1
|
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
|
2
|
Kramer K, Sari M, Schulze K, Flegel H, Stehr M, Mey I, Janshoff A, Steinem C. From LUVs to GUVs─How to Cover Micrometer-Sized Pores with Membranes. J Phys Chem B 2022; 126:8233-8244. [PMID: 36210780 DOI: 10.1021/acs.jpcb.2c05685] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Pore-spanning membranes (PSMs) are a versatile tool to investigate membrane-confined processes in a bottom-up approach. Pore sizes in the micrometer range are most suited to visualize PSMs using fluorescence microscopy. However, the preparation of these PSMs relies on the spreading of giant unilamellar vesicles (GUVs). GUV production faces several limitations. Thus, alternative ways to generate PSMs starting from large or small unilamellar vesicles that are more reproducibly prepared are highly desirable. Here we describe a method to produce PSMs obtained from large unilamellar vesicles, making use of droplet-stabilized GUVs generated in a microfluidic device. We analyzed the lipid diffusion in the free-standing and supported parts of the PSMs using z-scan fluorescence correlation spectroscopy and fluorescence recovery after photobleaching experiments in combination with finite element simulations. Employing atomic force indentation experiments, we also investigated the mechanical properties of the PSMs. Both lipid diffusion constants and lateral membrane tension were compared to those obtained on PSMs derived from electroformed GUVs, which are known to be solvent- and detergent-free, under otherwise identical conditions. Our results demonstrate that the lipid diffusion, as well as the mechanical properties of the resulting PSMs, is almost unaffected by the GUV formation procedure but depends on the chosen substrate functionalization. With the new method in hand, we were able to reconstitute the syntaxin-1A transmembrane domain in microfluidic GUVs and PSMs, which was visualized by fluorescence microscopy.
Collapse
Affiliation(s)
- Kristina Kramer
- Institute of Organic and Biomolecular Chemistry, University of Göttingen, Tammannstrasse 2, 37077Göttingen, Germany
| | - Merve Sari
- Institute of Organic and Biomolecular Chemistry, University of Göttingen, Tammannstrasse 2, 37077Göttingen, Germany
| | - Kathrin Schulze
- Institute of Organic and Biomolecular Chemistry, University of Göttingen, Tammannstrasse 2, 37077Göttingen, Germany
| | - Hendrik Flegel
- Institute of Organic and Biomolecular Chemistry, University of Göttingen, Tammannstrasse 2, 37077Göttingen, Germany
| | - Miriam Stehr
- Institute of Organic and Biomolecular Chemistry, University of Göttingen, Tammannstrasse 2, 37077Göttingen, Germany
| | - Ingo Mey
- Institute of Organic and Biomolecular Chemistry, University of Göttingen, Tammannstrasse 2, 37077Göttingen, Germany
| | - Andreas Janshoff
- Institute of Physical Chemistry, University of Göttingen, Tammannstrasse 6, 37077Göttingen, Germany
| | - Claudia Steinem
- Institute of Organic and Biomolecular Chemistry, University of Göttingen, Tammannstrasse 2, 37077Göttingen, Germany.,Max Planck Institute for Dynamics and Self-Organization, Am Fassberg 17, 37077Göttingen, Germany
| |
Collapse
|
3
|
Molaei M, Kandy SK, Graber ZT, Baumgart T, Radhakrishnan R, Crocker JC. Probing lipid membrane bending mechanics using gold nanorod tracking. PHYSICAL REVIEW RESEARCH 2022; 4:L012027. [PMID: 35373142 PMCID: PMC8975244 DOI: 10.1103/physrevresearch.4.l012027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Lipid bilayer membranes undergo rapid bending undulations with wavelengths from tens of nanometers to tens of microns due to thermal fluctuations. Here, we probe such undulations and the membranes' mechanics by measuring the time-varying orientation of single gold nanorods (GNRs) adhered to the membrane, using high-speed dark field microscopy. In a lipid vesicle, such measurements allow the determination of the membrane's viscosity, bending rigidity, and tension as well as the friction coefficient for sliding of the monolayers over one another. The in-plane rotation of the GNR is hindered by undulations in a tension dependent manner, consistent with simulations. The motion of single GNRs adhered to the plasma membrane of living cultured cells similarly reveals the membrane's complex physics and coupling to the cell's actomyosin cortex.
