1
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Armanious A, Gerelli Y, Micciulla S, Pace HP, Welbourn RJL, Sjöberg M, Agnarsson B, Höök F. Probing the Separation Distance between Biological Nanoparticles and Cell Membrane Mimics Using Neutron Reflectometry with Sub-Nanometer Accuracy. J Am Chem Soc 2022; 144:20726-20738. [DOI: 10.1021/jacs.2c08456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Antonius Armanious
- Department of Physics, Chalmers University of Technology, 41296Gothenburg, Sweden
| | - Yuri Gerelli
- Institut Max von Laue-Paul Langevin (ILL), 38042Grenoble, France
- Department of Life and Environmental Sciences, Università Politecnica delle Marche, 60131Ancona, Italy
| | | | - Hudson P. Pace
- Department of Physics, Chalmers University of Technology, 41296Gothenburg, Sweden
| | - Rebecca J. L. Welbourn
- ISIS Facility, STFC, Rutherford Appleton Laboratory, Chilton, Didcot, OxonOX11 0QX, United Kingdom
| | - Mattias Sjöberg
- Department of Physics, Chalmers University of Technology, 41296Gothenburg, Sweden
| | - Björn Agnarsson
- Department of Physics, Chalmers University of Technology, 41296Gothenburg, Sweden
| | - Fredrik Höök
- Department of Physics, Chalmers University of Technology, 41296Gothenburg, Sweden
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2
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Hossain M, Blanchard GJ. Ceramide-mediation of diffusion in supported lipid bilayers. Chem Phys Lipids 2021; 238:105090. [PMID: 33971138 DOI: 10.1016/j.chemphyslip.2021.105090] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 04/09/2021] [Accepted: 05/05/2021] [Indexed: 11/30/2022]
Abstract
The fluidity and compositional heterogeneity of the mammalian plasma membrane play deterministic roles in a variety of membrane functions. Designing model bilayer systems allows for compositional control over these properties. Ceramide is a phospholipid capable of extensive headgroup-region hydrogen bonding, and we report here on the role of ceramide in planar model bilayers. We use fluorescence recovery after photobleaching (FRAP) to obtain translational diffusion constants of two chromophores in supported model bilayers composed of cholesterol, 1,2-dioleoyl-sn-phosphatidylcholine (DOPC), sphingomyelin, and ceramide. FRAP data for perylene report on the acyl chain region of the model bilayer and FRAP data for 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine-N-(lissamine rhodamine B sulfonyl) sense diffusional dynamics in the bilayer headgroup region. Dynamics in the headgroup region exhibit anomalous diffusion behavior that is characteristic of spatially heterogeneous media.
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Affiliation(s)
- Masroor Hossain
- Michigan State University, Department of Chemistry, 578 S. Shaw Lane, East Lansing, MI, 48824, USA
| | - G J Blanchard
- Michigan State University, Department of Chemistry, 578 S. Shaw Lane, East Lansing, MI, 48824, USA.
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3
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Nordendorf G, Schafforz SL, Käkel EB, Miao S, Lorenz A. Surface grafted agents with various molecular lengths and photochemically active benzophenone moieties. Phys Chem Chem Phys 2020; 22:1774-1783. [DOI: 10.1039/c9cp05722f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Homologues of benzophenone silane, a covalently graftable, photochemically active surface functionalizing agent, are investigated as surface functionalization agents for both small particles and planar substrates.
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Affiliation(s)
- Gaby Nordendorf
- Department of Chemistry
- Paderborn University
- 33098 Paderborn
- Germany
| | | | - Eireen B. Käkel
- Institute of Chemistry
- University of Kassel
- 34132 Kassel
- Germany
| | - Shunyi Miao
- Department of Chemistry
- Paderborn University
- 33098 Paderborn
- Germany
| | - Alexander Lorenz
- Department of Chemistry
- Paderborn University
- 33098 Paderborn
- Germany
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4
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Preparation of an integrated porous substrate of 11-mercaptoundecanoic acid and chitosan on gold for electrochemical study of pores and pore forming interactions in lipid bilayers. Electrochim Acta 2020. [DOI: 10.1016/j.electacta.2019.135174] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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5
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Ahmed IN, Chang R, Keng MC, Chien HW, Chen HY, Tsai WB. Immobilization of functional polymers on poly(4-benzoyl-pxylylene-co-p-xylylene) films via photochemical conjugation for modulation of cell adhesion. Colloids Surf B Biointerfaces 2019; 174:360-366. [DOI: 10.1016/j.colsurfb.2018.11.016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Revised: 10/17/2018] [Accepted: 11/07/2018] [Indexed: 12/25/2022]
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6
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Kumari A, Rekhi L, Datta S. Reversibly Attached Phospholipid Bilayer-Functionalized Membrane Pores. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:14395-14401. [PMID: 30392365 DOI: 10.1021/acs.langmuir.8b03404] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We report the development of reversibly attached phospholipid bilayer (PLB)-functionalized membrane pores that enabled reusability of the membrane matrix as well as the phospholipid. The functionalized architecture was constructed based on electrostatic interactions, which facilitate the reversible attachment-detachment sequence of the functional moieties within membrane pores. To demonstrate potential application, an enzyme, glucose oxidase (GOx), was electrostatically immobilized within the PLB-functionalized membrane and enzymatic catalysis was conducted under the convective flow mode. The GOx-immobilized membrane demonstrated satisfactory activity and stability. Convective flow of the substrate solution resulted in significantly higher activity than diffusive flow. Then, the enzyme was detached keeping the functional PLB backbone intact. Detachment of the enzyme without affecting the functional activity of PLB backbone permits attachment of fresh enzyme. In addition, reusability of the phospholipids is also of great importance as they have wide range of applications, but their usage is limited by higher cost. We have demonstrated the detachment of the PLB from the membrane using a simple technique. Characterization of the detached phospholipid confirmed retention of the original structural and functional properties as exhibited before attachment. To the best of our knowledge, this is the first study on reversible PLB formation within membrane pores and demonstration of a detachment technique, while maintaining the structural and functional properties of the phospholipid.
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Affiliation(s)
- Anju Kumari
- Department of Biotechnology , Indian Institute of Technology Roorkee , Roorkee 247667 , Uttarakhand , India
| | - Lavie Rekhi
- Department of Biotechnology , Indian Institute of Technology Roorkee , Roorkee 247667 , Uttarakhand , India
| | - Saurav Datta
- Department of Biotechnology , Indian Institute of Technology Roorkee , Roorkee 247667 , Uttarakhand , India
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7
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8
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Tunable cell-surface mimetics as engineered cell substrates. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1860:2076-2093. [PMID: 29935145 DOI: 10.1016/j.bbamem.2018.06.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Revised: 05/18/2018] [Accepted: 06/08/2018] [Indexed: 12/21/2022]
Abstract
Most recent breakthroughs in understanding cell adhesion, cell migration, and cellular mechanosensitivity have been made possible by the development of engineered cell substrates of well-defined surface properties. Traditionally, these substrates mimic the extracellular matrix (ECM) environment by the use of ligand-functionalized polymeric gels of adjustable stiffness. However, such ECM mimetics are limited in their ability to replicate the rich dynamics found at cell-cell contacts. This review focuses on the application of cell surface mimetics, which are better suited for the analysis of cell adhesion, cell migration, and cellular mechanosensitivity across cell-cell interfaces. Functionalized supported lipid bilayer systems were first introduced as biomembrane-mimicking substrates to study processes of adhesion maturation during adhesion of functionalized vesicles (cell-free assay) and plated cells. However, while able to capture adhesion processes, the fluid lipid bilayer of such a relatively simple planar model membrane prevents adhering cells from transducing contractile forces to the underlying solid, making studies of cell migration and cellular mechanosensitivity largely impractical. Therefore, the main focus of this review is on polymer-tethered lipid bilayer architectures as biomembrane-mimicking cell substrate. Unlike supported lipid bilayers, these polymer-lipid composite materials enable the free assembly of linkers into linker clusters at cellular contacts without hindering cell spreading and migration and allow the controlled regulation of mechanical properties, enabling studies of cellular mechanosensitivity. The various polymer-tethered lipid bilayer architectures and their complementary properties as cell substrates are discussed.
