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Gubała D, Taylor N, Harniman R, Rawle J, Hussain H, Robles E, Chen M, Briscoe WH. Structure, Nanomechanical Properties, and Wettability of Organized Erucamide Layers on a Polypropylene Surface. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:6521-6532. [PMID: 34015220 DOI: 10.1021/acs.langmuir.1c00686] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Understanding the nanostructure and nanomechanical properties of surface layers of erucamide, in particular the molecular orientation of the outermost layer, is important to its widespread use as a slip additive in polymer materials. Extending our recent observations of nanomorphologies of erucamide layers on a hydrophilic silica substrate, here we evaluate its nanostructure on a more hydrophobic polypropylene surface. Atomic force microscopy (AFM) imaging revealed the molecular packing, thickness, and surface coverage of the erucamide layers, while peak force quantitative nanomechanical mapping (QNM) showed that erucamide reduced the adhesive response on polypropylene. Synchrotron X-ray reflectivity (XRR) was used to probe the out-of-plane structure of the surface layers. Static contact angle measurements further corroborated on the resulting wettability, also demonstrating the efficacy of erucamide physisorption in facilitating control over polypropylene surface wetting. The results show the formation of erucamide monolayers, bilayers and multilayers, depending on the concentration in the spin-cast solution. Correlation of AFM, XRR and wettability results consistently points to the molecular orientation in the outermost layer, i.e. with the erucamide tails pointing outward for the surface nanostructures with different morphologies (i.e., bilayers and multilayers). Rare occurrence of monolayers with exposed hydrophilic head groups were observed only at the lowest erucamide concentration. Compared with our previous observations on the hydrophilic surface, the erucamide surface coverage was much higher on the more hydrophobic propylene surface at similar erucamide concentrations in the spin-cast solution. Furthermore, the structure, molecular orientation and nanomechanical properties of the spin-cast erucamide multilayers atop polypropylene were also similar to those on industrially relevant polypropylene fibers coated with erucamide via blooming. These findings shed light on the nanostructural features of the erucamide surface layer underpinning its nanomechanical properties, relevant to many applications in which erucamide is commonly used as a slip additive.
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Affiliation(s)
- Dajana Gubała
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, United Kingdom
| | - Nicholas Taylor
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, United Kingdom
| | - Robert Harniman
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, United Kingdom
| | - Jonathan Rawle
- Diamond Light Source, Diamond House, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, United Kingdom
| | - Hadeel Hussain
- Diamond Light Source, Diamond House, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, United Kingdom
| | - Eric Robles
- Household Care Analytical, Procter & Gamble Newcastle Innovation Centre, Whitley Road, Longbenton, Newcastle NE12 9TS, United Kingdom
| | - Meng Chen
- Procter & Gamble Beijing Innovation Centre, 35 Yu'an Rd, Shunyi District, Beijing 101312, China
| | - Wuge H Briscoe
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, United Kingdom
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Heads or tails: Nanostructure and molecular orientations in organised erucamide surface layers. J Colloid Interface Sci 2021; 590:506-517. [PMID: 33567375 DOI: 10.1016/j.jcis.2021.01.087] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 01/26/2021] [Accepted: 01/27/2021] [Indexed: 11/21/2022]
Abstract
HYPOTHESIS Despite the widespread industrial usage of erucamide as a slip additive to modify polymer surface properties, a controversy appears to have persisted regarding the nanostructure of erucamide surface layers, particularly the molecular orientation at the outermost layer. The erucamide nanostructure and molecular orientation, along with its surface coverage, hydrophobicity, and adhesive response, can be tuned by simply varying the erucamide concentration in the solution from which the spin coated layer is prepared. EXPERIMENTS Synchrotron X-ray reflectivity (XRR) allowed a comprehensive characterisation of the out-of-plane structural parameters (e.g. molecular packing and thickness) of the erucamide layers prepared via spin coating from nonaqueous solution on silica. Complementary Atomic Force Microscopy (AFM) imaging with high lateral resolution revealed localised in-plane structures. Contact angle measurements provided information on the wettability of erucamide-coated surfaces. Peak Force Quantitative Nanomechanical Mapping (QNM) allowed a correlation between the erucamide nanostructure with the surface nanomechanical properties (i.e. adhesive response). FINDINGS Our results reveal erucamide surface nanostructures on silica as patchy monolayers, isolated circular bilayers/rounded rectangle-like aggregates and overlapping plate-like multilayers as the erucamide concentration in the spin coating solution was varied. In all the cases, XRR and AFM results were consistent with the picture that the erucamide tails were oriented outwards. The QNM adhesion force mapping of all the observed morphologies also supported this molecular orientation at the outermost erucamide monolayer. The wettability study further confirmed this conclusion with the observed increase in the surface hydrophobicity and coverage upon increasing erucamide concentration, with the macroscopic water contact angle θ = 92.9° ± 2.9° at the highest erucamide concentration of 2 wt%.
