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Gakhar S, Risbud SH, Longo ML. Structure retention of silica gel-encapsulated bacteriorhodopsin in purple membrane and in lipid nanodiscs. Colloids Surf B Biointerfaces 2019; 186:110680. [PMID: 31835183 DOI: 10.1016/j.colsurfb.2019.110680] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Accepted: 11/26/2019] [Indexed: 11/24/2022]
Abstract
The integral membrane protein, bacteriorhodopsin (BR) was encapsulated in sol-gel derived porous silica gel monoliths in native purple membrane (BR-PM) and synthetic lipid nanodisc (BR nanodisc) environments. BR nanodiscs were synthesized by solubilizing purple membrane in discoidal phospholipid bilayer stabilized by amphipathic Styrene-Maleic Acid (SMA) copolymer. UV-vis absorbance spectroscopy and dynamic-light scattering indicated the formation of BR monomers solubilized in lipid nanodiscs 10.2 ± 0.7 nm in average diameter. Fluorescence and absorbance spectroscopic techniques were utilized to probe conformational, environmental, and rotational changes associated with the tryptophan residues and the covalently-bound retinal moiety of BR upon entrapment in the silica matrix. We show that the immobilized BR in both membrane environments retained its bound retinal cofactor and the ability of the cofactor to undergo conformational changes upon light illumination necessary for BR's activity as a proton transporter. For purple membrane fragments, the results indicated that the local pH in the pores around BR after encapsulation was important for its stability at temperatures higher than 50 °C. Under the same buffering conditions, retinal was released from silica-encapsulated BR-PM and BR nanodiscs beginning at 80 °C (without a conformational change) and 50 °C (with a conformational change), respectively, reflecting differences in protein-protein (trimeric vs. monomeric) and protein-lipid interactions.
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Affiliation(s)
- Sukriti Gakhar
- Department of Chemical Engineering, University of California Davis, Davis, California, 95616, United States
| | - Subhash H Risbud
- Department of Materials Science and Engineering, University of California Davis, Davis, California, 95616, United States
| | - Marjorie L Longo
- Department of Chemical Engineering, University of California Davis, Davis, California, 95616, United States.
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Lewandowska-Łańcucka J, Mystek K, Gilarska A, Kamiński K, Romek M, Sulikowski B, Nowakowska M. Silicone-stabilized liposomes as a possible novel nanostructural drug carrier. Colloids Surf B Biointerfaces 2016; 143:359-370. [DOI: 10.1016/j.colsurfb.2016.03.057] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Revised: 03/17/2016] [Accepted: 03/18/2016] [Indexed: 12/11/2022]
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3
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Zeno WF, Hilt S, Risbud SH, Voss JC, Longo ML. Spectroscopic Characterization of Structural Changes in Membrane Scaffold Proteins Entrapped within Mesoporous Silica Gel Monoliths. ACS APPLIED MATERIALS & INTERFACES 2015; 7:8640-8649. [PMID: 25849085 PMCID: PMC5522711 DOI: 10.1021/acsami.5b00898] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The changes in the orientation and conformation of three different membrane scaffold proteins (MSPs) upon entrapment in sol-gel-derived mesoporous silica monoliths were investigated. MSPs were examined in either a lipid-free or a lipid-bound conformation, where the proteins were associated with lipids to form nanolipoprotein particles (NLPs). NLPs are water-soluble, disk-shaped patches of a lipid bilayer that have amphiphilic MSPs shielding the hydrophobic lipid tails. The NLPs in this work had an average thickness of 5 nm and diameters of 9.2, 9.7, and 14.8 nm. We have previously demonstrated that NLPs are more suitable lipid-based structures for silica gel entrapment than liposomes because of their size compatibility with the mesoporous network (2-50 nm) and minimally altered structure after encapsulation. Here we further elaborate on that work by using a variety of spectroscopic techniques to elucidate whether or not different MSPs maintain their protein-lipid interactions after encapsulation. Fluorescence spectroscopy and quenching of the tryptophan residues with acrylamide, 5-DOXYL-stearic acid, and 16-DOXYL-stearic acid were used to determine the MSP orientation. We also utilized fluorescence anisotropy of tryptophans to measure the relative size of the NLPs and MSP aggregates after entrapment. Finally, circular dichroism spectroscopy was used to examine the secondary structure of the MSPs. Our results showed that, after entrapment, all of the lipid-bound MSPs maintained orientations that were minimally changed and indicative of association with lipids in NLPs. The tryptophan residues appeared to remain buried within the hydrophobic core of the lipid tails in the NLPs and appropriately spaced from the bilayer center. Also, after entrapment, lipid-bound MSPs maintained a high degree of α-helical content, a secondary structure associated with protein-lipid interactions. These findings demonstrate that NLPs are capable of serving as viable hosts for functional integral membrane proteins in the synthesis of sol-gel-derived bioinorganic hybrid nanomaterials.
