1
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Transdermal diffusion of resveratrol by multilamellar liposomes: Effect of encapsulation on its stability. J Drug Deliv Sci Technol 2022. [DOI: 10.1016/j.jddst.2022.103742] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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2
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Shetty S, Yandrapalli N, Pinkwart K, Krafft D, Vidakovic-Koch T, Ivanov I, Robinson T. Directed Signaling Cascades in Monodisperse Artificial Eukaryotic Cells. ACS NANO 2021; 15:15656-15666. [PMID: 34570489 PMCID: PMC8552445 DOI: 10.1021/acsnano.1c04219] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Indexed: 05/28/2023]
Abstract
The bottom-up assembly of multicompartment artificial cells that are able to direct biochemical reactions along a specific spatial pathway remains a considerable engineering challenge. In this work, we address this with a microfluidic platform that is able to produce monodisperse multivesicular vesicles (MVVs) to serve as synthetic eukaryotic cells. Using a two-inlet polydimethylsiloxane channel design to co-encapsulate different populations of liposomes we are able to produce lipid-based MVVs in a high-throughput manner and with three separate inner compartments, each containing a different enzyme: α-glucosidase, glucose oxidase, and horseradish peroxidase. We demonstrate the ability of these MVVs to carry out directed chemical communication between the compartments via the reconstitution of size-selective membrane pores. Therefore, the signal transduction, which is triggered externally, follows a specific spatial pathway between the compartments. We use this platform to study the effects of enzyme cascade compartmentalization by direct analytical comparison between bulk, one-, two-, and three-compartment systems. This microfluidic strategy to construct complex hierarchical structures is not only suitable to study compartmentalization effects on biochemical reactions but is also applicable for developing advanced drug delivery systems as well as minimal cells in the field of bottom-up synthetic biology.
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Affiliation(s)
- Sunidhi
C. Shetty
- Theory
and Bio-Systems, Max Planck Institute of
Colloids and Interfaces, Am Mühlenberg 1, 14476 Potsdam, Germany
| | - Naresh Yandrapalli
- Theory
and Bio-Systems, Max Planck Institute of
Colloids and Interfaces, Am Mühlenberg 1, 14476 Potsdam, Germany
| | - Kerstin Pinkwart
- Theory
and Bio-Systems, Max Planck Institute of
Colloids and Interfaces, Am Mühlenberg 1, 14476 Potsdam, Germany
| | - Dorothee Krafft
- Max
Planck Institute for Dynamics of Complex Technical Systems, Sandtorstrasse 1, 39106 Magdeburg, Germany
| | - Tanja Vidakovic-Koch
- Max
Planck Institute for Dynamics of Complex Technical Systems, Sandtorstrasse 1, 39106 Magdeburg, Germany
| | - Ivan Ivanov
- Max
Planck Institute for Dynamics of Complex Technical Systems, Sandtorstrasse 1, 39106 Magdeburg, Germany
| | - Tom Robinson
- Theory
and Bio-Systems, Max Planck Institute of
Colloids and Interfaces, Am Mühlenberg 1, 14476 Potsdam, Germany
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3
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What is the fate of multi-lamellar liposomes of controlled size, charge and elasticity in artificial and animal skin? Eur J Pharm Biopharm 2020; 151:18-31. [DOI: 10.1016/j.ejpb.2020.03.017] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 03/17/2020] [Accepted: 03/22/2020] [Indexed: 11/21/2022]
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4
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Tsubone TM, Baptista MS, Itri R. Understanding membrane remodelling initiated by photosensitized lipid oxidation. Biophys Chem 2019; 254:106263. [DOI: 10.1016/j.bpc.2019.106263] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Revised: 08/13/2019] [Accepted: 09/03/2019] [Indexed: 12/19/2022]
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5
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Emami S, Su WC, Purushothaman S, Ngassam VN, Parikh AN. Permeability and Line-Tension-Dependent Response of Polyunsaturated Membranes to Osmotic Stresses. Biophys J 2018; 115:1942-1955. [PMID: 30366629 DOI: 10.1016/j.bpj.2018.09.031] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Revised: 09/06/2018] [Accepted: 09/26/2018] [Indexed: 11/17/2022] Open
Abstract
