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VERSION:2.0
PRODID:-//RLASKEY//CALENDEROUS//EN
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METHOD:PUBLISH
BEGIN:VEVENT
DTSTAMP:20260825T002147Z
LAST-MODIFIED:20121116T203436Z
DTSTART:20090623T200000Z
DTEND:20090623T210000Z
UID:event459@bu.edu
URL:http://physics.bu.edu/internal/events/show/459
SUMMARY:Nanostructured Lipid Droplets
DESCRIPTION:Featuring Otto Glatter\, University of Graz\, Austria\nHosted b
	y: Rama Bansil\nPoster: http://physics.bu.edu/internal//posters/2009_Spring
	/06232009.pdf\n\nPart of the Biophysics/Condensed Matter Seminar Series.\n\
	nAbstract:\nIn this seminar we present our results on hierarchically organi
	zed fluid particles\, i.e.\, sub-micron sized lipid droplets kinetically st
	abilized as an aqueous emulsion having a self-assembled nanostructured inte
	rior [1-3]. The nanostructures in the kinetically stabilized particles are 
	thermodynamic equilibrium structures based on monolinolein or phytantriol. 
	The stabilizer can be of polymeric type\, like Pluronics F127\, or of collo
	idal type like Laponite nanoparticles [4]. The addition of tetradecane or o
	ther oils induces a transition of the internal particle nanostructure from 
	continuous Pn3m (cubosomes) to H2 (hexosomes)\, discontinuous cubic Fd3m (m
	icellar cubosomes) and W/O microemulsions (emulsified microemulsion\, EMEs)
	 at a given temperature. Most interestingly\, these systems allow us to stu
	dy transfer of lipidic phases or of other molecules inserted to the interio
	r of the droplets [5]. \nThe solubilisation of oleic acid (OA) in monoolein
	 (MO) based cubosomes decreases the interfacial curvature of the liquid cry
	stalline phase to more negative values. pH variation between 2 and 8 in a O
	A-MO system shows that the internal particle structure strongly depends on 
	the pH of the aqueous phase. At high enough OA concentration\, transformati
	ons from structure less emulsions to emulsified microemulsion (EME)\, emuls
	ified Fd3m\, hexosomes\, bicontinuous cubosomes and vesicles can be observe
	d as a function of pH. Interestingly\, the liquid crystalline structure to 
	vesicle transition always occurs at intestinal pH values. All transitions w
	ith pH are reversible.  \nAn apparent pKa for OA in MO is evaluated from th
	e change of structure with pH. This value is within in the physiological pH
	 range of the intestine (between pH 5.5 and 7.5). For pure OA a higher pKa 
	value between 8 and 8.5 was given in literature.  \nThe structures of these
	 systems have been studied by SAXS. For the transfer kinetic experiments we
	 developed a special high flux laboratory system with a flow cell\, equippe
	d with a CCD camera which allows time resolved measurements down to one exp
	eriment per minute. These structural studies are complemented by Cryo-TEM a
	nd dynamic light scattering experiments.  \n\n \nTransfer Kinetics:     pH 
	Variation: \n\n \n\n \n\nReferences \n[1] L. de Campo\, et al.\, 2004 Langm
	uir 20\, 5254.  \n[2] A. Yaghmur\, et al.\, 2005 Langmuir 21\, 569. \n[3] A
	. Yaghmur\, et al.\, 2006 Langmuir 22\, 517. \n[4] A. Salonen\, et al.\, 20
	08 Langmuir 24\, 5306.  \n[5] Ch. Moitzi\, et al.\, 2007 Adv. Materials 19\
	,  1352.
LOCATION:SCI 352\, 590 Commonwealth Avenue\, 02215
STATUS:CONFIRMED
CLASS:PUBLIC
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