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Affiliation(s)
- Wade F. Zeno
- Department of Chemical Engineering and Materials Science, University of California Davis, Davis, California, 95616
| | - Silvia Hilt
- Department of Biochemistry and Molecular Medicine, University of California Davis, Davis, California, 95616
| | - Subhash H. Risbud
- Department of Chemical Engineering and Materials Science, University of California Davis, Davis, California, 95616
| | - John C. Voss
- Department of Biochemistry and Molecular Medicine, University of California Davis, Davis, California, 95616
| | - Marjorie L. Longo
- Department of Chemical Engineering and Materials Science, University of California Davis, Davis, California, 95616
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Zeno WF, Hilt S, Aravagiri K, Risbud SH, Voss JC, Parikh AN, Longo ML. Analysis of lipid phase behavior and protein conformational changes in nanolipoprotein particles upon entrapment in sol-gel-derived silica. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:9780-9788. [PMID: 25062385 PMCID: PMC4140539 DOI: 10.1021/la5025058] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Revised: 07/24/2014] [Indexed: 06/02/2023]
Abstract
The entrapment of nanolipoprotein particles (NLPs) and liposomes in transparent, nanoporous silica gel derived from the precursor tetramethylorthosilicate was investigated. NLPs are discoidal patches of lipid bilayer that are belted by amphiphilic scaffold proteins and have an average thickness of 5 nm. The NLPs in this work had a diameter of roughly 15 nm and utilized membrane scaffold protein (MSP), a genetically altered variant of apolipoprotein A-I. Liposomes have previously been examined inside of silica sol-gels and have been shown to exhibit instability. This is attributed to their size (∼150 nm) and altered structure and constrained lipid dynamics upon entrapment within the nanometer-scale pores (5-50 nm) of the silica gel. By contrast, the dimensional match of NLPs with the intrinsic pore sizes of silica gel opens the possibility for their entrapment without disruption. Here we demonstrate that NLPs are more compatible with the nanometer-scale size of the porous environment by analysis of lipid phase behavior via fluorescence anisotropy and analysis of scaffold protein secondary structure via circular dichroism spectroscopy. Our results showed that the lipid phase behavior of NLPs entrapped inside of silica gel display closer resemblance to its solution behavior, more so than liposomes, and that the MSP in the NLPs maintain the high degree of α-helix secondary structure associated with functional protein-lipid interactions after entrapment. We also examined the effects of residual methanol on lipid phase behavior and the size of NLPs and found that it exerts different influences in solution and in silica gel; unlike in free solution, silica entrapment may be inhibiting NLP size increase and/or aggregation. These findings set precedence for a bioinorganic hybrid nanomaterial that could incorporate functional integral membrane proteins.
