Injectable In Situ-Forming pH/Thermo-Sensitive Hydrogel for Bone Tissue Engineering

Authors
Kim, Hea KyungShim, Woo SunKim, Sung EunLee, Kweon-HaengKang, EunahKim, Jong-HoKim, KwangmeyungKwon, Ick ChanLee, Doo Sung
Issue Date
2009-04
Publisher
MARY ANN LIEBERT, INC
Citation
TISSUE ENGINEERING PART A, v.15, no.4, pp.923 - 933
Abstract
We developed a novel pH- and thermo-sensitive hydrogel as a scaffold for autologous bone tissue engineering. We synthesized this polymer by adding pH- sensitive sulfamethazine oligomers (SMOs) to both ends of a thermo-sensitive poly(epsilon-caprolactone-co-lactide)-poly(ethylene glycol)-poly(e-caprolactone-co-lactide) (PCLA-PEG-PCLA) block copolymer, yielding a pH/thermo-sensitive SMO-PCLA-PEG-PCLA-SMO block copolymer. The synthesized block copolymer solution rapidly formed a stable gel under physiological conditions (pH 7.4 and 37 degrees C), whereas it formed a sol at pH 8.0 and 37 degrees C, making it injectable. This pH/thermo-sensitive hydrogel exhibited high biocompatibility in a Dulbecco's modified Eagle's medium extract test. Under physiological conditions, the hydrogel easily encapsulated human mesenchymal stem cells (hMSCs) and recombinant human bone morphogenetic protein-2 (rhBMP-2), with encapsulating efficiencies of about 90% and 85%, respectively. To assay for ectopic bone formation in vivo, we subcutaneously injected a polymer solution containing hMSCs and rhBMP-2 into the back of mice, after which we could observe hMSC differentiation for up to 7 weeks. Histological studies revealed mineralized tissue formation and high levels of alkaline phosphatase activity in the mineralized tissue. Therefore, this pH/thermo-sensitive SMO-PCLA-PEG-PCLA-SMO block copolymer demonstrated potential as an injectable scaffold for bone tissue engineering, with in situ formation capabilities.
Keywords
MESENCHYMAL STEM-CELLS; MORPHOGENETIC PROTEIN-2; ADIPOSE-TISSUE; OSTEOGENIC DIFFERENTIATION; DELIVERY; PH; DEGRADATION; SCAFFOLDS; MATRICES; MESENCHYMAL STEM-CELLS; MORPHOGENETIC PROTEIN-2; ADIPOSE-TISSUE; OSTEOGENIC DIFFERENTIATION; DELIVERY; PH; DEGRADATION; SCAFFOLDS; MATRICES
ISSN
1937-3341
URI
https://pubs.kist.re.kr/handle/201004/132617
DOI
10.1089/ten.tea.2007.0407
Appears in Collections:
KIST Article > 2009
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