrodynamically induced mobility anisotropy, which favours displacements parallel to the walls, an effect which has already been experimentally observed in collagen gels.
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Affiliation(s)
- Nerea Alcázar-Cano
- Departamento de Física Teórica de la Materia Condensada, Universidad Autónoma de Madrid and Condensed Matter Physics Center (IFIMAC), Madrid, Spain.
| | - Rafael Delgado-Buscalioni
- Departamento de Física Teórica de la Materia Condensada, Universidad Autónoma de Madrid and Condensed Matter Physics Center (IFIMAC), Madrid, Spain.
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34
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Pastore R, Ciarlo A, Pesce G, Sasso A, Greco F. A model-system of Fickian yet non-Gaussian diffusion: light patterns in place of complex matter. SOFT MATTER 2022; 18:351-364. [PMID: 34888591 DOI: 10.1039/d1sm01133b] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Fickian yet non-Gaussian Diffusion (FnGD), widely observed for colloidal particles in a variety of complex and biological fluids, emerges as a most intriguing open issue in Soft Matter. To fully monitor FnGD and advance its understanding, recording many trajectories over a large time range is crucial, which makes experiments challenging. Here we exploit a recently introduced experimental model of finely tunable FnGD: a quasi-2d system of Brownian beads in water moving in a heterogeneous energy landscape generated by a static and spatially random optical force field (speckle pattern). By performing experiments at different optical power, we succeed in monitoring the evolution as well as the precursors of FnGD. Fickian scaling of the mean square displacement is always attained after a subdiffusive regime while the displacement distributions keep on being non-Gaussian, which allows for measuring a characteristic length- and time-scale for the onset of FnGD, ξf and tf. We find that ξf stays constant, whereas tf grows as the inverse of the long-time diffusion coefficient tf ∝ D-1 for increasing the optical power. Deviations from the standard Gaussian shape of the displacement distribution are neatly characterized on a broad range of times, focusing on the excess probability at small displacements and on the decay-length of the distinctive exponential tails. Such deviations are fully built in the subdiffusive regime and, at the FnGD onset, grow with the optical power. As time goes on, the small-displacement probability narrows and the exponential tails progressively break up, with a tendency to recover the Gaussian behaviour. Overall, both subdiffusion and FnGD become more marked and persistent on increasing the optical power, suggesting a strict relation between these two regimes. As clearly demonstrated by our results, the adopted model-system represents a privileged stage for in-depth study of FnGD and opens the way to unveil the nature of this phenomenon through finely tuned and well-controlled experiments.
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Affiliation(s)
- Raffaele Pastore
- Department of Chemical, Materials and Production Engineering, University of Naples Federico II, P.le Tecchio 80, 80125 Napoli, Italy.
| | - Antonio Ciarlo
- Department of Physics E. Pancini, University of Naples Federico II, Complesso Universitario Monte S. Angelo, Via Cintia, 80126 Napoli, Italy
| | - Giuseppe Pesce
- Department of Physics E. Pancini, University of Naples Federico II, Complesso Universitario Monte S. Angelo, Via Cintia, 80126 Napoli, Italy
| | - Antonio Sasso
- Department of Physics E. Pancini, University of Naples Federico II, Complesso Universitario Monte S. Angelo, Via Cintia, 80126 Napoli, Italy
| | - Francesco Greco
- Department of Chemical, Materials and Production Engineering, University of Naples Federico II, P.le Tecchio 80, 80125 Napoli, Italy.
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35
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Doerries TJ, Chechkin AV, Schumer R, Metzler R. Rate equations, spatial moments, and concentration profiles for mobile-immobile models with power-law and mixed waiting time distributions. Phys Rev E 2022; 105:014105. [PMID: 35193292 DOI: 10.1103/physreve.105.014105] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Accepted: 12/17/2021] [Indexed: 06/14/2023]
Abstract
We present a framework for systems in which diffusion-advection transport of a tracer substance in a mobile zone is interrupted by trapping in an immobile zone. Our model unifies different model approaches based on distributed-order diffusion equations, exciton diffusion rate models, and random-walk models for multirate mobile-immobile mass transport. We study various forms for the trapping time dynamics and their effects on the tracer mass in the mobile zone. Moreover, we find the associated breakthrough curves, the tracer density at a fixed point in space as a function of time, and the mobile and immobile concentration profiles and the respective moments of the transport. Specifically, we derive explicit forms for the anomalous transport dynamics and an asymptotic power-law decay of the mobile mass for a Mittag-Leffler trapping time distribution. In our analysis we point out that even for exponential trapping time densities, transient anomalous transport is observed. Our results have direct applications in geophysical contexts, but also in biological, soft matter, and solid state systems.
