1
|
Ivanov M, Lyubartsev AP. Development of a bottom-up coarse-grained model for interactions of lipids with TiO 2 nanoparticles. J Comput Chem 2024; 45:1364-1379. [PMID: 38380763 DOI: 10.1002/jcc.27310] [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: 11/14/2023] [Revised: 12/29/2023] [Accepted: 01/03/2024] [Indexed: 02/22/2024]
Abstract
Understanding interactions of inorganic nanoparticles with biomolecules is important in many biotechnology, nanomedicine, and toxicological research, however, the size of typical nanoparticles makes their direct modeling by atomistic simulations unfeasible. Here, we present a bottom-up coarse-graining approach for modeling titanium dioxide (TiO 2 ) nanomaterials in contact with phospholipids that uses the inverse Monte Carlo method to optimize the effective interactions from the structural data obtained in small-scale all-atom simulations of TiO 2 surfaces with lipids in aqueous solution. The resulting coarse-grained models are able to accurately reproduce the structural details of lipid adsorption on different titania surfaces without the use of an explicit solvent, enabling significant computational resource savings and favorable scaling. Our coarse-grained simulations show that small spherical TiO 2 nanoparticles ( r = 2 nm) can only be partially wrapped by a lipid bilayer with phosphoethanolamine headgroups, however, the lipid adsorption increases with the radius of the nanoparticle. The current approach can be used to study the effect of the size and shape of TiO 2 nanoparticles on their interactions with cell membrane lipids, which can be a determining factor in membrane wrapping as well as the recently discovered phenomenon of nanoquarantining, which involves the formation of layered nanomaterial-lipid structures.
Collapse
Affiliation(s)
- Mikhail Ivanov
- Department of Materials and Environmental Chemistry, Stockholm University, Stockholm, Sweden
| | - Alexander P Lyubartsev
- Department of Materials and Environmental Chemistry, Stockholm University, Stockholm, Sweden
| |
Collapse
|
2
|
Wen CY, Luo YL, Madsen JJ. Optimizing Coarse-Grained Models for Large-Scale Membrane Protein Simulation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.13.594009. [PMID: 38798639 PMCID: PMC11118278 DOI: 10.1101/2024.05.13.594009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2024]
Abstract
Coarse-grained (CG) models have been developed for studying membrane proteins at physiologically relevant scales. Such methods, including popular CG lipid models, exhibit stability and efficiency at moderate scales, but they can become impractical or even unusable beyond a critical size due to various technical issues. Here, we report that these scale-dependent issues can arise from progressively slower relaxation dynamics and become confounded by unforeseen instabilities observed only at larger scales. To address these issues, we systemically optimized a 4-site solvent-free CG lipid model that is suitable for conducting micron-scale molecular dynamics simulations of membrane proteins under various membrane properties. We applied this lipid model to explore the long-range membrane deformation induced by a large mechanosensitive ion channel, PIEZO. We show that the optimized CG models are powerful in elucidating the structural and dynamic interplay between PIEZO and the membrane. Furthermore, we anticipate that our methodological insights can prove useful for resolving issues stemming from scale-dependent limitations of similar CG methodologies.
Collapse
|
3
|
Zhao Y, Wu Y, Islam K, Paul R, Zhou Y, Qin X, Li Q, Liu Y. Microphysiologically Engineered Vessel-Tumor Model to Investigate Vascular Transport Dynamics of Immune Cells. ACS APPLIED MATERIALS & INTERFACES 2024; 16. [PMID: 38652824 PMCID: PMC11082852 DOI: 10.1021/acsami.4c00391] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Revised: 04/01/2024] [Accepted: 04/09/2024] [Indexed: 04/25/2024]
Abstract
Cancer immunotherapy has emerged as a promising therapeutic strategy to combat cancer effectively. However, it is hard to observe and quantify how this in vivo process happens. Three-dimensional (3D) microfluidic vessel-tumor models offer valuable capability to study how immune cells transport during cancer progression. We presented an advanced 3D vessel-supported tumor model consisting of the endothelial lumen and vessel network for the study of T cells' transportation. The process of T cell transport through the vessel network and interaction with tumor spheroids was represented and monitored in vitro. Specifically, we demonstrate that the endothelial glycocalyx serving in the T cells' transport can influence the endothelium-immune interaction. Furthermore, after vascular transport, how programmed cell death protein 1 (PD-1) immune checkpoint inhibition influences the delivered activated-T cells on tumor killing was evaluated. Our in vitro vessel-tumor model provides a microphysiologically engineered platform to represent T cell vascular transportation during tumor immunotherapy. The reported innovative vessel-tumor platform is believed to have the potential to explore the tumor-induced immune response mechanism and preclinically evaluate immunotherapy's effectiveness.
Collapse
Affiliation(s)
- Yuwen Zhao
- Department
of Bioengineering, Lehigh University, Bethlehem, Pennsylvania 18015, United States
| | - Yue Wu
- Department
of Bioengineering, Lehigh University, Bethlehem, Pennsylvania 18015, United States
| | - Khayrul Islam
- Department
of Mechanical Engineering and Mechanics, Lehigh University, Bethlehem, Pennsylvania 18015, United States
| | - Ratul Paul
- Department
of Mechanical Engineering and Mechanics, Lehigh University, Bethlehem, Pennsylvania 18015, United States
| | - Yuyuan Zhou
- Department
of Bioengineering, Lehigh University, Bethlehem, Pennsylvania 18015, United States
| | - Xiaochen Qin
- Department
of Bioengineering, Lehigh University, Bethlehem, Pennsylvania 18015, United States
| | - Qiying Li
- Department
of Electrical and Computer Engineering, Lehigh University, Bethlehem, Pennsylvania 18015, United States
| | - Yaling Liu
- Department
of Bioengineering, Lehigh University, Bethlehem, Pennsylvania 18015, United States
- Department
of Mechanical Engineering and Mechanics, Lehigh University, Bethlehem, Pennsylvania 18015, United States
| |
Collapse
|
4
|
Morton W, Vácha R, Angioletti-Uberti S. Valency of Ligand-Receptor Binding from Pair Potentials. J Chem Theory Comput 2024; 20:2901-2907. [PMID: 38516954 PMCID: PMC11008093 DOI: 10.1021/acs.jctc.4c00112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2024] [Revised: 03/10/2024] [Accepted: 03/11/2024] [Indexed: 03/23/2024]
Abstract
Coarse grained molecular dynamics simulations have been crucial for investigating the dynamics of nanoparticle uptake by cell membranes via ligand-receptor interactions. These models have enabled researchers to evaluate the effects of nanoparticle size, shape, and ligand distribution on cellular uptake. However, when pair potentials are used to represent ligand-receptor interactions, the number of receptors interacting with one ligand, valency, may vary. We demonstrate that the curvature of a nanoparticle, strength of ligand-receptor interactions, and ligand or receptor concentration change the valency, ranging from 3.4 to 5.1 in this study. Such a change in valency can create inaccurate comparisons between nanoparticles or even result in the uptake of smaller nanoparticles than would be expected. To rectify this inconsistency, we propose the adoption of a model based on bond formation and use it to determine the extent to which previous studies may have been affected. This work recommends avoiding pair potentials for modeling ligand-receptor interactions to ensure methodological consistency in nanoparticle studies.
Collapse
Affiliation(s)
- William Morton
- Department
of Materials, Imperial College, London SW7 2AZ, U.K.
| | - Robert Vácha
- CEITEC—Central
European Institute of Technology, Masaryk
University, Brno 62500, Czech Republic
- National
Centre for Biomolecular Research, Faculty of Science, Masaryk University, Brno 62500, Czech Republic
- Department
of Condensed Matter Physics, Faculty of Science, Masaryk University, Brno 62500, Czech Republic
| | | |
Collapse
|
5
|
Del Razo MJ, Crommelin D, Bolhuis PG. Data-driven dynamical coarse-graining for condensed matter systems. J Chem Phys 2024; 160:024108. [PMID: 38193550 DOI: 10.1063/5.0177553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Accepted: 12/05/2023] [Indexed: 01/10/2024] Open
Abstract
Simulations of condensed matter systems often focus on the dynamics of a few distinguished components but require integrating the full system. A prime example is a molecular dynamics simulation of a (macro)molecule in a solution, where the molecule(s) and the solvent dynamics need to be integrated, rendering the simulations computationally costly and often unfeasible for physically/biologically relevant time scales. Standard coarse graining approaches can reproduce equilibrium distributions and structural features but do not properly include the dynamics. In this work, we develop a general data-driven coarse-graining methodology inspired by the Mori-Zwanzig formalism, which shows that macroscopic systems with a large number of degrees of freedom can be described by a few relevant variables and additional noise and memory terms. Our coarse-graining method consists of numerical integrators for the distinguished components, where the noise and interaction terms with other system components are substituted by a random variable sampled from a data-driven model. The model is parameterized using data from multiple short-time full-system simulations, and then, it is used to run long-time simulations. Applying our methodology to three systems-a distinguished particle under a harmonic and a bistable potential and a dimer with two metastable configurations-the resulting coarse-grained models are capable of reproducing not only the equilibrium distributions but also the dynamic behavior due to temporal correlations and memory effects. Remarkably, our method even reproduces the transition dynamics between metastable states, which is challenging to capture correctly. Our approach is not constrained to specific dynamics and can be extended to systems beyond Langevin dynamics, and, in principle, even to non-equilibrium dynamics.
Collapse
Affiliation(s)
- Mauricio J Del Razo
- Department of Mathematics and Computer Science, Freie Universität Berlin, Berlin, Germany
- Van't Hoff Institute for Molecular Sciences, University of Amsterdam, PO Box 94157, 1090GD Amsterdam, The Netherlands
- Korteweg-de Vries Institute for Mathematics, University of Amsterdam, PO Box 94248, 1090GD Amsterdam, The Netherlands
- Dutch Institute for Emergent Phenomena, University of Amsterdam, Amsterdam, The Netherlands
| | - Daan Crommelin
- Korteweg-de Vries Institute for Mathematics, University of Amsterdam, PO Box 94248, 1090GD Amsterdam, The Netherlands
- Centrum Wiskunde & Informatica, 1098 XG Amsterdam, The Netherlands
| | - Peter G Bolhuis
- Van't Hoff Institute for Molecular Sciences, University of Amsterdam, PO Box 94157, 1090GD Amsterdam, The Netherlands
| |
Collapse
|
6
|
Tesei G, Hsiao YW, Dabkowska A, Grönberg G, Yanez Arteta M, Ulkoski D, Bray DJ, Trulsson M, Ulander J, Lund M, Lindfors L. Lipid shape and packing are key for optimal design of pH-sensitive mRNA lipid nanoparticles. Proc Natl Acad Sci U S A 2024; 121:e2311700120. [PMID: 38175863 PMCID: PMC10786277 DOI: 10.1073/pnas.2311700120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Accepted: 11/27/2023] [Indexed: 01/06/2024] Open
Abstract
The ionizable-lipid component of RNA-containing nanoparticles controls the pH-dependent behavior necessary for an efficient delivery of the cargo-the so-called endosomal escape. However, it is still an empirical exercise to identify optimally performing lipids. Here, we study two well-known ionizable lipids, DLin-MC3-DMA and DLin-DMA using a combination of experiments, multiscale computer simulations, and electrostatic theory. All-atom molecular dynamics simulations, and experimentally measured polar headgroup pKa values, are used to develop a coarse-grained representation of the lipids, which enables the investigation of the pH-dependent behavior of lipid nanoparticles (LNPs) through Monte Carlo simulations, in the absence and presence of RNA molecules. Our results show that the charge state of the lipids is determined by the interplay between lipid shape and headgroup chemistry, providing an explanation for the similar pH-dependent ionization state observed for lipids with headgroup pKa values about one-pH-unit apart. The pH dependence of lipid ionization is significantly influenced by the presence of RNA, whereby charge neutrality is achieved by imparting a finite and constant charge per lipid at intermediate pH values. The simulation results are experimentally supported by measurements of α-carbon 13C-NMR chemical shifts for eGFP mRNA LNPs of both DLin-MC3-DMA and DLin-DMA at various pH conditions. Further, we evaluate the applicability of a mean-field Poisson-Boltzmann theory to capture these phenomena.
