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dc.contributor.authorHollars, Christopher W.
dc.contributor.authorDunn, Robert C.
dc.date.accessioned2014-12-05T16:57:41Z
dc.date.available2014-12-05T16:57:41Z
dc.date.issued2000-02-01
dc.identifier.citationHollars, Christopher W. & Dunn, Robert C. "Probing single molecule orientations in model lipid membranes with near-field scanning optical microscopy." J. Chem. Phys. 112, 7822 (2000); http://dx.doi.org/10.1063/1.481367.
dc.identifier.urihttp://hdl.handle.net/1808/16053
dc.descriptionThis is the published version, also available here: http://dx.doi.org/10.1063/1.481367.
dc.description.abstractSingle molecule near-field fluorescence measurements are utilized to characterize the molecular level structure in Langmuir–Blodgett monolayers of L-α-dipalmitoylphosphatidylcholine (DPPC).Monolayers incorporating 3×10−4 mol % of the fluorescent lipid analog N-(6-tetramethylrhodaminethiocarbamoyl)-1,2-dihexadecanoyl-sn- glycero-3-phosphoethanolamine, triethylammonium salt (TRITC–DHPE) are transferred onto a freshly cleaved mica surface at low (π=8 mN/m) and high (π=30 mN/m)surfacepressures. The near-field fluorescence images exhibit shapes in the single molecule images that are indicative of the lipid analog probe orientation within the films. Modeling the fluorescence patterns yields the single molecule tilt angle distribution in the monolayers which indicates that the majority of the molecules are aligned with their absorption dipole moment pointed approximately normal to the membrane plane. Histograms of the data indicate that the average orientation of the absorption dipole moment is 2.2° (σ=4.8°) in monolayers transferred at π=8 mN/m and 2.4° (σ=5.0°) for monolayers transferred at π=30 mN/m. There is no statistical difference in the mean tilt angle or distribution for the two monolayer conditions studied. The insensitivity of tilt angle to filmsurfacepressure may arise from small chromophore doped domains of trapped liquid-expanded lipid phase remaining at high surfacepressure. There is no evidence in the near-field fluorescence images for probe molecules oriented with their dipole moment aligned parallel with the membrane plane. We do, however, find a small but significant population of probe molecules (∼13%) with tilt angles greater than 16°. Comparison of the simultaneously collected near-field fluorescence and force images suggests that these large angle orientations are not the result of significant defects in the films. Instead, this small population may represent a secondary insertion geometry for the probe molecule into the lipidmonolayer.
dc.publisherAmerican Institute of Physics
dc.subjectMonolayers
dc.subjectFluorescence
dc.subjectLipids
dc.subjectElectric dipole moments
dc.subjectHigh pressure
dc.titleProbing single molecule orientations in model lipid membranes with near-field scanning optical microscopy
dc.typeArticle
kusw.kuauthorHollars, Christopher W.
kusw.kuauthorDunn, Robert C.
kusw.kudepartmentChemistry
kusw.oanotesJournal: Biophysical Journal (ISSN: 0006-3495, ESSN: 1542-0086) RoMEO: This is a RoMEO green journal Paid OA: A paid open access option is available for this journal. Author's Pre-print: Author can archive pre-print (ie pre-refereeing) Author's Post-print: Author can archive post-print (ie final draft post-refereeing) Publisher's Version/PDF: Author can archive publisher's version/PDF General Conditions: Pre-prints on private websites only Post-prints on author or institutional server only Must link to publisher version Authors version can be archived immediately following publication If funding agency rules apply, authors may post their post print in PubMed Central 12 months after publication Set phrase to accompany author's version Publisher's version/PDF may be used Publisher copyright and source must be acknowledged Some articles can be made open access (Creative Commons Attribution Non-Commercial License) for a fee, and publisher will also submit to PubMed Central with no embargo Please see Elsevier (Cell Press) for articles published in 2009 onwards Mandated OA: (Awaiting information) Paid Open Access: Biophysical Journal Open Access Copyright: Policy (pdf) Updated: 12-Aug-2009 - Suggest an update for this record Link to this page: http://www.sherpa.ac.uk/romeo/issn/0006-3495/ Published by: Biophysical Society [Client Organisation] - Green Policies in RoMEO Other parties: Elsevier (Cell Press) [Commercial Publisher] - Blue Policies in RoMEO Guidance: Please see the list of Publisher Categories in RoMEO for guidance on interpreting the priority of multiple publishers.
dc.identifier.doi10.1063/1.481367
kusw.oaversionScholarly/refereed, publisher version
kusw.oapolicyThis item does not meet KU Open Access policy criteria.
dc.rights.accessrightsopenAccess


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