Collapse
Affiliation(s)
- Mehdi Molaei
- Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Sreeja Kutti Kandy
- Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Zachary T. Graber
- Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Tobias Baumgart
- Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Ravi Radhakrishnan
- Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
- Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - John C. Crocker
- Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
- Corresponding author:
| |
Collapse
|
4
|
The Elucidation of the Molecular Mechanism of the Extrusion Process. MATERIALS 2021; 14:ma14154278. [PMID: 34361472 PMCID: PMC8348501 DOI: 10.3390/ma14154278] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Revised: 07/27/2021] [Accepted: 07/27/2021] [Indexed: 02/02/2023]
Abstract
Extrusion is a popular method for producing homogenous population of unilamellar liposomes. The technique relies on forcing a lipid suspension through cylindrical pores in a polycarbonate membrane. The quantification of the extrusion and/or recalibration processes make possible the acquisition of experimental data, which can be correlated with the mechanical properties of the lipid bilayer. In this work, the force needed for the extrusion process was correlated with the mechanical properties of a lipid bilayer derived from other experiments. Measurements were performed using a home-made dedicated device capable of maintaining a stable volumetric flux of a liposome suspension through well-defined pores and to continuously measure the extrusion force. Based on the obtained results, the correlation between the lipid bilayer bending rigidity and extrusion force was derived. Specifically, it was found that the bending rigidity of liposomes formed from well-defined lipid mixtures agrees with data obtained by others using flicker-noise spectroscopy or micromanipulation. The other issue addressed in the presented studies was the identification of molecular mechanisms leading to the formation of unilamellar vesicles in the extrusion process. Finally, it was demonstrated that during the extrusion, lipids are not exchanged between vesicles, i.e., vesicles can divide but no membrane fusion or lipid exchange between bilayers was detected.
Collapse
|
5
|
Witt H, Savić F, Verbeek S, Dietz J, Tarantola G, Oelkers M, Geil B, Janshoff A. Membrane fusion studied by colloidal probes. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2021; 50:223-237. [PMID: 33599795 PMCID: PMC8071799 DOI: 10.1007/s00249-020-01490-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Accepted: 12/19/2020] [Indexed: 12/12/2022]
Abstract
Membrane-coated colloidal probes combine the benefits of solid-supported membranes with a more complex three-dimensional geometry. This combination makes them a powerful model system that enables the visualization of dynamic biological processes with high throughput and minimal reliance on fluorescent labels. Here, we want to review recent applications of colloidal probes for the study of membrane fusion. After discussing the advantages and disadvantages of some classical vesicle-based fusion assays, we introduce an assay using optical detection of fusion between membrane-coated glass microspheres in a quasi two-dimensional assembly. Then, we discuss free energy considerations of membrane fusion between supported bilayers, and show how colloidal probes can be combined with atomic force microscopy or optical tweezers to access the fusion process with even greater detail.
Collapse
Affiliation(s)
- Hannes Witt
- Institute for Physical Chemistry, University of Göttingen, 37075, Göttingen, Germany.,Physics of Living Systems, Vrije Universiteit Amsterdam, 1081 HV, Amsterdam, The Netherlands
| | - Filip Savić
- Institute for Physical Chemistry, University of Göttingen, 37075, Göttingen, Germany
| | - Sarah Verbeek
- Institute for Physical Chemistry, University of Göttingen, 37075, Göttingen, Germany
| | - Jörn Dietz
- Institute for Physical Chemistry, University of Göttingen, 37075, Göttingen, Germany
| | - Gesa Tarantola
- Institute for Physical Chemistry, University of Göttingen, 37075, Göttingen, Germany
| | - Marieelen Oelkers
- Institute for Physical Chemistry, University of Göttingen, 37075, Göttingen, Germany
| | - Burkhard Geil
- Institute for Physical Chemistry, University of Göttingen, 37075, Göttingen, Germany
| | - Andreas Janshoff
- Institute for Physical Chemistry, University of Göttingen, 37075, Göttingen, Germany.
| |
Collapse
|
6
|
Sun Y, Zang X, Sun Y, Wang L, Gao Z. Lipid membranes supported by planar porous substrates. Chem Phys Lipids 2020; 228:104893. [PMID: 32097619 DOI: 10.1016/j.chemphyslip.2020.104893] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Accepted: 02/10/2020] [Indexed: 12/18/2022]
Abstract
Biological membranes play key roles in cell life, but their intrinsic complexity motivated the study and development of artificial lipid membranes with the primary aim to reconstitute and understand the natural functions in vitro. Porous-supported lipid membrane (pSLM) has emerged as a flexible platform for studying the surface chemistry of the cell due to their high stability and fluidity, and their ability to study the transmembrane process of the molecules. In this review, the pSLM, for the first time, to our knowledge, was divided into three types according to the way of the porous materials support the lipid membrane, containing the lipid membrane on the pores of the porous materials, the lipid membrane on both sides of the porous materials, the lipid membrane in the pores of the porous materials. All of these pSLMs were systematically elaborated from several aspects, including the substrates, formation, and characterization. Meanwhile, the advantages and disadvantages of each model membranes were summarized. Finally, suggestions for selecting appropriate pSLM and future directions in this area are discussed.