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Mendozza M, Balestri A, Montis C, Berti D. Controlling the Kinetics of an Enzymatic Reaction through Enzyme or Substrate Confinement into Lipid Mesophases with Tunable Structural Parameters. Int J Mol Sci 2020; 21:ijms21145116. [PMID: 32698376 PMCID: PMC7404178 DOI: 10.3390/ijms21145116] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 07/15/2020] [Accepted: 07/17/2020] [Indexed: 12/15/2022] Open
Abstract
Lipid liquid crystalline mesophases, resulting from the self-assembly of polymorphic lipids in water, have been widely explored as biocompatible drug delivery systems. In this respect, non-lamellar structures are particularly attractive: they are characterized by complex 3D architectures, with the coexistence of hydrophobic and hydrophilic regions that can conveniently host drugs of different polarities. The fine tunability of the structural parameters is nontrivial, but of paramount relevance, in order to control the diffusive properties of encapsulated active principles and, ultimately, their pharmacokinetics and release. In this work, we investigate the reaction kinetics of p-nitrophenyl phosphate conversion into p-nitrophenol, catalysed by the enzyme Alkaline Phosphatase, upon alternative confinement of the substrate and of the enzyme into liquid crystalline mesophases of phytantriol/H2O containing variable amounts of an additive, sucrose stearate, able to swell the mesophase. A structural investigation through Small-Angle X-ray Scattering, revealed the possibility to finely control the structure/size of the mesophases with the amount of the included additive. A UV-vis spectroscopy study highlighted that the enzymatic reaction kinetics could be controlled by tuning the structural parameters of the mesophase, opening new perspectives for the exploitation of non-lamellar mesophases for confinement and controlled release of therapeutics.
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Fox LJ, Matthews L, Stockdale H, Pichai S, Snow T, Richardson RM, Briscoe WH. Structural changes in lipid mesophases due to intercalation of dendritic polymer nanoparticles: Swollen lamellae, suppressed curvature, and augmented structural disorder. Acta Biomater 2020; 104:198-209. [PMID: 31904557 DOI: 10.1016/j.actbio.2019.12.036] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Revised: 12/21/2019] [Accepted: 12/30/2019] [Indexed: 12/19/2022]
Abstract
Understanding interactions between nanoparticles and model membranes is relevant to functional nano-composites and the fundamentals of nanotoxicity. In this study, the effect of polyamidoamine (PAMAM) dendrimers as model nanoparticles (NP) on the mesophase behaviour of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine (POPE) has been investigated using high-pressure small-angle X-ray scattering (HP-SAXS). The pressure-temperature (p-T) diagrams for POPE mesophases in excess water were obtained in the absence and presence of G2 and G4 polyamidoamine (PAMAM) dendrimers (29 Å and 45 Å in diameter, respectively) at varying NP-lipid number ratio (ν = 0.0002-0.02) over the pressure range p = 1-3000 bar and temperature range T = 20-80 °C. The p-T phase diagram of POPE exhibited the Lβ, Lα and HII phases. Complete analysis of the phase diagrams, including the relative area pervaded by different phases, phase transition temperatures (Tt) and pressures (pt), the lattice parameters (d-spacing), the pressure-dependence of d-spacing (Δd/Δp), and the structural ordering in the mesophase as gauged by the Scherrer coherence length (L) permitted insights into the size- and concentration-dependent interactions between the dendrimers and the model membrane system. The addition of dendrimers changed the phase transition pressure and temperature and resulted in the emergence of highly swollen lamellar phases, dubbed Lβ-den and Lα-den. G4 PAMAM dendrimers at the highest concentration ν = 0.02 suppressed the formation of the HII phase within the temperature range studied, whereas the addition of G2 PAMAM dendrimers at the same concentration promoted an extended mixed lamellar region in which Lα and Lβ phases coexisted. STATEMENT OF SIGNIFICANCE: Using high pressure small angle X-ray scattering in the pressure range 1-3000 bar and temperature range 20-60 °C, we have studied interactions between PAMAM dendrimers (as model nanoparticles) and POPE lipid mesophases (as model membranes). We report the pressure-temperature phase diagrams for the dendrimer-lipid mesophases for the first time. We find that the dendrimers alter the phase transition temperatures (Tt) and pressures (pt), the lattice parameters (d-spacing), and the structural order in the mesophase. We interpret these unprecedented results in terms of the fluidity of the lipid membranes and the interactions between the dendrimers and the membranes. Our findings are of fundamental relevance to the field of nanotoxicity and functional nanomaterials that integrate nanoparticles and organized lipid structures.
