title: Durability of the binding inhibition of albumin coating on tympanostomy tubes.
abstract: OBJECTIVE
  Occlusion and prolonged otorrhea are typical problems associated with the use of middle-ear ventilation tubes. Albumin coating of ventilation tubes has been introduced to prevent tube occlusions by granulation tissue, blood clot, or pus. In this study, the durability of the binding inhibition (BI) of fibronectin was examined on the tube surface in albumin-coated tubes in different environments during an 8-month trial.
  
  
  METHODS
  Human serum albumin (HSA) was used to coat silicone tympanostomy tubes. Fibronectin, a typical adhesive protein in serum and exudates, was used as a model representative of exudates of the ear. The durability of BI of this glue protein on the tube surface was tested in different time periods with radiolabelled fibronectin. Scanning electron microscopy (SEM) was performed on the tubes.
  
  
  RESULTS
  The BI of fibronectin, achieved with the albumin coating, was still strong after 8 months of storage at +4 degrees C. A slight decline in BI was noted between the first and third months of storage at +37 degrees C. A significant difference between HSA-coated and uncoated tympanostomy tubes was noted in SEM. The uncoated surface generally appeared to be rougher than that of HSA-coated tubes when either titanium or silicone tubes were tested.
  
  
  CONCLUSIONS
  Albumin coating markedly inhibits the binding of fibronectin on tube surfaces in vitro. A clear BI achieved by albumin coating on tube surfaces was shown to persist throughout an 8-month trial, although some reduction of the BI was seen over time. The result emphasizes the role of albumin coating in preventing the adherence of foreign material on tympanostomy tubes. No advantage was achieved by using a cross-linking chemical in the albumin coating.
authors.affiliation: Department of Otolaryngology, Helsinki University Central Hospital, PO Box 220, FIN-00029, Helsinki, Finland. teemu.kinnari@hus.fi
authors.forename: Teemu J
authors.initials: TJ
authors.lastname: Kinnari
authors.forename: Eeva-Marjatta
authors.initials: EM
authors.lastname: Salonen
authors.forename: Jussi
authors.initials: J
authors.lastname: Jero
mesh_terms: D000418:Albumins / Q000737:chemistry* / Q000648:ultrastructure; D001665:Binding Sites; D018441:Biofilms; D020099:Coated Materials, Biocompatible; D004867:Equipment Design; D004868:Equipment Failure; D004869:Equipment Safety; D005353:Fibronectins / Q000737:chemistry* / Q000648:ultrastructure; D006801:Humans; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D008876:Middle Ear Ventilation / Q000295:instrumentation*; D011183:Postoperative Complications / Q000517:prevention & control; D011336:Probability; D012680:Sensitivity and Specificity; D013499:Surface Properties
chemical_list: D000418:Albumins; D020099:Coated Materials, Biocompatible; D005353:Fibronectins