Collapse
Affiliation(s)
- Yanping Sun
- Department of Pharmacy, Hebei University of Science and Technology, Shijiazhuang, 050018, China; State Key Laboratory Breeding Base - Hebei Province Key Laboratory of Molecular Chemistry for Drugs, Hebei University of Science and Technology, Shijiazhuang, 050018, China; Hebei Research Center of Pharmaceutical and Chemical Engineering, Hebei University of Science and Technology, Shijiazhuang, 050018, China
| | - Xianghuan Zang
- Department of Pharmacy, Hebei University of Science and Technology, Shijiazhuang, 050018, China
| | - Yongjun Sun
- Department of Pharmacy, Hebei University of Science and Technology, Shijiazhuang, 050018, China; Hebei Research Center of Pharmaceutical and Chemical Engineering, Hebei University of Science and Technology, Shijiazhuang, 050018, China
| | - Long Wang
- State Key Laboratory Breeding Base - Hebei Province Key Laboratory of Molecular Chemistry for Drugs, Hebei University of Science and Technology, Shijiazhuang, 050018, China; Department of Family and Consumer Sciences, California State University, Long Beach, CA, 90840, USA.
| | - Zibin Gao
- Department of Pharmacy, Hebei University of Science and Technology, Shijiazhuang, 050018, China; State Key Laboratory Breeding Base - Hebei Province Key Laboratory of Molecular Chemistry for Drugs, Hebei University of Science and Technology, Shijiazhuang, 050018, China; Hebei Research Center of Pharmaceutical and Chemical Engineering, Hebei University of Science and Technology, Shijiazhuang, 050018, China.
| |
Collapse
|
7
|
Sibold J, Tewaag VE, Vagedes T, Mey I, Steinem C. Phase separation in pore-spanning membranes induced by differences in surface adhesion. Phys Chem Chem Phys 2020; 22:9308-9315. [DOI: 10.1039/d0cp00335b] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
A porous scaffold providing different adhesion energies alters the behaviour of coexisting phases in lipid membranes considerably.
Collapse
Affiliation(s)
- Jeremias Sibold
- Institute of Organic and Biomolecular Chemistry
- University of Göttingen
- 37077 Göttingen
- Germany
| | - Vera E. Tewaag
- Institute of Organic and Biomolecular Chemistry
- University of Göttingen
- 37077 Göttingen
- Germany
| | - Thomas Vagedes
- Institute of Organic and Biomolecular Chemistry
- University of Göttingen
- 37077 Göttingen
- Germany
| | - Ingo Mey
- Institute of Organic and Biomolecular Chemistry
- University of Göttingen
- 37077 Göttingen
- Germany
| | - Claudia Steinem
- Institute of Organic and Biomolecular Chemistry
- University of Göttingen
- 37077 Göttingen
- Germany
- Max Planck Institute for Dynamics and Self-Organization
| |
Collapse
|
8
|
Gumí-Audenis B, Costa L, Ferrer-Tasies L, Ratera I, Ventosa N, Sanz F, Giannotti MI. Pulling lipid tubes from supported bilayers unveils the underlying substrate contribution to the membrane mechanics. NANOSCALE 2018; 10:14763-14770. [PMID: 30043793 DOI: 10.1039/c8nr03249a] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Cell processes like endocytosis, membrane resealing, signaling and transcription involve conformational changes which depend on the chemical composition and the physicochemical properties of the lipid membrane. The better understanding of the mechanical role of lipids in cell membrane force-triggered and sensing mechanisms has recently become the focus of attention. Different membrane models and experimental methodologies are commonly explored. While general approaches involve controlled vesicle deformation using micropipettes or optical tweezers, due to the local and dynamic nature of the membrane, high spatial resolution atomic force microscopy (AFM) has been widely used to study the mechanical compression and indentation of supported lipid bilayers (SLBs). However, the substrate contribution remains unkown. Here, we demonstrate how pulling lipid tubes with an AFM out of model SLBs can be used to assess the nanomechanics of SLBs through the evaluation of the tube growing force (Ftube), allowing for very local evaluation with high spatial and force resolution of the lipid membrane tension. We first validate this approach to determine the contribution of different phospholipids, by varying the membrane composition, in both one-component and phase-segregated membranes. Finally, we successfully assess the contribution of the underlying substrate to the membrane mechanics, demonstrating that SLB models may represent an intermediate scenario between a free membrane (blebs) and a cytoskeleton supported membrane.