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9
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Lee TH, Hirst DJ, Kulkarni K, Del Borgo MP, Aguilar MI. Exploring Molecular-Biomembrane Interactions with Surface Plasmon Resonance and Dual Polarization Interferometry Technology: Expanding the Spotlight onto Biomembrane Structure. Chem Rev 2018; 118:5392-5487. [PMID: 29793341 DOI: 10.1021/acs.chemrev.7b00729] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The molecular analysis of biomolecular-membrane interactions is central to understanding most cellular systems but has emerged as a complex technical challenge given the complexities of membrane structure and composition across all living cells. We present a review of the application of surface plasmon resonance and dual polarization interferometry-based biosensors to the study of biomembrane-based systems using both planar mono- or bilayers or liposomes. We first describe the optical principals and instrumentation of surface plasmon resonance, including both linear and extraordinary transmission modes and dual polarization interferometry. We then describe the wide range of model membrane systems that have been developed for deposition on the chips surfaces that include planar, polymer cushioned, tethered bilayers, and liposomes. This is followed by a description of the different chemical immobilization or physisorption techniques. The application of this broad range of engineered membrane surfaces to biomolecular-membrane interactions is then overviewed and how the information obtained using these techniques enhance our molecular understanding of membrane-mediated peptide and protein function. We first discuss experiments where SPR alone has been used to characterize membrane binding and describe how these studies yielded novel insight into the molecular events associated with membrane interactions and how they provided a significant impetus to more recent studies that focus on coincident membrane structure changes during binding of peptides and proteins. We then discuss the emerging limitations of not monitoring the effects on membrane structure and how SPR data can be combined with DPI to provide significant new information on how a membrane responds to the binding of peptides and proteins.
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Affiliation(s)
- Tzong-Hsien Lee
- Department of Biochemistry and Molecular Biology and Biomedicine Discovery Institute , Monash University , Clayton , VIC 3800 , Australia
| | - Daniel J Hirst
- Department of Biochemistry and Molecular Biology and Biomedicine Discovery Institute , Monash University , Clayton , VIC 3800 , Australia
| | - Ketav Kulkarni
- Department of Biochemistry and Molecular Biology and Biomedicine Discovery Institute , Monash University , Clayton , VIC 3800 , Australia
| | - Mark P Del Borgo
- Department of Biochemistry and Molecular Biology and Biomedicine Discovery Institute , Monash University , Clayton , VIC 3800 , Australia
| | - Marie-Isabel Aguilar
- Department of Biochemistry and Molecular Biology and Biomedicine Discovery Institute , Monash University , Clayton , VIC 3800 , Australia
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10
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Zhang Y, Xuan S, Owoseni O, Omarova M, Li X, Saito ME, He J, McPherson GL, Raghavan SR, Zhang D, John VT. Amphiphilic Polypeptoids Serve as the Connective Glue to Transform Liposomes into Multilamellar Structures with Closely Spaced Bilayers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:2780-2789. [PMID: 28248521 DOI: 10.1021/acs.langmuir.6b04190] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We report the ability of hydrophobically modified polypeptoids (HMPs), which are amphiphilic pseudopeptidic macromolecules, to connect across lipid bilayers and thus form layered structures on liposomes. The HMPs are obtained by attaching hydrophobic decyl groups at random points along the polypeptoid backbone. Although native polypeptoids (with no hydrophobes) have no effect on liposomal structure, the HMPs remodel the unilamellar liposomes into structures with comparable diameters but with multiple concentric bilayers. The transition from single-bilayer to multiple-bilayer structures is revealed by small-angle neutron scattering (SANS) and cryo-transmission electron microscopy (cryo-TEM). The spacing between bilayers is found to be relatively uniform at ∼6.7 nm. We suggest that the amphiphilic nature of the HMPs explains the formation of multibilayered liposomes; i.e., the HMPs insert their hydrophobic tails into adjacent bilayers and thereby serve as the connective glue between bilayers. At higher HMP concentrations, the liposomes are entirely disrupted into much smaller micellelike structures through extensive hydrophobe insertion. Interestingly, these small structures can reattach to fresh unilamellar liposomes and self-assemble to form new two-bilayer liposomes. The two-bilayer liposomes in our study are reminiscent of two-bilayer organelles such as the nucleus in eukaryotic cells. The observations have significance in designing new nanoscale drug delivery carriers with multiple drugs on separate lipid bilayers and extending liposome circulation times with entirely biocompatible materials.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Srinivasa R Raghavan
- Department of Chemical and Biomolecular Engineering, University of Maryland , College Park, Maryland 20742, United States
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11
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Lee E, Kim D, Yang SY, Oh JW, Yoon J. Photo-crosslinkable comb-type copolymers bearing a benzophenone moiety for the enhanced swelling kinetics of hydrogels. Polym Chem 2017. [DOI: 10.1039/c7py01647f] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The fast responding 3D hydrogel object was fabricated using developed photo-crosslinkable copolymers bearing grafted PNIPAm and a benzophenone moiety.
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Affiliation(s)
- Eunsu Lee
- Department of Chemistry
- Dong-A University
- Busan
- Republic of Korea
| | - Dowan Kim
- Department of Chemistry Education
- Graduate Department of Chemical Materials
- and Institute for Plastic Information and Energy Materials
- Pusan National University
- Busan
| | - Seung Yun Yang
- Department Biomaterials Science
- Pusan National University
- Republic of Korea
| | - Jin-Woo Oh
- Department of Nanoenergy Engineering
- Pusan National University
- Republic of Korea
| | - Jinhwan Yoon
- Department of Chemistry Education
- Graduate Department of Chemical Materials
- and Institute for Plastic Information and Energy Materials
- Pusan National University
- Busan
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12
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Carroll GT, Lancaster JR, Turro NJ, Koberstein JT, Mammana A. Electroless Deposition of Nickel on Photografted Polymeric Microscale Patterns. Macromol Rapid Commun 2016; 38. [PMID: 27873447 DOI: 10.1002/marc.201600564] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2016] [Revised: 10/11/2016] [Indexed: 11/09/2022]
Abstract
This report demonstrates the electroless deposition of Ni onto micropatterns of poly (acrylic acid) (PAA) photografted to phthalimide-terminated self-assembled monolayers (SAMs). PAA is spin-coated onto phthalimide SAMs and covered with a photomask. UV irradiation selectively binds PAA to exposed regions of the surface, allowing PAA on unexposed regions to be rinsed off. A Pd catalyst is then selectively adsorbed to regions of the surface where PAA is bound. The adsorbed catalyst selectively initiates Ni plating upon immersion of the substrate into a Ni(SO4 ) bath.
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Affiliation(s)
- Gregory T Carroll
- Department of Chemistry, Columbia University, New York, NY, 10027, USA
| | | | - Nicholas J Turro
- Department of Chemistry, Columbia University, New York, NY, 10027, USA.,Department of Chemical Engineering, Columbia University, New York, NY, 10027, USA
| | - Jeffrey T Koberstein
- Department of Chemical Engineering, Columbia University, New York, NY, 10027, USA
| | - Angela Mammana
- Department of Chemistry, University of Dayton, Dayton, OH, 45469, USA
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13
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Polymeric nanoparticles modified with fatty acids encapsulating betamethasone for anti-inflammatory treatment. Int J Pharm 2015. [PMID: 26222745 DOI: 10.1016/j.ijpharm.2015.07.044] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Topical glucocorticosteroids were incorporated into nanocarrier-based formulations, to overcome side effects of conventional formulations and to achieve maximum skin deposition. Nanoparticulate carriers have the potential to prolong the anti-inflammatory effect and provide higher local concentration of drugs, offering a better solution for treating dermatological conditions and improving patient compliance. Nanoparticles were formulated with poly-ϵ-caprolactone as the polymeric core along with stearic acid as the fatty acid, for incorporation of betamethasone-21-acetate. Oleic acid was applied as the coating fatty acid. Improvement of the drug efficacy, and reduction in drug degradation with time in the encapsulated form was examined, while administering it locally through controlled release. Nanoparticles were spherical with mean size of 300 nm and negatively charged surface. Encapsulation efficiency was 90%. Physicochemical stability in aqueous media of the empty and loaded nanoparticles was evaluated for six months. Drug degradation was reduced compared to free drug, after encapsulation into nanoparticles, avoiding the potency decline and promoting a controlled drug release over one month. Fourier transform infrared spectroscopy and thermal analysis confirmed drug entrapment, while cytotoxicity studies performed in vitro on human keratinocytes, Saccharomyces cerevisiae models and Artemia salina, showed a dose-response relationship for nanoparticles and free drug. In all models, drug loaded nanoparticles had a greater inhibitory effect. Nanoparticles increased drug permeation into lipid membranes in vitro. Preliminary safety and permeation studies conducted on rats, showed betamethasone-21-acetate in serum after 48 h application of a gel containing nanoparticles. No skin reactions were observed. In conclusion, the developed nanoparticles may be applied as topical treatment, after encapsulation of betamethasone-21-acetate, as nanoparticles promote prolonged drug release, increase drug stability in aqueous media, reducing drug degradation, and increase drug permeability through lipid membranes.
