51
|
Peng S, Hartley PG, Hughes TC, Guo Q. Enhancing thermal stability and mechanical properties of lyotropic liquid crystals through incorporation of a polymerizable surfactant. SOFT MATTER 2015; 11:6318-6326. [PMID: 26166631 DOI: 10.1039/c5sm01646k] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We present a facile method to prepare thermally stable and mechanically robust crosslinked lyotropic liquid crystals (LLCs) through incorporation of a polymerizable amphiphile into a binary LLC system comprising commercially available surfactant Brij 97 and water. Thermal stability and mechanical properties of the polymerized LLCs were significantly enhanced after polymerization of the incorporated polymerizable surfactant. The effect of incorporating a polymerizable amphiphile on the phase behavior of the LLC system was studied in detail. In situ photo-rheology was used to monitor the change in the mechanical properties of the LLCs, namely the storage modulus, loss modulus, and viscosity, upon polymerization. The retention of the LLC nanostructures was evaluated by small angle X-ray scattering (SAXS). The ability to control the thermal stability and mechanical strength of LLCs simply by adding a polymerizable amphiphile, without tedious organic synthesis or harsh polymerization conditions, could prove highly advantageous in the preparation of robust nanomaterials with well-defined periodic structures.
Collapse
Affiliation(s)
- Shuhua Peng
- Polymers Research Group, Institute for Frontier Materials, Deakin University, Locked Bag 20000, Geelong, Victoria 3220, Australia.
| | | | | | | |
Collapse
|
52
|
Chong JYT, Mulet X, Keddie DJ, Waddington L, Mudie ST, Boyd BJ, Drummond CJ. Novel steric stabilizers for lyotropic liquid crystalline nanoparticles: PEGylated-phytanyl copolymers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:2615-2629. [PMID: 25068381 DOI: 10.1021/la501471z] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Lyotropic liquid crystalline nanostructured particles (e.g., cubosomes and hexosomes) are being investigated as delivery systems for therapeutics in biomedical and pharmaceutical applications. Long term stability of these particulate dispersions is generally provided by steric stabilizers, typically commercially available amphiphilic copolymers such as Pluronic F127. Few examples exist of tailored molecular materials designed for lyotropic liquid crystalline nanostructured particle stabilization. A library of PEGylated-phytanyl copolymers (PEG-PHYT) with varying PEG molecular weights (200-14K Da) was synthesized to assess their performance as steric stabilizers for cubosomes and to establish structure-property relationships. The PEGylated-lipid copolymers were first found to self-assemble in excess water in the absence of cubosomes and also displayed thermotropic liquid crystal phase behavior under cross-polarized light microscopy. An accelerated stability assay was used to assess the performance of the copolymers, compared to Pluronic F127, for stabilizing phytantriol-based cubosomes. Several of the PEGylated-lipid copolymers showed steric stabilizer effectiveness comparable to Pluronic F127. Using synchrotron small-angle X-ray scattering and cryo-transmission electron microscopy, the copolymers were shown to retain the native internal lyotropic liquid crystalline structure, double diamond cubic phase (Q2(D)), of phytantriol dispersions; an important attribute for controlling downstream performance.
Collapse
Affiliation(s)
- Josephine Y T Chong
- CSIRO Materials Science and Engineering, Private Bag 10, Clayton, VIC 3169, Australia
| | | | | | | | | | | | | |
Collapse
|
53
|
Chen Z, Greaves TL, Caruso RA, Drummond CJ. Effect of cosolvents on the self-assembly of a non-ionic polyethylene oxide–polypropylene oxide–polyethylene oxide block copolymer in the protic ionic liquid ethylammonium nitrate. J Colloid Interface Sci 2015; 441:46-51. [DOI: 10.1016/j.jcis.2014.11.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Revised: 10/29/2014] [Accepted: 11/02/2014] [Indexed: 11/27/2022]
|
54
|
Liang YL, Conn CE, Drummond CJ, Darmanin C. Uptake of the butyrate receptors, GPR41 and GPR43, in lipidic bicontinuous cubic phases suitable for in meso crystallization. J Colloid Interface Sci 2015; 441:78-84. [DOI: 10.1016/j.jcis.2014.11.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Revised: 11/03/2014] [Accepted: 11/04/2014] [Indexed: 10/24/2022]
|
55
|
Zhai J, Scoble JA, Li N, Lovrecz G, Waddington LJ, Tran N, Muir BW, Coia G, Kirby N, Drummond CJ, Mulet X. Epidermal growth factor receptor-targeted lipid nanoparticles retain self-assembled nanostructures and provide high specificity. NANOSCALE 2015; 7:2905-2913. [PMID: 25516406 DOI: 10.1039/c4nr05200e] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Next generation drug delivery utilising nanoparticles incorporates active targeting to specific sites. In this work, we combined targeting with the inherent advantages of self-assembled lipid nanoparticles containing internal nano-structures. Epidermal growth factor receptor (EGFR)-targeting, PEGylated lipid nanoparticles using phytantriol and 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-PEG-maleimide amphiphiles were created. The self-assembled lipid nanoparticles presented here have internal lyotropic liquid crystalline nano-structures, verified by synchrotron small angle X-ray scattering and cryo-transmission electron microscopy, that offer the potential of high drug loading and enhanced cell penetration. Anti-EGFR Fab' fragments were conjugated to the surface of nanoparticles via a maleimide-thiol reaction at a high conjugation efficiency and retained specificity following conjugation to the nanoparticles. The conjugated nanoparticles were demonstrated to have high affinity for an EGFR target in a ligand binding assay.
Collapse
Affiliation(s)
- Jiali Zhai
- CSIRO Manufacturing Flagship, Private Bag 10, Clayton, VIC 3169, Australia.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
56
|
Barriga HMG, Tyler AII, McCarthy NLC, Parsons ES, Ces O, Law RV, Seddon JM, Brooks NJ. Temperature and pressure tuneable swollen bicontinuous cubic phases approaching nature's length scales. SOFT MATTER 2015; 11:600-607. [PMID: 25430049 DOI: 10.1039/c4sm02343a] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Bicontinuous cubic structures offer enormous potential in applications ranging from protein crystallisation to drug delivery systems and have been observed in cellular membrane structures. One of the current bottlenecks in understanding and exploiting these structures is that cubic scaffolds produced in vitro are considerably smaller in size than those observed in biological systems, differing by almost an order of magnitude in some cases. We have addressed this technological bottleneck and developed a methodology capable of manufacturing highly swollen bicontinuous cubic membranes with length scales approaching those seen in vivo. Crucially, these cubic systems do not require the presence of proteins. We have generated highly swollen Im3m symmetry bicontinuous cubic phases with lattice parameters of up to 480 Å, composed of ternary mixtures of monoolein, cholesterol and negatively charged lipid (DOPS or DOPG) and we have been able to tune their lattice parameters. The swollen cubic phases are highly sensitive to both temperature and pressure; these structural changes are likely to be controlled by a fine balance between lipid headgroup repulsions and lateral pressure in the hydrocarbon chain region.
Collapse
Affiliation(s)
- H M G Barriga
- Department of Chemistry, Imperial College London, South Kensington Campus, London SW7 2AZ, UK.
| | | | | | | | | | | | | | | |
Collapse
|
57
|
Abstract
In this chapter the use of X-ray diffraction to study the structure of lyotropic phases and lipid model membranes is described. Determination of the phase symmetry and lattice parameters from small-angle X-ray scattering (SAXS), and of the nature of the hydrocarbon chain packing from wide-angle X-ray scattering (WAXS), are discussed. Methods by which the sign of the interfacial curvature of non-lamellar phases may be determined are then presented. Finally, the calculation of electron density profiles from the intensities of the observed Bragg peaks is described, for the lamellar phase and for the inverse hexagonal phase.
Collapse
Affiliation(s)
- Arwen I I Tyler
- Department of Chemistry, Imperial College London, South Kensington Campus, London, SW7 2AZ, UK,
| | | | | |
Collapse
|
58
|
Tran N, Mulet X, Hawley AM, Hinton TM, Mudie ST, Muir BW, Giakoumatos EC, Waddington LJ, Kirby NM, Drummond CJ. Nanostructure and cytotoxicity of self-assembled monoolein–capric acid lyotropic liquid crystalline nanoparticles. RSC Adv 2015. [DOI: 10.1039/c5ra02604k] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Monoolein–capric acid combinations form into particles with internal nanostructures, including inverse hexagonal and bicontinuous cubic mesophases, with differing cytotoxicity.
