Elasticity of native and cross-linked polyelectrolyte multilayer films

Biomacromolecules. Sep-Oct 2004;5(5):1908-16. doi: 10.1021/bm0498023.


Mechanical properties of polyelectrolyte multilayer films were studied by nanoindentation using the atomic force microscope (AFM). Force-distance measurements using colloidal probe tips were systematically obtained for supported films of poly(L-lysine) and hyaluronan that are suited to bio-application. Both native and covalently cross-linked films were studied as a function of increasing layer number, which increases film thickness. The effective Young's modulus perpendicular to the film, Eperpendicular, was determined to be a function of film thickness, cross-linking, and sample age. Thick PEM films exhibited a lower Eperpendicular than thinner PEM, whereas the Young's modulus of cross-linked films was more than 10-fold larger than native films. Moduli range from approximately 20 kPa for native films up to approximately 800 kPa for cross-linked ones. Young's moduli increased slightly with sample age, plateauing after approximately 4 weeks. Spreading of smooth muscle cells on these substrates with pre-attached collagen proved to be highly dependent on film rigidity with stiffer films giving greater cell spreading.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cross-Linking Reagents / analysis
  • Cross-Linking Reagents / chemistry*
  • Elasticity
  • Electrolytes / analysis
  • Electrolytes / chemistry
  • Hyaluronic Acid / analysis
  • Hyaluronic Acid / chemistry*
  • Polylysine / analysis
  • Polylysine / chemistry*
  • Solutions / analysis
  • Solutions / chemistry


  • Cross-Linking Reagents
  • Electrolytes
  • Solutions
  • Polylysine
  • Hyaluronic Acid