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14
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Banks JM, Harley BAC, Bailey RC. Tunable, Photoreactive Hydrogel System To Probe Synergies between Mechanical and Biomolecular Cues on Adipose-Derived Mesenchymal Stem Cell Differentiation. ACS Biomater Sci Eng 2015; 1:718-725. [DOI: 10.1021/acsbiomaterials.5b00196] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
| | - Brendan A. C. Harley
- Carl
R. Woese Institute for Genomic Biology, University of Illinois at Urbana—Champaign, 1206 West Gregory Drive, Urbana, Illinois 61801, United States
| | - Ryan C. Bailey
- Carl
R. Woese Institute for Genomic Biology, University of Illinois at Urbana—Champaign, 1206 West Gregory Drive, Urbana, Illinois 61801, United States
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15
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Su CT, Yuan RH, Chen YC, Lin TJ, Chien HW, Hsieh CC, Tsai WB, Chang CH, Chen HY. A facile approach toward protein-resistant biointerfaces based on photodefinable poly-p-xylylene coating. Colloids Surf B Biointerfaces 2014; 116:727-33. [DOI: 10.1016/j.colsurfb.2013.11.044] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2013] [Revised: 11/21/2013] [Accepted: 11/23/2013] [Indexed: 11/30/2022]
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16
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Coutable A, Thibault C, Chalmeau J, François JM, Vieu C, Noireaux V, Trévisiol E. Preparation of tethered-lipid bilayers on gold surfaces for the incorporation of integral membrane proteins synthesized by cell-free expression. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:3132-3141. [PMID: 24568716 DOI: 10.1021/la5004758] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
There is an increasing interest to express and study membrane proteins in vitro. New techniques to produce and insert functional membrane proteins into planar lipid bilayers have to be developed. In this work, we produce a tethered lipid bilayer membrane (tBLM) to provide sufficient space for the incorporation of the integral membrane protein (IMP) Aquaporin Z (AqpZ) between the tBLM and the surface of the sensor. We use a gold (Au)-coated sensor surface compatible with mechanical sensing using a quartz crystal microbalance with dissipation monitoring (QCM-D) or optical sensing using the surface plasmon resonance (SPR) method. tBLM is produced by vesicle fusion onto a thin gold film, using phospholipid-polyethylene glycol (PEG) as a spacer. Lipid vesicles are composed of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) and 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-poly(ethyleneglycol)-2000-N-[3-(2-pyridyldithio)propionate], so-called DSPE-PEG-PDP, at different molar ratios (respectively, 99.5/0.5, 97.5/2.5, and 95/5 mol %), and tBLM formation is characterized using QCM-D, SPR, and atomic force technology (AFM). We demonstrate that tBLM can be produced on the gold surface after rupture of the vesicles using an α helical (AH) peptide, derived from hepatitis C virus NS5A protein, to assist the fusion process. A cell-free expression system producing the E. coli integral membrane protein Aquaporin Z (AqpZ) is directly incubated onto the tBLMs for expression and insertion of the IMP at the upper side of tBLMs. The incorporation of AqpZ into bilayers is monitored by QCM-D and compared to a control experiment (without plasmid in the cell-free expression system). We demonstrate that an IMP such as AqpZ, produced by a cell-free expression system without any protein purification, can be incorporated into an engineered tBLM preassembled at the surface of a gold-coated sensor.
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Affiliation(s)
- Angélique Coutable
- Université de Toulouse , INSA, UPS, INP, LISBP, 135 Avenue de Rangueil, F-31077 Toulouse, France
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17
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Chang CH, Yeh SY, Lee BH, Hsu CW, Chen YC, Chen CJ, Lin TJ, Hung-Chih Chen M, Huang CT, Chen HY. Compatibility balanced antibacterial modification based on vapor-deposited parylene coatings for biomaterials. J Mater Chem B 2014; 2:8496-8503. [DOI: 10.1039/c4tb00992d] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
An advanced antibacterial modification technique is conducted by immobilizing antibacterial agents to reduce bacterial attachment and show balanced biocompatibility.
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Affiliation(s)
- Chih-Hao Chang
- Department of Orthopedic Surgery
- National Taiwan University Hospital and National Taiwan University College of Medicine
- Taipei 10018, Taiwan
| | - Shu-Yun Yeh
- Department of Chemical Engineering
- National Taiwan University
- Taipei 10617, Taiwan
| | - Bing-Heng Lee
- Department of Orthopedic Surgery
- National Taiwan University Hospital and National Taiwan University College of Medicine
- Taipei 10018, Taiwan
| | - Che-Wei Hsu
- Department of Orthopedic Surgery
- National Taiwan University Hospital and National Taiwan University College of Medicine
- Taipei 10018, Taiwan
| | - Yung-Chih Chen
- Department of Chemical Engineering
- National Taiwan University
- Taipei 10617, Taiwan
| | - Chia-Jie Chen
- Department of Orthopedic Surgery
- National Taiwan University Hospital and National Taiwan University College of Medicine
- Taipei 10018, Taiwan
| | - Ting-Ju Lin
- Department of Chemical Engineering
- National Taiwan University
- Taipei 10617, Taiwan
| | - Mark Hung-Chih Chen
- Department of Orthopedic Surgery
- National Taiwan University Hospital and National Taiwan University College of Medicine
- Taipei 10018, Taiwan
| | - Ching-Tsan Huang
- Department of Biochemical Science and Technology
- National Taiwan University
- Taipei 10617, Taiwan
| | - Hsien-Yeh Chen
- Department of Chemical Engineering
- National Taiwan University
- Taipei 10617, Taiwan
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18
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Sterling SM, Allgeyer ES, Fick J, Prudovsky I, Mason MD, Neivandt DJ. Phospholipid diffusion coefficients of cushioned model membranes determined via z-scan fluorescence correlation spectroscopy. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:7966-74. [PMID: 23705855 PMCID: PMC3758428 DOI: 10.1021/la400768s] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Model cellular membranes enable the study of biological processes in a controlled environment and reduce the traditional challenges associated with live or fixed cell studies. However, model membrane systems based on the air/water or oil/solution interface do not allow for incorporation of transmembrane proteins or for the study of protein transport mechanisms. Conversely, a phospholipid bilayer deposited via the Langmuir-Blodgett/Langmuir-Schaefer method on a hydrogel layer is potentially an effective mimic of the cross section of a biological membrane and facilitates both protein incorporation and transport studies. Prior to application, however, such membranes must be fully characterized, particularly with respect to the phospholipid bilayer phase transition temperature. Here we present a detailed characterization of the phase transition temperature of the inner and outer leaflets of a chitosan supported model membrane system. Specifically, the lateral diffusion coefficient of each individual leaflet has been determined as a function of temperature. Measurements were performed utilizing z-scan fluorescence correlation spectroscopy (FCS), a technique that yields calibration-free diffusion information. Analysis via the method of Wawrezinieck and co-workers revealed that phospholipid diffusion changes from raftlike to free diffusion as the temperature is increased-an insight into the dynamic behavior of hydrogel supported membranes not previously reported.
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Affiliation(s)
- Sarah M. Sterling
- Department of Chemical and Biological Engineering, University of Maine, Orono, Maine 04469
- Graduate School of Biomedical Sciences, University of Maine, Orono, Maine 04469
| | - Edward S. Allgeyer
- Department of Physics and Astronomy, University of Maine, Orono, Maine 04469
| | - Jörg Fick
- Department of Chemical and Biological Engineering, University of Maine, Orono, Maine 04469
| | - Igor Prudovsky
- Graduate School of Biomedical Sciences, University of Maine, Orono, Maine 04469
- Maine Medical Center Research Institute, Scarborough, ME 04074
- Institute for Molecular Biophysics, Orono, Maine 04469
| | - Michael D. Mason
- Department of Chemical and Biological Engineering, University of Maine, Orono, Maine 04469
- Institute for Molecular Biophysics, Orono, Maine 04469
| | - David J. Neivandt
- Department of Chemical and Biological Engineering, University of Maine, Orono, Maine 04469
- Graduate School of Biomedical Sciences, University of Maine, Orono, Maine 04469
- Institute for Molecular Biophysics, Orono, Maine 04469
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Mashaghi S, Jadidi T, Koenderink G, Mashaghi A. Lipid nanotechnology. Int J Mol Sci 2013; 14:4242-82. [PMID: 23429269 PMCID: PMC3588097 DOI: 10.3390/ijms14024242] [Citation(s) in RCA: 150] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2012] [Revised: 01/29/2013] [Accepted: 01/30/2013] [Indexed: 01/14/2023] Open
Abstract
Nanotechnology is a multidisciplinary field that covers a vast and diverse array of devices and machines derived from engineering, physics, materials science, chemistry and biology. These devices have found applications in biomedical sciences, such as targeted drug delivery, bio-imaging, sensing and diagnosis of pathologies at early stages. In these applications, nano-devices typically interface with the plasma membrane of cells. On the other hand, naturally occurring nanostructures in biology have been a source of inspiration for new nanotechnological designs and hybrid nanostructures made of biological and non-biological, organic and inorganic building blocks. Lipids, with their amphiphilicity, diversity of head and tail chemistry, and antifouling properties that block nonspecific binding to lipid-coated surfaces, provide a powerful toolbox for nanotechnology. This review discusses the progress in the emerging field of lipid nanotechnology.