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Affiliation(s)
- Wade F. Zeno
- Department
of Chemical Engineering and Materials Science and Department of
Biochemistry and Molecular Medicine, University
of California Davis, Davis, California 95616, United States
| | - Silvia Hilt
- Department
of Chemical Engineering and Materials Science and Department of
Biochemistry and Molecular Medicine, University
of California Davis, Davis, California 95616, United States
| | - Kannan
K. Aravagiri
- Department
of Chemical Engineering and Materials Science and Department of
Biochemistry and Molecular Medicine, University
of California Davis, Davis, California 95616, United States
| | - Subhash H. Risbud
- Department
of Chemical Engineering and Materials Science and Department of
Biochemistry and Molecular Medicine, University
of California Davis, Davis, California 95616, United States
| | - John C. Voss
- Department
of Chemical Engineering and Materials Science and Department of
Biochemistry and Molecular Medicine, University
of California Davis, Davis, California 95616, United States
| | - Atul N. Parikh
- Department
of Chemical Engineering and Materials Science and Department of
Biochemistry and Molecular Medicine, University
of California Davis, Davis, California 95616, United States
| | - Marjorie L. Longo
- Department
of Chemical Engineering and Materials Science and Department of
Biochemistry and Molecular Medicine, University
of California Davis, Davis, California 95616, United States
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Gupta G, Iyer S, Leasure K, Virdone N, Dattelbaum AM, Atanassov PB, López GP. Stable and fluid multilayer phospholipid-silica thin films: mimicking active multi-lamellar biological assemblies. ACS NANO 2013; 7:5300-5307. [PMID: 23706112 DOI: 10.1021/nn401123p] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Phospholipid-based nanomaterials are of interest in several applications including drug delivery, sensing, energy harvesting, and as model systems in basic research. However, a general challenge in creating functional hybrid biomaterials from phospholipid assemblies is their fragility, instability in air, insolubility in water, and the difficulty of integrating them into useful composites that retain or enhance the properties of interest, therefore limiting there use in integrated devices. We document the synthesis and characterization of highly ordered and stable phospholipid-silica thin films that resemble multilamellar architectures present in nature such as the myelin sheath. We have used a near room temperature chemical vapor deposition method to synthesize these robust functional materials. Highly ordered lipid films are exposed to vapors of silica precursor resulting in the formation of nanostructured hybrid assemblies. This process is simple, scalable, and offers advantages such as exclusion of ethanol and no (or minimal) need for exposure to mineral acids, which are generally required in conventional sol-gel synthesis strategies. The structure of the phospholipid-silica assemblies can be tuned to either lamellar or hexagonal organization depending on the synthesis conditions. The phospholipid-silica films exhibit long-term structural stability in air as well as when placed in aqueous solutions and maintain their fluidity under aqueous or humid conditions. This platform provides a model for robust implementation of phospholipid multilayers and a means toward future applications of functional phospholipid supramolecular assemblies in device integration.
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Affiliation(s)
- Gautam Gupta
- Center for Biomedical Engineering, Department of Chemical and Nuclear Engineering, University of New Mexico, Albuquerque, New Mexico 87131, USA
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Abstract
Time-resolved stimulated emission spectroscopy was employed to probe the local environment of DASPMI (4-(4-(dimethylamino)styryl)-N-methyl-pyridinium iodide) in binary solvents of different viscosity and in a sol-gel matrix. DASPMI is one of the molecules of choice to probe local environments, and the dependence of its fluorescence emission decay on viscosity has been previously used for this purpose in biological samples, solid matrices as well as in solution. The results presented in this paper show that time-resolved stimulated emission of DASPMI is a suitable means to probe the viscosity of local environments. Having the advantage of a higher time resolution, stimulated emission can provide information that is complementary to that obtained from fluorescence decay measurements, making it feasible to probe systems with lower viscosity.
