Abstract
It is well known that the surface chemistry of biomaterials is important for both initial cell attachment and the downstream cell response. Surface chemistry gradients are a new format that allows the screening of the subtleties of cell-surface interactions in high throughput. In this study, two surface chemical gradients were fabricated using diffusion control during plasma polymerization via a tilted mask. Acrylic acid (AA) plasma polymer gradients were coated on a uniform 1,7-octadiene (OD) plasma polymer layer to generate OD-AA plasma polymer gradients, whilst diethylene glycol dimethyl ether (DG) plasma polymer gradients were coated on a uniform AA plasma polymer layer to generate AA-DG plasma polymer gradients. Gradient surfaces were characterized by X-ray photoelectron spectroscopy, infrared microscopy mapping, profilometry, water contact angle (WCA) goniometry and atomic force microscopy. Cell attachment density and differentiation into osteo- and adipo-lineages of rat-bone-marrow mesenchymal stem cells (rBMSCs) was studied on gradients. Cell adhesion after 24 h culture was sensitive to the chemical gradients, resulting in a cell density gradient along the substrate. The slope of the cell density gradient changed between 24 and 6 days due to cell migration and growth. Induction of rBMSCs into osteoblast- and adipocyte-like cells on the two plasma polymer gradients suggested that osteogenic differentiation was sensitive to local cell density, but adipogenic differentiation was not. Using mixed induction medium (50% osteogenic and 50% adipogenic medium), thick AA plasma polymer coating (>40 nm thickness with ∼11% COOH component and 35° WCA) robustly supported osteogenic differentiation as determined by colony formation and calcium deposition. This study establishes a simple but powerful approach to the formation of plasma polymer based gradients, and demonstrates that MSC behavior can be influenced by small changes in surface chemistry.
Original language | English |
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Pages (from-to) | 58-67 |
Number of pages | 10 |
Journal | Acta Biomaterialia |
Volume | 11 |
Issue number | 1 |
DOIs | |
Publication status | Published - 2015 |
Externally published | Yes |
Keywords
- Differentiation
- Mesenchymal stem cells
- Plasma polymers
- Surface chemistry
- Surface-bound gradients
ASJC Scopus subject areas
- Biomaterials
- Biomedical Engineering
- Biotechnology
- Biochemistry
- Molecular Biology
- General Medicine