Surface structural conformations of fibrinogen polypeptides for improved biocompatibility

Mohammed Yaseen, Xiubo Zhao, Amy Freund, Alexander M. Seifalian, Jian R. Lu

Research output: Contribution to journalArticle

35 Citations (Scopus)

Abstract

This work reports on how incorporation of silica nanocages into poly(urethane) copolymers (PU) affects conformational orientations of adsorbed fibrinogen and how different surfaces subsequently influenced HeLa cell attachment and proliferation. Incorporation of 2 wt% silica nanocages into poly(urethane) (PU4) substantially altered the surface topography of the films and some 50% of the surface was covered with the nanocages due to their preferential exposure AFM studies revealed the deposition of a dense protein network on the soft polymeric domains of PU4 and much reduced fibrinogen adsorption on the hard nanocage domains As on the bare SiO(2) control surface, fibrinogen molecules adsorbed on top of the hard nanocages mainly took the dominant trinodular structures in monomeric and dimeric forms In addition, net positively charged long alpha chains were prone to being hidden beneath the D domains whilst gamma chains predominantly remained exposed Dynamic interfacial adsorption as probed by spectroscopic ellipsometry revealed fast changes in interfacial conformation induced by electrostatic interactions between different segments of fibrinogen and the surface, consistent with the AFM imaging. On the PU surfaces without nanocage incorporation (PUA), however, adsorbed fibrinogen molecules formed beads-like chain networks, consistent with the structure featured on the soft PU4 domains, showing very different effects of surface chemical nature. Monoclonal antibodies specific to the alpha and gamma chains showed reduced a but increased gamma chain binding at the silicon oxide control and PU4 surfaces, whilst on the PUA, C18 and amine surfaces (organic surface controls) the opposite binding trend was detected with alpha chain binding dominant, showing different fibrinogen conformations Cell attachment studies revealed differences in cell attachment and proliferation, consistent with the different polypeptide conformations on the two types of surfaces, showing a strong preference to the extent of exposure of gamma chains
Original languageEnglish
Pages (from-to)3781-3792
Number of pages12
JournalBiomaterials
Volume31
Issue number14
DOIs
Publication statusPublished - May 2010
Externally publishedYes

Keywords

  • Biocompatibility
  • Protein adsorption
  • Fibrinogen
  • Cell adhesion
  • Polyurethane
  • Silica nanocage

Cite this