In vitro response of MC3T3-E1 pre-osteoblasts within three-dimensional apatite-coated PLGA scaffolds.
Biomimetic apatites have been reported to promote osteogenic activities in numerous in vivo and in vitro models, but the precise mechanism by which the apatite microenvironment promotes such activities is not well understood. Such mechanistic studies require reproducible model systems that are relevant to tissue engineering practices. Although two-dimensional (2D) apatite-coated polystyrene culture dishes provide practicality and reproducibility, they do not simulate the effects of the three-dimensional (3D) microenvironment and degrading polymeric substrates. A simple 3D model system to address these relevant effects, and its utilization in the investigation of apatite-promoted osteoblastic differentiation in vitro is reported in this paper. Apatite coating was achieved by sequentially immersing poly(lactide-co-glycolide) (PLGA) scaffolds into different simulated body fluids (SBF). SEM, EDX, FTIR, TEM electron diffraction confirmed the apatite coating to comprise of calcium-deficient carbonated hydroxyapatite crystals. While both apatite-coated and non-coated PLGA scaffolds supported MC3T3-E1 attachment, spreading, and proliferation, significant differences in osteoblastic differentiation were observed. Relative to non-coated controls, quantitative real-time PCR revealed significant apatite-associated suppression of alkaline phosphatase (ALP), early upregulation of osteopontin (OPN) at 3 days, and upregulation of osteocalcin (OCN) and bone sialoprotein (BSP) at 4 weeks. In summary, apatite-promoted osteoblastic differentiation can be observed in a 3D model system that is relevant to tissue engineering.
Department of Bioengineering, 7525 Boelter Hall, University of California, Los Angeles, California 90095, USA.
Yu-Fen
YF
Chou
James C Y
JC
Dunn
Benjamin M
BM
Wu
D000818:Animals; D001031:Apatites / Q000737:chemistry* / Q000494:pharmacology*; D040761:Biomimetic Materials / Q000737:chemistry / Q000494:pharmacology; D002454:Cell Differentiation / Q000187:drug effects*; D049109:Cell Proliferation / Q000187:drug effects; D048430:Cell Shape / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D005109:Extracellular Matrix / Q000378:metabolism; D005786:Gene Expression Regulation / Q000187:drug effects; D019344:Lactic Acid / Q000737:chemistry* / Q000494:pharmacology*; D051379:Mice; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D010006:Osteoblasts / Q000166:cytology / Q000187:drug effects*; D011100:Polyglycolic Acid / Q000737:chemistry* / Q000494:pharmacology*; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D016133:Polymerase Chain Reaction; D011108:Polymers / Q000737:chemistry* / Q000494:pharmacology*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D017550:Spectroscopy, Fourier Transform Infrared; D013234:Stem Cells / Q000166:cytology / Q000187:drug effects*; D023822:Tissue Engineering
D001031:Apatites; D011108:Polymers; D012333:RNA, Messenger; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid