title: Scaffold-free tissue-engineered construct-hydroxyapatite composites generated by an alternate soaking process: potential for repair of bone defects.
abstract: Mesenchymal stem cell (MSC)-based tissue-engineered construct (TEC)-hydroxyapatite (HAp) composites were developed by an alternate soaking process. The TEC derived from cultured synovial MSCs was alternately immersed in varying concentrations of CaCl(2)/Tris-HCl and Na(2)HPO(4)/Tris-HCl buffers, and HAp formation was analyzed by Fourier transform infrared spectroscopy (FT-IR), wide-angle X-ray diffraction, and scanning electron microscopy (SEM). These analyses clearly demonstrated HAp formation in the TEC. Specifically, SEM assessments showed that spherical HAp crystals of approximately 1 mum were directly formed on the surfaces of the cells and extracellular matrix (ECM) fibers. Cytotoxicity from exposure to calcium or phosphate buffers of >100 mM concentrations as assessed by LIVE/DEAD staining and total DNA assays was detected, but such cytotoxicity was not detected following exposure to concentrations of <50 mM. The HAp nanocrystals (ca. approximately 500 nm) were formed after 20 cycles in 10 mM calcium or phosphate buffers, and cell survival in the composites was confirmed. Moreover, preliminary implantation of TEC-HAp composites derived from rabbit synovial MSCs to rabbit osteochondral defects exhibited accelerated osteoinduction. These composites may be the first example of a hybrid material that consists of ECM, HAp nanocrystals, and living MSCs, and the TEC-HAp composite could be a unique and useful material for bone tissue engineering.
authors.affiliation: Department of Applied Chemistry, Graduate School of Engineering, Osaka University, Suita, Osaka, Japan.
authors.forename: Michiya
authors.initials: M
authors.lastname: Matsusaki
authors.forename: Koji
authors.initials: K
authors.lastname: Kadowaki
authors.forename: Kosuke
authors.initials: K
authors.lastname: Tateishi
authors.forename: Chikahisa
authors.initials: C
authors.lastname: Higuchi
authors.forename: Wataru
authors.initials: W
authors.lastname: Ando
authors.forename: David A
authors.initials: DA
authors.lastname: Hart
authors.forename: Yoshinari
authors.initials: Y
authors.lastname: Tanaka
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Take
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Akashi
authors.forename: Hideki
authors.initials: H
authors.lastname: Yoshikawa
authors.forename: Norimasa
authors.initials: N
authors.lastname: Nakamura
mesh_terms: D000328:Adult; D000818:Animals; D018786:Bone Substitutes / Q000737:chemistry*; D002021:Buffers; D002118:Calcium / Q000737:chemistry; D002478:Cells, Cultured; D020219:Chondrogenesis; D017886:Durapatite / Q000737:chemistry*; D005109:Extracellular Matrix / Q000737:chemistry; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008297:Male; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000648:ultrastructure; D010710:Phosphates / Q000737:chemistry; D011817:Rabbits; D017550:Spectroscopy, Fourier Transform Infrared; D013583:Synovial Membrane / Q000166:cytology; D023822:Tissue Engineering / Q000379:methods*; D054457:Tissue Scaffolds; D014184:Transplantation, Homologous; D014961:X-Ray Diffraction
chemical_list: D018786:Bone Substitutes; D002021:Buffers; D010710:Phosphates; D017886:Durapatite; D002118:Calcium