Multilayers of a globular protein and a weak polyacid: role of polyacid ionization in growth and decomposition in salt solutions. Academic Article uri icon


  • Thin films obtained from a layer-by-layer deposition of a weak polycarboxylic acid and a positively charged globular protein were studied by in situ ATR-FTIR. The system was chicken egg lysozyme (Lys), bovine pancrease ribonuclease A (RNase), or bovine gamma-globulin (IgG) self-assembled with polycarboxylic acids. When the pH value was lowered below a critical point, the growth of films and their tolerance to decomposition by added sodium chloride improved dramatically. Stabilization of protein/polyacid films in salt solutions at lower pH values occurred due to the onset of nonelectrostatic interactions to intermolecular binding within protein/polyacid multilayers and was controlled by polyacid ionization within the film rather than the pH of the external solution. A fractional ionization of polyacid in the pH-stabilization region was lower with protein-containing films than for polyacid/linear polycation films, reflecting hindrance of the inter-association of protonated carboxylic groups by protein globules. Practical ramifications of the pH-stabilization effect might extend to areas of biotechnology and biomaterials.

published proceedings

  • Biomacromolecules

author list (cited authors)

  • Izumrudov, V. A., Kharlampieva, E., & Sukhishvili, S. A

citation count

  • 116

complete list of authors

  • Izumrudov, Vladimir A||Kharlampieva, Eugenia||Sukhishvili, Svetlana A

publication date

  • May 2005