Bone formation by three-dimensional stromal osteoblast culture in biodegradable polymer scaffolds

• Published in: Journal of biomedical materials research Vol. 36; no. 1; pp. 17 - 28
• Main Authors: Ishaug, Susan L., Crane, Genevieve M., Miller, Michael J., Yasko, Alan W., Yaszemski, Michael J., Mikos, Antonios G.
• Format: Journal Article
• Language: English
• Published: New York John Wiley & Sons, Inc 01-07-1997; John Wiley & Sons
• Subjects: Alkaline Phosphatase - metabolism; Animals; Biocompatible Materials; Biodegradation, Environmental; Biological and medical sciences; Bone Marrow Cells; Bone Regeneration; Cell Division; Cells, Cultured; Lactic Acid; Life Sciences (General); Materials Testing; Medical sciences; Microscopy, Confocal; Microscopy, Electron, Scanning; Minerals - metabolism; Osteoblasts - cytology; Osteoblasts - metabolism; Osteoblasts - transplantation; Polyglycolic Acid; Polylactic Acid-Polyglycolic Acid Copolymer; Polymers; Radiotherapy. Instrumental treatment. Physiotherapy. Reeducation. Rehabilitation, orthophony, crenotherapy. Diet therapy and various other treatments (general aspects); Rats; Surface Properties; Technology. Biomaterials. Equipments. Material. Instrumentation; Non-Nasa Center; Nasa Discipline Cell Biology; Cell proliferation; Cell culture; Rat; Biodegradability; Rodentia; Histology; Glycolic acid polymer; Metabolism; In vitro; Osteoarticular system; Vertebrata; Lactic acid polymer; Mammalia; Three dimensional culture; Foam; Animal; Osteoblast; Biomaterial; Stromal cell; Morphometry; Osteogenesis; NASA Discipline Cell Biology; Non-NASA Center
• ISSN: 0021-9304; 1097-4636
• DOI: 10.1002/(SICI)1097-4636(199707)36:1<17::AID-JBM3>3.0.CO;2-O

Bone formation was investigated in vitro by culturing stromal osteoblasts in three-dimensional (3-D), biodegradable poly(DL-lactic-co-glycolic acid) foams. Three polymer foam pore sizes, ranging from 150-300, 300-500, and 500-710 microns, and two different cell seeding densities, 6.83 x 10(5) cells/cm2 and 22.1 x 10(5) cells/cm2, were examined over a 56-day culture period. The polymer foams supported the proliferation of seeded osteoblasts as well as their differentiated function, as demonstrated by high alkaline phosphatase activity and deposition of a mineralized matrix by the cells. Cell number, alkaline phosphatase activity, and mineral deposition increased significantly over time for all the polymer foams. Osteoblast foam constructs created by seeding 6.83 x 10(5) cells/cm2 on foams with 300-500 microns pores resulted in a cell density of 4.63 x 10(5) cells/cm2 after 1 day in culture; they had alkaline phosphatase activities of 4.28 x 10(-7) and 2.91 x 10(-6) mumol/cell/min on Days 7 and 28, respectively; and they had a cell density that increased to 18.7 x 10(5) cells/cm2 by Day 56. For the same constructs, the mineralized matrix reached a maximum penetration depth of 240 microns from the top surface of the foam and a value of 0.083 mm for mineralized tissue volume per unit of cross sectional area. Seeding density was an important parameter for the constructs, but pore size over the range tested did not affect cell proliferation or function. This study suggests the feasibility of using poly(alpha-hydroxy ester) foams as scaffolding materials for the transplantation of autogenous osteoblasts to regenerate bone tissue.