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Interactions between PAMAM dendrimers and DOPC lipid multilayers: Membrane thinning and structural disorder. Biochim Biophys Acta Gen Subj 2020; 1865:129542. [PMID: 31987955 DOI: 10.1016/j.bbagen.2020.129542] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Revised: 01/18/2020] [Accepted: 01/22/2020] [Indexed: 11/22/2022]
Abstract
BACKGROUND Understanding the structure of hybrid nanoparticle-lipid multilayers is of fundamental importance to their bioanalytical applications and nanotoxicity, where nanoparticle-membrane interactions play an important role. Poly(amidoamine) (PAMAM) dendrimers are branched polymeric nanoparticles with potential biomedical applications due to precise tunability of their physicochemical properties. Here, the effect of PAMAM dendrimers (2.9-4.5 nm) with either a hydrophilic amine (NH2) or a hydrophobic C12 chain surface termination on the 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) multilayers has been studied for the first time. METHODS DOPC multilayers were created by the liposome-rupture method via drop-casting dendrimer-liposome dispersions with the dendrimers added at different concentrations and at three different stages. The multilayer structure was evaluated via the analysis of the synchrotron X-ray reflectivity (XRR) curves, obtaining the bilayer d-spacing, the coherence length from the Scherrer (Ls) analysis of the Bragg peaks, and the paracrystalline disorder parameter (g). RESULTS Dendrimer addition led to lipid bilayer thinning and more disordered multilayer structures. Larger hydrophobic dendrimers caused greater structural disruption to the multilayers compared to the smaller dendrimers. The smallest, positively charged dendrimers at their highest concentration caused the most pronounced bilayer thinning. The dendrimer-liposome mixing method also affected the multilayer structure due to different dendrimer aggregation involved. CONCLUSIONS These results show the complexity of the effect of dendrimer physicochemical properties and the addition method of dendrimers on the structure of mixed dendrimer-DOPC multilayers. GENERAL SIGNIFICANCE These insights are useful for fundamental understanding of nanotoxicity and future biomedical application of nanocomposite multilayer materials in which nanoparticles are added for enhanced properties and functionality.
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Bouraoui A, Ghanem R, Berchel M, Deschamps L, Vié V, Paboeuf G, Le Gall T, Montier T, Jaffrès PA. Branched lipid chains to prepare cationic amphiphiles producing hexagonal aggregates: supramolecular behavior and application to gene delivery. Org Biomol Chem 2020; 18:337-345. [DOI: 10.1039/c9ob02381j] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Cationic amphiphiles featuring ramified lipid chains self-organized in water as inverted hexagonal aggregates. They demonstrated high gene delivery efficiencies.