The lipidome of plant plasma membranes-enriched in cellular phospholipids containing at least one polyunsaturated fatty acid tail and a variety of phytosterols and phytosphingolipids-is adapted to significant abiotic stresses. But how mesoscale membrane properties of these membranes such as permeability and deformability, which arise from their unique molecular compositions and corresponding lateral organization, facilitate response to global mechanical stresses is largely unknown. Here, using giant vesicles reconstituting mixtures of polyunsaturated lipids (soy phosphatidylcholine), glucosylceramide, and sitosterol common to plant membranes, we find that the membranes adopt "janus-like" domain morphologies and display anomalous solute permeabilities. The former textures the membrane with a single sterol-glucosylceramide-enriched, liquid-ordered domain separated from a liquid-disordered phase consisting primarily of soy phosphatidylcholine. When subject to osmotic downshifts, the giant unilamellar vesicles (GUVs) respond by transiently producing well-known swell-burst cycles. In each cycle, the influx of water swells the GUV, rendering the membrane tense. Subsequent rupture of the membrane through transient poration, which localizes in the liquid-disordered phase or at the domain boundaries, reduces the osmotic stress by expelling some of the excess osmolytes (and solvent) before sealing. When subject to abrupt hypertonic stress, they deform by nucleating buds at the domain phase boundaries. Remarkably, this incipient vesiculation is reversed in a statistically significant fraction of GUVs because of the interplay with solute permeation timescales, which render osmotic stresses short-lived. This, then, suggests a novel control mechanism in which an interplay of permeability and deformability regulates osmotically induced membrane deformation and limits vesiculation-induced loss of membrane material. Interestingly, recapitulation of such dynamic morphological reconfigurability-switching between budded and nonbudded morphologies-due to the interplay of membrane permeability, which temporally reverses the osmotic gradient, and domain boundaries, which select modes of deformations, might prove valuable in endowing synthetic cells with novel morphological responsiveness.
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Affiliation(s)
- Shiva Emami
- Departments of Biomedical Engineering, University of California, Davis, California; Chemical Engineering, University of California, Davis, California
| | - Wan-Chih Su
- Chemistry, University of California, Davis, California
| | - Sowmya Purushothaman
- Departments of Biomedical Engineering, University of California, Davis, California
| | - Viviane N Ngassam
- Departments of Biomedical Engineering, University of California, Davis, California
| | - Atul N Parikh
- Departments of Biomedical Engineering, University of California, Davis, California; Chemistry, University of California, Davis, California; Chemical Engineering, University of California, Davis, California; Materials Science & Engineering, University of California, Davis, California.
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6
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Cholesterol modulates the liposome membrane fluidity and permeability for a hydrophilic molecule. Food Chem Toxicol 2018; 113:40-48. [PMID: 29337230 DOI: 10.1016/j.fct.2018.01.017] [Citation(s) in RCA: 134] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Revised: 01/09/2018] [Accepted: 01/11/2018] [Indexed: 01/27/2023]
Abstract
The effect of cholesterol (CHOL) content on the permeability and fluidity of dipalmitoylphosphatidylcholine (DPPC) liposome membrane was investigated. Liposomes encapsulating sulforhodamine B (SRB), a fluorescent dye, were prepared by reverse phase evaporation technique (REV) at various DPPC:CHOL molar ratios (from 100:0 to 100:100). The release kinetics of SRB was studied during 48 h in buffer (pH 7.4) containing NaCl at 37 °C. The DPPC:CHOL formulations were also characterized for their size, polydispersity index and morphology. Increasing CHOL concentration induced an increase in the mean liposomes size accompanying with a shape transition from irregular to nanosized, regular and spherical vesicles. The release kinetics of SRB showed a biphasic pattern; the release data was then analyzed using different mathematical models. On the overall, the SRB release was governed by a non-Fickian diffusion during the first period (0-10 h) while it followed a Fickian diffusion between 10 and 48 h. Changes in DPPC liposome membrane fluidity of various batches (CHOL% 0, 10, 20, 30 and 100) were monitored by using 5- and 16 doxyl stearic acids (DSA) as spin labels. CHOL induced a decrease in the bilayer fluidity. Concisely, CHOL represents a critical component in modulating the release of hydrophilic molecules from lipid vesicles.