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7
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Tran-Thi TH, Dagnelie R, Crunaire S, Nicole L. Optical chemical sensors based on hybrid organic–inorganic sol–gel nanoreactors. Chem Soc Rev 2011; 40:621-39. [DOI: 10.1039/c0cs00021c] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Esquembre R, Poveda JA, Mateo CR. Biophysical and Functional Characterization of an Ion Channel Peptide Confined in a Sol−Gel Matrix. J Phys Chem B 2009; 113:7534-40. [DOI: 10.1021/jp9019443] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Rocío Esquembre
- Instituto de Biología Molecular y Celular. Universidad Miguel Hernández de Elche, 03202 Elche (Alicante), Spain
| | - José Antonio Poveda
- Instituto de Biología Molecular y Celular. Universidad Miguel Hernández de Elche, 03202 Elche (Alicante), Spain
| | - C. Reyes Mateo
- Instituto de Biología Molecular y Celular. Universidad Miguel Hernández de Elche, 03202 Elche (Alicante), Spain
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Koehler JJ, Zhao J, Jedlicka SS, Porterfield DM, Rickus JL. Compartmentalized Nanocomposite for Dynamic Nitric Oxide Release. J Phys Chem B 2008; 112:15086-93. [DOI: 10.1021/jp803276u] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- John J. Koehler
- Department of Agricultural and Biological Engineering, Department of Horticulture and Landscape Architecture, Weldon School of Biomedical Engineering, Physiological Sensing Facility at the Bindley Bioscience Center, Purdue University, West Lafayette, IN
| | - Jianxiu Zhao
- Department of Agricultural and Biological Engineering, Department of Horticulture and Landscape Architecture, Weldon School of Biomedical Engineering, Physiological Sensing Facility at the Bindley Bioscience Center, Purdue University, West Lafayette, IN
| | - Sabrina S. Jedlicka
- Department of Agricultural and Biological Engineering, Department of Horticulture and Landscape Architecture, Weldon School of Biomedical Engineering, Physiological Sensing Facility at the Bindley Bioscience Center, Purdue University, West Lafayette, IN
| | - D. Marshall Porterfield
- Department of Agricultural and Biological Engineering, Department of Horticulture and Landscape Architecture, Weldon School of Biomedical Engineering, Physiological Sensing Facility at the Bindley Bioscience Center, Purdue University, West Lafayette, IN
| | - Jenna L. Rickus
- Department of Agricultural and Biological Engineering, Department of Horticulture and Landscape Architecture, Weldon School of Biomedical Engineering, Physiological Sensing Facility at the Bindley Bioscience Center, Purdue University, West Lafayette, IN
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11
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Brennan JD. Biofriendly sol-gel processing for the entrapment of soluble and membrane-bound proteins: toward novel solid-phase assays for high-throughput screening. Acc Chem Res 2007; 40:827-35. [PMID: 17458927 DOI: 10.1021/ar6000268] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The last decade has seen a revolution in the area of sol-gel-derived biomaterials since the demonstration that these materials can be used to encapsulate biological species such as enzymes, antibodies, and other proteins in a functional state. In particular, recent years have seen tremendous progress in the development of more "protein-friendly" sol-gel processing methods and their use for immobilization of delicate proteins, including key drug targets such as kinases and membrane-bound receptors. The latter example is particularly impressive, given the inherently low stability of membrane receptors and the need to stabilize an amphiphilic bilayer lipid membrane to maintain receptor function. In this Account, we provide an overview of the advances in biofriendly sol-gel processing methods developed in our research group and others and highlight recent accomplishments in the immobilization of both soluble and membrane-bound proteins, with particular emphasis on enzymes and membrane receptors that are drug targets. Emerging applications of sol-gel-entrapped proteins, focusing on the development platforms for high-throughput screening of small molecules, are also described.
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Affiliation(s)
- John D Brennan
- Department of Chemistry, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada.
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12
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Ghosh S, Mandal U, Adhikari A, Dey S, Bhattacharyya K. Study of organized and biological systems using an ultrafast laser. INT REV PHYS CHEM 2007. [DOI: 10.1080/01442350701416888] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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13
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Esquembre R, Ferrer ML, Gutiérrez MC, Mallavia R, Mateo CR. Fluorescence Study of the Fluidity and Cooperativity of the Phase Transitions of Zwitterionic and Anionic Liposomes Confined in Sol−Gel Glasses. J Phys Chem B 2007; 111:3665-73. [PMID: 17388546 DOI: 10.1021/jp068685y] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The current work makes use of different fluorescent reporter molecules and fluorescent spectroscopic techniques to characterize the thermotropic, physical, and dynamical properties of large unilamellar liposomes formed from either 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) or 1,2-dimyristoyl-sn-glycero-3-[phospho-rac-glycerol] (DMPG) encapsulated in sol-gel matrixes. In particular, cooperativity of the phase transition is analyzed from steady-state fluorescence anisotropy of 1,6-diphenyl-1,3,5-hexatriene (DPH), the interfacial properties are studied by measuring the spectral shift of Laurdan, and the structural organization (heterogeneity) of the lipid bilayer is determined from the fluorescence lifetime of trans-parinaric acid (t-PnA). In addition, information regarding order and dynamical properties in the bulk hydrophobic core is obtained from time-resolved fluorescence anisotropy of t-PnA and 3-(4-(6-phenyl)-1,3,5-hexatrienyl)-phenylpropionic acid (PA-DPH). The spectroscopic study reveals that upon encapsulation, the basic thermodynamic properties as well as the fluidity of the lipid bilayer practically remain intact for DMPG liposomes but not for DMPC liposomes, whose lipid bilayer exhibits large gel-fluid heterogeneity. On the basis of these experimental results, electrostatic interactions between phospholipid polar heads and the porous surface of the host matrix seem to play a capital role for the preservation of the structural integrity of encapsulated bilayer.
