Native and DPPA cross-linked collagen sponges seeded with fetal bovine epiphyseal chondrocytes used for cartilage tissue engineering

Collagen-based biomaterials in the form of sponges (bovine type I collagen, both native and cross-linked by treatment with diphenylphosphorylazide, no ted control and DPPA sponges respectively) were tested as three-dimensional scaffolds to support chondrocyte proliferation with maintenance of the phe notype in order to form neocartilage. Control and DPPA sponges were initial ly seeded with 10(6) or 10(7) foetal bovine epiphyseal chondrocytes and mai ntained for 4 weeks in culture under static conditions in RPMI/NCTC medium with 10% FCS and without addition of fresh ascorbic acid. Both supports wer e always present during the study and a partial decrease in size and weight was detected only with control sponges, both seeded and unseeded. Cell pro liferation was only noted in the 10(6) cells-seeded sponges (4-fold increas e after 4 weeks of culture). Specific cartilage collagens (types II and XI) were deposited in the matrix throughout the culture and traces of type I c ollagen were noticed only in the culture medium after 2-3 weeks and 4 weeks in the case of 10(6) and 10(7) cells-seeded sponges, respectively. Glycosa minoglycans accumulated in the matrix, up to 1.8 and 9.8% of total dry weig ht after one month with both seeding conditions, which was much lower than in the natural tissue. In the 10(7) cells-seeded sponges, mineral depositio n, observed with unseeded sponges, was significantly decreased (2- to 3-fol d). These in vitro results indicate that both collagen matrices can support the development of tissue engineered cartilage. (C) 2000 Elsevier Science Ltd. All rights reserved.