Collapse
Affiliation(s)
- Giulio Tesei
- Structural Biology and NMR Laboratory & The Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, CopenhagenDK-2200, Denmark
- Department of Chemistry, Division of Computational Chemistry, Lund University, LundSE-221 00, Sweden
| | - Ya-Wen Hsiao
- The Hartree Centre, Science and Technology Facilities Council (STFC) Daresbury Laboratory, WarringtonWA4 4AD, United Kingdom
| | - Aleksandra Dabkowska
- Advanced Drug Delivery, Pharmaceutical Sciences, BioPharmaceuticals Research and Development, AstraZeneca, Gothenburg, Mölndal431 83, Sweden
| | - Gunnar Grönberg
- Medicinal Chemistry, Early Respiratory & Immunology, BioPharmaceuticals Research and Development, AstraZeneca, Gothenburg, Mölndal431 83, Sweden
| | - Marianna Yanez Arteta
- Advanced Drug Delivery, Pharmaceutical Sciences, BioPharmaceuticals Research and Development, AstraZeneca, Gothenburg, Mölndal431 83, Sweden
| | - David Ulkoski
- Advanced Drug Delivery, Pharmaceutical Sciences, BioPharmaceuticals Research and Development, AstraZeneca, Gothenburg, Mölndal431 83, Sweden
| | - David J. Bray
- The Hartree Centre, Science and Technology Facilities Council (STFC) Daresbury Laboratory, WarringtonWA4 4AD, United Kingdom
| | - Martin Trulsson
- Department of Chemistry, Division of Computational Chemistry, Lund University, LundSE-221 00, Sweden
| | - Johan Ulander
- Data Science and Modelling, Pharmaceutical Sciences, BioPharmaceuticals Research and Development, AstraZeneca, Gothenburg, Mölndal431 83, Sweden
| | - Mikael Lund
- Department of Chemistry, Division of Computational Chemistry, Lund University, LundSE-221 00, Sweden
| | - Lennart Lindfors
- Advanced Drug Delivery, Pharmaceutical Sciences, BioPharmaceuticals Research and Development, AstraZeneca, Gothenburg, Mölndal431 83, Sweden
| |
Collapse
|
7
|
Zhang L, Liu N, Wang X. Probe the nanoparticle-nucleus interaction via coarse-grained molecular model. Phys Chem Chem Phys 2023; 25:30319-30329. [PMID: 37908190 DOI: 10.1039/d3cp02981f] [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: 11/02/2023]
Abstract
The present study reports on a computational model that systematically evaluates the effect of physical factors, including size, surface modification, and rigidity, on the nuclear uptake of nanoparticles (NPs). The NP-nucleus interaction is a crucial factor in biomedical applications such as drug delivery and cellular imaging. While experimental studies have provided evidence for the influence of size, shape, and surface modification on nuclear uptake, theoretical investigations on how these physical factors affect the entrance of NPs through the nuclear pore are lacking. Our results demonstrate that larger NPs require a higher amount of energy to enter the nucleus compared to smaller NPs. This highlights the importance of size as a critical factor in NP design for nuclear uptake. Additionally, surface modification of NPs can impact the nuclear uptake pathway, indicating the potential for tailored NP design for specific applications. Notably, our findings also reveal that the rigidity of NPs has a significant effect on the transport process. The interplay between physicochemical properties and nuclear pore is found to determine nuclear uptake efficiency. Taken together, our study provides new insights into the design of NPs for precise and controllable NP-nucleus interaction, with potential implications for the development of efficient and targeted drug delivery systems and imaging agents.
Collapse
Affiliation(s)
- Liuyang Zhang
- State Key Laboratory for Manufacturing Systems Engineering, Xi'an Jiaotong University, Xi'an, Shaanxi 710049, People's Republic of China
| | - Ning Liu
- School of Aerospace Engineering and Applied Mechanics, Tongji University, Shanghai 200092, P. R. China.
| | - Xianqiao Wang
- College of Engineering, University of Georgia, Athens, GA 30602, USA
| |
Collapse
|
8
|
Karal MAS, Billah MM, Ahmed M, Ahamed MK. A review on the measurement of the bending rigidity of lipid membranes. SOFT MATTER 2023; 19:8285-8304. [PMID: 37873600 DOI: 10.1039/d3sm00882g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
This review provides an overview of the latest developments in both experimental and simulation techniques used to assess the bending rigidity of lipid membranes. It places special emphasis on experimental methods that utilize model vesicles to manipulate lipid compositions and other experimental parameters to determine the bending rigidity of the membrane. It also describes two commonly used simulation methods for estimating bending rigidity. The impact of various factors on membrane bending rigidity is summarized, including cholesterol, lipids, salt concentration, surface charge, membrane phase state, peptides, proteins, and polyethylene glycol. These factors are shown to influence the bending rigidity, contributing to a better understanding of the biophysical properties of membranes and their role in biological processes. Furthermore, the review discusses future directions and potential advancements in this research field, highlighting areas where further investigation is required.
Collapse
Affiliation(s)
- Mohammad Abu Sayem Karal
- Department of Physics, Bangladesh University of Engineering and Technology, Dhaka 1000, Bangladesh.
| | - Md Masum Billah
- Department of Physics, Jashore University of Science and Technology, Jashore 7408, Bangladesh
| | - Marzuk Ahmed
- Integrated Bioscience Section, Graduate School of Science and Technology, Shizuoka University, Shizuoka 422-8529, Japan
| | - Md Kabir Ahamed
- Radiation, Transport and Waste Safety Division, Bangladesh Atomic Energy Regulatory Authority, Agargaon, Dhaka 1207, Bangladesh
| |
Collapse
|
9
|
Ugarte La Torre D, Takada S, Sugita Y. Extension of the iSoLF implicit-solvent coarse-grained model for multicomponent lipid bilayers. J Chem Phys 2023; 159:075101. [PMID: 37581417 DOI: 10.1063/5.0160417] [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: 06/01/2023] [Accepted: 07/26/2023] [Indexed: 08/16/2023] Open
Abstract
iSoLF is a coarse-grained (CG) model for lipid molecules with the implicit-solvent approximation used in molecular dynamics (MD) simulations of biological membranes. Using the original iSoLF (iSoLFv1), MD simulations of lipid bilayers consisting of either POPC or DPPC and these bilayers, including membrane proteins, can be performed. Here, we improve the original model, explicitly treating the electrostatic interactions between different lipid molecules and adding CG particle types. As a result, the available lipid types increase to 30. To parameterize the potential functions of the new model, we performed all-atom MD simulations of each lipid at three different temperatures using the CHARMM36 force field and the modified TIP3P model. Then, we parameterized both the bonded and non-bonded interactions to fit the area per lipid and the membrane thickness of each lipid bilayer by using the multistate Boltzmann Inversion method. The final model reproduces the area per lipid and the membrane thickness of each lipid bilayer at the three temperatures. We also examined the applicability of the new model, iSoLFv2, to simulate the phase behaviors of mixtures of DOPC and DPPC at different concentrations. The simulation results with iSoLFv2 are consistent with those using Dry Martini and Martini 3, although iSoLFv2 requires much fewer computations. iSoLFv2 has been implemented in the GENESIS MD software and is publicly available.
Collapse
Affiliation(s)
- Diego Ugarte La Torre
- Computational Biophysics Research Team, RIKEN Center for Computational Science, Kobe, Hyogo, Japan
| | - Shoji Takada
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto, Japan
| | - Yuji Sugita
- Computational Biophysics Research Team, RIKEN Center for Computational Science, Kobe, Hyogo, Japan
- Theoretical Molecular Science Laboratory, RIKEN Cluster for Pioneering Research, Wako, Saitama, Japan
- Laboratory for Biomolecular Function Simulation, RIKEN Center for Biosystems Dynamics Research, Kobe, Hyogo, Japan
| |
Collapse
|
10
|
Farnudi A, Ejtehadi MR, Everaers R. Dynamics of fluid bilayer vesicles: Soft meshes and robust curvature energy discretization. Phys Rev E 2023; 108:015301. [PMID: 37583159 DOI: 10.1103/physreve.108.015301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Accepted: 05/26/2023] [Indexed: 08/17/2023]
Abstract
Continuum models like the Helfrich Hamiltonian are widely used to describe fluid bilayer vesicles. Here we study the molecular dynamics compatible dynamics of the vertices of two-dimensional meshes representing the bilayer, whose in-plane motion is only weakly constrained. We show (i) that Jülicher's discretization of the curvature energy offers vastly superior robustness for soft meshes compared to the commonly employed expression by Gommper and Kroll and (ii) that for sufficiently soft meshes, the typical behavior of fluid bilayer vesicles can emerge even if the mesh connectivity remains fixed throughout the simulations. In particular, soft meshes can accommodate large shape transformations, and the model can generate the typical ℓ^{-4} signal for the amplitude of surface undulation modes of nearly spherical vesicles all the way up to the longest wavelength modes. Furthermore, we compare results for Newtonian, Langevin, and Brownian dynamics simulations of the mesh vertices to demonstrate that the internal friction of the membrane model is negligible, making it suitable for studying the internal dynamics of vesicles via coupling to hydrodynamic solvers or particle-based solvent models.
Collapse
Affiliation(s)
- Ali Farnudi
- Department of Physics, Sharif University of Technology, P.O. Box 11155-9161, Tehran, Iran
| | - Mohammad Reza Ejtehadi
- Department of Physics, Sharif University of Technology, P.O. Box 11155-9161, Tehran, Iran
| | - Ralf Everaers
- Ecole Normale Supérieure (ENS) de Lyon, CNRS, Laboratoire de Physique and Centre Blaise Pascal de l'ENS de Lyon, F-69342 Lyon, France
| |
Collapse
|
11
|
Yu S, Zhao J, Chu R, Li X, Wu G, Meng X. Anomalous Diffusion of Polyelectrolyte Segments on Supported Charged Lipid Bilayers. ENTROPY (BASEL, SWITZERLAND) 2023; 25:e25050796. [PMID: 37238551 DOI: 10.3390/e25050796] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Revised: 05/04/2023] [Accepted: 05/11/2023] [Indexed: 05/28/2023]
Abstract
This work provides mesoscale models for the anomalous diffusion of a polymer chain on a heterogeneous surface with rearranging randomly distributed adsorption sites. Both the "bead-spring" model and oxDNA model were simulated on supported lipid bilayer membranes with various molar fractions of charged lipids, using Brownian dynamics method. Our simulation results demonstrate that "bead-spring" chains exhibit sub-diffusion on charged lipid bilayers which agrees with previous experimental observations for short-time dynamics of DNA segments on membranes. In addition, the non-Gaussian diffusive behaviors of DNA segments have not been observed in our simulations. However, a simulated 17 base pairs double stranded DNA, using oxDNA model, performs normal diffusion on supported cationic lipid bilayers. Due to the number of positively charged lipids attracted by short DNA is small, the energy landscape that the short DNA experiences during diffusion is not as heterogeneous as that experienced by long DNA chains, which results in normal diffusion rather than sub-diffusion for short DNA.
Collapse
Affiliation(s)
- Shi Yu
- Department of Chemical Engineering, China University of Mining & Technology, Xuzhou 221116, China
| | - Jianqiao Zhao
- Department of Chemical Engineering, China University of Mining & Technology, Xuzhou 221116, China
| | - Ruizhi Chu
- Department of Chemical Engineering, China University of Mining & Technology, Xuzhou 221116, China
- Key Laboratory of Coal-Based CO2 Capture and Geological Storage, China University of Mining & Technology, Xuzhou 221116, China
| | - Xiao Li
- Department of Chemical Engineering, China University of Mining & Technology, Xuzhou 221116, China
- Key Laboratory of Coal-Based CO2 Capture and Geological Storage, China University of Mining & Technology, Xuzhou 221116, China
| | - Guoguang Wu
- Department of Chemical Engineering, China University of Mining & Technology, Xuzhou 221116, China
- Key Laboratory of Coal-Based CO2 Capture and Geological Storage, China University of Mining & Technology, Xuzhou 221116, China
| | - Xianliang Meng
- Department of Chemical Engineering, China University of Mining & Technology, Xuzhou 221116, China
- Key Laboratory of Coal-Based CO2 Capture and Geological Storage, China University of Mining & Technology, Xuzhou 221116, China
| |
Collapse
|
12
|
Islam K, Razizadeh M, Liu Y. Coarse-grained molecular simulation of extracellular vesicle squeezing for drug loading. Phys Chem Chem Phys 2023; 25:12308-12321. [PMID: 37082907 PMCID: PMC10337604 DOI: 10.1039/d3cp00387f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/08/2023]
Abstract
In recent years, extracellular vesicles have become promising carriers as next-generation drug delivery platforms. Effective loading of exogenous cargos without compromising the extracellular vesicle membrane is a major challenge. Rapid squeezing through nanofluidic channels is a widely used approach to load exogenous cargoes into the EV through the nanopores generated temporarily on the membrane. However, the exact mechanism and dynamics of nanopore opening, as well as cargo loading through nanopores during the squeezing process remains unknown and it is impossible to visualize or quantify it experimentally due to the small size of the EV and the fast transient process. This paper developed a systemic algorithm to simulate nanopore formation and predict drug loading during extracellular vesicle (EV) squeezing by leveraging the power of coarse-grain (CG) molecular dynamics simulations with fluid dynamics. The EV CG beads are coupled with implicit the fluctuating lattice Boltzmann solvent. The effects of EV properties and various squeezing test parameters, such as EV size, flow velocity, channel width, and length, on pore formation and drug loading efficiency are analyzed. Based on the simulation results, a phase diagram is provided as a design guide for nanochannel geometry and squeezing velocity to generate pores on the membrane without damaging the EV. This method can be utilized to optimize the nanofluidic device configuration and flow setup to obtain desired drug loading into EVs.