Collapse
Affiliation(s)
- Berta Gumí-Audenis
- Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology (BIST), Baldiri Reixac 10-12, 08028 Barcelona, Spain.
| | | | | | | | | | | | | |
Collapse
|
9
|
Doskocz J, Drabik D, Chodaczek G, Przybyło M, Langner M. Statistical Analysis of Bending Rigidity Coefficient Determined Using Fluorescence-Based Flicker-Noise Spectroscopy. J Membr Biol 2018; 251:601-608. [PMID: 29858612 DOI: 10.1007/s00232-018-0037-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Accepted: 05/29/2018] [Indexed: 10/14/2022]
Abstract
Bending rigidity coefficient describes propensity of a lipid bilayer to deform. In order to measure the parameter experimentally using flickering noise spectroscopy, the microscopic imaging is required, which necessitates the application of giant unilamellar vesicles (GUV) lipid bilayer model. The major difficulty associated with the application of the model is the statistical character of GUV population with respect to their size and the homogeneity of lipid bilayer composition, if a mixture of lipids is used. In the paper, the bending rigidity coefficient was measured using the fluorescence-enhanced flicker-noise spectroscopy. In the paper, the bending rigidity coefficient was determined for large populations of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine and 1,2-dioleoyl-sn-glycero-3-phosphocholine vesicles. The quantity of obtained experimental data allows to perform statistical analysis aiming at the identification of the distribution, which is the most appropriate for the calculation of the value of the membrane bending rigidity coefficient. It has been demonstrated that the bending rigidity coefficient is characterized by an asymmetrical distribution, which is well approximated with the gamma distribution. Since there are no biophysical reasons for that we propose to use the difference between normal and gamma fits as a measure of the homogeneity of vesicle population. In addition, the effect of a fluorescent label and types of instrumental setups on determined values has been tested. Obtained results show that the value of the bending rigidity coefficient does not depend on the type of a fluorescent label nor on the type of microscope used.
Collapse
Affiliation(s)
- Joanna Doskocz
- Department of Biomedical Engineering, Faculty of Fundamental Problems of Technology, Wrocław University of Science and Technology, Pl. Grunwaldzki 13, 50-377, Wrocław, Poland.
| | - Dominik Drabik
- Department of Biomedical Engineering, Faculty of Fundamental Problems of Technology, Wrocław University of Science and Technology, Pl. Grunwaldzki 13, 50-377, Wrocław, Poland
| | - Grzegorz Chodaczek
- Wroclaw Research Centre EIT+, ul. Stabłowicka 147, 54-066, Wrocław, Poland
| | - Magdalena Przybyło
- Department of Biomedical Engineering, Faculty of Fundamental Problems of Technology, Wrocław University of Science and Technology, Pl. Grunwaldzki 13, 50-377, Wrocław, Poland.,Lipid Systems sp. z o.o., ul. Krzemieniecka 48C, 54-613, Wrocław, Poland
| | - Marek Langner
- Department of Biomedical Engineering, Faculty of Fundamental Problems of Technology, Wrocław University of Science and Technology, Pl. Grunwaldzki 13, 50-377, Wrocław, Poland.,Lipid Systems sp. z o.o., ul. Krzemieniecka 48C, 54-613, Wrocław, Poland
| |
Collapse
|
10
|
Kim JH, Riehemann K, Fuchs H. Force Spectroscopy on a Cell Drum: AFM Measurements on the Basolateral Side of Cells via Inverted Cell Cultures. ACS APPLIED MATERIALS & INTERFACES 2018; 10:12485-12490. [PMID: 29595251 DOI: 10.1021/acsami.8b01990] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
The elasticity of a cell is one of the most critical measures of the difference between cancerous cells and healthy cells: cancer cells tend to be softer than healthy cells, and highly invasive cells tend to be more elastic than less aggressive cells. In this work, we present the novel "bottom-up" cell force spectroscopy method for the biophysical characterization of cancer cells, in which an atomic force microscopy (AFM) tip approach from the backside of a net-shaped culture substrate exposing the basolateral cell membrane drum, and compare it with the conventional "top-down" AFM measurements. We used two different human pancreatic carcinoma cell lines, PaTu8988S and PaTu8988T. Our bottom-up AFM tip approach provided a more statistically synchronized distribution of the measured elastic moduli of the cells, demonstrating its superior applicability for the clinical use of force spectroscopy, which is not attainable with the conventional top-down AFM approach.