Collapse
Affiliation(s)
- Nhiem Tran
- CSIRO Manufacturing Flagship
- Clayton
- 3168 Australia
- SAXS/WAXS beamline
- Australian Synchrotron
| | - Xavier Mulet
- CSIRO Manufacturing Flagship
- Clayton
- 3168 Australia
| | | | - Tracey M. Hinton
- CSIRO Animal, Food and Health Sciences
- Australian Animal Health Laboratory
- East Geelong
- 3219 Australia
| | | | | | | | | | - Nigel M. Kirby
- SAXS/WAXS beamline
- Australian Synchrotron
- Clayton
- 3168 Australia
| | - Calum J. Drummond
- CSIRO Manufacturing Flagship
- Clayton
- 3168 Australia
- School of Applied Sciences
- College of Science, Engineering and Health
| |
Collapse
|
59
|
Hartnett TE, Ladewig K, O'Connor AJ, Hartley PG, McLean KM. Physicochemical and cytotoxicity analysis of glycerol monoolein-based nanoparticles. RSC Adv 2015. [DOI: 10.1039/c4ra13890b] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
This article demonstrates the importance of stabiliser selection and temperature control when producing cubosomes using the ‘salt-induced’ production technique.
Collapse
Affiliation(s)
- Terence E. Hartnett
- Department of Chemical and Biomolecular Engineering and Particulate Fluids Processing Centre (PFPC)
- The University of Melbourne
- Parkville
- Australia
- Commonwealth Scientific and Industrial Research Organisation (CSIRO)
| | - Katharina Ladewig
- Department of Chemical and Biomolecular Engineering and Particulate Fluids Processing Centre (PFPC)
- The University of Melbourne
- Parkville
- Australia
| | - Andrea J. O'Connor
- Department of Chemical and Biomolecular Engineering and Particulate Fluids Processing Centre (PFPC)
- The University of Melbourne
- Parkville
- Australia
| | - Patrick G. Hartley
- Commonwealth Scientific and Industrial Research Organisation (CSIRO)
- Materials Science and Engineering
- Clayton
- Australia
| | - Keith M. McLean
- Commonwealth Scientific and Industrial Research Organisation (CSIRO)
- Materials Science and Engineering
- Clayton
- Australia
| |
Collapse
|
60
|
Meersman F, McMillan PF. High hydrostatic pressure: a probing tool and a necessary parameter in biophysical chemistry. Chem Commun (Camb) 2014; 50:766-75. [PMID: 24286104 DOI: 10.1039/c3cc45844j] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
High pressures extending up to several thousands of atmospheres provide extreme conditions for biological organisms to survive. Recent studies are investigating the survival mechanisms and biological function of microorganisms under natural and laboratory conditions extending into the GigaPascal range, with applications to understanding the Earth's deep biosphere and food technology. High pressure has also emerged as a useful tool and physical parameter for probing changes in the structure and functional properties of biologically important macromolecules and polymers encountered in soft matter science. Here we highlight some areas of current interest in high pressure biophysics and physical chemistry that are emerging at the frontier of this cross-disciplinary field.
Collapse
Affiliation(s)
- Filip Meersman
- Department of Chemistry, University College London, 20 Gordon St., London WC1H 0AJ, UK.
| | | |
Collapse
|
61
|
Brooks NJ. Pressure effects on lipids and bio-membrane assemblies. IUCRJ 2014; 1:470-7. [PMID: 25485127 PMCID: PMC4224465 DOI: 10.1107/s2052252514019551] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Accepted: 08/28/2014] [Indexed: 05/06/2023]
Abstract
Membranes are amongst the most important biological structures; they maintain the fundamental integrity of cells, compartmentalize regions within them and play an active role in a wide range of cellular processes. Pressure can play a key role in probing the structure and dynamics of membrane assemblies, and is also critical to the biology and adaptation of deep-sea organisms. This article presents an overview of the effect of pressure on the mesostructure of lipid membranes, bilayer organization and lipid-protein assemblies. It also summarizes recent developments in high-pressure structural instrumentation suitable for experiments on membranes.
Collapse
Affiliation(s)
- Nicholas J. Brooks
- Department of Chemistry, Imperial College London, South Kensington Campus, London SW7 2AZ, England
| |
Collapse
|
62
|
Chong JYT, Mulet X, Postma A, Keddie DJ, Waddington LJ, Boyd BJ, Drummond CJ. Novel RAFT amphiphilic brush copolymer steric stabilisers for cubosomes: poly(octadecyl acrylate)-block-poly(polyethylene glycol methyl ether acrylate). SOFT MATTER 2014; 10:6666-6676. [PMID: 25058647 DOI: 10.1039/c4sm01064g] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Copolymers, particularly Pluronics®, are typically used to sterically stabilise colloidal nanostructured particles composed of a lyotropic liquid crystalline bicontinuous cubic phase (cubosomes). There is a need to design and assess new functionalisable stabilisers for these colloidal drug delivery systems. Six amphiphilic brush copolymers, poly(octadecyl acrylate)-block-poly(polyethylene glycol methyl ether acrylate) (P(ODA)-b-P(PEGA-OMe)), synthesised by reversible addition-fragmentation chain transfer (RAFT), were assessed as novel steric stabilisers for cubosomes. It was found that increasing the density of PEG on the nanostructured particle surface by incorporating a PEG brush design (i.e., brush copolymer), provided comparable and/or increased stabilisation effectiveness compared to a linear PEG structure, Pluronic® F127, which is extensively used for steric stabilisation of cubosomes. Assessment was conducted both prior to and following the removal of the dodecyl trithiocarbonate end-group, by free radical-induced reduction. The reduced (P(ODA)-b-P(PEGA-OMe) copolymers were more effective steric stabilisers for phytantriol and monoolein colloidal particle dispersions than their non-reduced analogues. High throughput characterisation methodologies, including an accelerated stability assay (ASA) and synchrotron small angle X-ray scattering (SAXS), were implemented in this study for the rapid assessment of steric stabiliser effectiveness and lyotropic liquid crystalline phase identification. Phytantriol cubosomes stabilised with P(ODA)-b-P(PEGA-OMe) copolymers exhibited a double diamond cubic phase (Q(2)(D)), whilst monoolein cubosomes exhibited a primitive cubic phase (Q(2)(P)), analogous to those formed using Pluronic® F127.
Collapse
Affiliation(s)
- Josephine Y T Chong
- CSIRO Materials Science and Engineering, Private Bag 10, Clayton, VIC 3169, Australia.
| | | | | | | | | | | | | |
Collapse
|
63
|
Bye N, Hutt OE, Hinton TM, Acharya DP, Waddington LJ, Moffat BA, Wright DK, Wang HX, Mulet X, Muir BW. Nitroxide-loaded hexosomes provide MRI contrast in vivo. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:8898-8906. [PMID: 24979524 DOI: 10.1021/la5007296] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The purpose of this work was to synthesize and screen, for their effectiveness to act as T1-enhancing magnetic resonance imaging (MRI) contrast agents, a small library of nitroxide lipids incorporated into cubic-phase lipid nanoparticles (cubosomes). The most effective nitroxide lipid was then formulated into lower-toxicity lipid nanoparticles (hexosomes), and effective MR contrast was observed in the aorta and spleen of live rats in vivo. This new class of lower-toxicity lipid nanoparticles allowed for higher relaxivities on the order of those of clinically used gadolinium complexes. The new hexosome formulation presented herein was significantly lower in toxicity and higher in relaxivity than cubosome formulations previously reported by us.