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Affiliation(s)
- Samaneh Mashaghi
- Zernike Institute for Advanced Materials, Centre for Synthetic Biology, Nijenborgh 4, 9747 AG Groningen, The Netherlands; E-Mail:
| | - Tayebeh Jadidi
- Department of Physics, University of Osnabrück, Barbarastraße 7, 49076 Osnabrück, Germany; E-Mail:
| | - Gijsje Koenderink
- FOM Institute AMOLF, Science Park 104, 1098XG Amsterdam, The Netherlands; E-Mail:
| | - Alireza Mashaghi
- FOM Institute AMOLF, Science Park 104, 1098XG Amsterdam, The Netherlands; E-Mail:
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands
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20
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Prudovsky I, Kumar TKS, Sterling S, Neivandt D. Protein-phospholipid interactions in nonclassical protein secretion: problem and methods of study. Int J Mol Sci 2013; 14:3734-72. [PMID: 23396106 PMCID: PMC3588068 DOI: 10.3390/ijms14023734] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2012] [Revised: 01/24/2013] [Accepted: 01/25/2013] [Indexed: 12/30/2022] Open
Abstract
Extracellular proteins devoid of signal peptides use nonclassical secretion mechanisms for their export. These mechanisms are independent of the endoplasmic reticulum and Golgi. Some nonclassically released proteins, particularly fibroblast growth factors (FGF) 1 and 2, are exported as a result of their direct translocation through the cell membrane. This process requires specific interactions of released proteins with membrane phospholipids. In this review written by a cell biologist, a structural biologist and two membrane engineers, we discuss the following subjects: (i) Phenomenon of nonclassical protein release and its biological significance; (ii) Composition of the FGF1 multiprotein release complex (MRC); (iii) The relationship between FGF1 export and acidic phospholipid externalization; (iv) Interactions of FGF1 MRC components with acidic phospholipids; (v) Methods to study the transmembrane translocation of proteins; (vi) Membrane models to study nonclassical protein release.
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Affiliation(s)
- Igor Prudovsky
- Maine Medical Center Research Institute, 81 Research Drive, Scarborough, ME 04074, USA
| | | | - Sarah Sterling
- Department of Chemical and Biological Engineering, University of Maine, Orono, ME 04469, USA; E-Mails: (S.S.); (D.N.)
| | - David Neivandt
- Department of Chemical and Biological Engineering, University of Maine, Orono, ME 04469, USA; E-Mails: (S.S.); (D.N.)
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21
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Orski SV, Kundu S, Gross R, Beers KL. Design and implementation of two-dimensional polymer adsorption models: evaluating the stability of Candida antarctica lipase B/solid-support interfaces by QCM-D. Biomacromolecules 2013; 14:377-86. [PMID: 23286367 DOI: 10.1021/bm301557y] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
A two-dimensional model of a solid-supported enzyme catalyst bead is fabricated on a quartz crystal microbalance with dissipation monitoring (QCM-D) sensor to measure in situ interfacial stability and mechanical properties of Candida antarctica Lipase B (CAL B) under varied conditions relating to ring-opening polymerization. The model was fabricated using a dual photochemical approach, where poly(methyl methacrylate) (PMMA) thin films were cross-linked by a photoactive benzophenone monolayer and blended cross-linking agent. This process produces two-dimensional, homogeneous, rigid PMMA layers, which mimic commercial acrylic resins in a QCM-D experiment. Adsorption of CAL B to PMMA in QCM-D under varied buffer ionic strengths produces a viscoelastic enzyme surface that becomes more rigid as ionic strength increases. The rigid CAL B/PMMA interface demonstrates up to 20% desorption of enzyme with increasing trace water content. Increased polycaprolactone (PCL) binding at the enzyme surface was also observed, indicating greater PCL affinity for a more hydrated enzyme surface. The enzyme layer destabilized with increasing temperature, yielding near complete reversible catalyst desorption in the model.
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Affiliation(s)
- Sara V Orski
- Materials Science & Engineering Division, National Institute of Standards and Technology , Gaithersburg, MD 20899, United States
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22
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Abstract
Lipid bilayers are natural barriers of biological cells and cellular compartments. Membrane proteins integrated in biological membranes enable vital cell functions such as signal transduction and the transport of ions or small molecules. In order to determine the activity of a protein of interest at defined conditions, the membrane protein has to be integrated into artificial lipid bilayers immobilized on a surface. For the fabrication of such biosensors expertise is required in material science, surface and analytical chemistry, molecular biology and biotechnology. Specifically, techniques are needed for structuring surfaces in the micro- and nanometer scale, chemical modification and analysis, lipid bilayer formation, protein expression, purification and solubilization, and most importantly, protein integration into engineered lipid bilayers. Electrochemical and optical methods are suitable to detect membrane activity-related signals. The importance of structural knowledge to understand membrane protein function is obvious. Presently only a few structures of membrane proteins are solved at atomic resolution. Functional assays together with known structures of individual membrane proteins will contribute to a better understanding of vital biological processes occurring at biological membranes. Such assays will be utilized in the discovery of drugs, since membrane proteins are major drug targets.
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23
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Wang X, Shindel MM, Wang SW, Ragan R. Elucidating driving forces for liposome rupture: external perturbations and chemical affinity. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012; 28:7417-7427. [PMID: 22509939 DOI: 10.1021/la300127m] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Atomic force microscopy (AFM) studies under aqueous buffer probed the role of chemical affinity between liposomes, consisting of large unilamellar vesicles, and substrate surfaces in driving vesicle rupture and tethered lipid bilayer membrane (tLBM) formation on Au surfaces. 1,2-Distearoyl-sn-glycero-3-phosphoethanolamine-N-poly(ethylene glycol)-2000-N-[3-(2-pyridyldithio) propionate] (DSPE-PEG-PDP) was added to 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) vesicles to promote interactions via Au-thiolate bond formation. Forces induced by an AFM tip leading to vesicle rupture on Au were quantified as a function of DSPE-PEG-PDP composition with and without osmotic pressure. The critical forces needed to initiate rupture of vesicles with 2.5, 5, and 10 mol % DSPE-PEG-PDP are approximately 1.1, 0.8, and 0.5 nN, respectively. The critical force needed for tLBM formation decreases from 1.1 nN (without osmotic pressure) to 0.6 nN (with an osmotic pressure due to 5 mM of CaCl(2)) for vesicles having 2.5 mol % DSPE-PEG-PDP. Forces as high as 5 nN did not lead to LBM formation from pure POPC vesicles on Au. DSPE-PEG-PDP appears to be important to anchor and deform vesicles on Au surfaces. This study demonstrates how functional lipids can be used to tune vesicle-surface interactions and elucidates the role of vesicle-substrate interactions in vesicle rupture.
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Affiliation(s)
- Xi Wang
- Department of Chemical Engineering and Materials Science, University of California, Irvine, California 92697-2575, USA
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24
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Fabre RM, Okeyo GO, Talham DR. Supported lipid bilayers at skeletonized surfaces for the study of transmembrane proteins. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012; 28:2835-2841. [PMID: 22229749 DOI: 10.1021/la204485n] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Skeletonized zirconium phosphonate surfaces are used to support planar lipid bilayers and are shown to be viable substrates for studying transmembrane proteins. The skeletonized surfaces provide space between the bilayer and the solid support to enable protein insertion and avoid denaturation. The skeletonized zirconium octadecylphosphonate surfaces were prepared using Langmuir-Blodgett techniques by mixing octadecanol with octadecylphosphonic acid. After zirconation of the transferred monolayer, rinsing the coating with organic solvent removes the octadecanol, leaving holes in the film ranging from ∼50 to ∼500 nm in diameter, depending on the octadecanol content. Upon subsequent deposition of a lipid bilayer, either by vesicle fusion or by Langmuir-Blodgett/Langmuir-Schaefer techniques, the lipid assemblies span the holes providing reservoirs beneath the bilayer. The viability of the supported bilayers as model membranes for transmembrane proteins was demonstrated by examining two approaches for incorporating the proteins. The BK channel protein inserts directly into a preformed bilayer on the skeletonized surface, in contrast to a bilayer on a nonskeletonized film, for which the protein associates only weakly. As a second approach, the integrin α(5)β(1) was reconstituted in lipid vesicles, and its inclusion in supported bilayers on the skeletonized surface was achieved by vesicle fusion. The integrin retains its ability to recognize the extracellular matrix protein fibronectin when supported on the skeletonized film, again in contrast to the response if the bilayer is supported on a nonskeletonized film.