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Affiliation(s)
- Timo J Doerries
- Institute of Physics and Astronomy, University of Potsdam, 14476 Potsdam, Germany
| | - Aleksei V Chechkin
- Institute of Physics and Astronomy, University of Potsdam, 14476 Potsdam, Germany
- Faculty of Pure and Applied Mathematica, Hugo Steinhaus Center, Wrocław University of Science and Technology, Wyspianskiego 27, 50-370 Wrocław, Poland
- Akhiezer Institute for Theoretical Physics, 61108 Kharkov, Ukraine
| | - Rina Schumer
- Desert Research Institute, Reno, Nevada 89512, USA
| | - Ralf Metzler
- Institute of Physics and Astronomy, University of Potsdam, 14476 Potsdam, Germany
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36
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Chun DJ, Oh Y, Sung BJ. Translation-rotation decoupling of tracers reflects medium-range crystalline order in two-dimensional colloid glasses. Phys Rev E 2021; 104:054615. [PMID: 34942845 DOI: 10.1103/physreve.104.054615] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Accepted: 11/17/2021] [Indexed: 11/07/2022]
Abstract
The dynamic heterogeneity and the translation-rotation decoupling are the dynamic signatures of glasses and supercooled liquids. Whether and how the dynamic heterogeneity would relate to the local structure of glasses has been a puzzle for decades. In this work we perform molecular dynamics simulations for tracers in both two-dimensional polydisperse colloids (2DPC) and two-dimensional binary colloids (2DBC). In 2DPC glasses, hexatic local structures develop at low enough temperatures and grow quickly along with the dynamic correlation length of the 2DPC, which is well known as the medium-range crystalline order (MRCO). In 2DBC glasses, on the other hand, any explicit local structure has not been reported to grow significantly with the dynamic correlation length at low temperatures. We introduce two different types of tracers into colloidal systems: A diamond tracer that resembles the MRCO of 2DPC glasses and a square tracer that is dissimilar to any local structure of glasses. The translation-rotation decoupling of the diamond tracer in 2DPC glasses is much more significant than that of the square tracer in the same 2DPC glasses. On the other hand, such a tracer shape-dependence of the decoupling is not observed in 2DBC glasses where the local hexatic structure does not develop significantly. We introduce a shape-dependency parameter of the decoupling and find that the shape-dependency parameter grows along with the dynamic correlation length in 2DPC glasses but not in 2DBC glasses. This illustrates that the dynamic heterogeneity and the translation-rotation decoupling of tracers could reveal the local structure that develops in glasses.
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Affiliation(s)
- Dong Jae Chun
- Department of Chemistry, Sogang University, Seoul 04107, Republic of Korea
| | - Younghoon Oh
- Department of Chemistry, Sogang University, Seoul 04107, Republic of Korea
| | - Bong June Sung
- Department of Chemistry, Sogang University, Seoul 04107, Republic of Korea
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37
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Goychuk I, Pöschel T. Fingerprints of viscoelastic subdiffusion in random environments: Revisiting some experimental data and their interpretations. Phys Rev E 2021; 104:034125. [PMID: 34654105 DOI: 10.1103/physreve.104.034125] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Accepted: 09/01/2021] [Indexed: 11/07/2022]
Abstract
Many experimental studies revealed subdiffusion of various nanoparticles in diverse polymer and colloidal solutions, cytosol and plasma membrane of biological cells, which are viscoelastic and, at the same time, highly inhomogeneous randomly fluctuating environments. The observed subdiffusion often combines features of ergodic fractional Brownian motion (reflecting viscoelasticity) and nonergodic jumplike non-Markovian diffusional processes (reflecting disorder). Accordingly, several theories were proposed to explain puzzling experimental findings. Below we show that some of the significant and profound published experimental results are better rationalized within the viscoelastic subdiffusion approach in random environments, which is based on generalized Langevin dynamics in random potentials, than some earlier proposed theories.
