title: Three-dimensional cell seeding and growth in radial-flow perfusion bioreactor for in vitro tissue reconstruction.
abstract: Radial-flow perfusion bioreactor systems have been designed and evaluated to enable direct cell seeding into a three-dimensional (3-D) porous scaffold and subsequent cell culture for in vitro tissue reconstruction. However, one of the limitations of in vitro regeneration is the tissue necrosis that occurs at the central part of the 3-D scaffold. In the present study, tubular poly-L-lactic acid (PLLA) porous scaffolds with an optimized pore size and porosity were prepared by the lyophilization method, and the effect of different perfusion conditions on cell seeding and growth were compared with those of the conventional static culture. The medium flowed radially from the lumen toward the periphery of the tubular scaffolds. It was found that cell seeding under a radial-flow perfusion condition of 1.1 mL/cm2 x min was effective, and that the optimal flow rate for cell growth was 4.0 mL/cm2 x min. At this optimal rate, the increase in seeded cells in the perfusion culture over a period of 5 days was 7.3-fold greater than that by static culture over the same period. The perfusion cell seeding resulted in a uniform distribution of cells throughout the scaffold. Subsequently, the perfusion of medium and hence the provision of nutrients and oxygen permitted growth and maintenance of the tissue throughout the scaffold. The perfusion seeding/culture system was a much more effective strategy than the conventional system in which cells are seeded under a static condition and cultured in a bioreactor such as a spinner flask.
authors.affiliation: Department of Polymer Science and Engineering, Kyoto Institute of Technology, Matsugasaki, Kyoto 606-8585, Japan.
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Kitagawa
authors.forename: Tetsuji
authors.initials: T
authors.lastname: Yamaoka
authors.forename: Reiko
authors.initials: R
authors.lastname: Iwase
authors.forename: Akira
authors.initials: A
authors.lastname: Murakami
mesh_terms: D000818:Animals; D019149:Bioreactors; D002448:Cell Adhesion / Q000187:drug effects; D002452:Cell Count; D049109:Cell Proliferation / Q000187:drug effects; D019344:Lactic Acid / Q000737:chemistry / Q000494:pharmacology; D051379:Mice; D008855:Microscopy, Electron, Scanning; D041681:NIH 3T3 Cells; D011091:Polyesters; D011108:Polymers / Q000737:chemistry / Q000494:pharmacology; D011126:Polypropylenes / Q000737:chemistry; D012212:Rheology; D013499:Surface Properties; D046509:Tissue Culture Techniques / Q000295:instrumentation / Q000379:methods*; D023822:Tissue Engineering / Q000295:instrumentation / Q000379:methods*
chemical_list: D011091:Polyesters; D011108:Polymers; D011126:Polypropylenes; D019344:Lactic Acid; C033616:poly(lactide)