dc.contributor.author | Ghazvini, Saba | |
dc.contributor.author | Ricke, Brandon | |
dc.contributor.author | Zasadzinski, Joseph A. | |
dc.contributor.author | Dhar, Prajnaparamita | |
dc.date.accessioned | 2015-10-19T16:17:21Z | |
dc.date.available | 2015-10-19T16:17:21Z | |
dc.date.issued | 2015 | |
dc.identifier.citation | Ghazvini, Saba, Brandon Ricke, Joseph A. Zasadzinski, and Prajnaparamita Dhar. "Monitoring Phases and Phase Transitions in Phosphatidylethanolamine Monolayers Using Active Interfacial Microrheology." Soft Matter 11.17 (2015): 3313-321. http://dx.doi.org/10.1039/C4SM02900C | en_US |
dc.identifier.uri | http://hdl.handle.net/1808/18706 | |
dc.description | This is the published version. Copyright 2015 Royal Society of Chemistry | en_US |
dc.description.abstract | Active interfacial microrheology is a sensitive tool to detect phase transitions and headgroup order in phospholipid monolayers. The re-orientation of a magnetic nickel nanorod is used to explore changes in the surface rheology of 1,2-dilauroyl-sn-glycero-3-phosphoethanolamine (DLPE) and 1,2-dimyristoyl-sn-glycero-3-phosphoethanolamine (DMPE), which differ by two CH2 groups in their alkyl chains. Phosphatidylethanolamines such as DLPE and DMPE are a major component of cell membranes in bacteria and in the nervous system. At room temperature, DLPE has a liquid expanded (LE) phase for surface pressure, Π < ∼38 mN m−1; DMPE has an LE phase for Π < ∼7 mN m−1. In their respective LE phases, DLPE and DMPE show no measurable change in surface viscosity with Π, consistent with a surface viscosity <10−9 N s m−1, the resolution of our technique. However, there is a measurable, discontinuous change in the surface viscosity at the LE to liquid condensed (LC) transition for both DLPE and DMPE. This discontinuous change is correlated with a significant increase in the surface compressibility modulus (or isothermal two-dimensional bulk modulus). In the LC phase of DMPE there is an exponential increase in surface viscosity with Π consistent with a two-dimensional free area model. The second-order LC to solid (S) transition in DMPE is marked by an abrupt onset of surface elasticity; there is no measurable elasticity in the LC phase. A measurable surface elasticity in the S phase suggests a change in the molecular ordering or interactions of the DMPE headgroups that is not reflected in isotherms or in grazing incidence X-ray diffraction. This onset of measurable elasticity is also seen in DLPE, even though no indication of a LC–S transition is visible in the isotherms. | en_US |
dc.publisher | Royal Society of Chemistry | en_US |
dc.title | Monitoring phases and phase transitions in phosphatidylethanolamine monolayers using active interfacial microrheology | en_US |
dc.type | Article | |
kusw.kuauthor | Dhar, Prajna | |
kusw.kudepartment | Chemical & Petroleum Engr | en_US |
dc.identifier.doi | 10.1039/C4SM02900C | |
kusw.oaversion | Scholarly/refereed, publisher version | |
kusw.oapolicy | This item meets KU Open Access policy criteria. | |
dc.rights.accessrights | openAccess | |