Advances in Biomedical Engineering Research (ABER) Volume 4, 2016 doi: 10.14355/aber.2016.04.001
www.seipub.org/aber
A Mechanochemical Microarray for Studying Combinatorial Effects on Embryonic Mesenchymal Cell Differentiation Basma Hashmi1,2, Keekyoung Kim1,3,4, Jalil Zerdani3,5,6, Tadanori Mammoto2, Juani Feliz1, Ali Khaddemhosseini1,3,4 and Donald E. Ingber1,2,6* Wyss Institute for Biologically Inspired Engineering at Harvard University, Boston, MA 02115, USA
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Vascular Biology Program, Boston Children’s Hospital and Harvard Medical School, Boston, MA 02115, USA
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Biomaterials Innovation Research Center, Biomedical Engineering Division, Department of Medicine, Brigham and Women’s Hospital and Harvard Medical School Boston, MA 02115, USA 3
Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA 4
Laboratory of Stem Cell Bioengineering, Institute of Bioengineering, Ecole Polytechnique Fédérale de Lausanne, Lausanne 1015, Switzerland 5
Harvard School of Engineering and Applied Sciences, Cambridge, MA 02138, USA
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Corresponding author: Wyss Institute for Biologically Inspired Engineering, CLSB, 5th Floor, 3 Blackfan Circle, Boston, MA 02115, USA *
don.ingber@wyss.harvard.edu Abstract Embryonic mesenchymal cells mediate tooth formation during development as a result of physical and chemical interactions with their extracellular matrix (ECM) microenvironment. Engineering biomaterials relevant to tooth differentiation require a screening platform that incorporates both embryologically relevant properties relating to ECM stiffness as well as chemistry. Current ECM microarray technologies that screen for the effects of differences in substrate mechanical properties on cell differentiationare limited to ranges of high stiffness that are not relevant for the engineering of many cell types, such as stem cells and embryonic mesenchymal cell derivatives. Here, we describe the development of a novel polyacrylamide gel microarray platform and demonstrate its utility for the selection of odontogenic biomaterials. This microarray platform uses soft substrates (132, 558, and 1510 Pa) that closely mimic the embryonic microenvironment coatedwith the ECM proteins, Collagen VI and Tenascin (either alone or in combination), which have been shown to contribute to odontogenesis and permits combinatorial analysis of their effects on cell growth and differentiation. Using expression of the odontogenic transcription factor pax9 as a measure of tooth differentiation, we found that odontogenesis was the highest when mesenchymal cells isolated from embryonic mouse mandible (day 10) were cultured on 1510 Pa with Collagen VI (100 µ g/ml). This screening method is useful for selection and design of engineered materials for dental applications, as well as any challenge that involves engineering of tissues that depends on compliant ECM materials in combination with chemical cues from the microenvironment. Keywords Extracellular Matrix; Microarray; Combinatorial Screening; Mechanics; Polyacrylamide Gel; Differentiation; Tooth Formation; Odontogenesis
Introduction Hypodontia due to early tooth loss or agenesisis a significant problem in children. Although artificial teeth are often implanted in adulates, it is difficult to obtain stable dental implants in children who experience active jaw growth (Fekonja 2005; Bolton 1958; Holm-Pedersen, Lang, and Müller 2007), and thus tooth regeneration remains a promising alternative to existing treatments. Recent work on embryonic tooth formation has shown that the prococess by which odontogenesis is controlled involves complex interplay between mechanical and chemical cues (T. Mammoto et al. 2011; Hashmi et al. 2014). In particular, mechanical compression of cells during
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