title: Protein interactions with particulate Teflon: implications for the foreign body response.
abstract: OBJECTIVE
  This study examined the nature of protein interactions with particulate polytetrafluoroethylene (PTFE, Teflon) to elucidate possible mechanisms involved in the foreign body response directed against failed Proplast/Teflon implants.
  
  
  METHODS
  Fifty milligrams PTFE prepared to particle sizes ranging from < 32 microns to > 300 microns was incubated with newborn bovine serum. The total amount of protein adsorbed to the PTFE particles was determined using a standard colorimetric assay. The structural and functional integrity of the proteins adsorbed to PTFE was also examined. For these studies, xanthine oxidase was substituted for serum, and the enzymatic activity of xanthine oxidase adsorbed to PTFE was determined. Finally, primary interactions between protein and PTFE particles were assessed in experiments using water, 2 or 8 mol/L urea, 1 mol/L Nacl, or 1% sodium dodecyl sulfate in an attempt to dissociate bound protein from the surfaces of PTFE particles.
  
  
  RESULTS
  Serum proteins bind almost instantly to the surface of PTFE particles. The effective surface area of PTFE increases dramatically with reduction of the material to small particles, as does the total amount of protein adsorbed by the particulate PTFE. Proteins bind to PTFE principally by hydrophobic interactions, and their three-dimensional structure is significantly perturbed by this interaction. In the case of xanthine oxidase, adsorption to PTFE distorts protein structure to the extent that biologic activity is eliminated.
  
  
  CONCLUSIONS
  The amount of serum protein adsorbed to PTFE particles varies inversely with particle size for a constant mass of material. It is believed that the foreign body response directed against this material is related to the amount and relative distortion of proteins adsorbed to its surface. If so, it appears that reduction of an implant to small particles (typically 50 micron or less) will dramatically increase the biologic signal to local cell populations. Thus, the severity of the biologic response to PTFE debris may be dependent largely on the size of the debris particles.
authors.affiliation: Department of Oral and Maxillofacial Surgery, University of Texas Health Science Center, San Antonio 78284-7903, USA.
authors.forename: G
authors.initials: G
authors.lastname: Zardeneta
authors.forename: H
authors.initials: H
authors.lastname: Mukai
authors.forename: V
authors.initials: V
authors.lastname: Marker
authors.forename: S B
authors.initials: SB
authors.lastname: Milam
mesh_terms: D000327:Adsorption; D000818:Animals; D001798:Blood Proteins / Q000737:chemistry / Q000494:pharmacology*; D002417:Cattle; D004347:Drug Interactions; D005549:Foreign-Body Reaction / Q000209:etiology*; D007595:Joint Prosthesis; D010316:Particle Size; D011138:Polytetrafluoroethylene / Q000737:chemistry / Q000494:pharmacology*; D011485:Protein Binding; D011487:Protein Conformation; D013499:Surface Properties; D013704:Temporomandibular Joint; D014969:Xanthine Oxidase / Q000737:chemistry / Q000494:pharmacology
chemical_list: D001798:Blood Proteins; D011138:Polytetrafluoroethylene; D014969:Xanthine Oxidase