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Affiliation(s)
- Rocío Esquembre
- Instituto de Biología Molecular y Celular, Universidad Miguel HernAndez, 03202-Elche, Spain
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14
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Jedlicka SS, Little KM, Nivens DE, Zemlyanov D, Rickus JL. Peptide ormosils as cellular substrates. ACTA ACUST UNITED AC 2007. [DOI: 10.1039/b705393b] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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15
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Bégu S, Aubert Pouëssel A, Lerner DA, Tourné-Péteilh C, Devoisselle JM. Liposil, a promising composite material for drug storage and release. J Control Release 2006; 118:1-6. [PMID: 17250924 DOI: 10.1016/j.jconrel.2006.11.022] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2006] [Revised: 11/17/2006] [Accepted: 11/24/2006] [Indexed: 11/24/2022]
Abstract
Preliminary tests in the field of drug storage and release of composite materials known as liposils were described. These silica-based particles were obtained via liposome templating. The non-porous amorphous silica cladding of liposils protected the liposomes which retained the fundamental properties of their phospholipid bilayer. In an improved synthesis, two formulations were used, one with and the other without cholesterol in the phospholipid bilayer. Stability tests were done using carboxyfluorescein as a model hydrophilic drug loaded in the liposomes aqueous phase before the templating process. The stability of the loaded liposils was analyzed at two different pH (1.2 and 7.4) in a flow cell, according to the USP 28 norm. At pH 1.2, the silica shell was stable and prevented their rapid degradation. Interestingly, at pH 7.4 the analysis of the release kinetics revealed that the hydrolysis of the silica shell initially released intact liposomes. Characterizations of liposils were done at various steps of these processes. The stability observed for liposils make them good starting material for drug storage and release schemes. For instance, functionalization of their external surface should improve their capture by cells whereby drug release could then be induced by external stimuli, such as ultrasounds or microwaves.
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Affiliation(s)
- Sylvie Bégu
- UMR CNRS/ENSCM/UM1 5618, Institut C. Gerhardt, FR 1878, 8 rue de l'Ecole Normale, 34296 Montpellier cedex 5, France.
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16
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Sabín J, Ruso JM, González-Pérez A, Prieto G, Sarmiento F. Characterization of phospholipid+semifluorinated alkane vesicle system. Colloids Surf B Biointerfaces 2006; 47:64-70. [PMID: 16406518 DOI: 10.1016/j.colsurfb.2005.11.022] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2005] [Revised: 11/21/2005] [Accepted: 11/28/2005] [Indexed: 11/19/2022]
Abstract
The aim of this study is to characterize vesicles obtained by the incorporation of the semifluorinated alkane, (perfluoro-n-hexyl)ethane (diblock F6H2) to a standard lipid, egg yolk phosphatidylcholine (PC). Large unilamellar vesicles (LUVs), prepared by extrusion, were characterized by fluorescence spectroscopy, zeta potential (zeta-potential) and light scattering. By using the fluorescence spectroscopy technique, the anisotropy of l,6-diphenyl-l,3,5-hexatriene (DPH) probe at different temperatures was determined. It was demonstrated that F6H2 is placed inside of the lipid bilayer and that the hydrocarbon acyl chain in the bilayers has higher viscosity in the presence of fluoroalkane. The zeta-potential of the PC-F6H2 system is negative and increases (in absolute value) from -10 to -19 mV when the temperature rises from 10 to 25 degrees C, this last value keeping practically constant with a further increase of temperature. The adsorption of K+ ions on the liposome surface was measured by zeta-potential. This adsorption originates a sudden increase of the initial zeta-potential followed by a slight decrease with K+ concentration. The application of the DLVO theory of colloidal stability showed a growing dependence of the DLVO potential with K+ concentration and consequently a increasing stability.
