Adv Healthc Mater. 2019 Jul 22:e1900595. doi: 10.1002/adhm.201900595. [Epub ahead of print]

Differentiation of Rat Mesenchymal Stem Cells toward Osteogenic Lineage on Extracellular Matrix Protein Gradients.

Rasi Ghaemi S¹, Delalat B^1,2,3,4, Cavallaro A¹, Mierczynska-Vasilev A^1,5,6, Vasilev K^1,5, Voelcker NH^1,2,3,7.

Abstract

This report addresses the issue of optimizing extracellular matrix protein density required to support osteogenic lineage differentiation of mesenchymal stem cells (MSCs) by culturing MSCs on surface-bound density gradients of immobilized collagen type I (COL1) and osteopontin (OPN). A chemical surface gradient is prepared by tailoring the surface chemical composition from high hydroxyl groups to aldehyde groups using a diffusion-controlled plasma polymerization technique. Osteogenesis on the gradient surface is determined by immunofluorescence staining against Runx2 as an early marker and by staining of calcium phosphate deposits as a late stage differentiation marker. The Runx2 intensity and calcified area increase with increasing COL1 density up to a critical value corresponding to 124.2 ng cm^-2 , above which cell attachment and differentiation do not rise further, while this critical value for OPN is 19.0 ng cm^-2 . This gradient approach may facilitate the screening of an optimal biomolecule surface density on tissue-engineered scaffolds, implants, or tissue culture ware to obtain the desired cell response, and may generate opportunities for more cost-effective regenerative medicine.