Microparticle scaffolds support osteogenic differentiation of mscs

Abstract

Event Abstract Back to Event Microparticle scaffolds support osteogenic differentiation of mscs Karolina Stumbraite1, Ryan M. Clohessy1, Barbara D. Boyan1, 2 and Zvi Schwartz1, 3 1 Virginia Commonwealth University, Biomedical Engineering, United States 2 Georgia Institute of Technology, Biomedical Engineering, United States 3 University of Texas Health Science Center at San Antonio, Periodontics, United States Introduction: The effect metal surface features have on the differentiation of mesenchymal stem cells (MSCs) is well studied; however, less is known about polymers. Scaffolds with varying porosities, architectures, and topographies have been shown to support osteogenic differentiation, but they typically incorporate growth factors or small peptides or cells and are cultured in the presence of osteogenic media supplements. The objective of this study was to investigate the effect polymer surface roughness has on osteoblast differentiation of MSCs by examining the response to a sintered and etched poly-lactide-co-glycolide microparticle (PLGA) scaffold. Materials and Methods: PLGA (65:35) was cast at 150°C for 2h and ground into particles. Sieved particles (250-500µm) were packed into 15mm molds and heat sintered at 90°C for 2h. Scaffolds were etched with 5N NaOH for 1h (1hrEtch) or 2hr (2hrEtch), rinsed with ultrapure water, and dried. Scaffolds were characterized qualitatively by SEM, and quantitatively by CLSM and µCT. Construct yield stress and compressive modulus were measured at 10% strain/min using an MTS Instron Insight 30. Osteogenic differentiation of human MSCs on etched scaffolds was compared to cells on un-etched scaffolds (NoEtch). Cells cultured on tissue culture polystyrene (TCPS) served as a control. MSCs (20,000 cells/scaffold) were cultured in growth media (GM) for 2d, after which a subset of scaffolds were cultured in osteogenic media (OM) while the others continued in GM for 6d. DNA, alkaline phosphatase activity, osteocalcin, vascular endothelial growth factor (VEGF), bone morphogenetic protein-2 (BMP-2) and osteoprotegerin (OPG) were measured after eight days in culture. Results are n=6 cultures/variable for one representative experiment and analyzed by ANOVA and post-hoc by Bonferroni. Results: Etched micropits were visible on 1hrEtch and 2hrEtch that were not present on NoEtch samples. Total scaffold porosity was 43.9% (NoEtch), 42.3% (1hrEtch), and 45.4% (2hrEtch) with more than 99% of pores being open or interconnected. Etching significantly increased average scaffold roughness (Ra, µm: NoEtch 1.25±0.42; 1hrEtch 1.99±0.18; 2hrEtch 2.79±0.18). Compressive modulus and yield stress decreased as etching time increased. DNA content was lower on scaffolds than on TCPS (data not shown). Cells on etched scaffolds had elevated levels of osteocalcin, VEGF, BMP-2, and OPG (Fig 1) when treated with OM whereas OM did not affect cells on TCPS or non-etched scaffolds. Discussion and Conclusions: Microparticle scaffolds can be fabricated using a heat sintering process and surface modified through an etching treatment. The surface-etched scaffold enhanced effects of OM on osteoblast differentiation of MSCs after only 6d v. more than 14d on TCPS. Although etching decreased mechanical properties, the beneficial cell response outweighs this drawback and suggests that etched polymer scaffolds may be used as a bone substitute. Keywords: Scaffold, Bone repair, Nano/micro particle Conference: 10th World Biomaterials Congress, Montréal, Canada, 17 May - 22 May, 2016. Presentation Type: Poster Topic: Synthetic scaffolds as extracellular matrices Citation: Stumbraite K, Clohessy RM, Boyan BD and Schwartz Z (2016). Microparticle scaffolds support osteogenic differentiation of mscs. Front. Bioeng. Biotechnol. Conference Abstract: 10th World Biomaterials Congress. doi: 10.3389/conf.FBIOE.2016.01.02817 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 27 Mar 2016; Published Online: 30 Mar 2016. Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Karolina Stumbraite Ryan M Clohessy Barbara D Boyan Zvi Schwartz Google Karolina Stumbraite Ryan M Clohessy Barbara D Boyan Zvi Schwartz Google Scholar Karolina Stumbraite Ryan M Clohessy Barbara D Boyan Zvi Schwartz PubMed Karolina Stumbraite Ryan M Clohessy Barbara D Boyan Zvi Schwartz Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.