Collapse
Affiliation(s)
- Joo Hyoung Kim
- Institute of Physics , University of Münster , D-48149 Münster , Germany
- Center for Nanotechnology (CeNTech) , D-48149 Münster , Germany
| | - Kristina Riehemann
- Institute of Physics , University of Münster , D-48149 Münster , Germany
- Center for Nanotechnology (CeNTech) , D-48149 Münster , Germany
| | - Harald Fuchs
- Institute of Physics , University of Münster , D-48149 Münster , Germany
- Center for Nanotechnology (CeNTech) , D-48149 Münster , Germany
| |
Collapse
|
11
|
Zhang Y, Meng Z, Qin X, Keten S. Ballistic impact response of lipid membranes. NANOSCALE 2018; 10:4761-4770. [PMID: 29465729 DOI: 10.1039/c7nr08879e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Therapeutic agent loaded micro and nanoscale particles as high-velocity projectiles can penetrate cells and tissues, thereby serving as gene and drug delivery vehicles for direct and rapid internalization. Despite recent progress in developing micro/nanoscale ballistic tools, the underlying biophysics of how fast projectiles deform and penetrate cell membranes is still poorly understood. To understand the rate and size-dependent penetration processes, we present coarse-grained molecular dynamics simulations of the ballistic impact of spherical projectiles on lipid membranes. Our simulations reveal that upon impact, the projectile can pursue one of three distinct pathways. At low velocities below the critical penetration velocity, projectiles rebound off the surface. At intermediate velocities, penetration occurs after the projectile deforms the membrane into a tubular thread. At very high velocities, rapid penetration occurs through localized membrane deformation without tubulation. Membrane tension, projectile velocity and size govern which phenomenon occurs, owing to their positive correlation with the reaction force generated between the projectile and the membrane during impact. Two critical membrane tension values dictate the boundaries among the three pathways for a given system, due to the rate dependence of the stress generated in the membrane. Our findings provide broad physical insights into the ballistic impact response of soft viscous membranes and guide design strategies for drug delivery through lipid membranes using micro/nanoscale ballistic tools.
Collapse
Affiliation(s)
- Yao Zhang
- Department of Mechanical Engineering, Northwestern University, Evanston, Illinois 60208, USA.
| | | | | | | |
Collapse
|
12
|
Ayee MAA, LeMaster E, Shentu TP, Singh DK, Barbera N, Soni D, Tiruppathi C, Subbaiah PV, Berdyshev E, Bronova I, Cho M, Akpa BS, Levitan I. Molecular-Scale Biophysical Modulation of an Endothelial Membrane by Oxidized Phospholipids. Biophys J 2017; 112:325-338. [PMID: 28122218 DOI: 10.1016/j.bpj.2016.12.002] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Revised: 11/29/2016] [Accepted: 12/01/2016] [Indexed: 12/31/2022] Open
Abstract
The influence of two bioactive oxidized phospholipids on model bilayer properties, membrane packing, and endothelial cell biomechanics was investigated computationally and experimentally. The truncated tail phospholipids, 1-palmitoyl-2-(5-oxovaleroyl)-sn-glycero-3-phosphocholine (POVPC) and 1-palmitoyl-2-glutaroyl-sn-glycero-3-phosphocholine (PGPC), are two major oxidation products of the unsaturated phospholipid 1-palmitoyl-2-arachidonoyl-sn-glycero-phosphocholine. A combination of coarse-grained molecular dynamics simulations, Laurdan multiphoton imaging, and atomic force microscopy microindentation experiments was used to determine the impact of POVPC and PGPC on the structure of a multicomponent phospholipid bilayer and to assess the consequences of their incorporation on membrane packing and endothelial cell stiffness. Molecular simulations predicted differential bilayer perturbation effects of the two oxidized phospholipids based on the chemical identities of their truncated tails, including decreased bilayer packing, decreased bilayer bending modulus, and increased water penetration. Disruption of lipid order was consistent with Laurdan imaging results indicating that POVPC and PGPC decrease the lipid packing of both ordered and disordered membrane domains. Computational predictions of a larger membrane perturbation effect by PGPC correspond to greater stiffness of PGPC-treated endothelial cells observed by measuring cellular elastic moduli using atomic force microscopy. Our results suggest that disruptions in membrane structure by oxidized phospholipids play a role in the regulation of overall endothelial cell stiffness.
Collapse
Affiliation(s)
- Manuela A A Ayee
- Division of Pulmonary, Critical Care, Sleep and Allergy, Department of Medicine, University of Illinois at Chicago, Chicago, Illinois
| | - Elizabeth LeMaster
- Division of Pulmonary, Critical Care, Sleep and Allergy, Department of Medicine, University of Illinois at Chicago, Chicago, Illinois
| | - Tzu Pin Shentu
- Division of Pulmonary, Critical Care, Sleep and Allergy, Department of Medicine, University of Illinois at Chicago, Chicago, Illinois
| | - Dev K Singh
- Division of Pulmonary, Critical Care, Sleep and Allergy, Department of Medicine, University of Illinois at Chicago, Chicago, Illinois
| | - Nicolas Barbera
- Division of Pulmonary, Critical Care, Sleep and Allergy, Department of Medicine, University of Illinois at Chicago, Chicago, Illinois
| | - Dheeraj Soni
- Department of Pharmacology, University of Illinois at Chicago, Chicago, Illinois
| | | | - Papasani V Subbaiah
- Division of Endocrinology, Department of Medicine, University of Illinois at Chicago, Chicago, Illinois
| | | | | | - Michael Cho
- Department of Bioengineering, University of Illinois at Chicago, Chicago, Illinois
| | - Belinda S Akpa
- Department of Molecular Biomedical Sciences, North Carolina State University, Raleigh, North Carolina
| | - Irena Levitan
- Division of Pulmonary, Critical Care, Sleep and Allergy, Department of Medicine, University of Illinois at Chicago, Chicago, Illinois.