Collapse
Affiliation(s)
- Khayrul Islam
- Department of Mechanical Engineering and Mechanics, Lehigh University, Bethlehem, Pennsylvania 18015, USA.
| | - Meghdad Razizadeh
- Department of Developmental Neurobiology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Yaling Liu
- Department of Mechanical Engineering and Mechanics, Lehigh University, Bethlehem, Pennsylvania 18015, USA.
- Department of Bioengineering, Lehigh University, Bethlehem, Pennsylvania 18015, USA
| |
Collapse
|
13
|
Hardt M, Busse F, Raschke S, Honnigfort C, Carrascosa-Tejedor J, Wenk P, Gutfreund P, Campbell RA, Heuer A, Braunschweig B. Photo-Responsive Control of Adsorption and Structure Formation at the Air-Water Interface with Arylazopyrazoles. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:5861-5871. [PMID: 37058525 DOI: 10.1021/acs.langmuir.3c00294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Smart interfaces that are responsive to external triggers such as light are of great interest for the development of responsive or adaptive materials and interfaces. Using alkyl-arylazopyrazole butyl sulfonate surfactants (alkyl-AAP) that can undergo E/Z photoisomerization when irradiated with green (E) and UV (Z) lights, we demonstrate through a combination of experiments and computer simulations that there can be surprisingly large changes in surface tension and in the molecular structure and order at air-water interfaces. Surface tensiometry, vibrational sum-frequency generation (SFG) spectroscopy, and neutron reflectometry (NR) are applied to the study of custom-synthesized AAP surfactants with octyl- and H-terminal groups at air-water interfaces as a function of their bulk concentration and E/Z configuration. Upon photoswitching, a drastic influence of the alkyl chain on both the surface activity and the responsiveness of interfacial surfactants is revealed from changes in the surface tension, γ, where the largest changes in γ are observed for octyl-AAP (Δγ ∼ 23 mN/m) in contrast to H-AAP with Δγ < 10 mN/m. Results from vibrational SFG spectroscopy and NR show that the interfacial composition and the molecular order of the surfactants drastically change with E/Z photoisomerization and surface coverage. Indeed, from analysis of the S-O (head group) and C-H vibrational bands (hydrophobic tail), a qualitative analysis of orientational and structural changes of interfacial AAP surfactants is provided. The experiments are complemented by resolution of thermodynamic parameters such as equilibrium constants from ultra-coarse-grained simulations, which also capture details like island formation and interaction parameters of interfacial molecules. Here, the interparticle interaction ("stickiness") and the interaction with the surface are adjusted, closely reflecting experimental conditions.
Collapse
Affiliation(s)
- Michael Hardt
- Center for Soft Nanoscience, Busso-Peus-Straße 10, 48149 Münster, Germany
- Institute of Physical Chemistry, Corrensstraße 28/30, 48149 Münster, Germany
| | - Franziska Busse
- Institute of Physical Chemistry, Corrensstraße 28/30, 48149 Münster, Germany
| | - Simon Raschke
- Institute of Physical Chemistry, Corrensstraße 28/30, 48149 Münster, Germany
| | - Christian Honnigfort
- Center for Soft Nanoscience, Busso-Peus-Straße 10, 48149 Münster, Germany
- Institute of Physical Chemistry, Corrensstraße 28/30, 48149 Münster, Germany
| | - Javier Carrascosa-Tejedor
- Institut Laue-Langevin, 71 Avenue des Martyrs, CS 20156, 38042 Grenoble Cedex 9, France
- Division of Pharmacy & Optometry, University of Manchester, M13 9PT Manchester, U.K
| | - Paul Wenk
- Institute of Physical Chemistry, Corrensstraße 28/30, 48149 Münster, Germany
| | - Philipp Gutfreund
- Institut Laue-Langevin, 71 Avenue des Martyrs, CS 20156, 38042 Grenoble Cedex 9, France
| | - Richard A Campbell
- Division of Pharmacy & Optometry, University of Manchester, M13 9PT Manchester, U.K
| | - Andreas Heuer
- Institute of Physical Chemistry, Corrensstraße 28/30, 48149 Münster, Germany
| | - Björn Braunschweig
- Center for Soft Nanoscience, Busso-Peus-Straße 10, 48149 Münster, Germany
- Institute of Physical Chemistry, Corrensstraße 28/30, 48149 Münster, Germany
| |
Collapse
|
14
|
Brito ME, Mikhtaniuk SE, Neelov IM, Borisov OV, Holm C. Implicit-Solvent Coarse-Grained Simulations of Linear-Dendritic Block Copolymer Micelles. Int J Mol Sci 2023; 24:ijms24032763. [PMID: 36769091 PMCID: PMC9917066 DOI: 10.3390/ijms24032763] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 01/20/2023] [Accepted: 01/30/2023] [Indexed: 02/04/2023] Open
Abstract
The design of nanoassemblies can be conveniently achieved by tuning the strength of the hydrophobic interactions of block copolymers in selective solvents. These block copolymer micelles form supramolecular aggregates, which have attracted great attention in the area of drug delivery and imaging in biomedicine due to their easy-to-tune properties and straightforward large-scale production. In the present work, we have investigated the micellization process of linear-dendritic block copolymers in order to elucidate the effect of branching on the micellar properties. We focus on block copolymers formed by linear hydrophobic blocks attached to either dendritic neutral or charged hydrophilic blocks. We have implemented a simple protocol for determining the equilibrium micellar size, which permits the study of linear-dendritic block copolymers in a wide range of block morphologies in an efficient and parallelizable manner. We have explored the impact of different topological and charge properties of the hydrophilic blocks on the equilibrium micellar properties and compared them to predictions from self-consistent field theory and scaling theory. We have found that, at higher degrees of branching in the corona and for short polymer chains, excluded volume interactions strongly influence the micellar aggregation as well as their effective charge.
Collapse
Affiliation(s)
- Mariano E. Brito
- Institute for Computational Physics, University of Stuttgart, D-70569 Stuttgart, Germany
| | - Sofia E. Mikhtaniuk
- School of Computer Technologies and Control, St. Petersburg National Research University of Information Technologies, Mechanics and Optics, 197101 St. Petersburg, Russia
| | - Igor M. Neelov
- School of Computer Technologies and Control, St. Petersburg National Research University of Information Technologies, Mechanics and Optics, 197101 St. Petersburg, Russia
| | - Oleg V. Borisov
- School of Computer Technologies and Control, St. Petersburg National Research University of Information Technologies, Mechanics and Optics, 197101 St. Petersburg, Russia
- Institut des Sciences Analytiques et de Physico-Chimie pour l’Environnement et les Matériaux, UMR 5254 CNRS UPPA, 64053 Pau, France
| | - Christian Holm
- Institute for Computational Physics, University of Stuttgart, D-70569 Stuttgart, Germany
- Correspondence: ; Tel.: +49-711-685-63701
| |
Collapse
|
15
|
Salatto D, Huang Z, Benziger PT, Carrillo JMY, Bajaj Y, Gauer A, Tsapatsaris L, Sumpter BG, Li R, Takenaka M, Yin W, Thanassi DG, Endoh M, Koga T. Structure-Based Design of Dual Bactericidal and Bacteria-Releasing Nanosurfaces. ACS APPLIED MATERIALS & INTERFACES 2023; 15:3420-3432. [PMID: 36600562 DOI: 10.1021/acsami.2c18121] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Here, we report synergistic nanostructured surfaces combining bactericidal and bacteria-releasing properties. A polystyrene-block-poly(methyl methacrylate) (PS-block-PMMA) diblock copolymer is used to fabricate vertically oriented cylindrical PS structures ("PS nanopillars") on silicon substrates. The results demonstrate that the PS nanopillars (with a height of about 10 nm, size of about 50 nm, and spacing of about 70 nm) exhibit highly effective bactericidal and bacteria-releasing properties ("dual properties") against Escherichia coli for at least 36 h of immersion in an E. coli solution. Interestingly, the PS nanopillars coated with a thin layer (≈3 nm thick) of titanium oxide (TiO2) ("TiO2 nanopillars") show much improved dual properties against E. coli (a Gram-negative bacterium) compared to the PS nanopillars. Moreover, the dual properties emerge against Listeria monocytogenes (a Gram-positive bacterium). To understand the mechanisms underlying the multifaceted property of the nanopillars, coarse-grained molecular dynamics (MD) simulations of a lipid bilayer (as a simplified model for E. coli) in contact with a substrate containing hexagonally packed hydrophilic nanopillars were performed. The MD results demonstrate that when the bacterium-substrate interaction is strong, the lipid heads adsorb onto the nanopillar surfaces, conforming the shape of a lipid bilayer to the structure/curvature of nanopillars and generating high stress concentrations within the membrane (i.e., the driving force for rupture) at the edge of the nanopillars. Membrane rupture begins with the formation of pores between nanopillars (i.e., bactericidal activity) and ultimately leads to the membrane withdrawal from the nanopillar surface (i.e., bacteria-releasing activity). In the case of Gram-positive bacteria, the adhesion area to the pillar surface is limited due to the inherent stiffness of the bacteria, creating higher stress concentrations within a bacterial cell wall. The present study provides insight into the mechanism underlying the "adhesion-mediated" multifaceted property of nanosurfaces, which is crucial for the development of next-generation antibacterial surface coatings for relevant medical applications.
Collapse
Affiliation(s)
- Daniel Salatto
- Department of Materials Science and Chemical Engineering, Stony Brook University, Stony Brook, New York11794-2275, United States
| | - Zhixing Huang
- Department of Materials Science and Chemical Engineering, Stony Brook University, Stony Brook, New York11794-2275, United States
| | - Peter Todd Benziger
- Department of Microbiology and Immunology, Stony Brook University, Stony Brook, New York11794-5222, United States
- Center for Infectious Diseases, Stony Brook University, Stony Brook, New York11794-5120, United States
| | - Jan-Michael Y Carrillo
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee37831, United States
| | - Yashasvi Bajaj
- Department of Materials Science and Chemical Engineering, Stony Brook University, Stony Brook, New York11794-2275, United States
| | - Aiden Gauer
- Department of Materials Science and Chemical Engineering, Stony Brook University, Stony Brook, New York11794-2275, United States
| | - Leonidas Tsapatsaris
- Department of Materials Science and Chemical Engineering, Stony Brook University, Stony Brook, New York11794-2275, United States
| | - Bobby G Sumpter
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee37831, United States
| | - Ruipeng Li
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, New York11973, United States
| | - Mikihito Takenaka
- Institute for Chemical Research, Kyoto University, Uji, Kyoto611-0011, Japan
| | - Wei Yin
- Department of Biomedical engineering, Stony Brook University, Stony Brook, New York11794-5281, United States
| | - David G Thanassi
- Department of Microbiology and Immunology, Stony Brook University, Stony Brook, New York11794-5222, United States
- Center for Infectious Diseases, Stony Brook University, Stony Brook, New York11794-5120, United States
| | - Maya Endoh
- Department of Materials Science and Chemical Engineering, Stony Brook University, Stony Brook, New York11794-2275, United States
| | - Tadanori Koga
- Department of Materials Science and Chemical Engineering, Stony Brook University, Stony Brook, New York11794-2275, United States
- Department of Chemistry, Stony Brook University, Stony Brook, New York11794-3400, United States
| |
Collapse
|
16
|
Pinigin KV. Determination of Elastic Parameters of Lipid Membranes with Molecular Dynamics: A Review of Approaches and Theoretical Aspects. MEMBRANES 2022; 12:membranes12111149. [PMID: 36422141 PMCID: PMC9692374 DOI: 10.3390/membranes12111149] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Revised: 11/07/2022] [Accepted: 11/10/2022] [Indexed: 05/12/2023]
Abstract
Lipid membranes are abundant in living organisms, where they constitute a surrounding shell for cells and their organelles. There are many circumstances in which the deformations of lipid membranes are involved in living cells: fusion and fission, membrane-mediated interaction between membrane inclusions, lipid-protein interaction, formation of pores, etc. In all of these cases, elastic parameters of lipid membranes are important for the description of membrane deformations, as these parameters determine energy barriers and characteristic times of membrane-involved phenomena. Since the development of molecular dynamics (MD), a variety of in silico methods have been proposed for the determination of elastic parameters of simulated lipid membranes. These MD methods allow for the consideration of details unattainable in experimental techniques and represent a distinct scientific field, which is rapidly developing. This work provides a review of these MD approaches with a focus on theoretical aspects. Two main challenges are identified: (i) the ambiguity in the transition from the continuum description of elastic theories to the discrete representation of MD simulations, and (ii) the determination of intrinsic elastic parameters of lipid mixtures, which is complicated due to the composition-curvature coupling effect.