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7
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Cobo Solis AK, Correa NM, Molina PG. Determination of Benzyl-hexadecyldimethylammonium 1,4-Bis(2-ethylhexyl)sulfosuccinate Vesicle Permeability by Using Square Wave Voltammetry and an Enzymatic Reaction. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:12080-12086. [PMID: 28992699 DOI: 10.1021/acs.langmuir.7b03001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
This report describes the studies performed to determine the permeability coefficient value (P) of 1-naphthyl phosphate (1-NP) through the benzyl-hexadecyldimethylammonium 1,4-bis(2-ethylhexyl)sulfosuccinate (AOT-BHD) vesicle bilayer. 1-NP was added in the external phase and must cross the bilayer of the vesicle to react with the encapsulated enzyme (alkaline phosphatase) to yield 1-naphtholate (NPh-), the product of the enzymatic hydrolysis. This product is electrochemically detected, at basic pH value, by a square wave voltammetry technique, which can be a good alternative over the spectroscopic one, to measure the vesicle solutions because scattering (due to its turbidity) does not make any influence in the electrochemical signal. The experimental data allow us to propose a mathematical model, and a value of P = (1.00 ± 0.15) × 10-9 cm s-1 was obtained. Also, a value of P = (2.0 ± 0.5) × 10-9 cm s-1 was found by using an independent technique, ultraviolet-visible spectroscopy, for comparison. It is evident that the P values obtained from both the techniques are comparable (within the experimental error of both techniques) under the same experimental conditions. This study constitutes the first report of the 1-NP permeability determination in this new vesicle. We want to highlight the importance of the introduction of a new method and the electrochemical response of the product generated through an enzymatic reaction that occurs in the inner aqueous phase of the vesicle, where the enzyme is placed.
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Affiliation(s)
- Airam K Cobo Solis
- Departamento de Química, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto , Agencia Postal No. 3, 5800 Río Cuarto, Argentina
| | - N Mariano Correa
- Departamento de Química, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto , Agencia Postal No. 3, 5800 Río Cuarto, Argentina
| | - Patricia G Molina
- Departamento de Química, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto , Agencia Postal No. 3, 5800 Río Cuarto, Argentina
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8
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Luna MA, Silber JJ, Sereno L, Correa NM, Moyano F. Determining the substrate permeability through the bilayer of large unilamellar vesicles of DOPC. A kinetic study. RSC Adv 2016. [DOI: 10.1039/c6ra12847e] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
In this work we determine the permeability of DOPC vesicles in the presence of different cholesterol contents, by using the enzymatic hydrolysis of N-benzoyl-l-tyrosine p-nitroanilide catalyzed by α-chymotrypsin.
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Affiliation(s)
- Maria Alejandra Luna
- Departamento de Química
- Universidad Nacional de Río Cuarto
- C.P. X5804BYA Río Cuarto
- Argentina
| | - Juana J. Silber
- Departamento de Química
- Universidad Nacional de Río Cuarto
- C.P. X5804BYA Río Cuarto
- Argentina
| | - Leonides Sereno
- Departamento de Química
- Universidad Nacional de Río Cuarto
- C.P. X5804BYA Río Cuarto
- Argentina
| | - N. Mariano Correa
- Departamento de Química
- Universidad Nacional de Río Cuarto
- C.P. X5804BYA Río Cuarto
- Argentina
| | - Fernando Moyano
- Departamento de Química
- Universidad Nacional de Río Cuarto
- C.P. X5804BYA Río Cuarto
- Argentina
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9
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Abstract
Spherulites are onion-like structures composed of phospholipids and excipients. Initially discovered in an academic laboratory, these autoassembled nano-objects have been developed further by the start-up Capsulis (Bordeaux, France), and commercialized for veterinary and dermatological applications. Owing to economical strategies, the development of these objects have not been pursued, however, they are very interesting systems, which should be exploited further. The autoassembly of amphiphiles followed by a shear stress allows the formation of nano- to micrometer range nanoparticles, which could be interesting either for systemic or local delivery. Small molecules to macromolecules have been encapsulated in spherulites in the nanometer range. All have shown promising results. Hence, spherulite-encapsulated oligonucleotides have shown increased cell internalization. DNA was shown to be encapsulated in these neutral nanoparticles. Proof-of-concept of protein encapsulation was obtained leading to immune stimulation. This review summarizes the different ways to obtain spherulites, the results of the various investigations performed to date and indicates the limits and the interests of theses nanocarriers and proposes future prospects.
