BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Talks.cam//talks.cam.ac.uk//
X-WR-CALNAME:Talks.cam
BEGIN:VEVENT
SUMMARY:Nanostructure characterization of planar biomimetic membranes with
  neutron reflectometry - Dr. Marco Maccarini\, TIMC/IMAG\, Grenoble
DTSTART:20150508T130000Z
DTEND:20150508T140000Z
UID:TALK59211@talks.cam.ac.uk
CONTACT:Dr. Hernandez-Ainsa
DESCRIPTION:I will present neutron reflectometry (NR) data on model biolog
 ical membranes systems to point out how a biophysical approach can help ad
 dress specific biological problems.\nIn the first example I will describe 
 a structural characterization of floating lipid bilayers in the presence o
 f gold nanoparticles in the context of nano toxicity. The development of n
 ovel nano-engineered materials poses important questions on how these new 
 materials will interact with living systems. On the one hand\, possible ad
 verse effects must be assessed in order to prevent risks for health and en
 vironment [1]. On the other hand\, the understanding of how these material
 s interact with biological systems might result in the creation of novel b
 iomedical applications [2]. I will show NR experiments performed on zwitte
 rionic DSPC and  two-component negatively charged DSPC/DSPG double bilayer
 s in the presence of gold nanoparticles (NP) functionalized with cationic 
 and anionic head groups. Structural information was obtained that provided
  insight into the fate of the NPs with regard to the integrity of the mode
 l cell membranes. The information obtained might influence the strategy fo
 r a better nanoparticle risk assessment based on a surface charge evaluati
 on and contribute to nano-safety considerations already during their desig
 n.\nIn the second example\, I will provide insight into the nano-scale str
 ucture of OprF protein embedded in tethered lipid bilayers. OprF is the ma
 jor porin of the outer membrane of the PseudomonaAeuruginosa bacterium and
  it is a very novel target for new drugs that will kill bacteria resistant
  to standard antibiotics. The crystallographic high-resolution structure o
 f OprF is not available due to the difficulties involved in crystallising 
 membrane proteins. By the use of neutron reflectometry\, we provided an al
 ternative route to obtain fundamental low-resolution information on the na
 noscale structure OprF\, in an environment that mimics its native conditio
 n. NR allowed us to characterize the nanostructural details of the lipid m
 embrane\, the amount of the protein embedded in the bilayer\, the thicknes
 s and the orientation of the extramembrane domain of the proteins\, which 
 extends from the membrane. These investigations are not possible using the
  classical techniques of biology and reinforce the crucial role played by 
 neutron scattering in evincing fundamental details of biological samples.T
 his study showed that OprF made using the cell free protocol and incorpora
 ted into tethered lipid bilayer provides a controllable (and measurable at
  the nanoscale) biomimetic system constructed in vitro.\n\n[1] Maynard\, A
 .D. Nanotechnology: a Strategy for Addressing Risk\; Woodrow Wilson Intern
 ational Center for Scholars: Washington\, DC\, (2006).\n[2] Murphy\,C.J.\;
  Gole\, A.M.\;Stone\, J.W. Acc. Chem. Res. (2008)\, 41\, 1721–1730.\n[3]
  Tatur\, S.\; Maccarini\, M.\; Barker\, R.\; Fragneto\, G.\; Langumir (201
 3) 29 (22)\, 6606\n
LOCATION:Small Lecture Theatre\, Cavendish Laboratory.
END:VEVENT
END:VCALENDAR