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Affiliation(s)
- Igor Goychuk
- Institute for Multiscale Simulation, Department of Chemical and Biological Engineering, Friedrich-Alexander University of Erlangen-Nürnberg, Cauerstr. 3, 91058 Erlangen, Germany
| | - Thorsten Pöschel
- Institute for Multiscale Simulation, Department of Chemical and Biological Engineering, Friedrich-Alexander University of Erlangen-Nürnberg, Cauerstr. 3, 91058 Erlangen, Germany
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38
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Mashanov GI, Nenasheva TA, Mashanova A, Lape R, Birdsall NJM, Sivilotti L, Molloy JE. Heterogeneity of cell membrane structure studied by single molecule tracking. Faraday Discuss 2021; 232:358-374. [PMID: 34647559 PMCID: PMC8704140 DOI: 10.1039/d1fd00035g] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Heterogeneity in cell membrane structure, typified by microdomains with different biophysical and biochemical properties, is thought to impact on a variety of cell functions. Integral membrane proteins act as nanometre-sized probes of the lipid environment and their thermally-driven movements can be used to report local variations in membrane properties. In the current study, we have used total internal reflection fluorescence microscopy (TIRFM) combined with super-resolution tracking of multiple individual molecules, in order to create high-resolution maps of local membrane viscosity. We used a quadrat sampling method and show how statistical tests for membrane heterogeneity can be conducted by analysing the paths of many molecules that pass through the same unit area of membrane. We describe experiments performed on cultured primary cells, stable cell lines and ex vivo tissue slices using a variety of membrane proteins, under different imaging conditions. In some cell types, we find no evidence for heterogeneity in mobility across the plasma membrane, but in others we find statistically significant differences with some regions of membrane showing significantly higher viscosity than others. We use total internal reflection fluorescence microscopy combined with super-resolution tracking of multiple individual molecules, in order to create high-resolution maps of local membrane viscosity.![]()
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Affiliation(s)
| | - Tatiana A Nenasheva
- Koltzov Institute of Developmental Biology, 26 Vavilova Str., Moscow, 119334, Russia
| | - Alla Mashanova
- School of Life and Medical Sciences, University of Hertfordshire, College Lane, Hatfield, Hertfordshire, AL10 9AB, UK
| | - Remigijus Lape
- Department of Neuroscience, Physiology and Pharmacology, Division of Biosciences, University College London, Gower St., London, UK
| | | | - Lucia Sivilotti
- Department of Neuroscience, Physiology and Pharmacology, Division of Biosciences, University College London, Gower St., London, UK
| | - Justin E Molloy
- The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK.
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39
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Abstract
Granular particles exhibit rich collective behaviors on vibration beds, but the motion of an isolated particle is not well understood even for uniform particles with a simple shape such as disks or spheres. Here we measured the motion of a single disk confined to a quasi-two-dimensional horizontal box on a vertically vibrating stage. The translational displacements obey compressed exponential distributions whose exponent [Formula: see text] increases with the frequency, while the rotational displacements exhibit unimodal distributions at low frequencies and bimodal distributions at high frequencies. During short time intervals, the translational displacements are subdiffusive and negatively correlated, while the rotational displacements are superdiffusive and positively correlated. After prolonged periods, the rotational displacements become diffusive and their correlations decay to zero. Both the rotational and the translational displacements exhibit white noise at low frequencies, and blue noise for translational motions and Brownian noise for rotational motions at high frequencies. The translational kinetic energy obeys Boltzmann distribution while the rotational kinetic energy deviates from it. Most energy is distributed in translational motions at low frequencies and in rotational motions at high frequencies, which violates the equipartition theorem. Translational and rotational motions are not correlated. These experimental results show that the random diffusion of such driven particles is distinct from thermal motion in both the translational and rotational degrees of freedom, which poses new challenges to theory. The results cast new light on the motion of individual particles and the collective motion of driven granular particles.