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Affiliation(s)
- Roxane M Fabre
- Department of Chemistry, University of Florida, Gainesville, Florida 32611-7200, United States
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25
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Martin TA, Herman CT, Limpoco FT, Michael MC, Potts GK, Bailey RC. Quantitative photochemical immobilization of biomolecules on planar and corrugated substrates: a versatile strategy for creating functional biointerfaces. ACS APPLIED MATERIALS & INTERFACES 2011; 3:3762-71. [PMID: 21793535 PMCID: PMC3960923 DOI: 10.1021/am2009597] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Methods for the generation of substratespresenting biomolecules in a spatially controlled manner are enabling tools for applications in biosensor systems, microarray technologies, fundamental biological studies and biointerface science. We have implemented a method to create biomolecular patterns by using light to control the direct covalent immobilization of biomolecules onto benzophenone-modified glass substrates. We have generated substrates presenting up to three different biomolecules patterned in sequence, and demonstrate biomolecular photopatterning on corrugated substrates. The chemistry of the underlying monolayer was optimized to incorporate poly(ethylene glycol) to enable adhesive cell adhesion onto patterned extracellular matrix proteins. Substrates were characterized with contact angle goniometry, AFM, and immunofluorescence microscopy. Importantly, radioimmunoassays were performed to quantify the site density of immobilized biomolecules on photopatterned substrates. Retained function of photopatterned proteins was demonstrated both by native ligand recognition and cell adhesion to photopatterned substrates, revealing that substrates generated with this method are suitable for probing specific cell receptor-ligand interactions. This molecularly general photochemical patterning method is an enabling tool for the creation of substrates presenting both biochemical and topographical variation, which is an important feature of many native biointerfaces.
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Affiliation(s)
- Teresa A. Martin
- Department of Chemistry, University of Illinois at Urbana-Champaign, 600 S. Mathews Ave., Urbana, IL 61801
| | - Christine T. Herman
- Department of Chemistry, University of Illinois at Urbana-Champaign, 600 S. Mathews Ave., Urbana, IL 61801
| | - Francis T. Limpoco
- Department of Chemistry, University of Illinois at Urbana-Champaign, 600 S. Mathews Ave., Urbana, IL 61801
| | - Madeline C. Michael
- Department of Chemistry, University of Illinois at Urbana-Champaign, 600 S. Mathews Ave., Urbana, IL 61801
| | - Gregory K. Potts
- Department of Chemistry, University of Illinois at Urbana-Champaign, 600 S. Mathews Ave., Urbana, IL 61801
| | - Ryan C. Bailey
- Department of Chemistry, University of Illinois at Urbana-Champaign, 600 S. Mathews Ave., Urbana, IL 61801
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26
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Dhende VP, Samanta S, Jones DM, Hardin IR, Locklin J. One-step photochemical synthesis of permanent, nonleaching, ultrathin antimicrobial coatings for textiles and plastics. ACS APPLIED MATERIALS & INTERFACES 2011; 3:2830-7. [PMID: 21692449 DOI: 10.1021/am200324f] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Antimicrobial copolymers of hydrophobic N-alkyl and benzophenone containing polyethylenimines were synthesized from commercially available linear poly(2-ethyl-2-oxazoline), and covalently attached to surfaces of synthetic polymers, cotton, and modified silicon oxide using mild photo-cross-linking. Specifically, these polymers were applied to polypropylene, poly(vinyl chloride), polyethylene, cotton, and alkyl-coated oxide surfaces using solution casting or spray coating and then covalently cross-linked rendering permanent, nonleaching antimicrobial surfaces. The photochemical grafting of pendant benzophenones allows immobilization to any surface that contains a C-H bond. Incubating the modified materials with either Staphylococcus aureus or Escherichia coli demonstrated that the modified surfaces had substantial antimicrobial capacity against both Gram-positive and Gram-negative bacteria (>98% microbial death).
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Affiliation(s)
- Vikram P Dhende
- Department of Chemistry and Faculty of Engineering, University of Georgia , Athens, Georgia 30602, United States
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27
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Ross EE, Mok SW, Bugni SR. Assembly of lipid bilayers on silica and modified silica colloids by reconstitution of dried lipid films. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2011; 27:8634-8644. [PMID: 21634797 DOI: 10.1021/la200952c] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
A method is presented for the assembly of lipid bilayers on silica colloids via reconstitution of dried lipid films solvent-cast from chloroform within packed beds of colloids ranging from 100 nm to 10 μm in diameter. Rapid solvent evaporation from the packed bed void volume results in uniform distribution of dried lipid throughout the colloidal bed. Fluorescence measurements indicate that significant, if not quantitative, retention of DOPC or DPPC films cast between sub-bilayer and multilayer quantities occurs when the colloids are redispersed in aqueous solution. Phospholipid bilayers assembled in this manner are shown to effectively passivate the surface of 250 nm colloids to nonspecific adsorption of bovine serum albumin. The method is shown to be capable of preparing supported bilayers on colloid surfaces that do not generally support vesicle fusion such as poly(ethylene glycol) (PEG) modified silica colloids. Bilayers of lipids that have not been reported to self-assemble by vesicle fusion, including gel-phase lipids and single-chain diacetylene amphiphiles, can also be formed by this method. The utility of the solid-core support is demonstrated by the facile assembly of supported lipid bilayers within fused silica capillaries to generate materials that are potentially suitable for the analysis of membrane interactions in a microchannel format.
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Affiliation(s)
- Eric E Ross
- Department of Chemistry & Biochemistry, Gonzaga University, Spokane, Washington 99258, United States.
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28
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Herman CT, Potts GK, Michael MC, Tolan NV, Bailey RC. Probing dynamic cell-substrate interactions using photochemically generated surface-immobilized gradients: application to selectin-mediated leukocyte rolling. Integr Biol (Camb) 2011; 3:779-91. [PMID: 21614364 PMCID: PMC3960975 DOI: 10.1039/c0ib00151a] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Model substrates presenting biochemical cues immobilized in a controlled and well-defined manner are of great interest for their applications in biointerface studies that elucidate the molecular basis of cell receptor-ligand interactions. Herein, we describe a direct, photochemical method to generate surface-immobilized biomolecular gradients that are applied to the study of selectin-mediated leukocyte rolling. The technique employs benzophenone-modified glass substrates, which upon controlled exposure to UV light (350-365 nm) in the presence of protein-containing solutions facilitate the generation of covalently immobilized protein gradients. Conditions were optimized to generate gradient substrates presenting P-selectin and PSGL-1 (P-selectin glycoprotein ligand-1) immobilized at site densities over a 5- to 10-fold range (from as low as ∼200 molecules μm(-2) to as high as 6000 molecules μm(-2)). The resulting substrates were quantitatively characterized via fluorescence analysis and radioimmunoassays before their use in the leukocyte rolling assays. HL-60 promyelocytes and Jurkat T lymphocytes were assessed for their ability to tether to and roll on substrates presenting immobilized P-selectin and PSGL-1 under conditions of physiologically relevant shear stress. The results of these flow assays reveal the combined effect of immobilized protein site density and applied wall shear stress on cell rolling behavior. Two-component substrates presenting P-selectin and ICAM-1 (intercellular adhesion molecule-1) were also generated to assess the interplay between these two proteins and their effect on cell rolling and adhesion. These proof-of-principle studies verify that the described gradient generation approach yields well-defined gradient substrates that present immobilized proteins over a large range of site densities that are applicable for investigation of cell-materials interactions, including multi-parameter leukocyte flow studies. Future applications of this enabling methodology may lead to new insights into the biophysical phenomena and molecular mechanism underlying complex biological processes such as leukocyte recruitment and the inflammatory response.
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Affiliation(s)
- Christine T. Herman
- Department of Chemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, IL 61801, USA. Tel: 217-333-0676
| | - Gregory K. Potts
- Department of Chemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, IL 61801, USA. Tel: 217-333-0676
| | - Madeline C. Michael
- Department of Chemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, IL 61801, USA. Tel: 217-333-0676
| | - Nicole V. Tolan
- Department of Chemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, IL 61801, USA. Tel: 217-333-0676
| | - Ryan C. Bailey
- Department of Chemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, IL 61801, USA. Tel: 217-333-0676
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29
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Sumino A, Dewa T, Takeuchi T, Sugiura R, Sasaki N, Misawa N, Tero R, Urisu T, Gardiner AT, Cogdell RJ, Hashimoto H, Nango M. Construction and structural analysis of tethered lipid bilayer containing photosynthetic antenna proteins for functional analysis. Biomacromolecules 2011; 12:2850-8. [PMID: 21650465 DOI: 10.1021/bm200585y] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The construction and structural analysis of a tethered planar lipid bilayer containing bacterial photosynthetic membrane proteins, light-harvesting complex 2 (LH2), and light-harvesting core complex (LH1-RC) is described and establishes this system as an experimental platform for their functional analysis. The planar lipid bilayer containing LH2 and/or LH1-RC complexes was successfully formed on an avidin-immobilized coverglass via an avidin-biotin linkage. Atomic force microscopy (AFM) showed that a smooth continuous membrane was formed there. Lateral diffusion of these membrane proteins, observed by a fluorescence recovery after photobleaching (FRAP), is discussed in terms of the membrane architecture. Energy transfer from LH2 to LH1-RC within the tethered membrane was observed by steady-state fluorescence spectroscopy, indicating that the tethered membrane can mimic the natural situation.
