Scanning tunneling microscopy of biopolymers: Conditions for microtubule stabilization

Stuart R Hameroff, Jovana Simić-Krstić, Murray F. Kelley, Mark A. Voelker, Jackson D. He, Eustace L. Dereniak, Robert S. McCuskey, Conrad W. Schneiker

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

Applications of scanning tunneling microscopy (STM) to biological materials have been limited by poor conductivity and instability of biomolecules. We have used STM to probe three different biopolymer materials in air on graphite surfaces: collagen protein, phospholipid membranes, and microtubule protein assemblies. In the case of microtubules, we evaluated parameters for fixation and stabilization for STM imaging and found conditions which resulted in stable, reproducible images. STM of collagen showed linear strands ~ 1.5 nanometers (nm) in diam. Periodicity of ~ 3 nm was accentuated by “spikes” which appear to match pyrrolidine ring structures in amino acids proline and hydroxyproline. STM of Langmuir diphosphatidyl ethanolamine phospholipid membranes showed a lattice periodicity (0.4 to 0.5 nm) which appears to match the spacing of phospholipid molecules in membranes. Preparation of microtubules for STM which consistently resulted in reproducible and stable images includes a specific salt and magnesium containing buffer, glutaraldehyde fixation and 0.8 M glycerol. Freeze drying was also utilized, however stable images were also obtained without freeze drying. STM imaging of microtubules in several magnifications showed linear structures of appropriate (≈ 25 nm) width comprised of 4 nm wide protofilaments. Microtubules often appeared “buckled” and flattened and shaded images (not shown) demonstrated individual “tubulin” subunits. Evidence of tip interaction with the biopolymers was seen with collagen and phospholipid membranes. We feel STM and related technologies have great promise for the study of biomolecular surfaces.

Original languageEnglish (US)
Pages (from-to)2890-2894
Number of pages5
JournalJournal of Vacuum Science and Technology A: Vacuum, Surfaces and Films
Volume7
Issue number4
DOIs
StatePublished - 1989

Fingerprint

Biopolymers
biopolymers
Scanning tunneling microscopy
scanning tunneling microscopy
Stabilization
stabilization
Phospholipids
collagens
Collagen
membranes
Membranes
freeze drying
periodic variations
Drying
Hydroxyproline
Microtubule Proteins
Ethanolamines
proteins
Proteins
Imaging techniques

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films

Cite this

Scanning tunneling microscopy of biopolymers : Conditions for microtubule stabilization. / Hameroff, Stuart R; Simić-Krstić, Jovana; Kelley, Murray F.; Voelker, Mark A.; He, Jackson D.; Dereniak, Eustace L.; McCuskey, Robert S.; Schneiker, Conrad W.

In: Journal of Vacuum Science and Technology A: Vacuum, Surfaces and Films, Vol. 7, No. 4, 1989, p. 2890-2894.

Research output: Contribution to journalArticle

Hameroff, SR, Simić-Krstić, J, Kelley, MF, Voelker, MA, He, JD, Dereniak, EL, McCuskey, RS & Schneiker, CW 1989, 'Scanning tunneling microscopy of biopolymers: Conditions for microtubule stabilization', Journal of Vacuum Science and Technology A: Vacuum, Surfaces and Films, vol. 7, no. 4, pp. 2890-2894. https://doi.org/10.1116/1.576164
Hameroff, Stuart R ; Simić-Krstić, Jovana ; Kelley, Murray F. ; Voelker, Mark A. ; He, Jackson D. ; Dereniak, Eustace L. ; McCuskey, Robert S. ; Schneiker, Conrad W. / Scanning tunneling microscopy of biopolymers : Conditions for microtubule stabilization. In: Journal of Vacuum Science and Technology A: Vacuum, Surfaces and Films. 1989 ; Vol. 7, No. 4. pp. 2890-2894.
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