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40
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Korabel N, Han D, Taloni A, Pagnini G, Fedotov S, Allan V, Waigh TA. Local Analysis of Heterogeneous Intracellular Transport: Slow and Fast Moving Endosomes. ENTROPY (BASEL, SWITZERLAND) 2021; 23:958. [PMID: 34441098 PMCID: PMC8394768 DOI: 10.3390/e23080958] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 07/19/2021] [Accepted: 07/23/2021] [Indexed: 01/14/2023]
Abstract
Trajectories of endosomes inside living eukaryotic cells are highly heterogeneous in space and time and diffuse anomalously due to a combination of viscoelasticity, caging, aggregation and active transport. Some of the trajectories display switching between persistent and anti-persistent motion, while others jiggle around in one position for the whole measurement time. By splitting the ensemble of endosome trajectories into slow moving subdiffusive and fast moving superdiffusive endosomes, we analyzed them separately. The mean squared displacements and velocity auto-correlation functions confirm the effectiveness of the splitting methods. Applying the local analysis, we show that both ensembles are characterized by a spectrum of local anomalous exponents and local generalized diffusion coefficients. Slow and fast endosomes have exponential distributions of local anomalous exponents and power law distributions of generalized diffusion coefficients. This suggests that heterogeneous fractional Brownian motion is an appropriate model for both fast and slow moving endosomes. This article is part of a Special Issue entitled: "Recent Advances In Single-Particle Tracking: Experiment and Analysis" edited by Janusz Szwabiński and Aleksander Weron.
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Affiliation(s)
- Nickolay Korabel
- Department of Mathematics, The University of Manchester, Manchester M13 9PL, UK; (D.H.); (S.F.)
| | - Daniel Han
- Department of Mathematics, The University of Manchester, Manchester M13 9PL, UK; (D.H.); (S.F.)
- School of Biological Sciences, The University of Manchester, Manchester M13 9PT, UK;
- Biological Physics, Department of Physics and Astronomy, The University of Manchester, Manchester M13 9PL, UK
| | - Alessandro Taloni
- CNR—Consiglio Nazionale delle Ricerche, Istituto dei Sistemi Complessi, Via dei Taurini 19, 00185 Roma, Italy;
| | - Gianni Pagnini
- BCAM—Basque Center for Applied Mathematics, Mazarredo 14, 48009 Bilbao, Spain;
- Ikerbasque—Basque Foundation for Science, Plaza Euskadi 5, 48009 Bilbao, Spain
| | - Sergei Fedotov
- Department of Mathematics, The University of Manchester, Manchester M13 9PL, UK; (D.H.); (S.F.)
| | - Viki Allan
- School of Biological Sciences, The University of Manchester, Manchester M13 9PT, UK;
| | - Thomas Andrew Waigh
- Biological Physics, Department of Physics and Astronomy, The University of Manchester, Manchester M13 9PL, UK
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41
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Wang B, He W, Prosseda PP, Li L, Kowal TJ, Alvarado JA, Wang Q, Hu Y, Sun Y. OCRL regulates lysosome positioning and mTORC1 activity through SSX2IP-mediated microtubule anchoring. EMBO Rep 2021; 22:e52173. [PMID: 33987909 DOI: 10.15252/embr.202052173] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 03/18/2021] [Accepted: 04/08/2021] [Indexed: 11/09/2022] Open
Abstract
Lysosomal positioning and mTOR (mammalian target of rapamycin) signaling coordinate cellular responses to nutrient levels. Inadequate nutrient sensing can result in growth delays, a hallmark of Lowe syndrome. OCRL mutations cause Lowe syndrome, but the role of OCRL in nutrient sensing is unknown. Here, we show that OCRL is localized to the centrosome by its ASH domain and that it recruits microtubule-anchoring factor SSX2IP to the centrosome, which is important in the formation of the microtubule-organizing center. Deficiency of OCRL in human and mouse cells results in loss of microtubule-organizing centers and impaired microtubule-based lysosome movement, which in turn leads to mTORC1 inactivation and abnormal nutrient sensing. Centrosome-targeted PACT-SSX2IP can restore microtubule anchoring and mTOR activity. Importantly, boosting the activity of mTORC1 restores the nutrient sensing ability of Lowe patients' cells. Our findings highlight mTORC1 as a novel therapeutic target for Lowe syndrome.