Collapse
Affiliation(s)
- Konstantin V Pinigin
- A. N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, 31/4 Leninskiy Prospekt, 119071 Moscow, Russia
| |
Collapse
|
17
|
Paul T, Saha J. Domain formation in model lipid–cholesterol liquid-crystalline aggregation. MOLECULAR SIMULATION 2022. [DOI: 10.1080/08927022.2022.2134567] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Affiliation(s)
- T. Paul
- Department of Physics, University of Calcutta, Kolkata, India
| | - J. Saha
- Department of Physics, University of Calcutta, Kolkata, India
| |
Collapse
|
18
|
Khosravanizadeh A, Sens P, Mohammad-Rafiee F. Role of particle local curvature in cellular wrapping. J R Soc Interface 2022; 19:20220462. [PMID: 36321371 PMCID: PMC9627444 DOI: 10.1098/rsif.2022.0462] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Accepted: 10/06/2022] [Indexed: 12/14/2022] Open
Abstract
Cellular uptake through membranes plays an important role in adsorbing nutrients and fighting infection and can be used for nanomedicine developments. Endocytosis is one of the pathways of cellular uptake which associate with elastic deformation of the membrane wrapping around the foreign particle. The deformability of the membrane is strongly regulated by the presence of a cortical cytoskeleton placed underneath the membrane. It is shown that shape and orientation of the particles influence on their internalization. Here, we study the role of particle local curvature in cellular uptake by investigating the wrapping of an elastic membrane around a long cylindrical object with an elliptical cross-section. The membrane itself is adhered to a substrate mimicking the cytoskeleton. Membrane wrapping proceeds differently whether the initial contact occurs at the target's highly curved part (vertical) or along its long side (horizontal). We obtain a wrapping phase diagram as a function of the membrane-cytoskeleton and the membrane-target adhesion energy, which includes three distinct regimes (unwrapped, partially wrapped and fully wrapped), separated by two phase transitions. We also provide analytical expressions for the boundaries between the different regimes which confirm that the transitions strongly depend on the orientation and aspect ratio of the nanowire.
Collapse
Affiliation(s)
- Amir Khosravanizadeh
- Department of Physics, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan 45137-66731, Iran
- Université Paris Cité, CNRS, Institut Jacques Monod, Paris 75013, France
| | - Pierre Sens
- Institut Curie, PSL Research University, CNRS UMR 168, Paris, 75005 France
| | - Farshid Mohammad-Rafiee
- Department of Physics, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan 45137-66731, Iran
- Research Center for Basic Sciences and Modern Technologies (RBST), Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan 45137-66731, Iran
| |
Collapse
|
19
|
Singhal A, Sevink GJA. A Core-Shell Approach for Systematically Coarsening Nanoparticle-Membrane Interactions: Application to Silver Nanoparticles. NANOMATERIALS (BASEL, SWITZERLAND) 2022; 12:3859. [PMID: 36364637 PMCID: PMC9656456 DOI: 10.3390/nano12213859] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Revised: 10/28/2022] [Accepted: 10/28/2022] [Indexed: 06/16/2023]
Abstract
The continuous release of engineered nanomaterial (ENM) into the environment may bring about health concerns following human exposure. One important source of ENMs are silver nanoparticles (NPs) that are extensively used as anti-bacterial additives. The introduction of ENMs into the human body can occur via ingestion, skin uptake or the respiratory system. Therefore, evaluating how NPs translocate over bio-membranes is essential in assessing their primary toxicity. Unfortunately, data regarding membrane-NP interaction is still scarce, as is theoretical and in silico insight into what governs adhesion and translocation for the most relevant NPs and membranes. Coarse-grained (CG) molecular descriptions have the potential to alleviate this situation, but are hampered by the absence of a direct link to NP materials and membrane adhesion mechanisms. Here, we interrogate the relationship between the most common NP representation at the CG level and the adhesion characteristics of a model lung membrane. We find that this representation for silver NPs is non-transferable, meaning that a proper CG representation for one size is not suited for other sizes. We also identify two basic types of primary adhesion-(partial) NPs wrapping by the membrane and NP insertion into the membrane-that closely relate to the overall NP hydrophobicity and significantly differ in terms of lipid coatings. The proven non-transferability of the standard CG representation with size forms an inspiration for introducing a core-shell model even for bare NPs that are uniform in composition. Using existing all-atom molecular dynamics (MD) data as a reference, we show that this extension does allow us to reproduce size-dependent NP adhesion properties and lipid responses to NP binding at the CG level. The subsequent CGMD evaluation for 10 nm Ag NPs provides new insight into membrane binding for relevant NP sizes and into the role of water in trapping NPs into defected mixed monolayer-bilayer states. This development will be instrumental for simulating NP-membrane adhesion towards more experimentally relevant length and time scales for particular NP materials.
Collapse
|
20
|
Varma M, Deserno M. Distribution of cholesterol in asymmetric membranes driven by composition and differential stress. Biophys J 2022; 121:4001-4018. [PMID: 35927954 PMCID: PMC9674969 DOI: 10.1016/j.bpj.2022.07.032] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 07/11/2022] [Accepted: 07/27/2022] [Indexed: 11/25/2022] Open
Abstract
Many lipid membranes of eukaryotic cells are asymmetric, which means the two leaflets differ in at least one physical property, such as lipid composition or lateral stress. Maintaining this asymmetry is helped by the fact that ordinary phospholipids rarely transition between leaflets, but cholesterol is an exception: its flip-flop times are in the microsecond range, so that its distribution between leaflets is determined by a chemical equilibrium. In particular, preferential partitioning can draw cholesterol into a more saturated leaflet, and phospholipid number asymmetry can force it out of a compressed leaflet. Combining highly coarse-grained membrane simulations with theoretical modeling, we investigate how these two driving forces play against each other until cholesterol's chemical potential is equilibrated. The theory includes two coupled elastic sheets and a Flory-Huggins mixing free energy with a χ parameter. We obtain a relationship between χ and the interaction strength between cholesterol and lipids in either of the two leaflets, and we find that it depends, albeit weakly, on lipid number asymmetry. The differential stress measurements under various asymmetry conditions agree with our theoretical predictions. Using the two kinds of asymmetries in combination, we find that it is possible to counteract the phospholipid number bias, and the resultant stress in the membrane, via the control of cholesterol mixing in the leaflets.
Collapse
Affiliation(s)
- Malavika Varma
- Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania
| | - Markus Deserno
- Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania.
| |
Collapse
|
21
|
Jarin Z, Agolini O, Pastor RW. Finite-Size Effects in Simulations of Peptide/Lipid Assembly. J Membr Biol 2022; 255:437-449. [PMID: 35854128 PMCID: PMC9581812 DOI: 10.1007/s00232-022-00255-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Accepted: 06/17/2022] [Indexed: 11/29/2022]
Abstract
Abstract Molecular dynamics simulations are an attractive tool for understanding lipid/peptide self-assembly but can be plagued by inaccuracies when the system sizes are too small. The general guidance from self-assembly simulations of homogeneous micelles is that the total number of surfactants should be three to five times greater than the equilibrium aggregate number of surfactants per micelle. Herein, the heuristic is tested on the more complicated self-assembly of lipids and amphipathic peptides using the Cooke and Martini 3 coarse-grained models. Cooke model simulations with 50 to 1000 lipids and no peptide are dominated by finite-size effects, with usually one aggregate (micelle or nanodisc) containing most of the lipids forming at each system size. Approximately 200 systems of different peptide/lipid (P/L) ratios and sizes of up to 1000 lipids yield a “finite-size phase diagram” for peptide driven self-assembly, including a coexistence region of micelles and discs. Insights from the Cooke model are applied to the assembly of dimyristoylphosphatidylcholine and the ELK-neutral peptide using the Martini 3 model. Systems of 150, 450, and 900 lipids with P/L = 1/6.25 form mixtures of lipid-rich discs that agree in size with experiment and peptide-rich micelles. Only the 150-lipid system shows finite-size effects, which arise from the long-tailed distribution of aggregate sizes. The general rule of three to five times the equilibrium aggregate size remains a practical heuristic for the Cooke and Martini 3 systems investigated here. Graphical Abstract ![]()
Supplementary Information The online version contains supplementary material available at 10.1007/s00232-022-00255-9.
Collapse
Affiliation(s)
- Zack Jarin
- Laboratory of Computational Biology, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Olivia Agolini
- Laboratory of Computational Biology, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Richard W Pastor
- Laboratory of Computational Biology, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA.
| |
Collapse
|
22
|
Critical micelle concentration of SDS through DPD simulations using COSMO-RS–based interaction parameters, the thermal effects. Colloids Surf A Physicochem Eng Asp 2022. [DOI: 10.1016/j.colsurfa.2022.128867] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
|
23
|
Gao J, Hou R, Li L, Hu J. Membrane-Mediated Interactions Between Protein Inclusions. Front Mol Biosci 2021; 8:811711. [PMID: 35004858 PMCID: PMC8727768 DOI: 10.3389/fmolb.2021.811711] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Accepted: 11/30/2021] [Indexed: 11/13/2022] Open
Abstract
Integral or peripheral membrane proteins, or protein oligomers often get close to each other on cell membranes and carry out biological tasks in a collective manner. In addition to electrostatic and van der Waals interactions, those proteins also experience membrane-mediated interactions, which may be necessary for their functionality. The membrane-mediated interactions originate from perturbation of lipid membranes by the presence of protein inclusions, and have been the subject of intensive research in membrane biophysics. Here we review both theoretical and numerical studies of such interactions for membrane proteins and for nanoparticles bound to lipid membranes.
Collapse
Affiliation(s)
- Jie Gao
- Kuang Yaming Honors School, Nanjing University, Nanjing, China
| | - Ruihan Hou
- Kuang Yaming Honors School, Nanjing University, Nanjing, China
| | - Long Li
- State Key Laboratory of Nonlinear Mechanics (LNM) and Beijing Key Laboratory of Engineered Construction and Mechanobiology, Institute of Mechanics, Chinese Academy of Sciences, Beijing, China
| | - Jinglei Hu
- Kuang Yaming Honors School, Nanjing University, Nanjing, China
| |
Collapse
|
24
|
Chen T, Zhang Y, Li X, Li C, Lu T, Xiao S, Liang H. Curvature-Mediated Pair Interactions of Soft Nanoparticles Adhered to a Cell Membrane. J Chem Theory Comput 2021; 17:7850-7861. [PMID: 34865469 DOI: 10.1021/acs.jctc.1c00897] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The curvature-mediated interactions by cell membranes are crucial in many biological processes. We systematically studied the curvature-mediated wrapping of soft nanoparticles (NPs) by a tensionless membrane and the underlying pair interactions between NPs in determining it. We found that there are three types of wrapping pathways, namely, independence, cooperation, and tubulation. The particle size, adhesion strength, and softness are found to be strongly related with the wrapping mechanism. Reducing the adhesion strength transforms the wrapping pathway from cooperation to independence, while enhancing the NP softness requires a stronger adhesion to achieve the cooperative wrapping. This transformation of the wrapping pathway is controlled by the curvature-mediated interactions between NPs. For either soft or rigid NPs, the pair interactions are repulsive at short-ranged distances between NPs, while at long-ranged distances, a larger adhesion between NPs and a membrane is needed to generate attraction between NPs. Moreover, an enhancement of NP softness weakens the repulsion between NPs. These distinct behaviors of soft NPs are ascribed to the gentler deformation of the membrane at the face-to-face region between NPs due to the flattening and spreading of soft NPs along the membrane, requiring a reduced energy cost for soft NPs to approach each other. Our results provide a mechanistic understanding in detail about the membrane-mediated interactions between NPs and their interactions with cell membranes, which is helpful to understand the curvature-mediated assemblies of adhesive proteins or NPs on membranes, and offer novel possibilities for designing an effective NP-based vehicle for controlled drug delivery.