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Affiliation(s)
- Juan Sabín
- Biophysics and Interfaces Group, Department of Applied Physics, Faculty of Physics, University of Santiago de Compostela, E-15782 Santiago de Compostela, Spain
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Jedlicka SS, McKenzie JL, Leavesley SJ, Little KM, Webster TJ, Robinson JP, Nivens DE, Rickus JL. Sol-gel derived materials as substrates for neuronal differentiation: effects of surface features and protein conformation. ACTA ACUST UNITED AC 2006. [DOI: 10.1039/b602008a] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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18
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Lee TH, Aguilar MI. Trends in the development and application of functional biomembrane surfaces. BIOTECHNOLOGY ANNUAL REVIEW 2006; 12:85-136. [PMID: 17045193 DOI: 10.1016/s1387-2656(06)12004-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
Affiliation(s)
- Tzong-Hsien Lee
- Department of Biochemistry and Molecular Biology, Monash University, Victoria 3800, Australia
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19
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Avnir D, Coradin T, Lev O, Livage J. Recent bio-applications of sol–gel materials. ACTA ACUST UNITED AC 2006. [DOI: 10.1039/b512706h] [Citation(s) in RCA: 629] [Impact Index Per Article: 34.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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21
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Sen P, Mukherjee S, Patra A, Bhattacharyya K. Solvation Dynamics of DCM in a DPPC Vesicle Entrapped in a Sodium Silicate Derived Sol−Gel Matrix. J Phys Chem B 2005; 109:3319-23. [PMID: 16851359 DOI: 10.1021/jp0455327] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Solvation dynamics of 4-(dicyanomethylene)-2-methyl-6(p-dimethylaminostyryl) 4H-pyran (DCM) has been studied in a dipalmitoyl-phosphatidylcholine (DPPC) vesicle entrapped in a sodium silicate derived sol-gel glass. Solvation dynamics in DPPC in a sol-gel glass is described by two components of 350 +/- 50 ps (50%) and 2300 +/- 200 ps (50%) with a total dynamic Stokes shift of 1300 cm(-1). The fast component (350 ps) is similar to the fast component in a DPPC vesicle in bulk water (320 +/- 50 ps). This component may be ascribed to the dynamics of the water molecules inside the water pool of the vesicle. However, the slow component (2300 +/- 200 ps) is about 2.5 times slower compared to the slow component of solvation dynamics of DCM in a DPPC vesicle in bulk solvent (900 +/- 100 ps). The anisotropy decay of DCM in a DPPC vesicle both in sol-gel glass and in bulk water exhibits a very fast initial decay with a large residual anisotropy, which does not decay in approximately 10 ns. The time scale of anisotropy decay is very different from that of solvation dynamics.
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Affiliation(s)
- Pratik Sen
- Physical Chemistry Department, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India
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22
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Brustolon M, Barbon A, Bortolus M, Maniero AL, Sozzani P, Comotti A, Simonutti R. Dynamics of Alkoxy−Oligothiophene Ground and Excited States in Nanochannels. J Am Chem Soc 2004; 126:15512-9. [PMID: 15563180 DOI: 10.1021/ja046804m] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Two oligothiophenes, 4,4'-dipentoxy-2,2'-dithiophene and 4,4"-dipentoxy-2,2':5',2":5",2' ''-tetrathiophene, have been included in the nanochannels of the autoassembling host TPP (tris-o-phenylenedioxycyclotriphosphazene). The effect of the confinement on the structure and properties of the two dyes, as conformational arrangements, dynamics, and photophysical behavior, was addressed by the combination of high spinning speed solid-state NMR and time-resolved EPR spectroscopy. We compared the conformations of the dyes in their ground and photoexcited triplet states and described in detail the dynamics of the supramolecular adducts from 4 K to room temperature. Above 200 K surprisingly fast spinning rates of the dithiophene core were discovered, while the side chains show far slower reorientation motion, being in bulky gauche-rich conformations. These lateral plugs keep the planar core as appended in the space like a nanoscale gyroscope, allowing a reorientation in the motion regime of liquids and a long triplet lifetime at unusually high temperature. The nuclear magnetic properties of the guest dyes are also largely affected by the aromatic rings of the neighboring host, imparting an impressive magnetic susceptibility effect (2 ppm proton shift). The high mobility is due to the formation of a nanocage in a channel where aliphatic and aromatic functions isolate the thiophene moieties. Instead, two conformers of the tetrathiophene twisted on the central bond are stabilized by interaction with the host. They interconvert fast enough to be averaged in the NMR time scale.
