Scanning Tunneling Microscopy of Freeze Fracture Replicas of Biomaterials

  • John T. Woodward
  • Joseph A. Zasadzinski

Abstract

Under ambient conditions STM measurements of feature heights on biological and other soft materials are often much larger than expected and vary from point to point on the surface: STM imaging of these samples is also accompanied by deformations of the surface that would not be expected from the conventional picture of noncontact STM imaging through a vacuum gap. To explain these observations we have developed a two spring model for the interaction between the tip and sample that suggests that a fluid meniscus couples the tip to the sample leading to large height amplifications and the possibility of damage to the surface. To test this theory we imaged platinum carbon replicas of cadmium arachidate multilayer Langmuir-Blodgett films under a dry nitrogen environment, exposed to humid air, and returned to a nitrogen environment. Feature heights increased significantly in the humid environment, but were reversible upon return to a dry nitrogen environment.

Keywords

Scanning Tunneling Microscope Scanning Tunneling Microscope Imaging Inert Environment Freeze Fracture Freeze Fracture Replica 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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References

  1. 1.
    G. Binnig, H. Rohrer, Ch. Gerber, and E. Weibel, Surface study by scanning tunneling microscopy, Phys. Rev. Lett. 49: 57–60 (1982).CrossRefGoogle Scholar
  2. 2.
    G. Binnig, C. Quate, and Ch. Gerber, Atomic force microscope, Phys. Rev. Lett. 56: 930–933 (1986).CrossRefGoogle Scholar
  3. 3.
    J. Zasadzinski and S. Bailey, Applications of freeze fracture replication to problems in materials and colloid science, J. Electron Microsc. Tech. 13:309–344 (1989). This issue is an excellent reference for freeze fracture technique.Google Scholar
  4. 4.
    D. Schwartz, J. Garnaes, R. Viswanathan, and J. Zasadzinski, Surface order and stability of Langmuir-Blodgett films. Science 257: 508–511 (1992).CrossRefGoogle Scholar
  5. 5.
    P. Tippman-Krayer, H. Mohwald, and Yu L’vov, Structural changes before and during desorption of Langmuir-Blodgett films, Langmuir 7: 2298–2302 (1991).CrossRefGoogle Scholar
  6. 6.
    Y. Sasanuma, Y. Kitano, A. Ishitani, H. Nakahara, and K. Fukuda, Characterization of long-periodic layered structures by x-ray diffraction III: structure of a Langmuir-Blodgett film of cadmium arachidate at elevated temperatures, Thin Solid Films 199: 359–365 (1991).CrossRefGoogle Scholar
  7. 7.
    A. Tardieu, V. Luzzati, and F. Reman, Structure and polymorphism of the hydrocarbon chains of lipids: a study of lecithin-water phases, J. Mol. Bio. 75: 711–733 (1973).CrossRefGoogle Scholar
  8. 8.
    M. Janiak, D. Small, and G. Shipley Temperature and compositional dependence of the structure of hydrated dimyristoyl lecithin, J. Bio. Chem. 254: 6068–6078 (1979).Google Scholar
  9. 9.
    G. Smith, C. Safinya, D. Roux, and N. Clark, X-ray study of freely suspended films of a multilamellar lipid system, Mol. Cryst. Liq. Cryst. 144: 235–255 (1987).CrossRefGoogle Scholar
  10. 10.
    D. Wack and W. Webb, Synchrotron x-ray study of the modulated lamellar phase Pp, in the lecithin-water system, Phys. Rev. A 40: 2712–2730 (1989).Google Scholar
  11. 11.
    E. Luna and H. McConnell, The intermediate monoclinic phase of phosphatidylcholines, Biochim. et Biophys. Acta. 466: 381–392 (1977).CrossRefGoogle Scholar
  12. 12.
    D. Ruppel and E. Sackman, On defects in different phases of two-dimensional lipid bilayers, J. Phys. (Paris) 44: 1025–1034 (1983).Google Scholar
  13. 13.
    J. Zasadzinski and M. Schneider, Ripple wavelength, amplitude and configuration in lyotropic liquid crystals as a function of effective headgroup size, J. Phys. (Paris) 48: 2001–2011 (1987).Google Scholar
  14. 14.
    J. Zasadzinski, J. Schneir, J. Gurley, V. Eilings, and P. Hansrrla, Scanning tunneling microscopy of freeze-fracture replicas of biomembranes, Science 239: 1013–1015 (1988).CrossRefGoogle Scholar
  15. 15.
    J. Woodward, P. Hansma, and J. Zasadzinski, Precision height measurements of freeze fracture replicas using the scanning tunneling microscope, J. Vac. Sci. Technol. B 9: 1231–1235 (1991).CrossRefGoogle Scholar
  16. 16.
    J.-Y. Yuan, Z. Shao, and C. Gao, Alternative method of imaging surface topologies of nonconducting bulk specimens by scanning tunneling microscopy, Phys. Rev. Lett. 67:863–866 (1991). J.-Y. Yuan, Z Shao, C. Gao, Yuan, Shao, and Gao reply, Phys. Rev. Lett. 68: 2564 (1992).CrossRefGoogle Scholar
  17. 17.
    J. Woodward, J. Zasadzinski, and D. Schwartz, Comment on ‘Alternate method of imaging surface topologies of nonconducting bulk specimens by scanning tunneling microscopy’, Phys. Rev. Lett. 68: 2563 (1992).CrossRefGoogle Scholar
  18. 18.
    G. Ruben Ultrathin (1 nm) vertically shadowed platinum-carbon replicas for imaging individual molecules in freeze-etched biological DNA and material science metal and plastic specimens, J. Electron Microsc. Tech. 13: 335–354 (1989).CrossRefGoogle Scholar
  19. 19.
    H. Gross, T. Muller, I. Wildhaber, H. Winkler, High resolution metal replication, quantified by image processing of periodic test specimens, Ultramicroscopy 16: 287–304 (1985).CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media New York 1994

Authors and Affiliations

  • John T. Woodward
    • 1
  • Joseph A. Zasadzinski
    • 2
  1. 1.Department of PhysicsUniversity of California, Santa BarbaraSanta BarbaraUSA
  2. 2.Department of Chemical and Nuclear EngineeringUniversity of California, Santa BarbaraSanta BarbaraUSA

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