Use of X-Ray and Neutron Scattering Methods with Volume Measurements to Determine Lipid Bilayer Structure and Number of Water Molecules/Lipid

  • Stephanie Tristram-NagleEmail author
Part of the Subcellular Biochemistry book series (SCBI, volume 71)


In this chapter I begin with a historical perspective of membrane models, starting in the early twentieth century. As these membrane models evolved, so did experiments to characterize the structure and water content of purified lipid bilayers. The wide-spread use of the X-ray gravimetric, or Luzzati method, is critically discussed. The main motivation of the gravimetric technique is to determine the number of water molecules/lipid, nW, and then derive other important structural quantities, such as area/lipid, AL. Subsequent experiments from the Nagle/Tristram-Nagle laboratory using X-ray and neutron scattering, first determine AL and then calculate nW, using molecular lipid VL and water VW volumes. This chapter describes the details of our volume experiments to carefully measure VL. Our results also determine nW′, the steric water associated with the lipid headgroup, and how our calculated value compares to many literature values of tightly-associated headgroup water.


Waters/lipid Hydration Lipid bilayer X-ray scattering Neutron scattering 



Differential scanning calorimetry


Nuclear magnetic resonance


Electron spin resonance


Fourier transform infrared resonance


Main transition melting temperature


Number of waters/lipid


Steric number of waters/lipid




Molecular volume/lipid


Molecular volume/water


Multilamellar vesicles


Unilamellar vesicles

D, D-space

X-ray lamellar D-spacing

d, d-space

X-ray wide-angle chain spacing


Fluctuation parameter


Bending modulus


Bulk modulus


Vertical displacement


X-ray intensity


Form factor

MD simulation

Molecular dynamics simulation


Hydrocarbon thickness


Bilayer thickness


Headgroup thickness






















Egg phosphatidylcholine





























The author would like to thank Ben Sauerwine for preparing the snapshot of fluctuating bilayers from the Monte Carlo simulation. Funding was from NIH GM 44976.


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© Springer International Publishing Switzerland 2015

Authors and Affiliations

  1. 1.Biological Physics Group, Physics DepartmentCarnegie Mellon UniversityPittsburghUSA

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