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Affiliation(s)
- Biao Wang
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Wei He
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Philipp P Prosseda
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Liang Li
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Tia J Kowal
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Jorge A Alvarado
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Qing Wang
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Yang Hu
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Yang Sun
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA, USA.,Palo Alto Veterans Administration, Palo Alto, CA, USA
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42
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Smith M, Poling-Skutvik R, Slim AH, Willson RC, Conrad JC. Dynamics of Flexible Viruses in Polymer Solutions. Macromolecules 2021. [DOI: 10.1021/acs.macromol.1c00435] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Maxwell Smith
- Department of Chemical and Biomolecular Engineering, University of Houston, Houston, Texas 77204-4004, United States
| | - Ryan Poling-Skutvik
- Department of Chemical Engineering, University of Rhode Island, Kingston, Rhode Island 02881, United States
| | - Ali H. Slim
- Department of Chemical and Biomolecular Engineering, University of Houston, Houston, Texas 77204-4004, United States
| | - Richard C. Willson
- Department of Chemical and Biomolecular Engineering, University of Houston, Houston, Texas 77204-4004, United States
| | - Jacinta C. Conrad
- Department of Chemical and Biomolecular Engineering, University of Houston, Houston, Texas 77204-4004, United States
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43
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Åberg C, Poolman B. Glass-like characteristics of intracellular motion in human cells. Biophys J 2021; 120:2355-2366. [PMID: 33887228 DOI: 10.1016/j.bpj.2021.04.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 03/29/2021] [Accepted: 04/09/2021] [Indexed: 10/21/2022] Open
Abstract
The motion in the cytosol of microorganisms such as bacteria and yeast has been observed to undergo a dramatic slowing down upon cell energy depletion. These observations have been interpreted as the motion being "glassy," but whether this notion is useful also for active, motor-protein-driven transport in eukaryotic cells is less clear. Here, we use fluorescence microscopy of beads in human (HeLa) cells to probe the motion of membrane-surrounded structures that are carried along the cytoskeleton by motor proteins. Evaluating several hallmarks of glassy dynamics, we show that at short length scales, the motion is heterogeneous, is nonergodic, is well described by a model for the displacement distribution in glassy systems, and exhibits a decoupling of the exchange and persistence times. Overall, these results suggest that the short length scale behavior of objects that can be transported actively by motor proteins in human cells shares features with the motion in glassy systems.
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Affiliation(s)
- Christoffer Åberg
- Groningen Research Institute of Pharmacy, University of Groningen, Groningen, the Netherlands; Department of Biochemistry, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, the Netherlands.
| | - Bert Poolman
- Department of Biochemistry, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, the Netherlands
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44
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Pastore R, Ciarlo A, Pesce G, Greco F, Sasso A. Rapid Fickian Yet Non-Gaussian Diffusion after Subdiffusion. PHYSICAL REVIEW LETTERS 2021; 126:158003. [PMID: 33929249 DOI: 10.1103/physrevlett.126.158003] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2021] [Accepted: 03/11/2021] [Indexed: 05/23/2023]
Abstract
The recently discovered Fickian yet non-Gaussian diffusion (FnGD) is here finely tuned and investigated over a wide range of probabilities and timescales using a quasi-2D suspension of colloidal beads under the action of a static and spatially random optical force field. This experimental model allows one to demonstrate that a "rapid" FnGD regime with a diffusivity close to that of free suspension can originate from earlier subdiffusion. We show that these two regimes are strictly tangled: as subdiffusion deepens upon increasing the optical force, deviations from Gaussianity in the FnGD regime become larger and more persistent in time. In addition, the distinctive exponential tails of FnGD are quickly built up in the subdiffusive regime. Our results shed new light on previous experimental observations and suggest that FnGD may generally be a memory effect of earlier subdiffusive processes.