Collapse
Affiliation(s)
- Nicole Bye
- National Trauma Research Institute, Alfred Hospital and Department of Surgery, Monash University , Melbourne 3000, Australia
| | | | | | | | | | | | | | | | | | | |
Collapse
|
64
|
Hartnett TE, Ladewig K, O’Connor AJ, Hartley PG, McLean KM. Size and Phase Control of Cubic Lyotropic Liquid Crystal Nanoparticles. J Phys Chem B 2014; 118:7430-9. [DOI: 10.1021/jp502898a] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Affiliation(s)
- Terence E. Hartnett
- Department
of Chemical and Biomolecular Engineering and Particulate Fluids Processing
Centre (PFPC), The University of Melbourne, Parkville, VIC 3010, Australia
- Commonwealth
Scientific and Industrial Research Organisation (CSIRO), Materials Science and Engineering, Clayton, VIC 3168, Australia
| | - Katharina Ladewig
- Department
of Chemical and Biomolecular Engineering and Particulate Fluids Processing
Centre (PFPC), The University of Melbourne, Parkville, VIC 3010, Australia
| | - Andrea J. O’Connor
- Department
of Chemical and Biomolecular Engineering and Particulate Fluids Processing
Centre (PFPC), The University of Melbourne, Parkville, VIC 3010, Australia
| | - Patrick G. Hartley
- Commonwealth
Scientific and Industrial Research Organisation (CSIRO), Materials Science and Engineering, Clayton, VIC 3168, Australia
| | - Keith M. McLean
- Commonwealth
Scientific and Industrial Research Organisation (CSIRO), Materials Science and Engineering, Clayton, VIC 3168, Australia
| |
Collapse
|
65
|
Chong JYT, Mulet X, Boyd BJ, Drummond CJ. Accelerated stability assay (ASA) for colloidal systems. ACS COMBINATORIAL SCIENCE 2014; 16:205-10. [PMID: 24673241 DOI: 10.1021/co400155y] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Assessment of the stability of colloidal systems, in particular lyotropic liquid crystalline dispersions, such as cubosomes and hexosomes, is typically performed qualitatively or with limited throughput on specialized instruments. Here, an accelerated stability assay for colloidal particles has been developed in 384-well plates with standard laboratory equipment. These protocols enable quantitative assessments of colloidal stability. To demonstrate the applicability of the assay, several steric stabilizers for cubic phase nanostructured particles (cubosomes) have been compared to the current "gold standard" Pluronic F127.
Collapse
Affiliation(s)
- Josephine Y. T. Chong
- CSIRO Materials Science and Engineering, Private
Bag 10, Clayton, Victoria 3169, Australia
- Drug
Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical
Science, Monash University (Parkville Campus), 381 Royal Parade, Parkville, Victoria 3052, Australia
| | - Xavier Mulet
- CSIRO Materials Science and Engineering, Private
Bag 10, Clayton, Victoria 3169, Australia
- Drug
Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical
Science, Monash University (Parkville Campus), 381 Royal Parade, Parkville, Victoria 3052, Australia
| | - Ben J. Boyd
- Drug
Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical
Science, Monash University (Parkville Campus), 381 Royal Parade, Parkville, Victoria 3052, Australia
| | - Calum J. Drummond
- CSIRO Materials Science and Engineering, Private
Bag 10, Clayton, Victoria 3169, Australia
- School
of Applied Sciences, College of Science, Engineering and Health, RMIT University, GPO
Box 2476, Melbourne, Victoria 3001, Australia
| |
Collapse
|
66
|
Tang TYD, Seddon AM, Jeworrek C, Winter R, Ces O, Seddon JM, Templer RH. The effects of pressure and temperature on the energetics and pivotal surface in a monoacylglycerol/water gyroid inverse bicontinuous cubic phase. SOFT MATTER 2014; 10:3009-3015. [PMID: 24695766 DOI: 10.1039/c4sm00114a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We have studied the effect of pressure and temperature on the location of the pivotal surface in a lipid inverse bicontinuous gyroid cubic phase (Q(G)(II)), described by the area at the pivotal surface (An), the volume between the pivotal surface and the bilayer midplane (Vn), and the molecular volume of the lipid (V). Small angle X-ray scattering (SAXS) was used to measure the swelling behaviour of the lipid, monolinolein, as a function of pressure and temperature, and the data were fitted to two different geometric models: the parallel interface model (PIM), and the constant mean curvature model (CMCM). The results show that an increase in temperature leads to a shift in the location of the pivotal surface towards the bilayer midplane, whilst an increase in pressure causes the pivotal surface to move towards the interfacial region. In addition, we describe the relevance of An, Vn and V for modeling the energetics of curved mesophases with specific reference to the mean curvature at the pivotal surface and discuss the significance of this parameter for modelling the energetics of curved mesophases.
Collapse
Affiliation(s)
- T-Y Dora Tang
- Department of Chemistry, Imperial College London, Exhibition Road, London, SW7 2AY, UK
| | | | | | | | | | | | | |
Collapse
|
67
|
Feast GC, Hutt OE, Mulet X, Conn CE, Drummond CJ, Savage GP. The High-Throughput Synthesis and Phase Characterisation of Amphiphiles: A Sweet Case Study. Chemistry 2014; 20:2783-92. [DOI: 10.1002/chem.201303514] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Indexed: 12/12/2022]
|
68
|
Peng S, Guo Q, Hughes TC, Hartley PG. Reversible photorheological lyotropic liquid crystals. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:866-872. [PMID: 24011217 DOI: 10.1021/la4030469] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
We describe novel lyotropic liquid-crystalline (LLC) materials based on photoresponsive amphiphiles that exhibit rapid photoswitchable rheological properties of unprecedented magnitude between solidlike and liquidlike states. This was achieved through the synthesis of a novel azobenzene-containing surfactant (azo-surfactant) that actuates the transition between different LLC forms depending on illumination conditions. Initially, the azo-surfactant/water mixtures formed highly ordered and viscous LLC phases at 20-55 wt % water content. Spectroscopic, microscopic, and rheological analysis confirmed that UV irradiation induced the trans to cis isomerization of the azo-surfactant, leading to the disruption of the ordered LLC phases and a dramatic, rapid decrease in the viscosity and modulus resulting in a 3 orders of magnitude change from a solid (20,000 Pa) to a liquid (50 Pa) at rate of 13,500 Pa/s. Subsequent exposure to visible light reverses the transition, returning the viscosity essentially to its initial state. Such large, rapid, and reversible changes in rheological properties within this LLC system may open a door to new applications for photorheological fluids.
Collapse
Affiliation(s)
- Shuhua Peng
- Polymers Research Group, Institute for Frontier Materials, Deakin University , Locked Bag 2000, Geelong, Victoria 3220, Australia
| | | | | | | |
Collapse
|
69
|
Zahid NI, Conn CE, Brooks NJ, Ahmad N, Seddon JM, Hashim R. Investigation of the effect of sugar stereochemistry on biologically relevant lyotropic phases from branched-chain synthetic glycolipids by small-angle X-ray scattering. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:15794-15804. [PMID: 24274824 DOI: 10.1021/la4040134] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Synthetic branched-chain glycolipids are suitable as model systems in understanding biological cell membranes, particularly because certain natural lipids possess chain branching. Herein, four branched-chain glycopyranosides, namely, 2-hexyl-decyl-α-D-glucopyranoside (α-Glc-OC10C6), 2-hexyl-decyl-β-D-glucopyranoside (β-Glc-OC10C6), 2-hexyl-decyl-α-D-galactopyranoside (α-Gal-OC10C6), and 2-hexyl-decyl-β-D-galactopyranoside (β-Gal-OC10C6), with a total alkyl chain length of 16 carbon atoms have been synthesized, and their phase behavior has been studied. The partial binary phase diagrams of these nonionic surfactants in water were investigated by optical polarizing microscopy (OPM) and small-angle X-ray scattering (SAXS). The introduction of chain branching in the hydrocarbon chain region is shown to result in the formation of inverse structures such as inverse hexagonal and inverse bicontinuous cubic phases. A comparison of the four compounds showed that they exhibited different polymorphism, especially in the thermotropic state, as a result of contributions from anomeric and epimeric effects according to their stereochemistry. The neat α-Glc-OC10C6 compound exhibited a lamellar (Lα) phase whereas dry α-Gal-OC10C6 formed an inverse bicontinuous cubic Ia3d (QII(G)) phase. Both β-anomers of glucoside and galactoside adopted the inverse hexagonal phase (HII) in the dry state. Generally, in the presence of water, all four glycolipids formed inverse bicontinuous cubic Ia3d (QII(G)) and Pn3m (QII(D)) phases over wide temperature and concentration ranges. The formation of inverse nonlamellar phases by these Guerbet branched-chain glycosides confirms their potential as materials for novel biotechnological applications such as drug delivery and crystallization of membrane proteins.