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Affiliation(s)
| | - Rosy Ghanem
- Univ Brest
- INSERM
- groupe “Transfert de gènes et thérapie génique”
- UMR 1078
- CHRU de Brest
| | | | | | | | | | - Tony Le Gall
- Univ Brest
- INSERM
- groupe “Transfert de gènes et thérapie génique”
- UMR 1078
- CHRU de Brest
| | - Tristan Montier
- Univ Brest
- INSERM
- groupe “Transfert de gènes et thérapie génique”
- UMR 1078
- CHRU de Brest
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7
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Redeker C, Briscoe WH. Interactions between Mutant Bacterial Lipopolysaccharide (LPS-Ra) Surface Layers: Surface Vesicles, Membrane Fusion, and Effect of Ca 2+and Temperature. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:15739-15750. [PMID: 31604373 DOI: 10.1021/acs.langmuir.9b02609] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Lipopolysaccharides (LPS) are a major component of the protective outer membrane of Gram-negative bacteria. Understanding how the solution conditions may affect LPS-containing membranes is important to optimizing the design of antibacterial agents (ABAs) which exploit electrostatic and hydrophobic interactions to disrupt the bacteria membrane. Here, interactions between surface layers of LPS (Ra mutants) in aqueous media have been studied using a surface force apparatus (SFA), exploring the effects of temperature and divalent Ca2+ cations. Complementary dynamic light scattering (DLS) characterization suggests that vesicle-like aggregates of diameter ∼28-80 nm are formed by LPS-Ra in aqueous media. SFA results show that LPS-Ra vesicles adsorb weakly onto mica in pure water at room temperature (RT) and the surface layers are readily squeezed out as the two surfaces approach each other. However, upon addition of calcium (Ca2+) cations at near physiological concentration (2.5 mM) at RT, LPS multilayers or deformed LPS liposomes on mica are observed, presumably due to bridging between LPS phosphate groups and between LPS phosphates and negatively charged mica mediated by Ca2+, with a hard wall repulsion at surface separation D0 ∼ 30-40 nm. At 40 °C, which is above the LPS-Ra β-α acyl chain melting temperature (Tm = 36 °C), fusion events between the surface layers under compression could be observed, evident from δD ∼ 8-10 nm steps in the force-distance profiles attributed to LPS-bilayers being squeezed out due to enhanced fluidity of the LPS acyl-chain, with a final hard wall surface separation D0 ∼ 8-10 nm corresponding to the thickness of a single bilayer confined between the surfaces. These unprecedented SFA results reveal intricate structural responses of LPS surface layers to temperature and Ca2+, with implications to our fundamental understanding of the structures and interactions of bacterial membranes.
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Affiliation(s)
- Christian Redeker
- School of Chemistry , University of Bristol , Cantock's Close, Bristol BS8 1TS , United Kingdom
| | - Wuge H Briscoe
- School of Chemistry , University of Bristol , Cantock's Close, Bristol BS8 1TS , United Kingdom
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8
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Mendozza M, Caselli L, Salvatore A, Montis C, Berti D. Nanoparticles and organized lipid assemblies: from interaction to design of hybrid soft devices. SOFT MATTER 2019; 15:8951-8970. [PMID: 31680131 DOI: 10.1039/c9sm01601e] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
This contribution reviews the state of art on hybrid soft matter assemblies composed of inorganic nanoparticles (NP) and lamellar or non-lamellar lipid bilayers. After a short outline of the relevant energetic contributions, we address the interaction of NPs with synthetic lamellar bilayers, meant as cell membrane mimics. We then review the design of hybrid nanostructured materials composed of lipid bilayers and some classes of inorganic NPs, with particular emphasis on the effects on the amphiphilic phase diagram and on the additional properties contributed by the NPs. Then, we present the latest developments on the use of lipid bilayers as coating agents for inorganic NPs. Finally, we remark on the main achievements of the last years and our vision for the development of the field.
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Affiliation(s)
- Marco Mendozza
- Department of Chemistry "Ugo Schiff", University of Florence, and CSGI (Italian Center for Colloid and Surface Science, Via della Lastruccia 3, Sesto Fiorentino, 50019 Firenze, Italy.
| | - Lucrezia Caselli
- Department of Chemistry "Ugo Schiff", University of Florence, and CSGI (Italian Center for Colloid and Surface Science, Via della Lastruccia 3, Sesto Fiorentino, 50019 Firenze, Italy.
| | - Annalisa Salvatore
- Department of Chemistry "Ugo Schiff", University of Florence, and CSGI (Italian Center for Colloid and Surface Science, Via della Lastruccia 3, Sesto Fiorentino, 50019 Firenze, Italy.
| | - Costanza Montis
- Department of Chemistry "Ugo Schiff", University of Florence, and CSGI (Italian Center for Colloid and Surface Science, Via della Lastruccia 3, Sesto Fiorentino, 50019 Firenze, Italy.
| | - Debora Berti
- Department of Chemistry "Ugo Schiff", University of Florence, and CSGI (Italian Center for Colloid and Surface Science, Via della Lastruccia 3, Sesto Fiorentino, 50019 Firenze, Italy.
