Characterization and osteogenic effects of mesenchymal stem cells on microbeads composed of hydroxyapatite nanoparticles/reconstituted collagen.
Natural bone is comprised of nanosized blade-like crystals of hydroxyapatite grown in close contact with collagen (Col) fibers. Characteristics of artificial bone tissue differ considerably with those of natural ones, mainly from the unusual self-organizing interaction between the apatite crystals and the proteic components. Nanoparticle spheres of hydroxyapatite (n-HA), dispersed in reconstituted fibrous Col, were prepared in three weight ratios of 75:25, 65:35, and 50:50 (n-HA:Col). Bone marrow mesenchymal stem cells (MSCs) from rabbits were seeded and cultured on the n-HA/Col microbeads and characterized. n-HA were evenly distributed throughout the Col matrix and aggregated to microbeads as determined by scanning electron microscopy. Electron and confocal microscopy showed that the MSCs spread and attached to microbeads via focal adhesions, while staining for F-actin and DNA revealed the presence of stress fibers. The phenotype of the MSCs in the flow cytometry was identified as CD11a-, CD44+, and CD90.1+. The optimal weight ratio is 65:35 for the normalized alkaline phosphatase activities. The transduced MSCs, engineered by replication-defective adenovirus to express the BMP-2 gene, demonstrated synergic osteogenic effects in the microbeads. MSCs are capable of proliferating and differentiating in appropriate combinations of n-HA/Col. Thus it is a promising composite for future clinical applications.
Jeng
Long-Bin
LB
Department of Surgery, China Medical University Hospital, Taichung 404, Taiwan.
Chung
Hui-Ying
HY
Lin
Tsung-Min
TM
Chen
Jyh-Ping
JP
Chen
Yi-Ling
YL
Lu
Yi-Lung
YL
Wang
Yng-Jiin
YJ
Chang
Sophia Chia-Ning
SC
D000199:Actins / Q000737:chemistry; D000818:Animals; D040881:CD11a Antigen / Q000096:biosynthesis; D002417:Cattle; D003094:Collagen / Q000737:chemistry*; D017886:Durapatite / Q000737:chemistry*; D005434:Flow Cytometry / Q000379:methods; D018960:Hyaluronan Receptors / Q000096:biosynthesis; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000187:drug effects; D018613:Microscopy, Confocal / Q000379:methods; D008855:Microscopy, Electron, Scanning / Q000379:methods; D008863:Microspheres; D053758:Nanoparticles / Q000737:chemistry*; D010012:Osteogenesis; D011817:Rabbits; D018800:Thy-1 Antigens / Q000096:biosynthesis
D000199:Actins; D040881:CD11a Antigen; D018960:Hyaluronan Receptors; D018800:Thy-1 Antigens; D003094:Collagen; D017886:Durapatite