Ursula A' PerezSalas, Susan Krueger, Charles F' Majkrzak, Norman F' Berk

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Neutron Reflectometry Characterization of
Planar Soft-Supported Membrane-Mimetic Films
Ursula A. Perez-Salas, Susan Krueger, Charles F.
Majkrzak, Norman F. Berk NIST Keith M. Faucher,
Elliot L. Chaikof, M.D., Ph.D. Department of
Surgery Emory University School of Medicine
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Membrane-Mimetic Water filled Soft Support Planar
Substrate
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Membrane-Mimetic Water filled Soft Support Planar
Substrate
Soft-Supported Membrane-Mimetic system
Simplify and Clarify Biological Systems
Biosensors
Biofunctional Coatings Artificial Organs and
Implanted Medical Devices
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Polymeric-Phospholipid Monolayer Supported by a
Polyelectrolyte Multilayer
Au
Liu H., Faucher K.M., Sun X.-L., Feng J., Johnson
T.L., Orban J.M., Apkarian R.P., Dluhy R.A.,
Chaikof E.L. Langmuir, 2002, 18, p.1332.
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Fabrication of an Alkylated Polyelectrolyte
Multilayer
Poly-L-Lysine (PLL)
Alginate (ALG)
Terpolymer (TER)
PLL
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Vesicle Fusion and In-Situ Photopolymerization of
a Planar Lipid Assembly on an Alkylated
Polyelectrolyte Multilayer
Visible light EY/TEA/VP
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Goal

• Determine the water distribution in the
  Polyelectrolyte
• TerpolymerPhospholipid system
• 2) Infer if there is a single monolayer of
  Phospholipid over the
• Polyelectrolyte Terpolymer layers

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• Neutron Reflectivity Measurements
• NG1 vertical stage Reflectometer at the NCNR at
  the NIST
• q range 0.01 to 0.3 Å-1
• - samples inside a humidity chamber 92
• - two humid atmospheres used
• a)100 D2O
• b) 50 D2O and 50 H2O
• - temperature set to approximately 20C

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Measure
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Measure
Surround Variation Method
Berk N.F., Majkrzak C.F. J. Phys. Soc. Jpn.,
1996, 65, p.81 Majkrzak C.F., Berk N.F. Phys.
Rev. B., 1998, 58, p.15416 Majkrzak C.F. Acta
Phys. Pol. A., 1999, 96, p.81 Majkrzak C.F., Berk
N.F.,Silin V., Meuse C.W. Phys. B., 2000, 283,
p.248
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Polyelectrolyte Terpolymer Phospholipid dry
Paramteric B-Splines fitting procedure
Majkrzak C.F., Berk N.F. Phys. Rev. B., 1995, 52,
p.10827
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92 D2O humidity
Scattering length density (x10-6Å-2)
PE
Au
Z (Å)
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92 D2O humidity
Terpolymer
Scattering length density (x10-6Å-2)
PE
Au
Z (Å)
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92 D2O humidity
Terpolymer Phospholipid
Scattering length density (x10-6Å-2)
PE
Au
Z (Å)
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Polyelectrolyte Terpolymer Phospholipid
dry
Terpolymer Phospholipid
Scattering length density (x10-6Å-2)
PE
Au
Z (Å)
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Polyelectrolyte Terpolymer Phospholipid
dry
D2O
Terpolymer Phospholipid
H2O/D2O
Scattering length density (x10-6Å-2)
PE
Au
Z (Å)
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Polyelectrolyte Terpolymer Phospholipid
dry
D2O
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Water Distribution in Polyelectrolyte
Terpolymer Phospholipid layer
Terpolymer Phospholipid
PE
Au
Z (Å)
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Conclusion

• PETerpolymerphospholipid supported
  membrane-mimetic shows 40 water content in the
  cushion (PE) layer under humid conditions
• Because fusing phospholipid vesicles onto the
  PETerpolymer film does not change the thickness
  of the film significantly it can be inferred that
  a membrane monolayer was formed.

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Future Work

• Study all three films, ie, polyelectrolyte film,
  polyelectrolyte plus terpolymer film and
  polyelectrolyte plus terpolymer plus crosslinked
  PC film completely hydrated in D2O and in a
  50/50 D2O/H2O mixture.
• Fuse deuterated lipid vesicles on to the
  polyelectrolyte plus terpolymer film while
  completely hydrated.
• Get a crosslinkable deuterated phospholipid
• Measure biologically active surfaces.

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Acknowledgements
Anne Plant John T. Elliot Vitalii
Silin Biotechnology Division NIST