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10
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Schlicht B, Zagnoni M. Droplet-interface-bilayer assays in microfluidic passive networks. Sci Rep 2015; 5:9951. [PMID: 25909686 PMCID: PMC4408985 DOI: 10.1038/srep09951] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Accepted: 03/24/2015] [Indexed: 01/02/2023] Open
Abstract
Basic biophysical studies and pharmacological processes can be investigated by mimicking the intracellular and extracellular environments across an artificial cell membrane construct. The ability to reproduce in vitro simplified scenarios found in live cell membranes in an automated manner has great potential for a variety of synthetic biology and compound screening applications. Here, we present a fully integrated microfluidic system for the production of artificial lipid bilayers based on the miniaturisation of droplet-interface-bilayer (DIB) techniques. The platform uses a microfluidic design that enables the controlled positioning and storage of phospholipid-stabilized water-in-oil droplets, leading successfully to the scalable and automated formation of arrays of DIBs to mimic cell membrane processes. To ensure robustness of operation, we have investigated how lipid concentration, immiscible phase flow velocities and the device geometrical parameters affect the system performance. Finally, we produced proof-of-concept data showing that diffusive transport of molecules and ions across on-chip DIBs can be studied and quantified using fluorescence-based assays.
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Affiliation(s)
- Bárbara Schlicht
- Centre for Microsystems and Photonics, Electronic and Electrical Engineering, University of Strathclyde, Glasgow, G1 1XW, UK
| | - Michele Zagnoni
- Centre for Microsystems and Photonics, Electronic and Electrical Engineering, University of Strathclyde, Glasgow, G1 1XW, UK
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11
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Long noncoding RNA SPRY4-IT1 predicts poor patient prognosis and promotes tumorigenesis in gastric cancer. Tumour Biol 2015; 53:2016-2028. [PMID: 25835973 DOI: 10.1007/s12035-015-9142-1] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2014] [Accepted: 03/12/2015] [Indexed: 12/16/2022] Open
Abstract
Gastric cancer (GC) is the second common cause of cancer-related death worldwide. Long noncoding RNAs (lncRNAs) are emerging as novel regulators in the cancer paradigm. However, investigation of lncRNAs on GC is still in its infancy. In this study, we focused on lncRNA SPRY4 intronic transcript 1 (SPRY4-IT1) and investigated its expression pattern, clinical significance, biological function, and molecular mechanism in GC. SPRY4-IT1 expression was examined, and its correlation with clinicopathological characteristics and patient prognosis was analyzed. A series of assays were performed to understand the role of SPRY4-IT1 in GC. SPRY4-IT1 expression was elevated in GC tissues and cell lines, and SPRY4-IT1 levels were highly positively correlated with tumor size, invasion depth, distant metastasis, TNM stage, and reduced overall survival (OS) and disease-free survival (DFS). A multivariate analysis showed that SPRY4-IT1 expression is an independent prognostic factor of OS and DFS in patients with GC. Additionally, the results of in vitro assays showed that the suppression of SPRY4-IT1 expression in GC cell line MKN-45 significantly reduced cell proliferation, colony formation, and cell migration/invasion. Moreover, the tumorigenic effects of SPRY4-IT1 were partially mediated by the regulation of certain cyclins and matrix metalloproteinases (MMPs)-related genes. Our data suggest that SPRY4-IT1 plays a critical role in GC tumorigenesis and may represent a novel prognostic marker and potential therapeutic target in patients with GC.