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Affiliation(s)
- Raffaele Pastore
- Department of Chemical, Materials and Production Engineering, University of Naples Federico II, P.le Tecchio 80, Napoli 80125, Italy
| | - Antonio Ciarlo
- Department of Physics E. Pancini, University of Naples Federico II, Complesso Universitario Monte S. Angelo, Via Cintia, I-80126 Naples, Italy
| | - Giuseppe Pesce
- Department of Physics E. Pancini, University of Naples Federico II, Complesso Universitario Monte S. Angelo, Via Cintia, I-80126 Naples, Italy
| | - Francesco Greco
- Department of Chemical, Materials and Production Engineering, University of Naples Federico II, P.le Tecchio 80, Napoli 80125, Italy
| | - Antonio Sasso
- Department of Physics E. Pancini, University of Naples Federico II, Complesso Universitario Monte S. Angelo, Via Cintia, I-80126 Naples, Italy
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45
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Yamamoto E, Akimoto T, Mitsutake A, Metzler R. Universal Relation between Instantaneous Diffusivity and Radius of Gyration of Proteins in Aqueous Solution. PHYSICAL REVIEW LETTERS 2021; 126:128101. [PMID: 33834804 DOI: 10.1103/physrevlett.126.128101] [Citation(s) in RCA: 48] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2020] [Accepted: 02/09/2021] [Indexed: 06/12/2023]
Abstract
Protein conformational fluctuations are highly complex and exhibit long-term correlations. Here, molecular dynamics simulations of small proteins demonstrate that these conformational fluctuations directly affect the protein's instantaneous diffusivity D_{I}. We find that the radius of gyration R_{g} of the proteins exhibits 1/f fluctuations that are synchronous with the fluctuations of D_{I}. Our analysis demonstrates the validity of the local Stokes-Einstein-type relation D_{I}∝1/(R_{g}+R_{0}), where R_{0}∼0.3 nm is assumed to be a hydration layer around the protein. From the analysis of different protein types with both strong and weak conformational fluctuations, the validity of the Stokes-Einstein-type relation appears to be a general property.
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Affiliation(s)
- Eiji Yamamoto
- Department of System Design Engineering, Keio University, Yokohama, Kanagawa 223-8522, Japan
| | - Takuma Akimoto
- Department of Physics, Tokyo University of Science, Noda, Chiba 278-8510, Japan
| | - Ayori Mitsutake
- Department of Physics, Meiji University, Kawasaki, Kanagawa 214-8571, Japan
| | - Ralf Metzler
- Institute of Physics and Astronomy, University of Potsdam, 14476 Potsdam-Golm, Germany
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46
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Fluctuating Diffusivity of RNA-Protein Particles: Analogy with Thermodynamics. ENTROPY 2021; 23:e23030333. [PMID: 33808996 PMCID: PMC8002026 DOI: 10.3390/e23030333] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 03/05/2021] [Accepted: 03/08/2021] [Indexed: 01/01/2023]
Abstract
A formal analogy of fluctuating diffusivity to thermodynamics is discussed for messenger RNA molecules fluorescently fused to a protein in living cells. Regarding the average value of the fluctuating diffusivity of such RNA-protein particles as the analog of the internal energy, the analogs of the quantity of heat and work are identified. The Clausius-like inequality is shown to hold for the entropy associated with diffusivity fluctuations, which plays a role analogous to the thermodynamic entropy, and the analog of the quantity of heat. The change of the statistical fluctuation distribution is also examined from a geometric perspective. The present discussions may contribute to a deeper understanding of the fluctuating diffusivity in view of the laws of thermodynamics.
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47
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Ślęzak J, Burov S. From diffusion in compartmentalized media to non-Gaussian random walks. Sci Rep 2021; 11:5101. [PMID: 33658556 PMCID: PMC7930099 DOI: 10.1038/s41598-021-83364-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Accepted: 12/18/2020] [Indexed: 01/31/2023] Open
Abstract
In this work we establish a link between two different phenomena that were studied in a large and growing number of biological, composite and soft media: the diffusion in compartmentalized environment and the non-Gaussian diffusion that exhibits linear or power-law growth of the mean square displacement joined by the exponential shape of the positional probability density. We explore a microscopic model that gives rise to transient confinement, similar to the one observed for hop-diffusion on top of a cellular membrane. The compartmentalization of the media is achieved by introducing randomly placed, identical barriers. Using this model of a heterogeneous medium we derive a general class of random walks with simple jump rules that are dictated by the geometry of the compartments. Exponential decay of positional probability density is observed and we also quantify the significant decrease of the long time diffusion constant. Our results suggest that the observed exponential decay is a general feature of the transient regime in compartmentalized media.
