A piconewton force transducer and its application to measurement of the bending stiffness of phospholipid membranes

V. Heinrich, R. U. Waugh

Research output: Contribution to journalArticle

105 Citations (Scopus)

Abstract

The bending stiffness of a phospholipid bilayer (k(c)) was measured by forming thin bilayer cylinders (tethers) from giant phospholipid vesicles. Based on the balance of forces, the tether force was expected to be proportional to the square root of the membrane tension, with a constant of proportionality con raining k(c). The membrane tension was controlled via the aspiration pressure in a micropipette used to hold the vehicle. The force on the tether was generated by an electromagnet acting on a paramagnetic bead attached to the vesicle surface. The magnitude of the force was determined from measurements of the magnet current, which was adjusted to maintain the position of the bead. Measurements were performed on vesicles composed of stearoyl-oleoyl-phosphatidylcholine plus 5% (by mole) biotinylated phosphatidylethanolamine to mediate adhesion to streptavidin-coated beads. From each vesicle, tethers were formed repeatedly at different values of the membrane tension. The expected relationship between membrane tension and tether force was observed. The mean value of k(c) for 10 different vesicles was 1.17 x 10-19 J (SD =0.08 x 10-19 J). The precision of these data demonstrates the reliability of this approach, which avoids uncertainties of interpretation and measurement that may be associated with other methods for determining k(c).

Original languageEnglish (US)
Pages (from-to)595-605
Number of pages11
JournalAnnals of Biomedical Engineering
Volume24
Issue number5
StatePublished - Sep 1996
Externally publishedYes

Fingerprint

Bending (forming)
Phospholipids
Transducers
Stiffness
Membranes
Electromagnets
Magnets
Adhesion

Keywords

  • Bilayer membrane
  • Curvature elasticity
  • Magnetic particles
  • Mechanics
  • Micromanipulation

ASJC Scopus subject areas

  • Biomedical Engineering

Cite this

A piconewton force transducer and its application to measurement of the bending stiffness of phospholipid membranes. / Heinrich, V.; Waugh, R. U.

In: Annals of Biomedical Engineering, Vol. 24, No. 5, 09.1996, p. 595-605.

Research output: Contribution to journalArticle

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