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Affiliation(s)
- Ayumi Sumino
- Department of Frontier Materials, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555, Japan
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30
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Poudel KR, Keller DJ, Brozik JA. Single particle tracking reveals corralling of a transmembrane protein in a double-cushioned lipid bilayer assembly. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2011; 27:320-327. [PMID: 21141848 DOI: 10.1021/la104133m] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
A predominate question associated with supported bilayer assemblies containing proteins is whether or not the proteins remain active after incorporation. The major cause for concern is that strong interactions with solid supports can render the protein inactive. To address this question, a large transmembrane protein, the serotonin receptor, 5HT(3A), has been incorporated into several supported membrane bilayer assemblies of increasing complexity. The 5HT(3A) receptor has large extracellular domains on both sides of the membrane, which could cause strong interactions. The bilayer assemblies include a simple POPC (1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine) supported planar bilayer, a “single-cushion” POPC bilayer with a PEG (poly(ethylene glycol)) layer between membrane and support, and a “double-cushion” POPC bilayer with both a PEG layer and a layer of BSA (bovine serum albumin). Single-cushion systems are designed to lift the bilayer from the surface, and double-cushion systems are designed to both lift the membrane and passivate the solid support. As in previously reported work, protein mobilities measured by ensemble fluorescence recovery after photobleaching (FRAP) are quite low, especially in the double-cushion system. But single-particle tracking of fluorescent 5HT(3A) molecules shows that individual proteins in the double-cushion system have quite high local mobilities but are spatially confined within small corralling domains (<r(C)2> 450 nm). Comparisons with the simple POPC membrane and the single-cushion POPC−PEG membrane reveal that BSA both serves to minimize interactions with the solid support and creates the corrals that reduce the long-range (ensemble averaged) mobility of large transmembrane proteins. These results suggest that in double-cushion assemblies proteins with large extra-membrane domains may remain active and unperturbed despite low bulk diffusion constants.
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Affiliation(s)
- Kumud R Poudel
- Department of Chemistry, Washington State University, PO Box 644630, Pullman, Washington 99164-4630, United States
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31
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Jose B, Mallon CT, Forster RJ, Blackledge C, Keyes TE. Lipid bilayer assembly at a gold nanocavity array. Chem Commun (Camb) 2011; 47:12530-2. [DOI: 10.1039/c1cc15709d] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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32
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Wang X, Shindel MM, Wang SW, Ragan R. A facile approach for assembling lipid bilayer membranes on template-stripped gold. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2010; 26:18239-18245. [PMID: 21050009 DOI: 10.1021/la102774n] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Lipid vesicles are designed with functional chemical groups to promote vesicle fusion on template-stripped gold (TS Au) surfaces that does not spontaneously occur on unfunctionalized Au surfaces. Three types of vesicles were exposed to TS Au surfaces: (1) vesicles composed of only 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) lipids; (2) vesicles composed of lipid mixtures of 2.5 mol % of 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-poly(ethylene glycol)-2000-N-[3-(2-pyridyldithio)propionate] (DSPE-PEG-PDP) and 97.5 mol % of POPC; and (3) vesicles composed of 2.5 mol % of 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy(poly(ethylene glycol))-2000] (DSPE-PEG) and 97.5 mol % POPC. Atomic force microscopy (AFM) topography and force spectroscopy measurements acquired in a fluid environment confirmed tethered lipid bilayer membrane (tLBM) formation only for vesicles composed of 2.5 mol % DSPE-PEG-PDP/97.5 mol % POPC, thus indicating that the sulfur-containing PDP group is necessary to achieve tLBM formation on TS Au via Au-thiolate bonds. Analysis of force-distance curves for 2.5 mol % DSPE-PEG-PDP/97.5 mol % POPC tLBMs on TS Au yielded a breakthrough distance of 4.8 ± 0.4 nm, which is about 1.7 nm thicker than that of POPC lipid bilayer membrane formed on mica. Thus, the PEG group serves as a spacer layer between the tLBM and the TS Au surface. Fluorescence microscopy results indicate that these tLBMs also have greater mechanical stability than solid-supported lipid bilayer membranes made from the same vesicles on mica. The described process for assembling stable tLBMs on Au surfaces is compatible with microdispensing used in array fabrication.
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Affiliation(s)
- Xi Wang
- Department of Chemical Engineering and Materials Science, University of California, Irvine, California 92697-2575, United States
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33
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Progress report on microstructured surfaces based on chemical vapor deposition. Methods Mol Biol 2010. [PMID: 20967636 DOI: 10.1007/978-1-59745-551-0_16] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
This book chapter discusses recent advances in the fabrication of microscale surface patterns using chemical vapor deposition polymerization. Reactive poly(p-xylylene) (PPX) coatings are useful for their ability to immobilize specific biomolecules, as determined by the PPX functional group. PPXs can either be modified postdeposition, or they can be patterned onto a substrate in situ. Specific methods discussed in this progress report include microcontact printing, vapor-assisted micropatterning in replica structures, projection lithography-based patterning, and selective polymer deposition.
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34
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Surface patterning strategies for microfluidic applications based on functionalized poly-p-xylylenes. Bioanalysis 2010; 2:1717-28. [DOI: 10.4155/bio.10.124] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Microfluidic systems require precise surface modification in order to tailor the interfacial properties. For instance, in lab-on-a-chip research, defined surface chemistry is key to minimizing contamination and to increasing signal-to-noise ratios for bioconjugation schemes. Device efficiency and analytical output can also be maximized with devices that have defined surfaces. Similarly, minimizing biofouling is also crucial to suppress background noise and ensure device functions. Once defined, surface properties have been engineered, microstructuring of surfaces can provide defined microenvironments for cell-based culture systems. In this report, we highlight the use of functionalized poly-p-xylylenes for surface modification with a specific focus on microfluidic systems. Functionalized poly-p-xylylenes constitute a versatile group of reactive coatings that can provide a defined chemical makeup of substrate surfaces irrespective of underlying bulk material properties. Recent advances using reactive coatings for surface modification of microfluidics are introduced, including use as nonfouling coatings, fabrication of patterned surfaces, functionalization of previously assembled devices, as well as device-bonding applications.
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35
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Kataoka-Hamai C, Higuchi M, Iwai H, Miyahara Y. Detergent-mediated formation of polymer-supported phospholipid bilayers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2010; 26:14600-14605. [PMID: 20726608 DOI: 10.1021/la102151p] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Supported phospholipid bilayers can be formed by established methods such as vesicle fusion and the Langmuir-Blodgett (LB) technique. However, challenges remain in regards to creating supported bilayers from various lipid compositions, using various support surfaces, and incorporating membrane proteins. Here we report a detergent removal method as an alternative means of supported bilayer formation. The process consists of three steps: (1) incubation of phospholipid-poly(ethylene glycol) (PEG)-grafted glass with lipid-detergent micelles; (2) detergent removal by washing the surface with vesicles; and (3) incubation with the vesicles to complete lipid adsorption. These procedures yielded fluid planar bilayers of zwitterionic lipids. Because fluid structures were not obtained by vesicle fusion, the detergent seemed necessary to produce the polymer-supported bilayers. While anionic phospholipids inhibited the attachment of fluid bilayers in the absence of calcium ions, supported bilayers with almost full mobility were obtained from lipid mixtures containing 10-20 mol % anionic lipids in the presence of calcium ions. The incorporation of the anionic lipids in the bulk-facing leaflet was demonstrated by the binding of dye-labeled annexin V.
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Affiliation(s)
- Chiho Kataoka-Hamai
- Biomaterials Center, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
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36
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Structural characterization of an elevated lipid bilayer obtained by stepwise functionalization of a self-assembled alkenyl silane film. Biointerphases 2010; 2:109-18. [PMID: 20408645 DOI: 10.1116/1.2790852] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
This work reports a novel tethered lipid membrane supported on silicon oxide providing an improved model cell membrane. There is an increasing need for robust solid supported fluid model membranes that can be easily deposited on soft cushions. In such architecture the space between the membrane and the substrate should be tunable in the nanometer range. For this purpose a SiO(2) surface was functionalized with poly(ethylene glycol) (PEG)-lipid tethers and further modified with poly(ethylene glycol) making a biologically passivated substrate available for lipid bilayer deposition. First, a short chain self-assembled alkenyl silane film was oxidized to yield terminal COOH groups and then functionalized with amino-terminated PEG-lipids via N-hydroxysuccinimide chemistry. The functionalized silane film was then additionally passivated by functionalization of unreacted COOH groups with amino-terminated PEG of variable chain length. X-ray photoelectron spectroscopy (XPS) analysis of dry films, carried out near the C 1s ionization edge to characterize chemical groups formed in the near-surface region, confirmed binding of PEG-lipid tethers to the silane film. XPS further indicated that backfilling with PEG caused the lipid tails to stick up above the PEG layer which was confirmed by the x-ray reflectivity measurements. Lipid vesicle fusion on these surfaces in the presence of excess water resulted in the formation of supported membranes characterized by very high homogeneity and long range mobility, as confirmed by fluorescence bleaching experiments. Even after repeated drying-hydrating cycles, these robust surfaces provided good templates for high fluidity elevated membranes. X-ray reflectivity measurements of the tethered membranes, with a resolution of 0.6 nm in water, showed that these fluid membranes are elevated up to 8 nm above the silicon oxide surface.