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Affiliation(s)
- Jakub Ślęzak
- Physics Department, Bar-Ilan University, Ramat Gan, 5290002 Israel
| | - Stanislav Burov
- Physics Department, Bar-Ilan University, Ramat Gan, 5290002 Israel
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48
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Hubicka K, Janczura J. Time-dependent classification of protein diffusion types: A statistical detection of mean-squared-displacement exponent transitions. Phys Rev E 2021; 101:022107. [PMID: 32168604 DOI: 10.1103/physreve.101.022107] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Accepted: 01/23/2020] [Indexed: 01/26/2023]
Abstract
In this paper, we have proposed a statistical procedure for detecting transitions of the mean-square-displacement exponent value within a single trajectory. With this procedure, we have identified three regimes of proteins dynamics on a cell membrane, namely, subdiffusion, free diffusion, and immobility. The fourth considered dynamics type, namely, superdiffusion was not detected. We show that the analyzed protein trajectories are not stationary and not ergodic. Moreover, classification of the dynamics type performed without prior detection of transitions may lead to the overestimation of the proportion of subdiffusive trajectories.
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Affiliation(s)
- Katarzyna Hubicka
- Faculty of Pure and Applied Mathematics, Hugo Steinhaus Center, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland
| | - Joanna Janczura
- Faculty of Pure and Applied Mathematics, Hugo Steinhaus Center, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland
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49
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S Mogre S, Brown AI, Koslover EF. Getting around the cell: physical transport in the intracellular world. Phys Biol 2020; 17:061003. [PMID: 32663814 DOI: 10.1088/1478-3975/aba5e5] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Eukaryotic cells face the challenging task of transporting a variety of particles through the complex intracellular milieu in order to deliver, distribute, and mix the many components that support cell function. In this review, we explore the biological objectives and physical mechanisms of intracellular transport. Our focus is on cytoplasmic and intra-organelle transport at the whole-cell scale. We outline several key biological functions that depend on physically transporting components across the cell, including the delivery of secreted proteins, support of cell growth and repair, propagation of intracellular signals, establishment of organelle contacts, and spatial organization of metabolic gradients. We then review the three primary physical modes of transport in eukaryotic cells: diffusive motion, motor-driven transport, and advection by cytoplasmic flow. For each mechanism, we identify the main factors that determine speed and directionality. We also highlight the efficiency of each transport mode in fulfilling various key objectives of transport, such as particle mixing, directed delivery, and rapid target search. Taken together, the interplay of diffusion, molecular motors, and flows supports the intracellular transport needs that underlie a broad variety of biological phenomena.
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Affiliation(s)
- Saurabh S Mogre
- Department of Physics, University of California, San Diego, San Diego, California 92093, United States of America
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50
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Gires PY, Thampi M, Weiss M. Quantifying active diffusion in an agitated fluid. Phys Chem Chem Phys 2020; 22:21678-21684. [PMID: 32966453 DOI: 10.1039/d0cp03629c] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Mixing of reactants in microdroplets predominantly relies on diffusional motion due to small Reynolds numbers and the resulting absence of turbulent flows. Enhancing diffusion in microdroplets by an auxiliary noise source is therefore a topical problem. Here we report on how the diffusional motion of tracer beads is enhanced upon agitating the surrounding aqueous fluid with miniaturized magnetic stir bars that are compatible with microdroplets and microfluidic devices. Using single-particle tracking, we demonstrate via a broad palette of measures that local stirring of the fluid at different frequencies leads to an enhanced but apparently normal and homogenous diffusion process, i.e. diffusional steps follow the anticipated Gaussian distribution and no ballistic motion is observed whereas diffusion coefficients are significantly increased. The signature of stirring is, however, visible in the power-spectral density and in the velocity autocorrelation function of trajectories. Our data therefore demonstrate that diffusive mixing can be locally enhanced with miniaturized stir bars while only moderately affecting the ambient noise properties. The latter may also facilitate the controlled addition of nonequilibrium noise to complex fluids in future applications.
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Affiliation(s)
- Pierre-Yves Gires
- Experimental Physics I, University of Bayreuth, Universitätsstr. 30, D-95447 Bayreuth, Germany.
| | - Mithun Thampi
- Experimental Physics I, University of Bayreuth, Universitätsstr. 30, D-95447 Bayreuth, Germany.
| | - Matthias Weiss
- Experimental Physics I, University of Bayreuth, Universitätsstr. 30, D-95447 Bayreuth, Germany.
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