| |
Collapse
|
13
|
Identifying and quantifying two ligand-binding sites while imaging native human membrane receptors by AFM. Nat Commun 2015; 6:8857. [PMID: 26561004 PMCID: PMC4660198 DOI: 10.1038/ncomms9857] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Accepted: 10/11/2015] [Indexed: 01/29/2023] Open
Abstract
A current challenge in life sciences is to image cell membrane receptors while characterizing their specific interactions with various ligands. Addressing this issue has been hampered by the lack of suitable nanoscopic methods. Here we address this challenge and introduce multifunctional high-resolution atomic force microscopy (AFM) to image human protease-activated receptors (PAR1) in the functionally important lipid membrane and to simultaneously localize and quantify their binding to two different ligands. Therefore, we introduce the surface chemistry to bifunctionalize AFM tips with the native receptor-activating peptide and a tris-N-nitrilotriacetic acid (tris-NTA) group binding to a His10-tag engineered to PAR1. We further introduce ways to discern between the binding of both ligands to different receptor sites while imaging native PAR1s. Surface chemistry and nanoscopic method are applicable to a range of biological systems in vitro and in vivo and to concurrently detect and localize multiple ligand-binding sites at single receptor resolution.
Collapse
|
14
|
Janshoff A, Steinem C. Mechanics of lipid bilayers: What do we learn from pore-spanning membranes? BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2015; 1853:2977-83. [PMID: 26025679 DOI: 10.1016/j.bbamcr.2015.05.029] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2015] [Revised: 05/21/2015] [Accepted: 05/22/2015] [Indexed: 11/18/2022]
Abstract
The mechanical properties of biological membranes have become increasingly important not only from a biophysical viewpoint but also as they play a substantial role in the information transfer in cells and tissues. This minireview summarizes some of our recent understanding of the mechanical properties of artificial model membranes with particular emphasis on membranes suspending an array of pores, so called pore-spanning membranes. A theoretical description of the mechanical properties of these membranes might pave the way to biophysically describe and understand the complex behavior of native biological membranes. This article is part of a Special Issue entitled: Mechanobiology.
Collapse
Affiliation(s)
- Andreas Janshoff
- Institute of Organic and Biomolecular Chemistry, University of Göttingen, Tammannstr. 2, 37077 Göttingen, Germany; Institute of Physical Chemistry, University of Göttingen, Tammannstr. 6, 37077 Göttingen, Germany
| | - Claudia Steinem
- Institute of Organic and Biomolecular Chemistry, University of Göttingen, Tammannstr. 2, 37077 Göttingen, Germany; Institute of Physical Chemistry, University of Göttingen, Tammannstr. 6, 37077 Göttingen, Germany.
| |
Collapse
|
15
|
Alessandrini A, Facci P. Phase transitions in supported lipid bilayers studied by AFM. SOFT MATTER 2014; 10:7145-7164. [PMID: 25090108 DOI: 10.1039/c4sm01104j] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We review the capabilities of Atomic Force Microscopy (AFM) in the study of phase transitions in Supported Lipid Bilayers (SLBs). AFM represents a powerful technique to cover the resolution range not available to fluorescence imaging techniques and where spectroscopic data suggest what the relevant lateral scale for domain formation might be. Phase transitions of lipid bilayers involve the formation of domains characterized by different heights with respect to the surrounding phase and are therefore easily identified by AFM in liquid solution once the bilayer is confined to a flat surface. Even if not endowed with high time resolution, AFM allows light to be shed on some aspects related to lipid phase transitions in the case of both a single lipid component and lipid mixtures containing sterols also. We discuss here the obtained results in light of the peculiarities of supported lipid bilayer model systems.