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9
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Mendozza M, Caselli L, Montis C, Orazzini S, Carretti E, Baglioni P, Berti D. Inorganic nanoparticles modify the phase behavior and viscoelastic properties of non-lamellar lipid mesophases. J Colloid Interface Sci 2019; 541:329-338. [DOI: 10.1016/j.jcis.2019.01.091] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Revised: 01/21/2019] [Accepted: 01/22/2019] [Indexed: 11/30/2022]
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Kihara S, van der Heijden NJ, Seal CK, Mata JP, Whitten AE, Köper I, McGillivray DJ. Soft and Hard Interactions between Polystyrene Nanoplastics and Human Serum Albumin Protein Corona. Bioconjug Chem 2019; 30:1067-1076. [DOI: 10.1021/acs.bioconjchem.9b00015] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Shinji Kihara
- School of Chemical Sciences, The University of Auckland, Auckland 1010, New Zealand
- The MacDiarmid Institute for Advanced Materials and Nanotechnology, Wellington 6140, New Zealand
| | - Nadine J. van der Heijden
- School of Chemical Sciences, The University of Auckland, Auckland 1010, New Zealand
- The MacDiarmid Institute for Advanced Materials and Nanotechnology, Wellington 6140, New Zealand
| | - Chris K. Seal
- School of Chemical Sciences, The University of Auckland, Auckland 1010, New Zealand
- The MacDiarmid Institute for Advanced Materials and Nanotechnology, Wellington 6140, New Zealand
| | - Jitendra P. Mata
- Australian Centre for Neutron Scattering, Australian Nuclear Science and Technology Organisation, Lucas Heights, New South Wales 2234, Australia
| | - Andrew E. Whitten
- Australian Centre for Neutron Scattering, Australian Nuclear Science and Technology Organisation, Lucas Heights, New South Wales 2234, Australia
| | - Ingo Köper
- Institute for Nanoscale Science and Technology, College for Science and Engineering, Flinders University, Adelaide, South Australia 5042, Australia
| | - Duncan J. McGillivray
- School of Chemical Sciences, The University of Auckland, Auckland 1010, New Zealand
- The MacDiarmid Institute for Advanced Materials and Nanotechnology, Wellington 6140, New Zealand
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11
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Marlow JB, McCoy TM, Ho CQ, de Campo L, Knott R, Bell TDM, Tabor RF. Tuning the structure, thermal stability and rheological properties of liquid crystal phases via the addition of silica nanoparticles. Phys Chem Chem Phys 2019; 21:25649-25657. [PMID: 31723955 DOI: 10.1039/c9cp04908h] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The effects of adding silica nanoparticles of varying size and surface chemistry to a liquid crystal system were analysed using small-angle scattering and polarising light microscopy, with varying temperature and applied shear.
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Affiliation(s)
| | | | - Cat Q. Ho
- School of Chemistry
- Monash University
- Clayton 3800
- Australia
| | - Liliana de Campo
- Australian Centre for Neutron Scattering
- Australian Nuclear Science and Technology Organisation
- Lucas Heights
- Australia
| | - Robert Knott
- Australian Centre for Neutron Scattering
- Australian Nuclear Science and Technology Organisation
- Lucas Heights
- Australia
| | | | - Rico F. Tabor
- School of Chemistry
- Monash University
- Clayton 3800
- Australia
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12
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Wlodek M, Kolasinska-Sojka M, Szuwarzynski M, Kereïche S, Kovacik L, Zhou L, Islas L, Warszynski P, Briscoe WH. Supported lipid bilayers with encapsulated quantum dots (QDs) via liposome fusion: effect of QD size on bilayer formation and structure. NANOSCALE 2018; 10:17965-17974. [PMID: 30226255 DOI: 10.1039/c8nr05877f] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Understanding interactions between functional nanoparticles and lipid bilayers is important to many emerging biomedical and bioanalytical applications. In this paper, we report incorporation of hydrophobic cadmium sulphide quantum dots (CdS QDs) into mixed 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC)/1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine (POPE) liposomes, and into their supported bilayers (SLBs). The QDs were found embedded in the hydrophobic regions of the liposomes and the supported bilayers, which retained the QD fluorescent properties. In particular, we studied the effect of the QD size (2.7-5.4 nm in diameter) on the formation kinetics and structure of the supported POPC/POPE bilayers, monitored in situ using quartz crystal microbalance with dissipation monitoring (QCM-D), as the liposomes ruptured onto the substrate. The morphology of the obtained QD-lipid hybrid bilayers was studied using atomic force microscopy (AFM), and their structure by synchrotron X-ray reflectivity (XRR). It was shown that the incorporation of hydrophobic QDs promoted bilayer formation on the PEI cushion, evident from the rupture and fusion of the QD-endowed liposomes at a lower surface coverage compared to the liposomes without QDs. Furthermore, the degree of disruption in the supported bilayer structure caused by the QDs was found to be correlated with the QD size. Our results provide mechanistic insights into the kinetics of the rupturing and formation process of QD-endowed supported lipid bilayers via liposome fusion on polymer cushions.