Collapse
Affiliation(s)
- Tongwei Chen
- Department of Polymer Science and Engineering, CAS Key Laboratory of Soft Matter Chemistry, iChEM (Collaborative Innovation Center of Chemistry for Energy Materials), University of Science and Technology of China, Hefei, Anhui 230026, P. R. China
| | - Yunhan Zhang
- Department of Polymer Science and Engineering, CAS Key Laboratory of Soft Matter Chemistry, iChEM (Collaborative Innovation Center of Chemistry for Energy Materials), University of Science and Technology of China, Hefei, Anhui 230026, P. R. China
| | - Xuejin Li
- Department of Engineering Mechanics and Center for X-Mechanics, Zhejiang University, Hangzhou 310027, P. R. China
| | - Chengxu Li
- Department of Polymer Science and Engineering, CAS Key Laboratory of Soft Matter Chemistry, iChEM (Collaborative Innovation Center of Chemistry for Energy Materials), University of Science and Technology of China, Hefei, Anhui 230026, P. R. China
| | - Teng Lu
- Computer Network Information Center of the Chinese Academy of Sciences, Beijing 100083, P. R. China
| | - Shiyan Xiao
- Department of Polymer Science and Engineering, CAS Key Laboratory of Soft Matter Chemistry, iChEM (Collaborative Innovation Center of Chemistry for Energy Materials), University of Science and Technology of China, Hefei, Anhui 230026, P. R. China.,Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui 230026, P. R. China
| | - Haojun Liang
- Department of Polymer Science and Engineering, CAS Key Laboratory of Soft Matter Chemistry, iChEM (Collaborative Innovation Center of Chemistry for Energy Materials), University of Science and Technology of China, Hefei, Anhui 230026, P. R. China.,Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui 230026, P. R. China
| |
Collapse
|
25
|
Wu F, Jin X, Guan Z, Lin J, Cai C, Wang L, Li Y, Lin S, Xu P, Gao L. Membrane Nanopores Induced by Nanotoroids via an Insertion and Pore-Forming Pathway. NANO LETTERS 2021; 21:8545-8553. [PMID: 34623162 DOI: 10.1021/acs.nanolett.1c01331] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The formation of membrane nanopores is one of the crucial activities of cells and has attracted considerable attention. However, the understanding of their types and mechanisms is still limited. Herein, we report a novel nanopore formation phenomenon achieved through the insertion of polymeric nanotoroids into the cellular membrane. As revealed by theoretical simulations, the nanotoroid can embed in the membrane, leaving a nanopore on the cell. The through-the-cavity wrapping of lipids is critical for the retention of the nanotoroid in the membrane, which is attributed to both a relatively large inner cavity of the nanotoroid and a moderate attraction between the nanotoroid and membrane lipids. Under the guidance of the simulation predictions, experiments using polypeptide toroids as pore-forming agents were performed, confirming the unique biophysical phenomenon. This work demonstrates a distinctive pore-forming pathway, deepens the understanding of the membrane nanopore phenomenon, and assists in the design of advanced pore-forming materials.
Collapse
Affiliation(s)
- Fangsheng Wu
- Shanghai Key Laboratory of Advanced Polymeric Materials, Key Laboratory for Ultrafine Materials of Ministry of Education, Frontiers Science Center for Materiobiology and Dynamic Chemistry, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, People's Republic of China
| | - Xiao Jin
- Shanghai Key Laboratory of Advanced Polymeric Materials, Key Laboratory for Ultrafine Materials of Ministry of Education, Frontiers Science Center for Materiobiology and Dynamic Chemistry, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, People's Republic of China
| | - Zhou Guan
- Shanghai Key Laboratory of Advanced Polymeric Materials, Key Laboratory for Ultrafine Materials of Ministry of Education, Frontiers Science Center for Materiobiology and Dynamic Chemistry, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, People's Republic of China
| | - Jiaping Lin
- Shanghai Key Laboratory of Advanced Polymeric Materials, Key Laboratory for Ultrafine Materials of Ministry of Education, Frontiers Science Center for Materiobiology and Dynamic Chemistry, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, People's Republic of China
| | - Chunhua Cai
- Shanghai Key Laboratory of Advanced Polymeric Materials, Key Laboratory for Ultrafine Materials of Ministry of Education, Frontiers Science Center for Materiobiology and Dynamic Chemistry, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, People's Republic of China
| | - Liquan Wang
- Shanghai Key Laboratory of Advanced Polymeric Materials, Key Laboratory for Ultrafine Materials of Ministry of Education, Frontiers Science Center for Materiobiology and Dynamic Chemistry, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, People's Republic of China
| | - Yongsheng Li
- Shanghai Key Laboratory of Advanced Polymeric Materials, Key Laboratory for Ultrafine Materials of Ministry of Education, Frontiers Science Center for Materiobiology and Dynamic Chemistry, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, People's Republic of China
| | - Shaoliang Lin
- Shanghai Key Laboratory of Advanced Polymeric Materials, Key Laboratory for Ultrafine Materials of Ministry of Education, Frontiers Science Center for Materiobiology and Dynamic Chemistry, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, People's Republic of China
| | - Pengfei Xu
- Shanghai Key Laboratory of Advanced Polymeric Materials, Key Laboratory for Ultrafine Materials of Ministry of Education, Frontiers Science Center for Materiobiology and Dynamic Chemistry, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, People's Republic of China
| | - Liang Gao
- Shanghai Key Laboratory of Advanced Polymeric Materials, Key Laboratory for Ultrafine Materials of Ministry of Education, Frontiers Science Center for Materiobiology and Dynamic Chemistry, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, People's Republic of China
| |
Collapse
|
26
|
Wei T, Gu L, Zhou M, Zhou Y, Yang H, Li M. Impact of Shock-Induced Cavitation Bubble Collapse on the Damage of Cell Membranes with Different Lipid Peroxidation Levels. J Phys Chem B 2021; 125:6912-6920. [PMID: 34133190 DOI: 10.1021/acs.jpcb.1c02483] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Although the interaction mechanism between shock waves and cells is critical for advancing the medical applications of shock waves, we still have little understanding about it. This work aims to study the response of diseased cells subjected to lipid peroxidation to the nanojet from shock wave-induced bubble collapse by using the coarse-grained molecular dynamics simulation. Factors considered in the simulations include the shock velocity (up), movement time of piston (τp), bubble size (R), and peroxidation level of membranes. Here, we mainly focus on the role of peroxidation levels, that is, the degree (%) and the distribution of oxidized lipids in membranes. The results indicate that the shock damage threshold (up at which the pore in membranes is formed) of peroxidation membranes is less than that of normal membranes and decreases with the peroxidation degree. Importantly, the distribution of oxidized lipids has more effect on the damage threshold than the peroxidation degree. The threshold of membrane with 33% localized oxidized lipids is lower than that of membrane with 50% average oxidized lipids. The results can be explained by the stretching modulus (κs) and bending modulus (κb) of cell membranes. For example, the κb value (4.3 × 10-20 J) of 100% peroxidation membrane is about half of that (8.4 × 10-20 J) of a membrane without peroxidation. A lower modulus means high deformation under the same impact. Further analysis shows that peroxidation introduces a polar hydrophobic group to the tail of phospholipids that increases the hydrophilicity of tails and warps the tail of phospholipids toward the membrane-water interface, resulting in looser accumulation. This can be confirmed by the increased average phospholipid area with peroxidation levels. Indeed, most of the pores formed during the shock can heal. However, the permeation of water molecules across the healing membrane still increased. All these membrane-level information obtained from this study will be useful for improving the biomedical applications of shock waves.
Collapse
Affiliation(s)
- Tong Wei
- CAS Key Laboratory of Mechanical Behavior and Design of Materials, Department of Modern Mechanics, University of Science and Technology of China, Hefei 230026, China
- Institute of Chemical Materials, China Academy of Engineering and Physics, Mianyang 621900, China
| | - Lingzhi Gu
- Institute of Chemical Materials, China Academy of Engineering and Physics, Mianyang 621900, China
| | - Mi Zhou
- Institute of Chemical Materials, China Academy of Engineering and Physics, Mianyang 621900, China
| | - Yang Zhou
- Institute of Chemical Materials, China Academy of Engineering and Physics, Mianyang 621900, China
| | - Hong Yang
- Institute of Chemical Materials, China Academy of Engineering and Physics, Mianyang 621900, China
| | - Ming Li
- Institute of Chemical Materials, China Academy of Engineering and Physics, Mianyang 621900, China
| |
Collapse
|
27
|
Ergüder MF, Deserno M. Identifying systematic errors in a power spectral analysis of simulated lipid membranes. J Chem Phys 2021; 154:214103. [PMID: 34240970 DOI: 10.1063/5.0049448] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The elastic properties of lipid membranes can be measured by monitoring their thermal fluctuations. For instance, comparing the power spectra of membrane shape or lipid director fluctuations with predictions based on suitable continuum theories gives access to bending-, tilt-, and twist-moduli. However, to do so in a computer simulation, we must first define a continuum surface shape and lipid director field from the discrete configurations of lipid molecules in a typically fairly small box. Here, we show that the required mapping choices, as well as the details of the subsequent data analysis, can shift the measured values of these moduli by far more than their statistical uncertainties. We investigate the resulting systematic errors on the basis of atomistic simulation trajectories for 13 different lipids, previously published by Venable et al. [Chem. Phys. Lipids 192, 60-74 (2015)]. Specifically, we examine mapping choices for surface- and tilt-field definitions, normalizing and averaging lipid directors, accounting for wave vector dependent time autocorrelations, error propagation, and finding the right fitting range. We propose a set of criteria that may help to decide upon a particular combination of choices underlying the fluctuation analysis, and we make several recommendations based on these. While systematic shifts in observables that are extracted from large-wavelength limits vanish, in principle, for sufficiently large system size, no such exact limit exists for intrinsically local parameters, such as the twist modulus or the splay-tilt coupling, and so not all potential choices can be trivially verified.
Collapse
Affiliation(s)
- Muhammed F Ergüder
- Department of Physics, Carnegie Mellon University, 5000 Forbes Ave., Pittsburgh, Pennsylvania 15213, USA
| | - Markus Deserno
- Department of Physics, Carnegie Mellon University, 5000 Forbes Ave., Pittsburgh, Pennsylvania 15213, USA
| |
Collapse
|
28
|
Sousa AA, Schuck P, Hassan SA. Biomolecular interactions of ultrasmall metallic nanoparticles and nanoclusters. NANOSCALE ADVANCES 2021; 3:2995-3027. [PMID: 34124577 PMCID: PMC8168927 DOI: 10.1039/d1na00086a] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Accepted: 04/16/2021] [Indexed: 05/03/2023]
Abstract
The use of nanoparticles (NPs) in biomedicine has made a gradual transition from proof-of-concept to clinical applications, with several NP types meeting regulatory approval or undergoing clinical trials. A new type of metallic nanostructures called ultrasmall nanoparticles (usNPs) and nanoclusters (NCs), while retaining essential properties of the larger (classical) NPs, have features common to bioactive proteins. This combination expands the potential use of usNPs and NCs to areas of diagnosis and therapy traditionally reserved for small-molecule medicine. Their distinctive physicochemical properties can lead to unique in vivo behaviors, including improved renal clearance and tumor distribution. Both the beneficial and potentially deleterious outcomes (cytotoxicity, inflammation) can, in principle, be controlled through a judicious choice of the nanocore shape and size, as well as the chemical ligands attached to the surface. At present, the ability to control the behavior of usNPs is limited, partly because advances are still needed in nanoengineering and chemical synthesis to manufacture and characterize ultrasmall nanostructures and partly because our understanding of their interactions in biological environments is incomplete. This review addresses the second limitation. We review experimental and computational methods currently available to understand molecular mechanisms, with particular attention to usNP-protein complexation, and highlight areas where further progress is needed. We discuss approaches that we find most promising to provide relevant molecular-level insight for designing usNPs with specific behaviors and pave the way to translational applications.
Collapse
Affiliation(s)
- Alioscka A Sousa
- Department of Biochemistry, Federal University of São Paulo São Paulo SP 04044 Brazil
| | - Peter Schuck
- National Institute of Biomedical Imaging and Bioengineering, NIH Bethesda MD 20892 USA
| | - Sergio A Hassan
- BCBB, National Institute of Allergy and Infectious Diseases, NIH Bethesda MD 20892 USA
| |
Collapse
|
29
|
Bartoš L, Kabelka I, Vácha R. Enhanced translocation of amphiphilic peptides across membranes by transmembrane proteins. Biophys J 2021; 120:2296-2305. [PMID: 33864790 PMCID: PMC8390799 DOI: 10.1016/j.bpj.2021.04.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 02/11/2021] [Accepted: 04/08/2021] [Indexed: 11/12/2022] Open
Abstract
Cell membranes are phospholipid bilayers with a large number of embedded transmembrane proteins. Some of these proteins, such as scramblases, have properties that facilitate lipid flip-flop from one membrane leaflet to another. Scramblases and similar transmembrane proteins could also affect the translocation of other amphiphilic molecules, including cell-penetrating or antimicrobial peptides. We studied the effect of transmembrane proteins on the translocation of amphiphilic peptides through the membrane. Using two very different models, we consistently demonstrate that transmembrane proteins with a hydrophilic patch enhance the translocation of amphiphilic peptides by stabilizing the peptide in the membrane. Moreover, there is an optimum amphiphilicity because the peptide could become overstabilized in the transmembrane state, in which the peptide-protein dissociation is hampered, limiting the peptide translocation. The presence of scramblases and other proteins with similar properties could be exploited for more efficient transport into cells. The described principles could also be utilized in the design of a drug-delivery system by the addition of a translocation-enhancing peptide that would integrate into the membrane.
