title: Observation of chondrocyte aggregate formation and internal structure on micropatterned fibroin-coated surface.
abstract: Condensation/aggregation process of rabbit-derived chondrocytes on a fibroin-coated patterned substrate was observed to estimate initial aggregation process in fibroin sponge. Chondrocytes were seeded on array of 160 microm diameter pits in three densities: 5 cells/pit (2.5 x 10(4) cells/cm(2), LOW), 15 cells/pit (7.5 x 10(4) cells/cm(2), MID) and 25 cells/pit (12.5 x 10(4) cells/cm(2), HIGH). In the MID and HIGH groups, cells tended to form aggregates after 24 h after cell seeding. In the LOW group, cell aggregate were not seen in a majority of the pits. Observation of aggregates using confocal laser scanning microscope showed that the chondrocytes at the interface of the fibroin surface tended to extend to the surface, developing an extensive network of stress fibers throughout the cytoplasm. On the other hand, chondrocytes in the other part of the aggregates maintained spherical shape, and most of the actin was localized in the cell cortex as opposed to in stress fibers. These results suggest two functional structures in the aggregates, which may explain the good balance between the maintenance of their differentiated phenotype and proliferation rate in the fibroin sponge.
authors.affiliation: Graduate School of Engineering, Kyoto University, Kyoto, Japan.
authors.forename: Naoyoshi D
authors.initials: ND
authors.lastname: Kachi
authors.forename: Akihisa
authors.initials: A
authors.lastname: Otaka
authors.forename: Seungwoo
authors.initials: S
authors.lastname: Sim
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Kuwana
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Tamada
authors.forename: Junko
authors.initials: J
authors.lastname: Sunaga
authors.forename: Taiji
authors.initials: T
authors.lastname: Adachi
authors.forename: Naohide
authors.initials: N
authors.lastname: Tomita
mesh_terms: D000199:Actins / Q000737:chemistry; D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry*; D002358:Cartilage, Articular / Q000473:pathology; D002448:Cell Adhesion; D002465:Cell Movement; D019902:Chondrocytes / Q000737:chemistry* / Q000166:cytology; D020099:Coated Materials, Biocompatible; D003593:Cytoplasm / Q000378:metabolism; D005349:Fibroins / Q000737:chemistry*; D018613:Microscopy, Confocal / Q000379:methods; D011817:Rabbits; D013050:Spectrometry, Fluorescence / Q000379:methods; D013499:Surface Properties; D013997:Time Factors
chemical_list: D000199:Actins; D001672:Biocompatible Materials; D020099:Coated Materials, Biocompatible; D005349:Fibroins