Collapse
Affiliation(s)
- N Idayu Zahid
- Department of Chemistry, Faculty of Science, University of Malaya , 50603 Kuala Lumpur, Malaysia
| | | | | | | | | | | |
Collapse
|
70
|
Turek VA, Elliott LN, Tyler AII, Demetriadou A, Paget J, Cecchini MP, Kucernak AR, Kornyshev AA, Edel JB. Self-assembly and applications of ultraconcentrated nanoparticle solutions. ACS NANO 2013; 7:8753-8759. [PMID: 24070428 DOI: 10.1021/nn403131e] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
We demonstrate a highly efficient method for concentrating, purifying and separating gold nanoparticles. The method relies on localized density gradients that can be formed at an aqueous | organic phase interface. We show that this method is able to concentrate aqueous gold nanoparticles to the point where confinement leads to variable interparticle separations. Furthermore, the physical properties of the resulting solution are drastically altered when compared to water. For example, densities higher than 4.5 g/cm(3) could be generated without nanoparticle aggregation. As far as we are aware, this is one of the highest reported densities of an aqueous solution at room temperature. Finally, the compositions of the solutions generated are highly dependent on parameters such as particle size and background analyte making this technique highly advantageous for the separation of multimodal NP populations and chemical purification, with 99.5% and >99.9% efficiency, respectively.
Collapse
Affiliation(s)
- Vladimir A Turek
- Department of Chemistry, Imperial College London , South Kensington Campus, London, SW7 2AZ United Kingdon
| | | | | | | | | | | | | | | | | |
Collapse
|
71
|
Driever CD, Mulet X, Waddington LJ, Postma A, Thissen H, Caruso F, Drummond CJ. Layer-by-layer polymer coating on discrete particles of cubic lyotropic liquid crystalline dispersions (cubosomes). LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:12891-12900. [PMID: 24033086 DOI: 10.1021/la401660h] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Cubic phase lyotropic liquid crystalline colloidal dispersions (cubosomes) were surface-modified with seven polyelectrolyte layers using a layer-by-layer (LbL) approach. The first layer consisted of a copolymer synthesized from methacrylic acid and oleoyl methacrylate for enhanced incorporation within the bilayer of the cubic nanostructure. Six additional layers of poly(L-lysine) and poly(methacrylic acid) were then sequentially added, followed by a washing procedure to remove polymer aggregates from the soft matter particles. Polymer buildup was monitored via microelectrophoresis, dynamic light scattering, and small-angle X-ray scattering. Polymer-coated cubosomes were observed with cryo-transmission electron microscopy. A potential application of the modified nanostructured particles presented in this study is to reduce the burst-release effect associated with drug-loaded cubosomes. The effectiveness of this approach was demonstrated through loading and release results from a model hydrophilic small molecule (fluorescein).
Collapse
Affiliation(s)
- Chantelle D Driever
- Department of Chemical and Biomolecular Engineering, The University of Melbourne , Parkville, VIC 3010, Australia
| | | | | | | | | | | | | |
Collapse
|
72
|
Controlling nanostructure and lattice parameter of the inverse bicontinuous cubic phases in functionalised phytantriol dispersions. J Colloid Interface Sci 2013; 408:117-24. [DOI: 10.1016/j.jcis.2013.07.002] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2013] [Revised: 07/01/2013] [Accepted: 07/02/2013] [Indexed: 01/29/2023]
|
73
|
Rittman M, Amenitsch H, Rappolt M, Sartori B, O'Driscoll BMD, Squires AM. Control and analysis of oriented thin films of lipid inverse bicontinuous cubic phases using grazing incidence small-angle X-ray scattering. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:9874-9880. [PMID: 23837868 DOI: 10.1021/la401580y] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Lipid cubic phases are complex nanostructures that form naturally in a variety of biological systems, with applications including drug delivery and nanotemplating. Most X-ray scattering studies on lipid cubic phases have used unoriented polydomain samples as either bulk gels or suspensions of micrometer-sized cubosomes. We present a method of investigating cubic phases in a new form, as supported thin films that can be analyzed using grazing incidence small-angle X-ray scattering (GISAXS). We present GISAXS data on three lipid systems: phytantriol and two grades of monoolein (research and industrial). The use of thin films brings a number of advantages. First, the samples exhibit a high degree of uniaxial orientation about the substrate normal. Second, the new morphology allows precise control of the substrate mesophase geometry and lattice parameter using a controlled temperature and humidity environment, and we demonstrate the controllable formation of oriented diamond and gyroid inverse bicontinuous cubic along with lamellar phases. Finally, the thin film morphology allows the induction of reversible phase transitions between these mesophase structures by changes in humidity on subminute time scales, and we present time-resolved GISAXS data monitoring these transformations.
Collapse
Affiliation(s)
- Martyn Rittman
- Department of Chemistry, University of Reading, Whiteknights, Reading RG6 6AD, UK
| | | | | | | | | | | |
Collapse
|
74
|
Mulet X, Conn CE, Fong C, Kennedy DF, Moghaddam MJ, Drummond CJ. High-throughput development of amphiphile self-assembly materials: fast-tracking synthesis, characterization, formulation, application, and understanding. Acc Chem Res 2013; 46:1497-505. [PMID: 23427836 DOI: 10.1021/ar300285u] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Amphiphile self-assembly materials, which contain both a hydrophilic and a hydrophobic domain, have great potential in high-throughput and combinatorial approaches to discovery and development. However, the materials chemistry community has not embraced these ideas to anywhere near the extent that the medicinal chemistry community has. While this situation is beginning to change, extracting the full potential of high-throughput approaches in the development of self-assembling materials will require further development in the synthesis, characterization, formulation, and application domains. One of the key factors that make small molecule amphiphiles prospective building blocks for next generation multifunctional materials is their ability to self-assemble into complex nanostructures through low-energy transformations. Scientists can potentially tune, control, and functionalize these structures, but only after establishing their inherent properties. Because both robotic materials handling and customized rapid characterization equipment are increasingly available, high-throughput solutions are now attainable. These address traditional development bottlenecks associated with self-assembling amphiphile materials, such as their structural characterization and the assessment of end-use functional performance. A high-throughput methodology can help streamline materials development workflows, in accord with existing high-throughput discovery pipelines such as those used by the pharmaceutical industry in drug discovery. Chemists have identified several areas that are amenable to a high-throughput approach for amphiphile self-assembly materials development. These allow an exploration of not only a large potential chemical, compositional, and structural space, but also material properties, formulation, and application variables. These areas of development include materials synthesis and preparation, formulation, characterization, and screening performance for the desired end application. High-throughput data analysis is crucial at all stages to keep pace with data collection. In this Account, we describe high-throughput advances in the field of amphiphile self-assembly, focusing on nanostructured lyotropic liquid crystalline materials, which form when amphiphiles are added to a polar solvent. We outline recent progress in the automated preparation of amphiphile molecules and their nanostructured self-assembly systems both in the bulk phase and in dispersed colloidal particulate systems. Once prepared, we can structurally characterize these systems by establishing phase behavior in a high-throughput manner with both laboratory (infrared and light polarization microscopy) and synchrotron facilities (small-angle X-ray scattering). Additionally, we provide three case studies to demonstrate how chemists can use high-throughput approaches to evaluate the functional performance of amphiphile self-assembly materials. The high-throughput methodology for the set-up and characterization of large matrix in meso membrane protein crystallization trials can illustrate an application of bulk phase self-assembling amphiphiles. For dispersed colloidal systems, two nanomedicine examples highlight advances in high-throughput preparation, characterization, and evaluation: drug delivery and magnetic resonance imaging agents.