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Affiliation(s)
- Marina Brustolon
- Department of Chemical Sciences, University of Padua, and INSTM, UdR of Padua, Via Marzolo 1, 35131 Padua, Italy.
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Besanger TR, Easwaramoorthy B, Brennan JD. Entrapment of Highly Active Membrane-Bound Receptors in Macroporous Sol−Gel Derived Silica. Anal Chem 2004; 76:6470-5. [PMID: 15516143 DOI: 10.1021/ac0488210] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The immobilization of membrane-associated proteins remains a challenging task. Herein, we report on the entrapment of two classes of membrane-bound receptors into sol-gel derived silica. Both nicotinic acetylcholine receptor (nAChR), a ligand-gated ion channel, and dopamine D(2Short) receptor (D2R), a G-protein coupled receptor, were entrapped into a series of sol-gel derived nanocomposite materials. In cases where the silica had a bimodal pore size distribution wherein both mesopores and macropores were present, the two receptors showed 40-80% of solution activity over periods of at least 1 month. Furthermore, the dissociation constants of entrapped nAChR and D2R for binding to known agonists and antagonists were very close to the values obtained for free receptors in solution. These results indicate that membrane-bound receptors entrapped into bimodal meso/macroporous silica should provide a useful platform for the development of bioanalytical devices such as bioaffinity columns or microarrays, which could aid in diagnosis and high-throughput drug screening.
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Affiliation(s)
- Travis R Besanger
- Department of Chemistry, McMaster University, 1280 Main Street West, Hamilton, ON, L8S 4M1 Canada
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Sahu K, Roy D, Mondal SK, Halder A, Bhattacharyya K. Study of Solvation Dynamics in an Ormosil: CTAB in a Sol−Gel Matrix. J Phys Chem B 2004. [DOI: 10.1021/jp049152x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Kalyanasis Sahu
- Physical Chemistry Department, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India
| | - Durba Roy
- Physical Chemistry Department, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India
| | - Sudip Kumar Mondal
- Physical Chemistry Department, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India
| | - Arnab Halder
- Physical Chemistry Department, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India
| | - Kankan Bhattacharyya
- Physical Chemistry Department, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India
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Halder A, Sen S, Burman AD, Patra A, Bhattacharyya K. Solvation Dynamics in Dimyristoyl-Phosphatidylcholine Entrapped Inside a Sol−Gel Matrix. J Phys Chem B 2004. [DOI: 10.1021/jp035685e] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Arnab Halder
- Physical Chemistry Department, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032, India, and Sol-Gel Division, Central Glass & Ceramic Research Institute, Jadavpur, Kolkata 700 032, India
| | - Sobhan Sen
- Physical Chemistry Department, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032, India, and Sol-Gel Division, Central Glass & Ceramic Research Institute, Jadavpur, Kolkata 700 032, India
| | - Anupam Das Burman
- Physical Chemistry Department, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032, India, and Sol-Gel Division, Central Glass & Ceramic Research Institute, Jadavpur, Kolkata 700 032, India
| | - Amitava Patra
- Physical Chemistry Department, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032, India, and Sol-Gel Division, Central Glass & Ceramic Research Institute, Jadavpur, Kolkata 700 032, India
| | - Kankan Bhattacharyya
- Physical Chemistry Department, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032, India, and Sol-Gel Division, Central Glass & Ceramic Research Institute, Jadavpur, Kolkata 700 032, India
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Bégu S, Girod S, Lerner DA, Jardiller N, Tourné-Péteilh C, Devoisselle JM. Characterization of a phospholipid bilayer entrapped into non-porous silica nanospheres. ACTA ACUST UNITED AC 2004. [DOI: 10.1039/b316045a] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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