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Lin J, Szymanski J, Searson PC, Hristova K. Effect of a polymer cushion on the electrical properties and stability of surface-supported lipid bilayers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2010; 26:3544-8. [PMID: 20175577 DOI: 10.1021/la903232b] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
A robust biomimetic cell membrane platform is critical for mechanistic studies of membrane protein channels. While polymer cushions are believed to facilitate the incorporation of membrane proteins in such a platform, a systematic characterization and optimization of such cushions is rarely performed. Here, we examine the influence of a polymer cushion on the electrical properties of supported 1,2-diphytanoyl-sn-glycero-3-phosphocholine (DPhPC) bilayers produced via a Langmuir-Blodgett deposition/vesicle fusion assembly process on single-crystal silicon. We show that the resistance of DPhPC bilayers is maximized at the calculated crossover concentration of the polymer (5.9 mol % PEG-lipids). Additionally, these bilayers are sufficiently stable to allow impedance analyses to be performed for nearly 3 weeks. These studies reveal the optimal PEG concentration that yields electrically robust bilayers and demonstrate the utility of the platform for future studies of membrane protein channels and membrane active peptides.
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Affiliation(s)
- Janice Lin
- Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, Maryland 21218, USA
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Ye Q, Konradi R, Textor M, Reimhult E. Liposomes tethered to omega-functional PEG brushes and induced formation of PEG brush supported planar lipid bilayers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2009; 25:13534-9. [PMID: 19736981 DOI: 10.1021/la902039g] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Self-assembly of planar supported lipid bilayers on top of hydrophilic polymer brushes is a desirable alternative to solid supported lipid bilayers and covalently tethered lipid bilayers for applications like sensing on transmembrane proteins which require a large aqueous volume between membrane and substrate. We present a simple dip-and-rinse method to produce poly(ethylene glycol) (PEG) brushes with sparse positively charged hydrophobic tethers, using poly(l-lysine)-graft-poly(ethylene glycol)-quaternary ammonium compound copolymers. The interaction of such polymer coatings with liposomes of different compositions and the conditions for formation of planar lipid bilayers of extraordinarily high fluidity on top of the >10 nm thick reservoir by liposome self-assembly and sequentially triggered rupture are investigated.
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Affiliation(s)
- Qiong Ye
- Swiss Federal Institute of Technology, Laboratory for Surface Science and Technology, Wolfgang-Pauli-Strasse 10, CH-8093 Zurich, Switzerland
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Tang Y, Wang Z, Xiao J, Yang S, Wang YJ, Tong P. Studies of Phospholipid Vesicle Deposition/Transformation on a Polymer Surface by Dissipative Quartz Crystal Microbalance and Atomic Force Microscopy. J Phys Chem B 2009; 113:14925-33. [DOI: 10.1021/jp9068224] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Toh CR, Fraterman TA, Walker DA, Bailey RC. Direct biophotolithographic method for generating substrates with multiple overlapping biomolecular patterns and gradients. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2009; 25:8894-8. [PMID: 19601565 PMCID: PMC3960942 DOI: 10.1021/la9019537] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
We describe an approach to generate multicomponent surface-immobilized patterns and gradients on the basis of the photochemically controlled covalent coupling of solution-phase biomolecules to benzophenone-modified substrates. Gradients were simply achieved by continuously varying the exposure to nondamaging UV light across the surface with the gradient profile controlled by biomolecule concentration and the spatial and temporal illumination of the surface. Sequential exposure of the same surface in the presence of different biomolecules resulted in overlapping patterns and gradients of proteins and carbohydrates. Finally, we preliminarily demonstrate that the resulting surfaces are suitable for generating model substrates to probe cell-substrate interactions.
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Gao Y, Nie Z, Li H. Synthesis of syndiotactic polystyrene-graft-poly(ethylene glycol) copolymer by photochemical reaction. JOURNAL OF POLYMER RESEARCH 2009. [DOI: 10.1007/s10965-009-9277-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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42
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Hoopes MI, Deserno M, Longo ML, Faller R. Coarse-grained modeling of interactions of lipid bilayers with supports. J Chem Phys 2009; 129:175102. [PMID: 19045374 DOI: 10.1063/1.3008060] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We characterize the differences between supported and unsupported lipid bilayer membranes using a mesoscopic simulation model and a simple particle-based realization for a flat support on to which the lipids are adsorbed. We show that the nanometer roughness of the support affects membrane binding strength very little. We then compare the lipid distributions and pressure profiles of free and supported membranes. The surface localization of the proximal leaflet breaks the symmetry seen in a free bilayer, and we quantify the entropic penalty for binding and the increased lateral compression modulus.
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Affiliation(s)
- Matthew I Hoopes
- Graduate Group in Biophysics, University of California, Davis, California 95616, USA
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Majd S, Mayer M. Generating Arrays with High Content and Minimal Consumption of Functional Membrane Proteins. J Am Chem Soc 2008; 130:16060-4. [DOI: 10.1021/ja8055485] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Sheereen Majd
- Departments of Biomedical Engineering and Chemical Engineering, University of Michigan, Ann Arbor, Michigan 48109-2110
| | - Michael Mayer
- Departments of Biomedical Engineering and Chemical Engineering, University of Michigan, Ann Arbor, Michigan 48109-2110
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Diaz AJ, Albertorio F, Daniel S, Cremer PS. Double cushions preserve transmembrane protein mobility in supported bilayer systems. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2008; 24:6820-6. [PMID: 18510376 PMCID: PMC3475160 DOI: 10.1021/la800018d] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Supported lipid bilayers (SLBs) have been widely used as model systems to study cell membrane processes because they preserve the same 2D membrane fluidity found in living cells. One of the most significant limitations of this platform, however, is its inability to incorporate mobile transmembrane species. It is often postulated that transmembrane proteins reconstituted in SLBs lose their mobility because of direct interactions between the protein and the underlying substrate. Herein, we demonstrate a highly mobile fraction for a transmembrane protein, annexin V. Our strategy involves supporting the lipid bilayer on a double cushion, where we not only create a large space to accommodate the transmembrane portion of the macromolecule but also passivate the underlying substrate to reduce nonspecific protein-substrate interactions. The thickness of the confined water layer can be tuned by fusing vesicles containing polyethyleneglycol (PEG)-conjugated lipids of various molecular weights to a glass substrate that has first been passivated with a sacrificial layer of bovine serum albumin (BSA). The 2D fluidity of these systems was characterized by fluorescence recovery after photobleaching (FRAP) measurements. Uniform, mobile phospholipid bilayers with lipid diffusion coefficients of around 3 x 10(-8) cm2/s and percent mobile fractions of over 95% were obtained. Moreover, we obtained annexin V diffusion coefficients that were also around 3 x 10(-8) cm2/s with mobile fractions of up to 75%. This represents a significant improvement over bilayer platforms fabricated directly on glass or using single cushion strategies.
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Affiliation(s)
- Arnaldo J. Diaz
- Department of Chemistry, Texas A&M University, College Station, Texas 77843
| | | | - Susan Daniel
- Department of Chemistry, Texas A&M University, College Station, Texas 77843
| | - Paul S. Cremer
- Department of Chemistry, Texas A&M University, College Station, Texas 77843
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Chen HY, Rouillard JM, Gulari E, Lahann J. Colloids with high-definition surface structures. Proc Natl Acad Sci U S A 2007; 104:11173-8. [PMID: 17592149 PMCID: PMC2040871 DOI: 10.1073/pnas.0702749104] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2007] [Indexed: 11/18/2022] Open
Abstract
Compared with the well equipped arsenal of surface modification methods for flat surfaces, techniques that are applicable to curved, colloidal surfaces are still in their infancy. This technological gap exists because spin-coating techniques used in traditional photolithographic processes are not applicable to the curved surfaces of spherical objects. By replacing spin-coated photoresist with a vapor-deposited, photodefinable polymer coating, we have now fabricated microstructured colloids with a wide range of surface patterns, including asymmetric and chiral surface structures, that so far were typically reserved for flat substrates. This high-throughput method can yield surface-structured colloidal particles at a rate of approximately 10(7) to 10(8) particles per operator per day. Equipped with spatially defined binding pockets, microstructured colloids can engage in programmable interactions, which can lead to directed self-assembly. The ability to create a wide range of colloids with both simple and complex surface patterns may contribute to the genesis of previously unknown colloidal structures and may have important technological implications in a range of different applications, including photonic and phononic materials or chemical sensors.