Collapse
Affiliation(s)
- Andrea Alessandrini
- Dipartimento di Scienze Fisiche, Informatiche e Matematiche, Via Campi 213/A, 41125, Modena, Italy.
| | | |
Collapse
|
16
|
Kuhlmann JW, Mey IP, Steinem C. Modulating the lateral tension of solvent-free pore-spanning membranes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:8186-8192. [PMID: 24950370 DOI: 10.1021/la5019086] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The plasma membrane of animal cells is attached to the cytoskeleton, which significantly contributes to the lateral tension of the membrane. Lateral membrane tension has been shown to be an important physical regulator of cellular processes such as cell motility and morphology as well as exo- and endocytosis. Here, we report on lipid bilayers spanning highly ordered pore arrays, where we can control the lateral membrane tension by chemically varying the surface functionalization of the porous substrate. Surface functionalization was achieved by a gold coating on top of the pore rims of the hexagonal array of pores in silicon nitride substrates with pore radii of 600 nm followed by subsequent incubation with various n-propanolic mixtures of 6-mercapto-1-hexanol (6MH) and O-cholesteryl N-(8'-mercapto-3',6'-dioxaoctyl)carbamate (CPEO3). Pore-spanning membranes composed of 1,2-diphytanoyl-sn-glycero-3-phosphocholine were prepared by spreading giant unilamellar vesicles on these functionalized porous silicon nitride substrates. Different mixtures of 6MH and CPEO3 provided self-assembled monolayers (SAMs) with different compositions as analyzed by contact angle and PM-IRRAS measurements. Site specific force-indentation experiments on the pore-spanning membranes attached to the different SAMs revealed a clear dependence of the amount of CPEO3 in the monolayer on the lateral membrane tension. While bilayers on pure 6MH monolayers show an average lateral membrane tension of 1.4 mN m(-1), a mixed monolayer of CPEO3 and 6MH obtained from a solution with 9.1 mol % CPEO3 exhibits a lateral tension of 5.0 mN m(-1). From contact angle and PM-IRRAS results, the mole fraction of CPEO3 in solution can be roughly translated into a CPEO3 surface concentration of 40 mol %. Our results clearly demonstrate that the free energy difference between the supported and freestanding part of the membrane depends on the chemical composition of the SAM, which controls the lateral membrane tension.
Collapse
Affiliation(s)
- Jan W Kuhlmann
- Institute of Organic and Biomolecular Chemistry, University of Göttingen , Tammannstraße 2, 37077 Göttingen, Germany
| | | | | |
Collapse
|
17
|
Loftus AF, Noreng S, Hsieh VL, Parthasarathy R. Robust measurement of membrane bending moduli using light sheet fluorescence imaging of vesicle fluctuations. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:14588-14594. [PMID: 24180269 DOI: 10.1021/la403837d] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The mechanical rigidity of lipid membranes is a key determinant of the energetics of cellular membrane deformation. Measurements of membrane bending moduli remain rare, however, and show a large variance, a situation that can be addressed by the development of improved techniques and by comparisons between disparate techniques applied to the same systems. We introduce here the use of selective plane illumination microscopy (SPIM, also known as light sheet fluorescence microscopy) to image thermal fluctuations of giant vesicles. The optical sectioning of SPIM enables high-speed fluorescence imaging of freely suspended vesicles and quantification of edge localization precision, yielding robust fluctuation spectra and rigidity estimates. For both lipid-only membranes and membranes bound by the intracellular trafficking protein Sar1p, which lowers membrane rigidity in a concentration-dependent manner, we show that the resulting bending modulus values are in close agreement with those derived from an independent assay based on membrane tether pulling. We also show that the fluctuation spectra of vesicles bound by the mammalian Sar1A protein, which stiffens membranes at high concentrations, are not well fit by a model of homogeneous quasi-spherical vesicles, suggesting that SPIM-based analysis can offer insights into spatially inhomogeneous properties induced by protein assemblies.
Collapse
Affiliation(s)
- Andrew F Loftus
- Department of Chemistry, ‡Department of Physics, and §Materials Science Institute, The University of Oregon , Eugene, Oregon 97403, United States
| | | | | | | |
Collapse
|
18
|
Solmaz ME, Sankhagowit S, Biswas R, Mejia CA, Povinelli ML, Malmstadt N. Optical stretching as a tool to investigate the mechanical properties of lipid bilayers. RSC Adv 2013; 3:10.1039/C3RA42510J. [PMID: 24244843 PMCID: PMC3827026 DOI: 10.1039/c3ra42510j] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Measurements of lipid bilayer bending modulus by various techniques produce widely divergent results. We attempt to resolve some of this ambiguity by measuring bending modulus in a system that can rapidly process large numbers of samples, yielding population statistics. This system is based on optical stretching of giant unilamellar vesicles (GUVs) in a microfluidic dual-beam optical trap (DBOT). The microfluidic DBOT system is used here to measure three populations of GUVs with distinct lipid compositions. We find that gel-phase membranes are significantly stiffer than liquid-phase membranes, consistent with previous reports. We also find that the addition of cholesterol does not alter the bending modulus of membranes composed of a monounsaturated phospholipid.