Collapse
Affiliation(s)
- Ladislav Bartoš
- Central European Institute of Technology (CEITEC) Masaryk University, Kamenice, Brno, Czech Republic; National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kamenice, Brno, Czech Republic
| | - Ivo Kabelka
- Central European Institute of Technology (CEITEC) Masaryk University, Kamenice, Brno, Czech Republic; National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kamenice, Brno, Czech Republic
| | - Robert Vácha
- Central European Institute of Technology (CEITEC) Masaryk University, Kamenice, Brno, Czech Republic; National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kamenice, Brno, Czech Republic; Department of Condensed Matter Physics, Faculty of Science, Masaryk University, Kotlářská, Brno, Czech Republic.
| |
Collapse
|
30
|
Patel P, Santo KP, Burgess S, Vishnyakov A, Neimark AV. Stability of Lipid Coatings on Nanoparticle-Decorated Surfaces. ACS NANO 2020; 14:17273-17284. [PMID: 33226210 DOI: 10.1021/acsnano.0c07298] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Lipid membranes supported on solid surfaces and nanoparticles find multiple applications in industrial and biomedical technologies. Here, we explore in silico the mechanisms of the interactions of lipid membranes with nanostructured surfaces with deposited nanoparticles and explain the characteristic particle size dependence of the uniformity and stability of lipid coatings observed in vitro. Simulations are performed to demonstrate the specifics of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) lipid membrane adhesion to hydrophilic and hydrophobic nanoparticles ranging in size from 1.5 to 40 nm using an original coarse-grained molecular dynamics model with implicit solvent and large simulation boxes (scales up to 280 × 154 × 69 nm3). We find that one of the major factors that affects the uniformity and stability of lipid coatings is the disjoining pressure in the water hydration layer formed between the lipid membrane and hydrophilic solid surface. This effect is accounted for by introducing a special long-range lipid-solid interaction potential that mimics the effects of the disjoining pressure in thin water layers. Our simulations reveal the physical mechanisms of interactions of lipid bilayers with solid surfaces that are responsible for the experimentally observed nonmonotonic particle size dependence of the uniformity and stability of lipid coatings: particles smaller than the hydration layer thickness (<2-3 nm) or larger than ∼20 nm are partially or fully enfolded by a lipid bilayer, whereas particles of the intermediate size (5-20 nm) cause membrane perforation and pore formation. In contrast, hydrophobic nanoparticles, which repel the hydration layer, tend to be encapsulated within the hydrophobic interior of the membrane and coated by the lipid monolayer. The proposed model can be further extended and applied to a wide class of systems comprising nanoparticles and nanostructured substrates interacting with lipid and surfactant bilayers and monolayers.
Collapse
Affiliation(s)
- Parva Patel
- Department of Chemical and Biochemical Engineering, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, United States
| | - Kolattukudy P Santo
- Department of Chemical and Biochemical Engineering, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, United States
| | - Sean Burgess
- Department of Chemical and Biochemical Engineering, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, United States
| | - Aleksey Vishnyakov
- Department of Chemical and Biochemical Engineering, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, United States
- Skolkovo Institute of Technology, Moscow 143005, Russia
| | - Alexander V Neimark
- Department of Chemical and Biochemical Engineering, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, United States
| |
Collapse
|
31
|
Abstract
Biological membranes can dramatically accelerate the aggregation of normally soluble protein molecules into amyloid fibrils and alter the fibril morphologies, yet the molecular mechanisms through which this accelerated nucleation takes place are not yet understood. Here, we develop a coarse-grained model to systematically explore the effect that the structural properties of the lipid membrane and the nature of protein-membrane interactions have on the nucleation rates of amyloid fibrils. We identify two physically distinct nucleation pathways-protein-rich and lipid-rich-and quantify how the membrane fluidity and protein-membrane affinity control the relative importance of those molecular pathways. We find that the membrane's susceptibility to reshaping and being incorporated into the fibrillar aggregates is a key determinant of its ability to promote protein aggregation. We then characterize the rates and the free-energy profile associated with this heterogeneous nucleation process, in which the surface itself participates in the aggregate structure. Finally, we compare quantitatively our data to experiments on membrane-catalyzed amyloid aggregation of α-synuclein, a protein implicated in Parkinson's disease that predominately nucleates on membranes. More generally, our results provide a framework for understanding macromolecular aggregation on lipid membranes in a broad biological and biotechnological context.
Collapse
|
32
|
Ugarte La Torre D, Takada S. Coarse-grained implicit solvent lipid force field with a compatible resolution to the Cα protein representation. J Chem Phys 2020; 153:205101. [PMID: 33261497 DOI: 10.1063/5.0026342] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Biological membranes have been prominent targets for coarse-grained (CG) molecular dynamics simulations. While minimal CG lipid models with three beads per lipid and quantitative CG lipid models with >10 beads per lipid have been well studied, in between them, CG lipid models with a compatible resolution to residue-level CG protein models are much less developed. Here, we extended a previously developed three-bead lipid model into a five-bead model and parameterized it for two phospholipids, POPC (1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine) and DPPC (1,2-dipalmitoyl-sn-glycero-3-phosphatidylcholine). The developed model, iSoLF, reproduced the area per lipid, hydrophobic thickness, and phase behaviors of the target phospholipid bilayer membranes at the physiological temperature. The model POPC and DPPC membranes were in liquid and gel phases, respectively, in accordance with experiments. We further examined the spontaneous formation of a membrane bilayer, the temperature dependence of physical properties, the vesicle dynamics, and the POPC/DPPC two-component membrane dynamics of the CG lipid model, showing some promise. Once combined with standard Cα protein models, the iSoLF model will be a powerful tool to simulate large biological membrane systems made of lipids and proteins.
Collapse
Affiliation(s)
- Diego Ugarte La Torre
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto, Japan
| | - Shoji Takada
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto, Japan
| |
Collapse
|
33
|
Liu N, Becton M, Zhang L, Wang X. Mechanism of Coupling Nanoparticle Stiffness with Shape for Endocytosis: From Rodlike Penetration to Wormlike Wriggling. J Phys Chem B 2020; 124:11145-11156. [DOI: 10.1021/acs.jpcb.0c08089] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Ning Liu
- College of Engineering, University of Georgia, Athens, Georgia 30602, United States
| | - Matthew Becton
- College of Engineering, University of Georgia, Athens, Georgia 30602, United States
| | - Liuyang Zhang
- State Key Laboratory for Manufacturing Systems Engineering, Xi’an Jiaotong University, Xi’an, Shaanxi 710049, China
| | - Xianqiao Wang
- College of Engineering, University of Georgia, Athens, Georgia 30602, United States
| |
Collapse
|
34
|
Foley S, Deserno M. Stabilizing Leaflet Asymmetry under Differential Stress in a Highly Coarse-Grained Lipid Membrane Model. J Chem Theory Comput 2020; 16:7195-7206. [PMID: 33126796 DOI: 10.1021/acs.jctc.0c00862] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We present a version of the coarse-grained Cooke lipid model, modified to simulate asymmetric lipid membranes. It is inspired by a method employed by Wang et al. [ Commun. Comput. Phys. 2013, 13, 1093-1106] for artificially penalizing lipid flip-flop but copes more robustly with differential stress, at the cost of one additional bead per lipid and the concomitant increase in computational overhead. Bilayer asymmetry ultimately breaks down beyond a system size dependent critical differential stress, which can be predicted from a simple analytical model. We remeasure many important material parameters for the new model and find it to be consistent with typical fluid lipid membranes. Maintaining a stable stress asymmetry has many applications, and we give two examples: (i) connecting monolayer stress to lipid number asymmetry in order to directly measure the monolayer area modulus and (ii) finding its strain-dependent higher-order correction by monitoring the equilibrium bilayer area.
Collapse
Affiliation(s)
- Samuel Foley
- Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Markus Deserno
- Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| |
Collapse
|
35
|
Bolmatov D, Carrillo JMY, Sumpter BG, Katsaras J, Lavrentovich MO. Double membrane formation in heterogeneous vesicles. SOFT MATTER 2020; 16:8806-8817. [PMID: 33026033 DOI: 10.1039/d0sm01167c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Lipids are capable of forming a variety of structures, including multi-lamellar vesicles. Layered lipid membranes are found in cell organelles, such as autophagosomes and mitochondria. Here, we present a mechanism for the formation of a double-walled vesicle (i.e., two lipid bilayers) from a unilamellar vesicle through the partitioning and phase separation of a small molecule. Using molecular dynamics simulations, we show that double membrane formation proceeds via a nucleation and growth process - i.e., after a critical concentration of the small molecules, a patch of double membrane nucleates and grows to cover the entire vesicle. We discuss the implications of this mechanism and theoretical approaches for understanding the evolution and formation of double membranes.
Collapse
Affiliation(s)
- Dima Bolmatov
- Large Scale Structures Group, Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA. and Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996, USA. and Shull-Wollan Center, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Jan-Michael Y Carrillo
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA. and Computational Sciences and Engineering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Bobby G Sumpter
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA. and Computational Sciences and Engineering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - John Katsaras
- Large Scale Structures Group, Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA. and Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996, USA. and Shull-Wollan Center, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Maxim O Lavrentovich
- Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996, USA. and Shull-Wollan Center, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| |
Collapse
|
36
|
Kelley EG, Butler PD, Ashkar R, Bradbury R, Nagao M. Scaling relationships for the elastic moduli and viscosity of mixed lipid membranes. Proc Natl Acad Sci U S A 2020; 117:23365-23373. [PMID: 32883879 PMCID: PMC7519290 DOI: 10.1073/pnas.2008789117] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The elastic and viscous properties of biological membranes play a vital role in controlling cell functions that require local reorganization of the membrane components as well as dramatic shape changes such as endocytosis, vesicular trafficking, and cell division. These properties are widely acknowledged to depend on the unique composition of lipids within the membrane, yet the effects of lipid mixing on the membrane biophysical properties remain poorly understood. Here, we present a comprehensive characterization of the structural, elastic, and viscous properties of fluid membranes composed of binary mixtures of lipids with different tail lengths. We show that the mixed lipid membrane properties are not simply additive quantities of the single-component analogs. Instead, the mixed membranes are more dynamic than either of their constituents, quantified as a decrease in their bending modulus, area compressibility modulus, and viscosity. While the enhanced dynamics are seemingly unexpected, we show that the measured moduli and viscosity for both the mixed and single-component bilayers all scale with the area per lipid and collapse onto respective master curves. This scaling links the increase in dynamics to mixing-induced changes in the lipid packing and membrane structure. More importantly, the results show that the membrane properties can be manipulated through lipid composition the same way bimodal blends of surfactants, liquid crystals, and polymers are used to engineer the mechanical properties of soft materials, with broad implications for understanding how lipid diversity relates to biomembrane function.
Collapse
Affiliation(s)
- Elizabeth G Kelley
- Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899;
| | - Paul D Butler
- Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, DE 19716
- Department of Chemistry, The University of Tennessee, Knoxville, TN 37996
| | - Rana Ashkar
- Physics Department, Virginia Tech, Blacksburg, VA 20461
- Center for Soft Matter and Biological Physics, Virginia Tech, Blacksburg, VA 20461
| | - Robert Bradbury
- Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899
- Center for Exploration of Energy and Matter, Indiana University, Bloomington, IN 47408
| | - Michihiro Nagao
- Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899
- Center for Exploration of Energy and Matter, Indiana University, Bloomington, IN 47408
- Department of Physics and Astronomy, University of Delaware, Newark, DE 19716
| |
Collapse
|
37
|
Razizadeh M, Nikfar M, Paul R, Liu Y. Coarse-Grained Modeling of Pore Dynamics on the Red Blood Cell Membrane under Large Deformations. Biophys J 2020; 119:471-482. [PMID: 32645292 PMCID: PMC7399477 DOI: 10.1016/j.bpj.2020.06.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 05/22/2020] [Accepted: 06/16/2020] [Indexed: 12/17/2022] Open
Abstract
Transient pore formation on the membrane of red blood cells (RBCs) under high mechanical tensions is of great importance in many biomedical applications, such as RBC damage (hemolysis) and mechanoporation-based drug delivery. The dynamic process of pore formation, growth, and resealing is hard to visualize in experiments. We developed a mesoscale coarse-grained model to study the characteristics of transient pores on a patch of the lipid bilayer that is strengthened by an elastic meshwork representing the cytoskeleton. Unsteady molecular dynamics was used to study the pore formation and reseal at high strain rates close to the physiological ranges. The critical strain for pore formation, pore characteristics, and cytoskeleton effects were studied. Results show that the presence of the cytoskeleton increases the critical strain of pore formation and confines the pore growth. Moreover, the pore recovery process under negative strain rates (compression) is analyzed. Simulations show that pores can remain open for a long time during the high-speed tank-treading induced stretching and compression process that a patch of the RBC membrane usually experiences under high shear flow. Furthermore, complex loading conditions can affect the pore characteristics and result in denser pores. Finally, the effects of strain rate on pore formation are analyzed. Higher rate stretching of membrane patch can result in a significant increase in the critical areal strain and density of pores. Such a model reveals the dynamic molecular process of RBC damage in biomedical devices and mechanoporation that, to our knowledge, has not been reported before.
