help button home button Biophys. J.
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH
Biophys. J. BioFAST: First Published June 23, 2006. doi:10.1529/biophysj.106.085688
© 2006 by the Biophysical Society.

A more recent version of this article appeared on October 1, 2006.
This Article
Right arrow Full Text (Rapid PDF)
Right arrow All Versions of this Article:
biophysj.106.085688v1
91/7/2532    most recent
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Higgins, M. J.
Right arrow Articles by Jarvis, S.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Higgins, M. J.
Right arrow Articles by Jarvis, S.

MEMBRANES

Structured Water Layers Adjacent to Biological Membranes

Michael John Higgins 1*, Martin Polcik 1, Takeshi Fukuma 1, John Sader 2, Yoshikazu Nakayama 3 and Suzi Jarvis 1

1 Trinity College Dublin
2 University of Melbourne
3 Osaka Prefecture University

* To whom correspondence should be addressed. E-mail: michael.higgins{at}tcd.ie.

Submitted on March 24, 2006
Revised on April 24, 2006
Accepted on 8 June 2006


  Abstract
Water amidst the restricted space of crowded biological macromolecules and at membrane interfaces is essential for cell function, though the structure and function of this 'biological water' itself remains poorly defined. The force required to remove strongly bound water is referred to as the hydration force and due to its widespread importance, it has been studied in numerous systems. Here, by using a highly sensitive dynamic atomic force microscope (AFM) technique in conjunction with a carbon nanotube (CNT) probe, we reveal a hydration force with an oscillatory profile that reflects the removal of up to 5 structured water layers from between the probe and biological membrane surface. Further, we find that the hydration force can be modified by changing the membrane fluidity. For 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) gel (L{beta}) phase bilayers, each oscillation in the force profile indicates the force required to displace a single layer of water molecules from between the probe and bilayer. In contrast, DPPC fluid (L{alpha}) phase bilayers at 60°C and 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) fluid (L{alpha}) phase bilayers at 24°C seriously disrupt the molecular ordering of the water and result predominantly in a monotonic force profile.

Key Words: Atomic Force Microscopy (AFM), Frequency Modulation Detection AFM (FM-AFM), Hydration Force, Lipid Bilayers, Molecular Resolution Imaging, Oscillatory Force




This article has been cited by other articles:


Home page
 Biophys. JHome page
J. Zhang, T. Hadlock, A. Gent, and G. R. Strichartz
Tetracaine-Membrane Interactions: Effects of Lipid Composition and Phase on Drug Partitioning, Location, and Ionization
Biophys. J., June 1, 2007; 92(11): 3988 - 4001.
[Abstract] [Full Text] [PDF]

Home page
 Biophys. JHome page
T. Fukuma, M. J. Higgins, and S. P. Jarvis
Direct Imaging of Individual Intrinsic Hydration Layers on Lipid Bilayers at Angstrom Resolution
Biophys. J., May 15, 2007; 92(10): 3603 - 3609.
[Abstract] [Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH
Copyright © 2006 by the Biophysical Society.