MgO Nanomaterials Improve Fibroblast Adhesion and Proliferation
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MgO Nanomaterials Improve Fibroblast Adhesion and Proliferation Daniel J. Hickey1 and Thomas J. Webster1,2 1 Department of Chemical Engineering, Northeastern University, Boston, MA 02115, U.S.A. 2 Center of Excellence for Advanced Materials Research, King Abdulaziz University, Jeddah, Saudi Arabia ABSTRACT Magnesium (Mg) plays an important role in the body mediating cell-extracellular matrix (ECM) interactions, bone apatite structure and density, and nucleic acid chemistries. While Mg has been investigated as a biomaterial for bone applications, it has not been studied for applications within soft tissues. This study investigated, for the first time, the response of fibroblasts to magnesium oxide (MgO) nanoparticles for soft tissue engineering applications. Primary human dermal fibroblasts were cultured both on tissue culture polystyrene in media supplemented with MgO nanoparticles as well as on poly-L-lactic acid (PLLA)-MgO nanoparticle composites. As this study was conducted concurrently with a study aimed at bone tissue engineering, hydroxyapatite (HA) nanomaterials were used for comparison. Results showed for the first time that fibroblasts adhered onto MgO-containing composites roughly three times better than HA-PLLA samples and roughly 4.5 times better than plain PLLA samples. Fibroblasts also proliferated to statistically higher densities when cultured in medium supplemented with MgO nanoparticles compared to un-supplemented medium and medium supplemented with HA nanoparticles. These preliminary results together suggest that MgO nanoparticles should be further investigated as materials to improve the regeneration of soft tissues as well as bone. INTRODUCTION The integration of soft into hard tissues is a complex process that often results in suboptimal healing and low stability at the site of interest. For example, procedures to secure anterior cruciate ligament (ACL) grafts into bone have a failure rate of 5-25%, with 100,000 operations taking place each year in the U.S., and the failure rate of rotator cuff reconstructions jumps to 30-94%, depending on the specific criteria of failure [1]. Thus, biomaterials capable of enhancing the regeneration of both soft and hard tissues are badly needed to aid in the proper integration of these tissues with very different properties. Based on its broad and crucial role in the body, it is possible that magnesium (Mg)-based biomaterials could provide a simple solution. Mg is a biocompatible, biodegradable, low-cost and environmentally friendly material that exists naturally in the human body (~0.4 g magnesium/kg [2]). Mg exists in its highest concentrations within bone where it plays several critical roles affecting bone health and mechanical properties [3-6]. However, beyond its presence within bone, Mg ions play a key role in mediating the functions of all cells in the body, specifically through their activation of integrins. Divalent Mg2+ (as well as Ca2+) ions initiate conformational activation of integrins for ligand binding by attaching to sites on the integrin α-c