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12
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Wheaten SA, Lakshmanan A, Almeida PF. Statistical analysis of peptide-induced graded and all-or-none fluxes in giant vesicles. Biophys J 2014; 105:432-43. [PMID: 23870264 DOI: 10.1016/j.bpj.2013.05.055] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2013] [Revised: 05/27/2013] [Accepted: 05/31/2013] [Indexed: 10/26/2022] Open
Abstract
Antimicrobial, cytolytic, and cell-penetrating peptides induce pores or perturbations in phospholipid membranes that result in fluxes of dyes into or out of lipid vesicles. Here we examine the fluxes induced by four of these membrane-active peptides in giant unilamellar vesicles. The type of flux is determined from the modality of the distributions of vesicles as a function of their dye content using the statistical Hartigan dip test. Graded and all-or-none fluxes correspond to unimodal and bimodal distributions, respectively. To understand how these distributions arise, we perform Monte Carlo simulations of peptide-induced dye flux into vesicles using a very simple model. The modality of the distributions depends on the rate constants of pore opening and closing, and dye flux. If the rate constants of pore opening and closing are both much smaller than that of dye flux through the pore, all-or-none influx occurs. However, if one of them, especially the rate constant for pore opening, increases significantly relative to the flux rate constant, the process becomes graded. In the experiments, we find that the flux type is the same in giant and large vesicles, for all peptides except one. But this one exception indicates that the flux type cannot be used to unambiguously predict the mechanism of membrane permeabilization by the peptides.
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Affiliation(s)
- Sterling A Wheaten
- Department of Chemistry and Biochemistry, University of North Carolina Wilmington, Wilmington, North Carolina, USA
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13
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Effect of onion-type multilamellar liposomes on Trametes versicolor laccase activity and stability. Biochimie 2012; 94:59-65. [DOI: 10.1016/j.biochi.2011.10.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2011] [Accepted: 10/13/2011] [Indexed: 11/21/2022]
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14
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Heuvingh J, Bonneau S. Asymmetric oxidation of giant vesicles triggers curvature-associated shape transition and permeabilization. Biophys J 2010; 97:2904-12. [PMID: 19948119 DOI: 10.1016/j.bpj.2009.08.056] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2009] [Revised: 08/03/2009] [Accepted: 08/17/2009] [Indexed: 01/05/2023] Open
Abstract
Oxidation of unsaturated lipids is a fundamental process involved in cell bioenergetics as well as in cell death. Using giant unilamellar vesicles and a chlorin photosensitizer, we asymmetrically oxidized the outer or inner monolayers of lipid membranes. We observed different shape transitions such as oblate to prolate and budding, which are typical of membrane curvature modifications. The asymmetry of the shape transitions is in accordance with a lowered effective spontaneous curvature of the leaflet being targeted. We interpret this effect as a decrease in the preferred area of the targeted leaflet compared to the other, due to the secondary products of oxidation (cleaved-lipids). Permeabilization of giant vesicles by light-induced oxidation is observed after a lag and is characterized in relation with the photosensitizer concentration. We interpret permeabilization as the opening of a pore above a critical membrane tension, resulting from the budding of vesicles. The evolution of photosensitized giant vesicle lysis tension was measured and yields an estimation of the effective spontaneous curvature at lysis. Additionally photo-oxidation was shown to be fusogenic.
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Affiliation(s)
- Julien Heuvingh
- Université Paris Diderot, Laboratoire de Physique et Mécanique des Milieux Hétérogènes, UMR7636, Centre National de la Recherche Scientifique/Ecole Superieure Physique Chimie Industrielles Ville de Paris, Université Pierre et Marie Curie, Paris, France.