Collapse
Affiliation(s)
- Xavier Mulet
- CSIRO Materials Science and Engineering, Private Bag 10, Clayton, VIC 3169, Australia
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University (Parkville campus), 381 Royal Parade, Parkville, VIC 3052, Australia
| | - Charlotte E. Conn
- CSIRO Materials Science and Engineering, Private Bag 10, Clayton, VIC 3169, Australia
| | - Celesta Fong
- CSIRO Materials Science and Engineering, Private Bag 10, Clayton, VIC 3169, Australia
| | - Danielle F. Kennedy
- CSIRO Materials Science and Engineering, Private Bag 10, Clayton, VIC 3169, Australia
| | - Minoo J. Moghaddam
- CSIRO Materials Science and Engineering, Riverside Life Sciences Centre, 11 Julius Avenue, North Ryde, NSW 2113, Australia
| | - Calum J. Drummond
- CSIRO Materials Science and Engineering, Private Bag 10, Clayton, VIC 3169, Australia
| |
Collapse
|
75
|
Abstract
The physiological properties of biological soft matter are the product of collective interactions, which span many time and length scales. Recent computational modeling efforts have helped illuminate experiments that characterize the ways in which proteins modulate membrane physics. Linking these models across time and length scales in a multiscale model explains how atomistic information propagates to larger scales. This paper reviews continuum modeling and coarse-grained molecular dynamics methods, which connect atomistic simulations and single-molecule experiments with the observed microscopic or mesoscale properties of soft-matter systems essential to our understanding of cells, particularly those involved in sculpting and remodeling cell membranes.
Collapse
Affiliation(s)
- Ryan Bradley
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Ravi Radhakrishnan
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104, USA
- Author to whom correspondence should be addressed; ; Tel.: +1-215-898-0487; Fax: +1-215-573-2071
| |
Collapse
|
76
|
Recent Developments in the Production, Analysis, and Applications of Cubic Phases Formed by Lipids. ACTA ACUST UNITED AC 2013. [DOI: 10.1016/b978-0-12-411515-6.00006-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
|
77
|
Hutt OE, Mulet X, Savage GP. Click-chemistry as a mix-and-match kit for amphiphile synthesis. ACS COMBINATORIAL SCIENCE 2012; 14:565-9. [PMID: 22998021 DOI: 10.1021/co300080g] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
A small library of amphiphilic compounds was synthesized in an array using the Huisgen 1,3-dipolar cycloaddition of terminal alkynes with azides (CuAAC or click reaction). The self-assembling properties of these compounds were evaluated by polarizing microscopy and synchrotron small-angle X-ray scattering analysis.
Collapse
Affiliation(s)
- Oliver E. Hutt
- CSIRO Materials Science and Engineering, Private Bag 10, Clayton South MDC, Vic 3169, Australia
| | - Xavier Mulet
- CSIRO Materials Science and Engineering, Private Bag 10, Clayton South MDC, Vic 3169, Australia
| | - G. Paul Savage
- CSIRO Materials Science and Engineering, Private Bag 10, Clayton South MDC, Vic 3169, Australia
| |
Collapse
|
78
|
Kulkarni CV. Lipid crystallization: from self-assembly to hierarchical and biological ordering. NANOSCALE 2012; 4:5779-91. [PMID: 22899223 DOI: 10.1039/c2nr31465g] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Lipid crystallization is ubiquitous in nature, observed in biological structures as well as in commercial products and applications. In a dehydrated state most of the lipids form well ordered crystals, whereas in an aqueous environment they self-assemble into various crystalline, liquid crystalline or sometimes macroscopically disordered phases. Lipid self-organization extends further to hierarchical levels including structured emulsions and nanostructured particles. Many consumer products including cosmetics, foods and medicines account for such lipid architectures. Cell membranes primarily consist of planar lipid bilayers; however sub-cellular biomembranes are more of a convoluted type. Some of the biological entities have lipids in truly crystalline form; yet liquid crystalline lipid phases are prevalent, in general. Crystallization of fats - triglyceride lipids - has been relatively well documented and reviewed more often, but this review features other areas where lipid organization is crucial and diverse. Some recent advances along with a few explicit examples of model lipid phases and biological evidences are also reported.
Collapse
Affiliation(s)
- Chandrashekhar V Kulkarni
- Biological and Soft Systems, Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0HE, UK.
| |
Collapse
|
79
|
Tang TYD, Brooks NJ, Jeworrek C, Ces O, Terrill NJ, Winter R, Templer RH, Seddon JM. Hydrostatic pressure effects on the lamellar to gyroid cubic phase transition of monolinolein at limited hydration. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012; 28:13018-13024. [PMID: 22894718 DOI: 10.1021/la3025843] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Monoacylglycerol based lipids are highly important model membrane components and attractive candidates for drug encapsulation and as delivery agents. However, optimizing the properties of these lipids for applications requires a detailed understanding of the thermodynamic factors governing the self-assembled structures that they form. Here, we report on the effects of hydrostatic pressure, temperature, and water composition on the structural behavior and stability of inverse lyotropic liquid crystalline phases adopted by monolinolein (an unsaturated monoacylglycerol having cis-double bonds at carbon positions 9 and 12) under limited hydration conditions. Six pressure-temperature phase diagrams have been determined using small-angle X-ray diffraction at water contents between 15 wt % and 27 wt % water, in the range 10-40 °C and 1-3000 bar. The gyroid bicontinuous cubic (Q(II)(G)) phase is formed at low pressure and high temperatures, transforming to a fluid lamellar (L(α)) phase at high pressures and low temperature via a region of Q(II)(G)/L(α) coexistence. Pressure stabilizes the lamellar phase over the Q(II)(G) phase; at fixed pressure, increasing the water content causes the coexistence region to move to lower temperature. These trends are consistent throughout the hydration range studied. Moreover, at fixed temperature, increasing the water composition increases the pressure at which the Q(II)(G) to L(α) transition takes place. We discuss the qualitative effect of pressure, temperature, and water content on the stability of the Q(II)(G) phase.
Collapse
Affiliation(s)
- T-Y Dora Tang
- Department of Chemistry, Imperial College London, London, United Kingdom
| | | | | | | | | | | | | | | |
Collapse
|
80
|
Hyde ST, Schröder-Turk GE. Geometry of interfaces: topological complexity in biology and materials. Interface Focus 2012. [DOI: 10.1098/rsfs.2012.0035] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Stephen T. Hyde
- Department of Applied Mathematics, Research School of Physics and Engineering, The Australian National University, Canberra, Australian Capital Territory 0200, Australia
| | - Gerd E. Schröder-Turk
- Theoretische Physik, Friedrich-Alexander Universität Erlangen-Nürnberg, Staudtstrasse 7B, 91058 Erlangen, Germany
| |
Collapse
|
81
|
Chong JYT, Mulet X, Waddington LJ, Boyd BJ, Drummond CJ. High-throughput discovery of novel steric stabilizers for cubic lyotropic liquid crystal nanoparticle dispersions. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012; 28:9223-9232. [PMID: 22630595 DOI: 10.1021/la301874v] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
High-throughput methodologies have been employed to establish structure-property relationships and assess the effectiveness of nonionic steric stabilizers for inverse bicontinuous cubic lyotropic liquid crystalline nanoparticulate dispersions of monoolein and phytantriol. The ability of the stabilizers to disperse the lipids was compared with that of the commonly employed triblock poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) copolymer Pluronic F127, which was used as a positive control. The poly(ethylene oxide) stearate class of stabilizers (commercially known as Myrj) were discovered to be effective as steric stabilizers for cubosomes, while retaining the internal nanostructure of the "parent" bulk phase. In particular, Myrj 59, with an average of 100 poly(ethylene oxide) units, was more effective than F127 at dispersing phytantriol, forming stable phytantriol cubosome dispersions at a concentration of 0.1 wt %, 5-fold lower than that achievable with Pluronic F127. The discovery of this new effective class of stabilizers for cubosomes, specifically enabled by high-throughput approaches, broadens the versatility of components from which to construct these interesting potential drug delivery and medical imaging nanoparticles.