Collapse
Affiliation(s)
- Meghdad Razizadeh
- Department of Mechanical Engineering and Mechanics, Lehigh University, Bethlehem, Pennsylvania
| | - Mehdi Nikfar
- Department of Mechanical Engineering and Mechanics, Lehigh University, Bethlehem, Pennsylvania
| | - Ratul Paul
- Department of Mechanical Engineering and Mechanics, Lehigh University, Bethlehem, Pennsylvania
| | - Yaling Liu
- Department of Mechanical Engineering and Mechanics, Lehigh University, Bethlehem, Pennsylvania; Department of Bioengineering, Lehigh University, Bethlehem, Pennsylvania.
| |
Collapse
|
38
|
Brožek R, Kabelka I, Vácha R. Effect of Helical Kink on Peptide Translocation across Phospholipid Membranes. J Phys Chem B 2020; 124:5940-5947. [PMID: 32603116 DOI: 10.1021/acs.jpcb.0c03291] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Biological membranes present a major obstacle for the delivery of therapeutic agents into cells. Some peptides have been shown to translocate across the membrane spontaneously, and they could be thus used as drug-carriers. However, the advantageous peptide properties for the translocation remain unclear. Of particular interest is the effect of a proline-induced kink in α-helical peptides, because the kink was previously reported to both increase and decrease the antimicrobial activity. The antimicrobial activity of peptides could be related to their translocation across the membrane as is the case of the buforin 2 peptide investigated here. Using computer simulations with two independent models, we consistently showed that the presence of the kink has (1) no effect on the translocation barrier, (2) reduces the peptide affinity to the membrane, and (3) disfavors the transmembrane state. Moreover, we were able to determine that these effects are mainly caused by the peptide increased polarity, not the increased flexibility of the kink. The provided molecular understanding can be utilized for the design of cell-penetrating and drug-carrying peptides.
Collapse
Affiliation(s)
- Radim Brožek
- National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic.,CEITEC-Central European Institute of Technology, Masaryk University, Kamenice 753/5, 625 00 Brno, Czech Republic
| | - Ivo Kabelka
- National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic.,CEITEC-Central European Institute of Technology, Masaryk University, Kamenice 753/5, 625 00 Brno, Czech Republic
| | - Robert Vácha
- National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic.,CEITEC-Central European Institute of Technology, Masaryk University, Kamenice 753/5, 625 00 Brno, Czech Republic.,Department of Condensed Matter Physics, Faculty of Science, Masaryk University, Kotlářská 267/2, 611 37 Brno, Czech Republic
| |
Collapse
|
39
|
An D, Thiyagarajan S, Antipov E, Alcott B, O’shaughnessy B. Membrane pore energetics and the pathways to membrane rupture.. [DOI: 10.1101/2020.06.29.178988] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
AbstractBiological membranes owe their strength and low permeability to the phospholipid bilayers at their core. Membrane strength is determined by the energetics and dynamics of membrane pores, whose tension-dependent nucleation and growth leads to rupture. Creation of nanoscale membrane pores is central to exocytosis, trafficking and other processes fundamental to life that require breaching of secure plasma or organelle membranes, and is the basis for biotechnologies using drug delivery, delivery of genetic material for gene editing and antimicrobial peptides. A prevailing view from seminal electroporation and membrane rupture studies is that pore growth and bilayer rupture are controlled by macroscopically long-lived metastable defect states that precede fully developed pores. It was argued that defect nucleation becomes rate-limiting at high tensions, explaining the exponential tension-dependence of rupture times [E. Evans et al., Biophys. J. 85, 2342-2350 (2003)]. Here we measured membrane pore free energies and bilayer rupture using highly coarse-grained simulations that probe very long time scales. We find no evidence of metastable pore states. At lower tensions, small hydrophobic pores mature into large hydrophilic pores on the pathway to rupture, with classical tension dependence of rupture times. Above a critical tension membranes rupture directly from a small hydrophobic pore, and rupture times depend exponentially on tension. Thus, we recover the experimentally reported regimes, but the origin of the high tension exponential regime is unrelated to macroscopically long-lived pre-pore defects. It arises because hydrophilic pores cannot exist above a critical tension, leading to radically altered pore dynamics and rupture kinetics.
Collapse
|
40
|
Pang YT, Ge Z, Zhang B, Xiu P, Li Q, Wang Y. Pore formation induced by nanoparticles binding to a lipid membrane. NANOSCALE 2020; 12:7902-7913. [PMID: 32227042 DOI: 10.1039/c9nr10534d] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Nanoparticles (NPs) enter a cell primarily via endocytosis, during which they are engulfed by the cell and reside in lipid vesicles named endosomes. Apart from when an endosome is pinched off the plasma membrane, structural integrity of its lipid membrane is usually well maintained. Under certain circumstances, however, such structural integrity can be considerably perturbed by a nanoparticle. For instance, recent experiments [Chu et al., Sci. Rep., 2014, 4, 4495] indicate that nanodiamonds with sharp corners can escape from an endosome by piercing its lipid membrane. Nonetheless, the energetics of this behavior and how it may be controlled by membrane adhesion and NP morphology remain unclear. In this work, we employ continuum modeling to investigate membrane pore formation induced by the spontaneous binding of a sharp nanoparticle. Based on two axial-symmetric NP models, we characterize the indispensable role played by curvature heterogeneity, membrane adhesion, and the sharpness as well as the size of a nanoparticle in 'breaking' a lipid membrane. Apart from revealing a general mechanism of NP binding-induced membrane pore formation, our results provide the reference for improving the endosomal escape of nanoparticles through manipulating their morphology, a direction that can be explored either independently or combined with existing strategies targeting NP surface chemistry.
Collapse
Affiliation(s)
- Yui Tik Pang
- Department of Physics, Chinese University of Hong Kong, Shatin, N.T., Hong Kong.
| | | | | | | | | | | |
Collapse
|
41
|
Dey S, Saha J. Minimal Coarse-Grained Modeling toward Implicit Solvent Simulation of Generic Bolaamphiphiles. J Phys Chem B 2020; 124:2938-2949. [DOI: 10.1021/acs.jpcb.0c00734] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Somajit Dey
- Department of Physics, University of Calcutta, 92, A.P.C Road, Kolkata 700009, India
| | - Jayashree Saha
- Department of Physics, University of Calcutta, 92, A.P.C Road, Kolkata 700009, India
| |
Collapse
|
42
|
Tuerkova A, Kabelka I, Králová T, Sukeník L, Pokorná Š, Hof M, Vácha R. Effect of helical kink in antimicrobial peptides on membrane pore formation. eLife 2020; 9:47946. [PMID: 32167466 PMCID: PMC7069690 DOI: 10.7554/elife.47946] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Accepted: 02/18/2020] [Indexed: 12/19/2022] Open
Abstract
Every cell is protected by a semipermeable membrane. Peptides with the right properties, for example Antimicrobial peptides (AMPs), can disrupt this protective barrier by formation of leaky pores. Unfortunately, matching peptide properties with their ability to selectively form pores in bacterial membranes remains elusive. In particular, the proline/glycine kink in helical peptides was reported to both increase and decrease antimicrobial activity. We used computer simulations and fluorescence experiments to show that a kink in helices affects the formation of membrane pores by stabilizing toroidal pores but disrupting barrel-stave pores. The position of the proline/glycine kink in the sequence further controls the specific structure of toroidal pore. Moreover, we demonstrate that two helical peptides can form a kink-like connection with similar behavior as one long helical peptide with a kink. The provided molecular-level insight can be utilized for design and modification of pore-forming antibacterial peptides or toxins.
Collapse
Affiliation(s)
- Alzbeta Tuerkova
- CEITEC - Central European Institute of Technology, Masaryk University, Kamenice, Czech Republic.,National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kamenice, Czech Republic
| | - Ivo Kabelka
- CEITEC - Central European Institute of Technology, Masaryk University, Kamenice, Czech Republic.,National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kamenice, Czech Republic
| | - Tereza Králová
- CEITEC - Central European Institute of Technology, Masaryk University, Kamenice, Czech Republic
| | - Lukáš Sukeník
- CEITEC - Central European Institute of Technology, Masaryk University, Kamenice, Czech Republic.,Department of Condensed Matter Physics, Faculty of Science, Masaryk University, Kotlářská, Czech Republic
| | - Šárka Pokorná
- J. Heyrovsky Institute of Physical Chemistry, Czech Academy of Sciences, Prague, Czech Republic
| | - Martin Hof
- J. Heyrovsky Institute of Physical Chemistry, Czech Academy of Sciences, Prague, Czech Republic
| | - Robert Vácha
- CEITEC - Central European Institute of Technology, Masaryk University, Kamenice, Czech Republic.,National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kamenice, Czech Republic.,Department of Condensed Matter Physics, Faculty of Science, Masaryk University, Kotlářská, Czech Republic
| |
Collapse
|
43
|
Hossein A, Deserno M. Spontaneous Curvature, Differential Stress, and Bending Modulus of Asymmetric Lipid Membranes. Biophys J 2019; 118:624-642. [PMID: 31954503 DOI: 10.1016/j.bpj.2019.11.3398] [Citation(s) in RCA: 99] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Revised: 11/20/2019] [Accepted: 11/25/2019] [Indexed: 12/24/2022] Open
Abstract
Lipid bilayers can exhibit asymmetric states, in which the physical characteristics of one leaflet differ from those of the other. This most visibly manifests in a different lipid composition, but it can also involve opposing lateral stresses in each leaflet that combine to an overall vanishing membrane tension. Here, we use theoretical modeling and coarse-grained simulation to explore the interplay between a compositional asymmetry and a nonvanishing differential stress. Minimizing the total elastic energy leads to a preferred spontaneous curvature that balances torques due to both bending moments and differential stress, with sometimes unexpected consequences. For instance, asymmetric flat bilayers, whose specific areas in each leaflet are matched to those of corresponding tensionless symmetric flat membranes, still exhibit a residual differential stress because the conditions of vanishing area strain and vanishing bending moment differ. We also measure the curvature rigidity of asymmetric bilayers and find that a sufficiently strong differential stress, but not compositional asymmetry alone, can increase the bending modulus. The likely cause is a stiffening of the compressed leaflet, which appears to be related to its gel transition but not identical with it. We finally show that the impact of cholesterol on differential stress depends on the relative strength of elastic and thermodynamic driving forces: if cholesterol solvates equally well in both leaflets, it will redistribute to cancel both leaflet tensions almost completely, but if its partitioning free energy prefers one leaflet over the other, the resulting distribution bias may even create differential stress. Because cells keep most of their lipid bilayers in an asymmetric nonequilibrium steady state, our findings suggest that biomembranes are elastically more complex than previously thought: besides a spontaneous curvature, they might also exhibit significant differential stress, which could strongly affect their curvature energetics.