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15
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Debecker DP, Faure C, Meyre ME, Derré A, Gaigneaux EM. A new bio-inspired route to metal-nanoparticle-based heterogeneous catalysts. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2008; 4:1806-1812. [PMID: 18844300 DOI: 10.1002/smll.200800304] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Onion-type multilamellar vesicles are made of concentric bilayers of organic surfactant and are mainly known for their potential applications in biotechnology. They can be used as microreactors for the spontaneous and controlled production of metal nanoparticles. This process does not require any thermal treatment and, hence, it is also attractive for material sciences such as heterogeneous catalysis. In this paper, silver-nanoparticle-based catalysts are prepared by transferring onion-grown silver nanoparticles onto inorganic supports. The resulting materials are active in the total oxidation of benzene, attesting that this novel bio-inspired concept is promising in inorganic catalysis.
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Affiliation(s)
- Damien P Debecker
- Université Catholique de Louvain, Unité de Catalyse et Chimie des Matériaux Divisés, Croix du Sud 2/17, B-1348 Louvain-la-Neuve, Belgium.
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16
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Meyre ME, Tréguer-Delapierre M, Faure C. Radiation-induced synthesis of gold nanoparticles within lamellar phases. Formation of aligned colloidal gold by radiolysis. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2008; 24:4421-4425. [PMID: 18402491 DOI: 10.1021/la703650d] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
A sheared lamellar phase has been used as a nanoreactor for the synthesis of gold nanoparticles by radiolysis and by a photochemical approach. A gold salt solution (KAuCl4, 10(-2) M) is introduced into the aqueous compartments between the lipid-based bilayers. Gold nanoparticles grow within the lamellar phase as shown by TEM analysis and X-ray diffraction, limiting the particle size. Homodisperse, 2.4- and 5.9-nm-sized, spherical nanoparticles are produced by gamma irradiation and UV irradiation, respectively. When produced by radiolysis, they are perfectly aligned along the lamellae. Their UV-vis spectra display a maximum at 565 nm suggesting that nanoparticles are coupled by dipole-dipole interactions within the lamellar phase.
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Affiliation(s)
- Marie-Edith Meyre
- CRPP-CNRS, Université Bordeaux I, Avenue du Dr. Schweitzer, 33600 Pessac, France
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17
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Olea D, Moreau P, Faure C. Polypyrrole–glucose oxidase biosensor. Effect of enzyme encapsulation in multilamellar vesicles on film growth and morphology. J Electroanal Chem (Lausanne) 2007. [DOI: 10.1016/j.jelechem.2007.03.027] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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18
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Chen LY, Cheng CW, Lin JJ, Chen WY. Exploring the effect of cholesterol in lipid bilayer membrane on the melittin penetration mechanism. Anal Biochem 2007; 367:49-55. [PMID: 17570332 DOI: 10.1016/j.ab.2007.04.039] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2006] [Revised: 02/27/2007] [Accepted: 04/24/2007] [Indexed: 11/22/2022]
Abstract
A vascular mimetic membrane system was used to investigate the effect of cholesterol content in lipid bilayer on the dynamics of the melittin-membrane penetration reaction with real-time monitoring by a piezoelectric sensor and the assessment morphology using atomic force microscopy (AFM). In the presence of 30% cholesterol in a noncharged phosphatidylcholine (PC) phospholipid membrane, KA1 (binding affinity constant) and KA2 (insertion affinity constant) derived from a two-step model decreased significantly. This result suggests that the high dose of cholesterol in phospholipid membrane inhibits both the binding and the insertion of melittin. Next, dynamic laser scattering and AFM were used to verify the structural changes of lipid bilayers in solutions and interfaces, respectively. The superstructures in both 0 and 10% cholesterol lipid bilayers were disrupted with penetration of melittin according to these verifications. However, kinetic analysis reveals that the different mechanisms are dependent on cholesterol, particularly for the insertion step.
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Affiliation(s)
- Liang-Yu Chen
- Department of Biotechnology, Ming-Chuan University, Gui-Shan 333, Taiwan
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