Hydrophobic and electrostatic interactions in the adsorption of fibronectin at maleic acid copolymer films

Research output: Contribution to journalResearch articleContributedpeer-review

Contributors

  • Toshihisa Osaki - , Leibniz Institute of Polymer Research Dresden (Author)
  • Lars Renner - , Leibniz Institute of Polymer Research Dresden (Author)
  • Manuela Herklotz - , Leibniz Institute of Polymer Research Dresden (Author)
  • Carsten Werner - , Leibniz Institute of Polymer Research Dresden, University of Toronto (Author)

Abstract

Adsorption and desorption of fibronectin (FN) were investigated at thin films of alternating maleic acid copolymers with octadecene (POMA) and with propene (PPMA). The hydrophobicity and charge density of the polymers were modulated by the choice of the comonomer. In consequence, the dominant forces between the substrate and the protein were specified as hydrophobic interaction for POMA and electrostatic interaction for PPMA. The adsorption kinetics were investigated in situ as variations of the optical thickness, adsorbed mass, and viscoelastic properties (detected by reflectometric interference spectroscopy and quartz crystal microbalance technique, respectively) while alterations of the electrosurface properties were derived from surface conductivity data and isoelectric points (by streaming potential/current measurements using a microslit electrokinetic setup). The results demonstrate that the interfacial mode of adsorbed FN depends on the predominant interactions: large amounts of FN were tightly bound to POMA by hydrophobic interactions. In contrast, FN adsorbed on PPMA was concluded to attain an unfolded structure allowing for the "electrostatic matching" of positively charged residues on FN with the maleic acid groups. This conclusion was supported by the acidic IEP of 3.2 found for FN on PPMA and a significant reduction of the surface conductivity of the FN-covered polymer film, whereas FN on POMA showed an IEP of 4.2 (close to the intrinsic IEP of FN), indicating a stochastic orientation of the adsorbed protein.

Details

Original languageEnglish
Pages (from-to)12119-12124
Number of pages6
JournalThe journal of physical chemistry. B
Volume110
Issue number24
Publication statusPublished - 22 Jun 2006
Peer-reviewedYes
Externally publishedYes

External IDs

Scopus 33745794046
ORCID /0000-0003-0189-3448/work/173985692

Keywords

Keywords

  • Adsorption, Fibronectins/chemistry, Maleates/chemistry, Polymers/chemistry, Static Electricity