title: Evaluation of vacuum and dynamic cell seeding of polyglycolic acid and chitosan scaffolds for cartilage engineering.
abstract: OBJECTIVE
  To compare combined vacuum and rotation with the spinner flask technique for seeding chondrocytes on chitosan versus polyglycolic acid matrices.
  
  
  METHODS
  Porcine chondrocytes.
  
  
  METHODS
  A suspension containing 5 X 10(6) chondrocytes/scaffold was used to evaluate 2 seeding techniques, including a spinner flask and a custom-designed vacuum chamber used for 2 hours prior to transfer to a bioreactor. For each seeding technique, prewetted scaffolds were composed of polyglycolic acid (PGA) mesh or macroporous chitosan sponge. Constructs were collected at 48 hours for DNA quantification, measurement of water and gycosaminoglycan (GAG) content, and scanning electron microscopy.
  
  
  RESULTS
  Yield of both seeding techniques was similar for each type of scaffold. Percentage of cells contained in the center of PGA constructs was increased with seeding in the bioreactor (43% of total cell number), compared with the spinner flask (18%). The DNA content and cell number per construct were 10 times greater for PGA constructs, compared with chitosan constructs. Chitosan scaffolds seeded in the bioreactor yielded a significantly higher GAG:DNA ratio than did PGA scaffolds. Whereas chondrones formed on chitosan scaffolds, cell distribution was more uniform on PGA scaffolds.
  
  
  CONCLUSIONS
  The vacuum-bioreactor technique allowed seeded chondrocytes to attach to PGA scaffolds within 48 hours and improved uniformity of cell distribution, compared with the spinner technique. Although formation of extracellular matrix may be stimulated by seeding chitosan scaffolds in the bioreactor, further evaluations of the seeding technique and characteristics of chitosan scaffolds are warranted.
authors.affiliation: Department of Veterinary Clinical Medicine, College of Veterinary Medicine, University of Illinois, Urbana, IL 61802, USA.
authors.forename: Dominique J
authors.initials: DJ
authors.lastname: Griffon
authors.forename: M Reza
authors.initials: MR
authors.lastname: Sedighi
authors.forename: Aylin
authors.initials: A
authors.lastname: Sendemir-Urkmez
authors.forename: Allison A
authors.initials: AA
authors.lastname: Stewart
authors.forename: Russell
authors.initials: R
authors.lastname: Jamison
mesh_terms: D000818:Animals; D019149:Bioreactors; D002356:Cartilage / Q000254:growth & development* / Q000648:ultrastructure; D048271:Chitosan / Q000494:pharmacology*; D019902:Chondrocytes / Q000166:cytology* / Q000378:metabolism / Q000648:ultrastructure; D006025:Glycosaminoglycans / Q000032:analysis; D008855:Microscopy, Electron, Scanning / Q000662:veterinary; D011100:Polyglycolic Acid / Q000494:pharmacology*; D013552:Swine; D023822:Tissue Engineering / Q000379:methods* / Q000662:veterinary*; D014618:Vacuum
chemical_list: D006025:Glycosaminoglycans; D011100:Polyglycolic Acid; D048271:Chitosan