Collapse
Affiliation(s)
- Amirali Hossein
- Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania
| | - Markus Deserno
- Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania.
| |
Collapse
|
44
|
Terzi MM, Ergüder MF, Deserno M. A consistent quadratic curvature-tilt theory for fluid lipid membranes. J Chem Phys 2019; 151:164108. [PMID: 31675861 DOI: 10.1063/1.5119683] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The tilt of a lipid molecule describes the deviation of its orientation away from the local normal of its embedding membrane. Tilt is the subleading degree of freedom after a membrane's geometry, and it becomes relevant at scales comparable to lipid bilayer thickness. Building on earlier work by Hamm and Kozlov [Eur. Phys. J. E 3, 323 (2000)], who envisioned lipid membranes as thin prestressed fluid elastic films, and Terzi and Deserno [J. Chem. Phys. 147, 084702 (2017)], who discovered a new coupling term between splay and tilt divergence, we construct a theory of membrane elasticity that is quadratic in geometry and tilt and complete at order 1/length2. We show that a general and consistent treatment of both lateral and transverse depth-dependent shear stresses creates several contributions to the elastic energy density, of which only a subset had previously been identified. Apart from the well-known penalty of lipid twist (the curl of tilt), these terms generate no qualitatively new phenomenology, but they quantitatively revise the connections between the moduli of a tilt-curvature theory and its underlying microscopic foundation. In particular, we argue that the monolayer Gaussian curvature modulus κ¯m, widely believed to be equal to the second moment of the transmonolayer stress profile, acquires a second contribution from lipid twist, which is always negative. This could resolve the long-standing conundrum that many measured values of κ¯m appeared to have a sign that violates basic stability considerations. We also show that the previously discovered novel coupling between splay and tilt divergence is not simply proportional to κ¯m but acquires its own splay-tilt coupling modulus, κst,m. We explore the predictions of our theory for various elastic moduli and their mutual interrelations and use an extensive set of existing atomistic molecular dynamics simulations for 12 different lipid types to collectively reason about such predictions. We find that bending rigidities are captured fairly well by existing theories, while reliable predictions for local moduli, especially the splay-tilt coupling modulus, remain challenging.
Collapse
Affiliation(s)
- M Mert Terzi
- Department of Physics, Carnegie Mellon University, 5000 Forbes Ave., Pittsburgh, Pennsylvania 15213, USA
| | - Muhammed F Ergüder
- Department of Physics, Carnegie Mellon University, 5000 Forbes Ave., Pittsburgh, Pennsylvania 15213, USA
| | - Markus Deserno
- Department of Physics, Carnegie Mellon University, 5000 Forbes Ave., Pittsburgh, Pennsylvania 15213, USA
| |
Collapse
|
45
|
F Brandner A, Timr S, Melchionna S, Derreumaux P, Baaden M, Sterpone F. Modelling lipid systems in fluid with Lattice Boltzmann Molecular Dynamics simulations and hydrodynamics. Sci Rep 2019; 9:16450. [PMID: 31712588 PMCID: PMC6848203 DOI: 10.1038/s41598-019-52760-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Accepted: 10/21/2019] [Indexed: 11/09/2022] Open
Abstract
In this work we present the coupling between Dry Martini, an efficient implicit solvent coarse-grained model for lipids, and the Lattice Boltzmann Molecular Dynamics (LBMD) simulation technique in order to include naturally hydrodynamic interactions in implicit solvent simulations of lipid systems. After validating the implementation of the model, we explored several systems where the action of a perturbing fluid plays an important role. Namely, we investigated the role of an external shear flow on the dynamics of a vesicle, the dynamics of substrate release under shear, and inquired the dynamics of proteins and substrates confined inside the core of a vesicle. Our methodology enables future exploration of a large variety of biological entities and processes involving lipid systems at the mesoscopic scale where hydrodynamics plays an essential role, e.g. by modulating the migration of proteins in the proximity of membranes, the dynamics of vesicle-based drug delivery systems, or, more generally, the behaviour of proteins in cellular compartments.
Collapse
Affiliation(s)
- Astrid F Brandner
- CNRS, Université de Paris, UPR 9080, Laboratoire de Biochimie Théorique, 13 rue Pierre et Marie Curie, F-75005, Paris, France.,Institut de Biologie Physico-Chimique-Fondation Edmond de Rothschild, PSL Research University, Paris, France
| | - Stepan Timr
- CNRS, Université de Paris, UPR 9080, Laboratoire de Biochimie Théorique, 13 rue Pierre et Marie Curie, F-75005, Paris, France.,Institut de Biologie Physico-Chimique-Fondation Edmond de Rothschild, PSL Research University, Paris, France
| | - Simone Melchionna
- ISC-CNR, Dipartimento di Fisica, Università Sapienza, P.le A. Moro 5, 00185, Rome, Italy.,Lexma Technology 1337 Massachusetts Avenue, Arlington, MA, 02476, USA
| | - Philippe Derreumaux
- CNRS, Université de Paris, UPR 9080, Laboratoire de Biochimie Théorique, 13 rue Pierre et Marie Curie, F-75005, Paris, France.,Institut de Biologie Physico-Chimique-Fondation Edmond de Rothschild, PSL Research University, Paris, France
| | - Marc Baaden
- CNRS, Université de Paris, UPR 9080, Laboratoire de Biochimie Théorique, 13 rue Pierre et Marie Curie, F-75005, Paris, France.,Institut de Biologie Physico-Chimique-Fondation Edmond de Rothschild, PSL Research University, Paris, France
| | - Fabio Sterpone
- CNRS, Université de Paris, UPR 9080, Laboratoire de Biochimie Théorique, 13 rue Pierre et Marie Curie, F-75005, Paris, France. .,Institut de Biologie Physico-Chimique-Fondation Edmond de Rothschild, PSL Research University, Paris, France.
| |
Collapse
|
46
|
Curvature induction and sensing of the F-BAR protein Pacsin1 on lipid membranes via molecular dynamics simulations. Sci Rep 2019; 9:14557. [PMID: 31601944 PMCID: PMC6787258 DOI: 10.1038/s41598-019-51202-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Accepted: 09/24/2019] [Indexed: 01/04/2023] Open
Abstract
F-Bin/Amphiphysin/Rvs (F-BAR) domain proteins play essential roles in biological processes that involve membrane remodelling, such as endocytosis and exocytosis. It has been shown that such proteins transform the lipid membrane into tubes. Notably, Pacsin1 from the Pacsin/Syndapin subfamily has the ability to transform the membrane into various morphologies: striated tubes, featureless wide and thin tubes, and pearling vesicles. The molecular mechanism of this interesting ability remains elusive. In this study, we performed all-atom (AA) and coarse-grained (CG) molecular dynamics simulations to investigate the curvature induction and sensing mechanisms of Pacsin1 on a membrane. From AA simulations, we show that Pacsin1 has internal structural flexibility. In CG simulations with parameters tuned from the AA simulations, spontaneous assembly of two Pacsin1 dimers through lateral interaction is observed. Based on the complex structure, we show that the regularly assembled Pacsin1 dimers bend a tensionless membrane. We also show that a single Pacsin1 dimer senses the membrane curvature, binding to a buckled membrane with a preferred curvature. These results provide molecular insights into polymorphic membrane remodelling.
Collapse
|
47
|
Hoferer M, Bonfanti S, Taloni A, La Porta CAM, Zapperi S. Protein-driven lipid domain nucleation in biological membranes. Phys Rev E 2019; 100:042410. [PMID: 31770996 DOI: 10.1103/physreve.100.042410] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Indexed: 06/10/2023]
Abstract
Lipid rafts are heterogeneous dynamic lipid domains of the cell membranes that are involved in several biological processes, such as protein and lipid specific transport and signaling. Our understanding of lipid raft formation is still limited due to the transient and elusive nature of these domains in vivo, in contrast with the stable phase-separated domains observed in artificial membranes. Inspired by experimental findings highlighting the relevance of transmembrane proteins for lipid rafts, we investigate lipid domain nucleation by coarse-grained molecular dynamics and Ising-model simulations. We find that the presence of a transmembrane protein can trigger lipid domain nucleation in a flat membrane from an otherwise mixed lipid phase. Furthermore, we study the role of the lipid domain in the diffusion of the protein showing that its mobility is hindered by the presence of the raft. The results of our coarse-grained molecular-dynamics and Ising-model simulations thus coherently support the important role played by transmembrane proteins in lipid domain formation and stability.
Collapse
Affiliation(s)
- Moritz Hoferer
- ETH Zurich, Zürichbergstrasse 18, 8092 Zurich, Switzerland
| | - Silvia Bonfanti
- Center for Complexity and Biosystems, Department of Physics, University of Milan, Via Celoria 16, 20133 Milano, Italy
| | - Alessandro Taloni
- CNR - Consiglio Nazionale delle Ricerche, Istituto dei Sistemi Complessi, via dei Taurini 19, 00185 Roma, Italy
| | - Caterina A M La Porta
- Center for Complexity and Biosystems, Department of Environmental Science and Policy, University of Milan, via Celoria 26, 20133 Milano, Italy
- CNR - Consiglio Nazionale delle Ricerche, Istituto di Biofisica, Via Celoria 26, 20133 Milano, Italy
| | - Stefano Zapperi
- Center for Complexity and Biosystems, Department of Physics, University of Milan, Via Celoria 16, 20133 Milano, Italy
- CNR - Consiglio Nazionale delle Ricerche, Istituto di Chimica della Materia Condensata e di Tecnologie per l'Energia, Via R. Cozzi 53, 20125 Milano, Italy
| |
Collapse
|
48
|
Khosravanizadeh A, Sens P, Mohammad-Rafiee F. Wrapping of a nanowire by a supported lipid membrane. SOFT MATTER 2019; 15:7490-7500. [PMID: 31513228 DOI: 10.1039/c9sm00618d] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Internalization of particles by cells plays a crucial role for adsorbing nutrients and fighting infection. Endocytosis is one of the most important mechanisms of particle uptake, which encompasses multiple pathways. Although endocytosis is a complex mechanism involving biochemical signaling and active force generation, the energetic cost associated with the large deformations of the cell membrane wrapping around a foreign particle is an important factor controlling this process, which can be studied using quantitative physical models. Of particular interest is the competition between membrane-cytoskeleton and membrane-target adhesion. This competitive adhesion mechanism can be reproduced to some extent by studying particle wrapping by a membrane adhered to a substrate. We propose a theoretical analysis of this process. Here, we explore the wrapping of a lipid membrane around a long cylindrical object in the presence of a substrate mimicking the cytoskeleton. Using discretization of the Helfrich elastic energy, which accounts for the membrane bending rigidity and surface tension, we obtain a wrapping phase diagram as a function of the membrane-cytoskeleton and the membrane-target adhesion energy, which includes unwrapped, partially wrapped and fully wrapped states. We provide an analytical expression for the boundary between the different regimes. While the transition to partial wrapping is independent of the membrane tension, the transition to full wrapping is very much influenced by the membrane tension. We also show that target wrapping may proceed in an asymmetric fashion in the full wrapping regime.
Collapse
Affiliation(s)
- Amir Khosravanizadeh
- Department of Physics, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan 45137-66731, Iran.
| | | | | |
Collapse
|
49
|
Guan Z, Wang L, Lin J, Xue J. Endocytosis behaviours of nanoparticles with helically decorated ligands. POLYM INT 2019. [DOI: 10.1002/pi.5896] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- Zhou Guan
- Shanghai Key Laboratory of Advanced Polymeric Materials, Key Laboratory for Ultrafine Materials of the Ministry of Education, School of Materials Science and EngineeringEast China University of Science and Technology Shanghai China
| | - Liquan Wang
- Shanghai Key Laboratory of Advanced Polymeric Materials, Key Laboratory for Ultrafine Materials of the Ministry of Education, School of Materials Science and EngineeringEast China University of Science and Technology Shanghai China
| | - Jiaping Lin
- Shanghai Key Laboratory of Advanced Polymeric Materials, Key Laboratory for Ultrafine Materials of the Ministry of Education, School of Materials Science and EngineeringEast China University of Science and Technology Shanghai China
| | - Jiaxiao Xue
- Shanghai Key Laboratory of Advanced Polymeric Materials, Key Laboratory for Ultrafine Materials of the Ministry of Education, School of Materials Science and EngineeringEast China University of Science and Technology Shanghai China
| |
Collapse
|
50
|
Li W, Carrillo JMY, Katsaras J, Sumpter BG, Ashkar R, Kumar R. The influence of curvature on domain distribution in binary mixture membranes. SOFT MATTER 2019; 15:6642-6649. [PMID: 31328764 DOI: 10.1039/c9sm01262a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Curvature-induced domain sorting, a strategy exploited by cells to organize membrane components, is a promising mechanism to control self-assembly of materials. To understand this phenomenon, this work explores the effects of curvature on component rearrangement in thin polymer films and lipid bilayers supported on sinusoidal substrates. Specifically, self-consistent field theory (SCFT) was used to study the spatial distribution of polymers in blends containing conformationally asymmetric chains. In addition, coarse-grained molecular dynamics (MD) simulations were used to probe the arrangement of rigid lipid domains in a relatively soft lipid matrix. Besides the expected preference of rigid species localizing in regions with low mean curvature, both systems exhibit unexpected localization of rigid components in comparatively high curvature regions. The origins of this unexpected sorting are discussed in terms of entropic and enthalpic contributions. In summary, this study demonstrates that domain distribution strongly depends on local topography and further highlights the collective effects that thermodynamic forces have on the morphological behavior of membranes.
Collapse
Affiliation(s)
- Wei Li
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.
| | | | | | | | | | | |
Collapse
|