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Controlled‐release Of IGF‐I And TGF‐β1 In A Photopolymerizing Hydrogel For Cartilage Tissue Engineering
Published 2001 · Medicine
Photopolymerizing hydrogel systems provide a method to encapsulate cells and implant materials in a minimally invasive manner. Controlled release of growth factors in the hydrogels may enhance the ability to engineer tissues. IGF‐I and TGF‐β were loaded in PLGA microspheres using a double emulsion technique. 125 ng and 200 pg of active IGF‐I and TGF‐β, respectively, as measured by ELISA, were released over 15 days. The growth factor containing microspheres were photoencapsulated with bovine articular chondrocytes in PEO‐based hydrogels and incubated in vitro for two weeks. Statistically significant changes in glycosaminoglycan (GAG) production compared to control gels either without microspheres or with blank spheres were observed after a 14 day incubation with IGF‐I and IGF‐I/TGF‐β microspheres combined, with a maximum density of 8.41 ± 2.5% wet weight GAG. Total collagen density was low and decreased with the IGF‐I/TGF‐β microspheres after two weeks incubation, but otherwise remained unchanged in all other experimental groups. Cell content increased 10‐fold to 0.18 ± 0.056 × 106 cells/mg wet weight and extracellular matrix (ECM) staining by H&E increased in hydrogels with IGF‐I/TGF‐β microspheres. In conclusion, photoencapsulation of microspheres in PEO‐based hydrogels provides a method to deliver molecules such as growth factors in porous hydrogel systems. © 2001 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.