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Affiliation(s)
| | | | | | - Joerg Lahann
- Departments of Chemical Engineering
- Materials Science and Engineering, and
- Macromolecular Science and Engineering, University of Michigan, Ann Arbor, MI 48109
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Kang E, Park JW, McClellan S, Kim JM, Holland D, Lee GU, Franses E, Park K, Thompson DH. Specific adsorption of histidine-tagged proteins on silica surfaces modified with Ni2+/NTA-derivatized poly(ethylene glycol). LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2007; 23:6281-8. [PMID: 17444666 PMCID: PMC2533260 DOI: 10.1021/la063719e] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Silica surfaces modified with nitrilotriacetic acid (NTA)-polyethylene glycol (PEG) derivatives were used to immobilize hexahistidine-tagged green fluorescent protein (His6-GFP), biotin/streptavidin-AlexaFluor555 (His6-biotin/SA-AF), and gramicidin A-containing vesicles (His6-gA). Three types of surface-reactive PEG derivatives-NTA-PEG3400-Si(OMe)3, NTA-PEG3400-vinylsulfone, and mPEG5000-Si(OMe)3 (control)-were grafted onto silica and tested for their ability to capture His6-tag species via His6/Ni2+/NTA chelation. The composition and thicknesses of the PEG-modified surfaces were characterized using X-ray photoelectron spectroscopy, contact angle, and ellipsometry. Protein capture efficiencies of the NTA-PEG-grafted surfaces were evaluated by measuring fluorescence intensities of these surfaces after exposure to His6-tag species. XPS and ellipsometry data indicate that surface adsorption occurs via specific interactions between the His6-tag and the Ni2+/NTA-PEG-grafted surface. Protein immobilization was most effective for NTA-PEG3400-Si(OMe)3-modified surfaces, with maximal areal densities achieved at 45 pmol/cm2 for His6-GFP and 95 fmol/cm2 for His6-biotin/SA-AF. Lipid vesicles containing His6-gA in a 1:375 gA/lipid ratio could also be immobilized on Ni2+/NTA-PEG3400-Si(OMe)3-modified surfaces at 0.5 mM total lipid. Our results suggest that NTA-PEG-Si(OMe)3 conjugates may be useful tools for immobilizing His6-tag proteins on solid surfaces to produce protein-functionalized surfaces.
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Affiliation(s)
- Eunah Kang
- School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907
| | - Jin-won Park
- School of Chemical Engineering, Purdue University, West Lafayette, IN 47907
| | - Scott McClellan
- School of Chemical Engineering, Purdue University, West Lafayette, IN 47907
| | - Jong-Mok Kim
- Department of Chemistry, Purdue University, West Lafayette, IN 47907
| | - David Holland
- Department of Chemistry, Purdue University, West Lafayette, IN 47907
| | - Gil U. Lee
- School of Chemical Engineering, Purdue University, West Lafayette, IN 47907
| | - Elias Franses
- School of Chemical Engineering, Purdue University, West Lafayette, IN 47907
| | - Kinam Park
- School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907
- Department of Pharmaceutics, Purdue University, West Lafayette, IN 47907
| | - David H. Thompson
- Department of Chemistry, Purdue University, West Lafayette, IN 47907
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Hwang LY, Götz H, Hawker CJ, Frank CW. Glyco-acrylate copolymers for bilayer tethering on benzophenone-modified substrates. Colloids Surf B Biointerfaces 2007; 54:127-35. [PMID: 17207977 DOI: 10.1016/j.colsurfb.2006.08.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2006] [Revised: 08/05/2006] [Accepted: 08/08/2006] [Indexed: 11/17/2022]
Abstract
Model biological membranes are becoming increasingly important for studying fundamental biophysical phenomena and developing membrane-based devices. To address the anticipated problem of non-physiological interactions between membrane proteins and substrates seen in "solid-supported lipid bilayers" that are formed directly on hydrophilic substrates, we have developed a polymer-tethered lipid bilayer system based on a random copolymer with multiple lipid analogue anchors and a glyco-acrylate backbone. This system is targeted at applications that, most importantly, require stability and robustness since each copolymer has multiple lipid analogues that insert into the bilayer. We have combined this copolymer with a flexible photochemical coupling scheme that covalently attaches the copolymer to the substrate. The Langmuir isotherms of mixed copolymer/free lipid monolayers measured at the air-water interface indicate that the alkyl chains of the copolymer lipid analogues and the free lipids dominate the film behavior. In addition, no significant phase transitions are seen in the isotherms, while hysteresis experiments confirm that no irreversible states are formed during the monolayer compression. Isobaric creep experiments at the air-water interface and AFM experiments of the transferred monolayer are used to guide processing parameters for creating a fluid, homogeneous bilayer. Bilayer homogeneity and fluidity are monitored using fluorescence microscopy. Continuous bilayers with lateral diffusion coefficients of 0.6 microm(2)/s for both leaflets of the bilayer are observed for a 5% copolymer system.
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Affiliation(s)
- Lisa Y Hwang
- Department of Chemical Engineering, Stanford University, 381 North-South Mall, Stanford, CA 94305-5025, USA
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Sheikh KH, Christenson HK, Bushby RJ, Evans SD. A Model System To Study the Insertion of Cholesterol into a Phospholipid Monolayer. J Phys Chem B 2006; 111:379-86. [PMID: 17214489 DOI: 10.1021/jp0636423] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Colloidal probe atomic force microscopy (AFM) was used to study the interaction between a surface bearing tethered cholesterol groups and an egg phosphatidylcholine (egg-PC) monolayer. The cholesterol bearing surface was comprised of a mixed self-assembled monolayer comprised of O-cholesteryl N-(8'-mecapto-3',6'-dioxaoctyl)carbamate (CPEO3) molecules and beta-mercaptoethanol formed on a 20 mum diameter gold-coated silica particle. The egg-PC monolayer was adsorbed onto an octadecylthiol monolayer formed on template-stripped gold. The force between the surfaces, as a function of separation, was measured for surface concentrations of CPEO3 from 0 to 100 mol %. At all concentrations there was a long-range repulsive double-layer force due to weak surface charges. At surface concentrations of CPEO3 from 1 to 29 mol % the interaction on the approach of the surfaces showed a maximum in the repulsive force, followed by a small (2-5 nm) jump into a force minimum corresponding to adhesion of the surfaces. On separation, a normalized pull-off force of 1.0-1.6 mN m(-1) was measured. Over the same concentration range, the calculated interaction energy per CPEO3 molecule decreased from 1.1 +/- 0.2 kT to 0.04 kT. At surface concentrations of 35 mol % and above there was no reproducible adhesion between the cholesterol-bearing surface and the phospholipid monolayer. We attribute the occurrence of short-range attraction and adhesion in the 1-29 mol % regime to the insertion of (some) cholesterol groups into the phospholipid monolayer. At higher surface concentrations the efficiency of insertion is reduced due to steric effects. We discuss the experimental results in the light of the energetics of the insertion of a cholesterol molecule into a lipid bilayer.
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Affiliation(s)
- Khizar H Sheikh
- School of Physics and Astronomy and Centre for Self-Organising Molecular Systems, The University of Leeds, Leeds LS2 9JT, United Kingdom
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50
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Castellana ET, Cremer PS. Solid supported lipid bilayers: From biophysical studies to sensor design. SURFACE SCIENCE REPORTS 2006; 61:429-444. [PMID: 32287559 PMCID: PMC7114318 DOI: 10.1016/j.surfrep.2006.06.001] [Citation(s) in RCA: 736] [Impact Index Per Article: 40.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2006] [Accepted: 06/27/2006] [Indexed: 05/18/2023]
Abstract
The lipid bilayer is one of the most eloquent and important self-assembled structures in nature. It not only provides a protective container for cells and sub-cellular compartments, but also hosts much of the machinery for cellular communication and transport across the cell membrane. Solid supported lipid bilayers provide an excellent model system for studying the surface chemistry of the cell. Moreover, they are accessible to a wide variety of surface-specific analytical techniques. This makes it possible to investigate processes such as cell signaling, ligand-receptor interactions, enzymatic reactions occurring at the cell surface, as well as pathogen attack. In this review, the following membrane systems are discussed: black lipid membranes, solid supported lipid bilayers, hybrid lipid bilayers, and polymer cushioned lipid bilayers. Examples of how supported lipid membrane technology is interfaced with array based systems by photolithographic patterning, spatial addressing, microcontact printing, and microfluidic patterning are explored. Also, the use of supported lipid bilayers in microfluidic devices for the development of lab-on-a-chip based platforms is examined. Finally, the utility of lipid bilayers in nanotechnology and future directions in this area are discussed.
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Affiliation(s)
- Edward T. Castellana
- Department of Chemistry, Texas A & M University, College Station, TX 77843, United States
| | - Paul S. Cremer
- Department of Chemistry, Texas A & M University, College Station, TX 77843, United States
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