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Affiliation(s)
- Magdalena Wlodek
- Jerzy Haber Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, Niezapominajek 8, PL-30239 Krakow, Poland.
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13
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PAMAM dendrimer - cell membrane interactions. Adv Colloid Interface Sci 2018; 257:1-18. [PMID: 30008347 DOI: 10.1016/j.cis.2018.06.005] [Citation(s) in RCA: 126] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Revised: 06/20/2018] [Accepted: 06/21/2018] [Indexed: 12/16/2022]
Abstract
PAMAM dendrimers have been conjectured for a wide range of biomedical applications due to their tuneable physicochemical properties. However, their application has been hindered by uncertainties in their cytotoxicity, which is influenced by dendrimer generation (i.e. size and surface group density), surface chemistry, and dosage, as well as cell specificity. In this review, biomedical applications of polyamidoamine (PAMAM) dendrimers and some related cytotoxicity studies are first outlined. Alongside these in vitro experiments, lipid membranes such as supported lipid bilayers (SLBs), liposomes, and Langmuir monolayers have been used as cell membrane models to study PAMAM dendrimer-membrane interactions. Related experimental and theoretical studies are summarized, and the physical insights from these studies are discussed to shed light on the fundamental understanding of PAMAM dendrimer-cell membrane interactions. We conclude with a summary of some questions that call for further investigations.
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Marlow JB, Pottage MJ, McCoy TM, De Campo L, Sokolova A, Bell TDM, Tabor RF. Structural and rheological changes of lamellar liquid crystals as a result of compositional changes and added silica nanoparticles. Phys Chem Chem Phys 2018; 20:16592-16603. [PMID: 29873369 DOI: 10.1039/c8cp02101e] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Lamellar liquid crystals comprising oil, water and surfactant(s) were formulated and analysed in order to examine how these materials responded to the inclusion of inorganic nanoparticles, in terms of their structural and rheological characteristics. Lamellar phases were formed from mixtures of water, para-xylene and Triton X-100, and analysis was performed via small-angle neutron scattering (SANS), polarising light microscopy (PLM), and amplitude and viscosity sweeps. The partial replacement of Triton X-100 with oleic acid appeared to cause an increase in bilayer thickness, attributed to less efficient packing of the different molecules. Addition of oleic acid also appeared to cause both a loss in lamellar repeat ordering, attributed to heterogeneity of the bilayers, and a rise in long range order, potentially caused by the stiffer bilayers. Adding silica nanoparticles of different size and surface chemistry caused a stiffening of the samples at the expense of a longer-range lamellar repeat order. This strengthening is attributed to aggregation at the domain boundaries, and it was found that hydrophobic particles tended to form stronger aggregates while for larger particles (20 nm as opposed to 10 nm) aggregation was apparently reversible. These results give a more comprehensive understanding of how to reliably control the structural and rheological properties of lamellar liquid crystals, and emphasise the importance of the size and surface chemistry of any inclusions, for applications in cosmetics, drug delivery, and microfluidics.
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Affiliation(s)
- Joshua B Marlow
- School of Chemistry, Monash University, Clayton 3800, Australia.
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15
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Mendozza M, Montis C, Caselli L, Wolf M, Baglioni P, Berti D. On the thermotropic and magnetotropic phase behavior of lipid liquid crystals containing magnetic nanoparticles. NANOSCALE 2018; 10:3480-3488. [PMID: 29404545 DOI: 10.1039/c7nr08478a] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The inclusion of superparamagnetic iron oxide nanoparticles (SPIONs) in lipid mesophases is a promising strategy for drug-delivery applications, combining the innate biocompatibility of lipid architectures with SPIONs' response to external magnetic fields. Moreover, the organization of SPIONs within the lipid scaffold can lead to locally enhanced SPIONs concentration and improved magnetic response, which is key to overcome the current limitations of hyperthermic treatments. Here we present a Small-Angle X-ray Scattering (SAXS) structural investigation of the thermotropic and magnetotropic behavior of glyceryl monooleate (GMO)/water mesophases, loaded with hydrophobic SPIONs. We prove that even very low amounts of SPIONs deeply alter the phase behavior and thermotropic properties of the mesophases, promoting a cubic to hexagonal phase transition, which is similarly induced upon application of an Alternating Magnetic Field (AMF). Moreover, in the hexagonal phase SPIONs spontaneously self-assemble within the lipid scaffold into a linear supraparticle. This phase behavior is interpreted in the framework of the Helfrich's theory, which shows that SPIONs affect the mesophase both from a viscoelastic and from a structural standpoint. Finally, the dispersion of these cubic phases into stable magnetic colloidal particles, which retain their liquid crystalline internal structure, is addressed as a promising route towards magneto-responsive drug-delivery systems (DDS).