Collapse
Affiliation(s)
- Josephine Y T Chong
- Commonwealth Scientific and Industrial Research Organisation (CSIRO) Materials Science and Engineering, Private Bag 10, Clayton, Victoria 3169, Australia
| | | | | | | | | |
Collapse
|
82
|
Darmanin C, Conn CE, Newman J, Mulet X, Seabrook SA, Liang YL, Hawley A, Kirby N, Varghese JN, Drummond CJ. High-throughput production and structural characterization of libraries of self-assembly lipidic cubic phase materials. ACS COMBINATORIAL SCIENCE 2012; 14:247-52. [PMID: 22428998 DOI: 10.1021/co2001718] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A protocol is presented for the high-throughput (HT) production of lyotropic liquid crystalline phases from libraries of lipids and lipid mixtures using standard liquid dispensing robotics, implementing methods that circumvent the problems traditionally associated with handling the highly viscous cubic phase. In addition, the ability to structurally characterize lipidic phases and assess functionality for membrane proteins contained within cubic phases, in a HT manner, is demonstrated. The techniques are combined and exemplified using the application of membrane protein crystallization within lipidic cubic phases.
Collapse
Affiliation(s)
- Connie Darmanin
- CSIRO Materials Science and Engineering, 343 Royal Parade, Parkville,
Victoria 3052, Australia
| | - Charlotte E. Conn
- CSIRO Materials Science and Engineering, Private Bag 10, Clayton South
MDC, Victoria 3169, Australia
| | - Janet Newman
- CSIRO Materials Science and Engineering, 343 Royal Parade, Parkville,
Victoria 3052, Australia
| | - Xavier Mulet
- CSIRO Materials Science and Engineering, Private Bag 10, Clayton South
MDC, Victoria 3169, Australia
- Drug Delivery, Disposition and
Dynamics, Monash Institute of Pharmaceutical Sciences, 381 Royal Parade, Parkville Victoria 3052, Australia
| | - Shane A. Seabrook
- CSIRO Materials Science and Engineering, 343 Royal Parade, Parkville,
Victoria 3052, Australia
| | - Yi-Lynn Liang
- CSIRO Materials Science and Engineering, 343 Royal Parade, Parkville,
Victoria 3052, Australia
- ARC Centre of Excellence for Coherent
X-ray Science, La Trobe University, Bundoora,
Victoria 3086, Australia
| | - Adrian Hawley
- Australian Synchrotron, 800 Blackburn
Rd, Clayton, Victoria 3168, Australia
| | - Nigel Kirby
- Australian Synchrotron, 800 Blackburn
Rd, Clayton, Victoria 3168, Australia
| | - Joseph N. Varghese
- CSIRO Materials Science and Engineering, 343 Royal Parade, Parkville,
Victoria 3052, Australia
| | - Calum J. Drummond
- CSIRO Materials Science and Engineering, Private Bag 10, Clayton South
MDC, Victoria 3169, Australia
| |
Collapse
|
83
|
Zahid NI, Abou-Zied OK, Hashim R, Heidelberg T. Fluorescence probing of the temperature-induced phase transition in a glycolipid self-assembly: hexagonal ↔ micellar and cubic ↔ lamellar. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012; 28:4989-95. [PMID: 22364590 DOI: 10.1021/la3001976] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Water-driven self-assembly of lipids displays a variety of liquid crystalline phases that are crucial for membrane functions. Herein, we characterize the temperature-induced phase transitions in two compositions of an aqueous self-assembly system of the octyl β-D-glucoside (βGlcOC(8)) system, using steady-state and time-resolved fluorescence measurements. The phase transitions hexagonal ↔ micellar and cubic ↔ lamellar were investigated using tryptophan (Trp) and two of its ester derivatives (Trp-C(4) and Trp-C(8)) to probe the polar headgroup region and pyrene to probe the hydrophobic tail region. The polarity of the headgroup region was estimated to be close to that of simple alcohols (methanol and ethanol) for all phases. The pyrene fluorescence indicates that the pyrene molecules are dispersed among the tails of the hydrophobic region, yet remain in close proximity to the polar head groups. Comparing the present results with our previously reported one for βMaltoOC(12), increasing the tail length of the hexagonal phase from C(8) to C(12) leads to less interaction with pyrene, which is attributed to the more random and wobbling motion of the longer alkyl tail. We measured a reduction (more hydrophobic) in the ratio of the vibronic peak intensities of pyrene (I(1)/I(3)) for the lamellar phase compared to that of the cubic phase. The higher polarity in the cubic phase can be correlated to the nature of its interface, which curves toward the bulk water. This geometry also explains the slight reduction in polarity of the headgroup region compared to the other phases. Upon the addition of Trp-C(8), the fluorescence lifetime of pyrene is reduced by 28% in the lamellar and cubic phases, whereas the I(1)/I(3) value is only slightly reduced. The results reflect the dominant role of dynamic interaction mechanism between the C(8) chain of Trp-C(8) and pyrene. This mechanism may be important for these two phases since they participate in the process of membrane fusion. Both lipid compositions show completely reversible temperature-induced phase transitions, reflecting the thermodynamic equilibrium structures of their mesophases. Probing both regions of the different lipid phases reveals a large degree of heterogeneity and flexibility of the lipid self-assembly. These properties are crucial for carrying out different biological functions such as the ability to accommodate various molecular sizes.
Collapse
Affiliation(s)
- N Idayu Zahid
- Department of Chemistry, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | | | | | | |
Collapse
|
84
|
Muir BW, Zhen G, Gunatillake P, Hartley PG. Salt Induced Lamellar to Bicontinuous Cubic Phase Transitions in Cationic Nanoparticles. J Phys Chem B 2012; 116:3551-6. [DOI: 10.1021/jp300239g] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Benjamin W. Muir
- CSIRO Materials
Science and Engineering, Bayview Avenue,
Clayton, VIC 3168, Australia
| | - Guoliang Zhen
- CSIRO Materials
Science and Engineering, Bayview Avenue,
Clayton, VIC 3168, Australia
| | - Pathiraja Gunatillake
- CSIRO Materials
Science and Engineering, Bayview Avenue,
Clayton, VIC 3168, Australia
| | - Patrick G. Hartley
- CSIRO Materials
Science and Engineering, Bayview Avenue,
Clayton, VIC 3168, Australia
| |
Collapse
|
85
|
Fraser SJ, Mulet X, Martin L, Praporski S, Mechler A, Hartley PG, Polyzos A, Separovic F. Surface immobilization of bio-functionalized cubosomes: sensing of proteins by quartz crystal microbalance. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012; 28:620-627. [PMID: 22085432 DOI: 10.1021/la2032994] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
A strategy for tethering lipid liquid crystalline submicrometer particles (cubosomes) to a gold surface for the detection of proteins is reported. Time-resolved quartz crystal microbalance (QCM-D) was used to monitor the cubosome-protein interaction in real time. To achieve specific binding, cubosomes were prepared from the nonionic surfactant phytantriol, block-copolymer, Pluronic F-127, and a secondary biotinylated lipid, 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[biotinyl(polyethyleneglycol)-2000], which enabled attachment of the particles to a neutravidin (NAv)-alkanethiol monolayer at the gold surface of the QCM sensor chip. A second set of cubosomes was further functionalized with addition of the glycolipid (G(M1)) to facilitate a specific binding uptake of the protein, cholera toxin B subunit (CT(B)), from solution. QCM-D confirmed the specificity of the cubosome-NAv binding. The analysis of titration experiments, also performed with QCM, suggests that an optimal concentration of cubosomes is required for the efficient packing of the particles at the surface: high cubosome concentrations lead to chaotic cubosome binding onto the surface, sterically inhibiting surface attachment, or require significant reorganization to permit uniform cubosome coverage. The methodology enabled the straightforward preparation of a complex nanostructured edifice, which was then used to specifically capture analyte proteins (cholera toxin B subunit or free NAv) from solution, supporting the potential for development of this approach as a biosensing platform.
