Adsorption of lipid liquid crystalline nanoparticles : effects of particle composition, internal structure, and phase behavior

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Adsorption of lipid liquid crystalline nanoparticles : effects of particle composition, internal structure, and phase behavior

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Publication Article, peer reviewed scientific
Title Adsorption of lipid liquid crystalline nanoparticles : effects of particle composition, internal structure, and phase behavior
Author(s) Chang, Debby P. ; Jankunec, Marija ; Barauskas, Justas ; Tiberg, Fredrik ; Nylander, Tommy
Date 2012
English abstract
Controlling the interfacial behavior and properties of lipid liquid crystalline nanoparticles (LCNPs) at surfaces is essential for their application for preparing functional surface coatings as well as understanding some aspects of their properties as drug delivery vehicles. Here we have studied a LCNP system formed by mixing soy phosphatidylcholine (SPC), forming liquid crystalline lamellar structures in excess water, and glycerol dioleate (GDO), forming reversed structures, dispersed into nanoparticle with the surfactant polysorbate 80 (P80) as stabilizer. LCNP particle properties were controlled by using different ratios of the lipid building blocks as well as different concentrations of the surfactant P80. The LCNP size, internal structure, morphology, and charge were characterized by dynamic light scattering (DLS), synchrotron small-ange X-ray scattering (SAXS), cryo-transmission electron microscopy (cryo-TEM), and zeta potential measurements, respectively. With increasing SPC to GDO ratio in the interval from 35:65 to 60:40, the bulk lipid phase structure goes from reversed cubic micellar phase with Fd3m space group to reversed hexagonal phase. Adding P80 results in a successive shift toward more disorganized lamellar type of structures. This is also seen from cryo-TEM images for the LCNPs, where higher P80 ratios results in more extended lamellar layers surrounding the inner, more dense, lipid-rich particle core with nonlamellar structure. When put in contact with a solid silica surface, the LCNPs adsorb to form multilayer structures with a surface excess and thickness values that increase strongly with the content of P80 and decreases with increasing SPC:GDO ratio. This is reflected in both the adsorption rate and steady-state values, indicating that the driving force for adsorption is largely governed by attractive interactions between poly(ethylene oxide) (PEO) units of the P80 stabilizer and the silica surface. On cationic surface, i.e., silica modified with 3-aminopropltriethoxysilane (APTES), the slightly negatively charged LCNPs give rise to a very significant adsorption, which is relatively independent of LCNP composition. Finally, the dynamic thickness measurements indicate that direct adsorption of intact particles occurred on the cationic surface, while a slow buildup of the layer thickness with time is seen for the weakly interacting systems.
DOI http://dx.doi.org/10.1021/la301579g (link to publisher's fulltext)
Publisher American Chemical Society
Host/Issue Langmuir;29
Volume 28
ISSN 0743-7463
Pages 10688-10696
Language eng (iso)
Subject(s) DRUG-DELIVERY APPLICATIONS
X-RAY-DIFFRACTION
CUBIC PHASE
HYDROPHOBIC SURFACES
WATER-INTERFACE
ELLIPSOMETRY
DISPERSIONS
MEMBRANES
Sciences
Research Subject Categories::NATURAL SCIENCES
Handle http://hdl.handle.net/2043/14295 (link to this page)

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