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Affiliation(s)
- Marco Mendozza
- Department of chemistry and CSGI, University of Florence, Via della Lastruccia 3, Sesto Fiorentino, 50019 Florence, Italy.
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Pauw BR, Smith AJ, Snow T, Terrill NJ, Thünemann AF. The modular small-angle X-ray scattering data correction sequence. J Appl Crystallogr 2017; 50:1800-1811. [PMID: 29217992 PMCID: PMC5713144 DOI: 10.1107/s1600576717015096] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Accepted: 10/17/2017] [Indexed: 12/24/2022] Open
Abstract
Data correction is probably the least favourite activity amongst users experimenting with small-angle X-ray scattering: if it is not done sufficiently well, this may become evident only during the data analysis stage, necessitating the repetition of the data corrections from scratch. A recommended comprehensive sequence of elementary data correction steps is presented here to alleviate the difficulties associated with data correction, both in the laboratory and at the synchrotron. When applied in the proposed order to the raw signals, the resulting absolute scattering cross section will provide a high degree of accuracy for a very wide range of samples, with its values accompanied by uncertainty estimates. The method can be applied without modification to any pinhole-collimated instruments with photon-counting direct-detection area detectors.
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Affiliation(s)
- B. R. Pauw
- Bundesanstalt für Materialforschung und -prüfung (BAM), 12205 Berlin, Germany
| | - A. J. Smith
- Diamond Light Source Ltd, Diamond House, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, UK
| | - T. Snow
- Diamond Light Source Ltd, Diamond House, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, UK
| | - N. J. Terrill
- Diamond Light Source Ltd, Diamond House, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, UK
| | - A. F. Thünemann
- Bundesanstalt für Materialforschung und -prüfung (BAM), 12205 Berlin, Germany
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17
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Tripathy A, Sen P, Su B, Briscoe WH. Natural and bioinspired nanostructured bactericidal surfaces. Adv Colloid Interface Sci 2017; 248:85-104. [PMID: 28780961 PMCID: PMC6643001 DOI: 10.1016/j.cis.2017.07.030] [Citation(s) in RCA: 248] [Impact Index Per Article: 35.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Revised: 07/25/2017] [Accepted: 07/25/2017] [Indexed: 01/22/2023]
Abstract
Bacterial antibiotic resistance is becoming more widespread due to excessive use of antibiotics in healthcare and agriculture. At the same time the development of new antibiotics has effectively ground to a hold. Chemical modifications of material surfaces have poor long-term performance in preventing bacterial build-up and hence approaches for realising bactericidal action through physical surface topography have become increasingly important in recent years. The complex nature of the bacteria cell wall interactions with nanostructured surfaces represents many challenges while the design of nanostructured bactericidal surfaces is considered. Here we present a brief overview of the bactericidal behaviour of naturally occurring and bio-inspired nanostructured surfaces against different bacteria through the physico-mechanical rupture of the cell wall. Many parameters affect this process including the size, shape, density, rigidity/flexibility and surface chemistry of the surface nanotextures as well as factors such as bacteria specificity (e.g. gram positive and gram negative) and motility. Different fabrication methods for such bactericidal nanostructured surfaces are summarised.
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Affiliation(s)
- Abinash Tripathy
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, UK; Centre for Nano Science and Engineering, Indian Institute of Science, Bangalore 560012, India
| | - Prosenjit Sen
- Centre for Nano Science and Engineering, Indian Institute of Science, Bangalore 560012, India
| | - Bo Su
- School of Oral and Dental Sciences, University of Bristol, Bristol BS1 2LY, UK
| | - Wuge H Briscoe
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, UK.