Collapse
Affiliation(s)
- Scott J Fraser
- School of Chemistry, Bio21 Institute, The University of Melbourne, Melbourne, VIC 3010, Australia
| | | | | | | | | | | | | | | |
Collapse
|
86
|
Chen Z, Greaves TL, Fong C, Caruso RA, Drummond CJ. Lyotropic liquid crystalline phase behaviour in amphiphile–protic ionic liquid systems. Phys Chem Chem Phys 2012; 14:3825-36. [DOI: 10.1039/c2cp23698b] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
87
|
Muir BW, Acharya DP, Kennedy DF, Mulet X, Evans RA, Pereira SM, Wark KL, Boyd BJ, Nguyen TH, Hinton TM, Waddington LJ, Kirby N, Wright DK, Wang HX, Egan GF, Moffat BA. Metal-free and MRI visible theranostic lyotropic liquid crystal nitroxide-based nanoparticles. Biomaterials 2011; 33:2723-33. [PMID: 22209558 DOI: 10.1016/j.biomaterials.2011.12.018] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2011] [Accepted: 12/06/2011] [Indexed: 02/05/2023]
Abstract
The development of improved, low toxicity, clinically viable nanomaterials that provide MRI contrast have tremendous potential to form the basis of translatable theranostic agents. Herein we describe a class of MRI visible materials based on lyotropic liquid crystal nanoparticles loaded with a paramagnetic nitroxide lipid. These readily synthesized nanoparticles achieved enhanced proton-relaxivities on the order of clinically used gadolinium complexes such as Omniscan™ without the use of heavy metal coordination complexes. Their low toxicity, high water solubility and colloidal stability in buffer resulted in them being well tolerated in vitro and in vivo. The nanoparticles were initially screened in vitro for cytotoxicity and subsequently a defined concentration range was tested in rats to determine the maximum tolerated dose. Pharmacokinetic profiles of the candidate nanoparticles were established in vivo on IV administration to rats. The lyotropic liquid crystal nanoparticles were proven to be effective liver MRI contrast agents. We have demonstrated the effective in vivo performance of a T1 enhancing, biocompatible, colloidally stable, amphiphilic MRI contrast agent that does not contain a metal.
Collapse
Affiliation(s)
- Benjamin W Muir
- CSIRO Materials Science and Engineering, Bayview Avenue, Clayton 3168, Australia.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
88
|
Kulkarni CV. Nanostructural studies on monoelaidin-water systems at low temperatures. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2011; 27:11790-11800. [PMID: 21846133 DOI: 10.1021/la201235h] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
In recent years, lipid based nanostructures have increasingly been used as model membranes to study various complex biological processes. For better understanding of such phenomena, it is essential to gain as much information as possible for model lipid structures under physiological conditions. In this paper, we focus on one of such lipids--monoelaidin (ME)--for its polymorphic nanostructures under varying conditions of temperature and water content. In the recent contribution (Soft Matter, 2010, 6, 3191), we have reported the phase diagram of ME above 30 °C and compared with the phase behavior of other lipids including monoolein (MO), monovaccenin (MV), and monolinolein (ML). Remarkable phase behavior of ME, stabilizing three bicontinuous cubic phases, motivates its study at low temperatures. Current studies concentrate on the low-temperature (<30 °C) behavior of ME and subsequent reconstruction of its phase diagram over the entire temperature-water composition space (temperature, 0-76 °C; and water content, 0-70%). The polymorphs found for the monoelaidin-water system include three bicontinuous cubic phases, i.e., Ia3d, Pn3m, and Im3m, and lamellar phases which exhibit two crystalline (L(c1) and L(c0)), two gel (L(β) and L(β*)), and a fluid lamellar (L(α)) states. The fluid isotropic phase (L(2)) was observed only for lower hydrations (<20%), whereas hexagonal phase (H(2)) was not found under studied conditions. Nanostructural parameters of these phases as a function of temperature and water content are presented together with some molecular level calculations. This study might be crucial for perception of the lyotropic phase behavior as well as for designing nanostructural assemblies for potential applications.
Collapse
Affiliation(s)
- Chandrashekhar V Kulkarni
- Department of Chemistry, Imperial College London, Exhibition Road, London - SW7 2AZ, United Kingdom.
| |
Collapse
|
89
|
Schröder-Turk GE, Varslot T, de Campo L, Kapfer SC, Mickel W. A bicontinuous mesophase geometry with hexagonal symmetry. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2011; 27:10475-10483. [PMID: 21728305 DOI: 10.1021/la201718a] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We report that a specific realization of Schwarz's triply periodic hexagonal minimal surface is isotropic with respect to the Doi-Ohta interface tensor and simultaneously has minimal packing and stretching frustration similar to those of the commonly found cubic bicontinuous mesophases. This hexagonal surface, of symmetry P6(3)/mmc with a lattice ratio of c/a = 0.832, is therefore a likely candidate geometry for self-assembled lipid/surfactant or copolymer mesophases. Furthermore, both the peak position ratios in its powder diffraction pattern and the elastic moduli closely resemble those of the cubic bicontinuous phases. We therefore argue that a genuine possibility of experimental misidentification exists.
Collapse
Affiliation(s)
- Gerd E Schröder-Turk
- Theoretische Physik, Friedrich-Alexander-Universität Erlangen-Nürnberg, D-91058 Erlangen, Germany.
| | | | | | | | | |
Collapse
|
90
|
Fong C, Weerawardena A, Sagnella SM, Mulet X, Krodkiewska I, Chong J, Drummond CJ. Monodisperse nonionic isoprenoid-type hexahydrofarnesyl ethylene oxide surfactants: high throughput lyotropic liquid crystalline phase determination. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2011; 27:2317-2326. [PMID: 21294552 DOI: 10.1021/la104736u] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The neat and lyotropic phase behavior of eight new ethylene oxide amphiphiles (EO = 1-8) with a hexahydrofarnesyl chain (3,7,11-trimethyldodecyl) and narrow polydispersity (>98.5% purity) is reported. Below five EO units the behavior of the neat surfactants show only a glass transition, Tg ∼ -90 °C. Above four EO units, crystallization (Tcrys) and crystal-isotropic liquid (Tm) transitions are also observed that increase with degree of ethoxylation of the surfactant headgroup. The lyotropic liquid crystalline phase behavior spans a complex spectrum of surfactant-water interfacial curvatures. Specifically, inverse phases are present below ambient temperatures for EO < 4, with HFarn(EO)2 exhibiting an inverse hexagonal (H(II)) phase stable to dilution. The phase diagram of HFarn(EO)3 displays both the gyroid (Ia3d) and double diamond (Pn3m) inverse bicontinuous cubic phases, with the latter being thermodynamically stable in excess water within the physiological regime. There is a strong preference for planar bilayer structures at intermediate headgroup ethoxylation, with the crossover to normal phases occurring at HFarn(EO)(7-8) which exhibits normal hexagonal (H(I)) and cubic (Q(I)) phases at ambient temperatures. The toxicity of colloidal dispersions of these EO amphiphiles was assayed against normal breast epithelial (HMEpiC) and breast cancer (MCF7) cell lines. The IC50 of the EO amphiphiles was similar in both cell lines with moderate toxicity ranging from ca. <5 to 140 μM in an in vitro cell viability assay. Observations are qualitatively rationalized in terms of the molecular geometry of the surfactant. The physicochemical behavior of the HFarnesyl ethylene oxide amphiphiles is compared to other ethylene oxide surfactants.
Collapse
Affiliation(s)
- Celesta Fong
- CSIRO Materials Science & Engineering (CMSE), Bag 10, Clayton South, VIC 3169, Australia
| | | | | | | | | | | | | |
Collapse
|
91
|
Sagnella SM, Gong X, Moghaddam MJ, Conn CE, Kimpton K, Waddington LJ, Krodkiewska I, Drummond CJ. Nanostructured nanoparticles of self-assembled lipid pro-drugs as a route to improved chemotherapeutic agents. NANOSCALE 2011; 3:919-24. [PMID: 21173998 DOI: 10.1039/c0nr00781a] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
We demonstrate that oral delivery of self-assembled nanostructured nanoparticles consisting of 5-fluorouracil (5-FU) lipid prodrugs results in a highly effective, target-activated, chemotherapeutic agent, and offers significantly enhanced efficacy over a commercially available alternative that does not self-assemble. The lipid prodrug nanoparticles have been found to significantly slow the growth of a highly aggressive mouse 4T1 breast tumour, and essentially halt the growth of a human MDA-MB-231 breast tumour in mouse xenografts. Systemic toxicity is avoided as prodrug activation requires a three-step, enzymatic conversion to 5-FU, with the third step occurring preferentially at the tumour site. Additionally, differences in the lipid prodrug chemical structure and internal nanostructure of the nanoparticle dictate the enzymatic conversion rate and can be used to control sustained release profiles. Thus, we have developed novel oral nanomedicines that combine sustained release properties with target-selective activation.