Collapse
Affiliation(s)
- Mehmet E. Solmaz
- Ming Hsieh Department of Electrical Engineering, University of Southern California, 3737 Watt Way, PHE 614, Los Angeles, CA 90089-0271, USA
- Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, 925 Bloom Walk, HED 216, Los Angeles, CA 90089-1211, USA
| | - Shalene Sankhagowit
- Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, 925 Bloom Walk, HED 216, Los Angeles, CA 90089-1211, USA
| | - Roshni Biswas
- Ming Hsieh Department of Electrical Engineering, University of Southern California, 3737 Watt Way, PHE 614, Los Angeles, CA 90089-0271, USA
| | - Camilo A. Mejia
- Ming Hsieh Department of Electrical Engineering, University of Southern California, 3737 Watt Way, PHE 614, Los Angeles, CA 90089-0271, USA
| | - Michelle L. Povinelli
- Ming Hsieh Department of Electrical Engineering, University of Southern California, 3737 Watt Way, PHE 614, Los Angeles, CA 90089-0271, USA
| | - Noah Malmstadt
- Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, 925 Bloom Walk, HED 216, Los Angeles, CA 90089-1211, USA
| |
Collapse
|
19
|
Schäfer E, Kliesch TT, Janshoff A. Mechanical properties of giant liposomes compressed between two parallel plates: impact of artificial actin shells. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:10463-10474. [PMID: 23869855 DOI: 10.1021/la401969t] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The mechanical response of giant liposomes to compression between two parallel plates is investigated in the context of an artificial actin cortex adjacent to the inner leaflet of the bilayer. We found that nonlinear membrane theory neglecting the impact of bending sufficiently describes the mechanical response of liposomes consisting of fluid lipids to compression whereas the formation of an actin cortex or the use of gel-phase lipids generally leads to substantial stiffening of the shell. Giant vesicles are gently adsorbed on glassy surfaces and are compressed with tipless cantilevers using an atomic force microscope. Force-compression curves display a nonlinear response that allows us to determine the membrane tension σ0 and the area compressibility modulus K(A) by computing the contour of the vesicle as a function of the compression depth. The values for KA of fluid membranes correspond well to what is known from micropipet-suction experiments and computed from monitoring membrane undulations. The presence of a thick actin shell adjacent to the inner leaflet of the liposome membrane stiffens the system considerably, as mirrored in a significantly higher apparent area compressibility modulus.
Collapse
Affiliation(s)
- Edith Schäfer
- Institute of Physical Chemistry, Georg-August-University of Goettingen, Tammannstr. 6, 37077 Goettingen
| | | | | |
Collapse
|
20
|
Solmaz ME, Biswas R, Sankhagowit S, Thompson JR, Mejia CA, Malmstadt N, Povinelli ML. Optical stretching of giant unilamellar vesicles with an integrated dual-beam optical trap. BIOMEDICAL OPTICS EXPRESS 2012; 3:2419-27. [PMID: 23082284 PMCID: PMC3469987 DOI: 10.1364/boe.3.002419] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2012] [Revised: 08/14/2012] [Accepted: 08/16/2012] [Indexed: 05/06/2023]
Abstract
We have integrated a dual-beam optical trap into a microfluidic platform and used it to study membrane mechanics in giant unilamellar vesicles (GUVs). We demonstrate the trapping and stretching of GUVs and characterize the membrane response to a step stress. We then measure area strain as a function of applied stress to extract the bending modulus of the lipid bilayer in the low-tension regime.
Collapse
Affiliation(s)
- Mehmet E. Solmaz
- Ming Hsieh Department of Electrical Engineering, University of Southern California, Los Angeles, CA 90089, USA
| | - Roshni Biswas
- Ming Hsieh Department of Electrical Engineering, University of Southern California, Los Angeles, CA 90089, USA
| | - Shalene Sankhagowit
- Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, CA 90089, USA
| | - James R. Thompson
- Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, CA 90089, USA
| | - Camilo A. Mejia
- Ming Hsieh Department of Electrical Engineering, University of Southern California, Los Angeles, CA 90089, USA
| | - Noah Malmstadt
- Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, CA 90089, USA
| | - Michelle L. Povinelli
- Ming Hsieh Department of Electrical Engineering, University of Southern California, Los Angeles, CA 90089, USA
| |
Collapse
|
21
|
Mey I, Steinem C, Janshoff A. Biomimetic functionalization of porous substrates: towards model systems for cellular membranes. ACTA ACUST UNITED AC 2012. [DOI: 10.1039/c2jm31737k] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|