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18
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Beddoes CM, Berge J, Bartenstein JE, Lange K, Smith AJ, Heenan RK, Briscoe WH. Hydrophilic nanoparticles stabilising mesophase curvature at low concentration but disrupting mesophase order at higher concentrations. SOFT MATTER 2016; 12:6049-6057. [PMID: 27340807 DOI: 10.1039/c6sm00393a] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Using high pressure small angle X-ray scattering (HP-SAXS), we have studied monoolein (MO) mesophases at 18 wt% hydration in the presence of 10 nm silica nanoparticles (NPs) at NP-lipid number ratios (ν) of 1 × 10(-6), 1 × 10(-5) and 1 × 10(-4) over the pressure range 1-2700 bar and temperature range 20-60 °C. In the absence of the silica NPs, the pressure-temperature (p-T) phase diagram of monoolein exhibited inverse bicontinuous cubic gyroid (Q), lamellar alpha (Lα), and lamellar crystalline (Lc) phases. The addition of the NPs significantly altered the p-T phase diagram, changing the pressure (p) and the temperature (T) at which the transitions between these mesophases occurred. In particular, a strong NP concentration effect on the mesophase behaviour was observed. At low NP concentration, the p-T region pervaded by the Q phase and the Lα-Q mixture increased, and we attribute this behaviour to the NPs forming clusters at the mesophase domain boundaries, encouraging transition to the mesophase with a higher curvature. At high NP concentrations, the Q phase was no longer observed in the p-T phase diagram. Instead, it was dominated by the lamellar (L) phases until the transition to a fluid isotropic (FI) phase at 60 °C at low pressure. We speculate that NPs formed aggregates with a "chain of pearls" structure at the mesophase domain boundaries, hindering transitions to the mesophases with higher curvatures. These observations were supported by small angle neutron scattering (SANS) and scanning electron microscopy (SEM). Our results have implications to nanocomposite materials and nanoparticle cellular entry where the interactions between NPs and organised lipid structures are an important consideration.
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Affiliation(s)
- Charlotte M Beddoes
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, UK. and Bristol Centre for Functional Nanomaterials, Centre for Nanoscience and Quantum Information, Tyndall Avenue, Bristol BS8 1FD, UK
| | - Johanna Berge
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, UK.
| | - Julia E Bartenstein
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, UK.
| | - Kathrin Lange
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, UK.
| | - Andrew J Smith
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire, OX11 0QX, UK
| | | | - Wuge H Briscoe
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, UK.
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19
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Orsi D, Rimoldi T, Guzmán E, Liggieri L, Ravera F, Ruta B, Cristofolini L. Hydrophobic Silica Nanoparticles Induce Gel Phases in Phospholipid Monolayers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:4868-4876. [PMID: 27133453 DOI: 10.1021/acs.langmuir.6b00813] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Silica nanoparticles (SiNP) can be incorporated in phospholipid layers to form hybrid organic-inorganic bidimensional mesostructures. Controlling the dynamics in these mesostructures paves the way to high-performance drug-delivery systems. Depending on the different hydrophobicity/hydrophilicity of SiNP, recent X-ray reflectivity experiments have demonstrated opposite structural effects. While these are reasonably well understood, less is known about the effects on the dynamics, which in turn determine molecular diffusivity and the possibility of drug release. In this work we characterize the dynamics of a mixed Langmuir layer made of phospholipid and hydrophobic SiNP. We combine X-ray photon correlation spectroscopy and epifluorescence discrete Fourier microscopy to cover more than 2 decades of Q-range (0.3-80 μm(-1)). We obtain evidence for the onset of an arrested state characterized by intermittent stress-relaxation rearrangement events, corresponding to a gel dominated by attractive interactions. We compare this with our previous results from phospholipid/hydrophilic SiNP films, which show an arrested glassy phase of repulsive disks.
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Affiliation(s)
- Davide Orsi
- Dipartimento di Fisica e Scienze della Terra, Università degli Studi di Parma , Parma, Italy
| | - Tiziano Rimoldi
- Dipartimento di Fisica e Scienze della Terra, Università degli Studi di Parma , Parma, Italy
| | - Eduardo Guzmán
- Consiglio Nazionale delle Ricerche - Istituto per l'Energetica e le Interfasi, U.O.S. Genova (CNR IENI) , Genova, Italy
| | - Libero Liggieri
- Consiglio Nazionale delle Ricerche - Istituto per l'Energetica e le Interfasi, U.O.S. Genova (CNR IENI) , Genova, Italy
| | - Francesca Ravera
- Consiglio Nazionale delle Ricerche - Istituto per l'Energetica e le Interfasi, U.O.S. Genova (CNR IENI) , Genova, Italy
| | - Beatrice Ruta
- ESRF-The European Synchrotron, CS 40220, 38043 Grenoble, Cedex 9, France
| | - Luigi Cristofolini
- Dipartimento di Fisica e Scienze della Terra, Università degli Studi di Parma , Parma, Italy
- Consiglio Nazionale delle Ricerche - Istituto per l'Energetica e le Interfasi, U.O.S. Genova (CNR IENI) , Genova, Italy
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