Collapse
Affiliation(s)
- Sharon M Sagnella
- CSIRO Materials Science and Engineering, PO Box 184, North Ryde, NSW 1670, Australia
| | | | | | | | | | | | | | | |
Collapse
|
92
|
Sagnella SM, Conn CE, Krodkiewska I, Drummond CJ. Nonionic diethanolamide amphiphiles with unsaturated C18 hydrocarbon chains: thermotropic and lyotropic liquid crystalline phase behavior. Phys Chem Chem Phys 2011; 13:13370-81. [DOI: 10.1039/c1cp21808e] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
93
|
Sagnella SM, Conn CE, Krodkiewska I, Drummond CJ. Nonionic diethanolamide amphiphiles with isoprenoid-type hydrocarbon chains: thermotropic and lyotropic liquid crystalline phase behaviour. Phys Chem Chem Phys 2011; 13:17511-20. [DOI: 10.1039/c1cp21845j] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
94
|
Fraser SJ, Dawson RM, Waddington LJ, Muir BW, Mulet X, Hartley PG, Separovic F, Polyzos A. Development of Cubosomes as a Cell-Free Biosensing Platform. Aust J Chem 2011. [DOI: 10.1071/ch10361] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The parallel between the lipidic microenvironments of the inverse bicontinuous cubic phase and the biological membrane distinguishes cubic phases as an attractive option for development of cell-free biosensors containing protein or glycolipid receptors. Herein we describe a novel strategy toward the creation of a biosensing platform derived from the surface attachment of a colloidally stable inverse cubic structure (cubosomes). We report the preparation of cubosomes composed of the amphiphile phytantriol, the membrane glycolipid receptor monosialoganglioside-GM1 and the biotin-functionalized amphiphile 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[biotinyl(polyethyleneglycol)-2000] (bDSPE). The tethering of cubosomes to the various surfaces was mediated through bDSPE binding to streptavidin- and avidin-modified surfaces. Allylamine plasma polymer surface modification enhanced the surface immobilization of avidin, which increased the density of bound cubosomes. The resultant polymer–protein–cubosome complex was imaged by cryo-transmission electron microscopy analysis and the cubosome structure was impressively preserved within the complex. Cholera toxin binding to cubosomes containing GM1 was used to assess the performance of the cubosomes, subsequent to surface attachment, via a modified enzyme-linked immunosorbent assay. Specific immobilization of complex protein–receptor–cubosome systems paves the way for development of a structurally complex, heterogeneous platform for sensing applications.
Collapse
|
95
|
Kulkarni CV, Wachter W, Iglesias-Salto G, Engelskirchen S, Ahualli S. Monoolein: a magic lipid? Phys Chem Chem Phys 2011; 13:3004-21. [DOI: 10.1039/c0cp01539c] [Citation(s) in RCA: 295] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
96
|
Tyler AII, Shearman GC, Brooks NJ, Delacroix H, Law RV, Templer RH, Ces O, Seddon JM. Hydrostatic pressure effects on a hydrated lipid inverse micellar Fd3m cubic phase. Phys Chem Chem Phys 2011; 13:3033-8. [DOI: 10.1039/c0cp01783c] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
97
|
Brooks NJ, Ces O, Templer RH, Seddon JM. Pressure effects on lipid membrane structure and dynamics. Chem Phys Lipids 2010; 164:89-98. [PMID: 21172328 DOI: 10.1016/j.chemphyslip.2010.12.002] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2010] [Revised: 12/07/2010] [Accepted: 12/09/2010] [Indexed: 11/30/2022]
Abstract
The effect of hydrostatic pressure on lipid structure and dynamics is highly important as a tool in biophysics and bio-technology, and in the biology of deep sea organisms. Despite its importance, high hydrostatic pressure remains significantly less utilised than other thermodynamic variables such as temperature and chemical composition. Here, we give an overview of some of the theoretical aspects which determine lipid behaviour under pressure and the techniques and technology available to study these effects. We also summarise several recent experiments which highlight the information available from these approaches.
Collapse
Affiliation(s)
- Nicholas J Brooks
- Membrane Biophysics Platform and Institute of Chemical Biology, Department of Chemistry, Imperial College London, South Kensington Campus, UK
| | | | | | | |
Collapse
|
98
|
Mulet X, Kaasgaard T, Conn CE, Waddington LJ, Kennedy DF, Weerawardena A, Drummond CJ. Nanostructured nonionic thymidine nucleolipid self-assembly materials. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2010; 26:18415-18423. [PMID: 21058676 DOI: 10.1021/la103370q] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Three nucleoside lipids have been synthesized: 3'-oleoylthymidine, 3',5'-dioleoylthymidine, and 3'-phytanoylthymidine. Differential scanning calorimetry and X-ray diffraction have been employed to characterize the physical properties of these neat lipids. Polarizing optical microscopy, small-angle X-ray scattering, and cryo-transmission electron microscopy techniques have been used to investigate the phase behavior in aqueous systems. Both oleoyl-based nucleoside lipids adopted a lamellar crystalline phase in the neat form at room temperature, and the phytanoyl derivative exhibited a fluid isotropic phase. Under excess water conditions, the presence of one branched (phytanoyl) or one unsaturated (oleoyl) chain promoted the formation of a liquid-crystalline lamellar phase at physiological temperatures. In contrast, the 3',5'-dioleoylthymidine derivative is nonswelling and does not exhibit lyotropic liquid-crystalline phase behavior. The nucleolipids' propensity for DNA-type binding and recognition has been evaluated by using a monolayer system to measure surface pressure-area isotherms in a Langmuir trough and indicates that the nucleoside base is available for nonspecific hydrogen bonding in the monolayer liquid expanded state for the single-chain nucleolipids but not for the dual-chain amphiphile.
Collapse
Affiliation(s)
- Xavier Mulet
- CSIRO Materials Science and Engineering, Bag 10, Clayton South MDC, VIC 3169, Australia
| | | | | | | | | | | | | |
Collapse
|
99
|
High throughput preparation and characterisation of amphiphilic nanostructured nanoparticulate drug delivery vehicles. Int J Pharm 2010; 395:290-7. [DOI: 10.1016/j.ijpharm.2010.05.029] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2010] [Revised: 05/04/2010] [Accepted: 05/15/2010] [Indexed: 11/17/2022]
|
100
|
Corsi J, Hawtin RW, Ces O, Attard GS, Khalid S. DNA lipoplexes: formation of the inverse hexagonal phase observed by coarse-grained molecular dynamics simulation. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2010; 26:12119-12125. [PMID: 20578750 DOI: 10.1021/la101448m] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Mixtures of dsDNA and lipids, so-called lipoplexes, are widely used as less toxic alternatives to viral vectors in transfection studies. However, the transfection efficiency achieved by lipoplexes is significantly lower than that of viral vectors and is a barrier to their use in the clinic. There is now significant evidence suggesting that the molecular organization and structure (nanoarchitecture) of lipoplexes might correlate with biological activity. As a consequence, the ability to predict quantitatively the nanoarchitecture of new systems, and how these might change intracellularly, would be a major tool in the development of rational discovery strategies for more efficient lipoplex formulations. Here we report the use of a coarse-grain molecular dynamics simulation to predict the phases formed by two lipoplex systems: dsDNA-DOPE and dsDNA-DOPE-DOTAP. The predictions of the simulations show excellent agreement with experimental data from polarized light microscopy and small-angle X-ray diffraction (SAXS); the simulations predicted the formation of phases with d-spacings that were comparable to those measured by SAXS. More significantly, the simulations were able to reproduce for the first time the experimentally observed change from a fluid lamellar to an inverse hexagonal phase in the dsDNA-DOPE-DOTAP system as a function of changes in lipid composition. Our studies indicate that coarse-grain MD simulations could provide a powerful tool to understand, and hence design, new lipoplex systems.
Collapse
Affiliation(s)
- Josephine Corsi
- School of Chemistry, University of Southampton, Highfield, Southampton, SO17 1 BJ, United Kingdom
| | | | | | | | | |
Collapse
|