Gelatin methacrylamide as coating material in cell culture

Unmodified gelatin (uG) is widely used as a coating material in cell culture for improving surface properties. In this study, the authors investigated if gelatin methacrylamide (GM) with a medium degree of methacrylamide modification (GM_1.5) and a high degree of methacrylamide modification (GM₄) are equally suitable for this purpose. Therefore, gold surfaces were coated with uG, GM_1.5, and GM₄ by adsorption of the polymers on the surfaces. Coating success was confirmed by spectroscopic ellipsometry, contact angle measurements, surface plasmon resonance spectroscopy (SPRS), and atomic force microscopy (AFM). The authors found that upon adsorption of uG, GM_1.5, a nd GM₄ on gold, thin films with thicknesses of 2.95 nm, 2.50 nm, and 2.26 nm were formed. The coated surfaces showed advancing contact angles of 46° (uG and GM_1.5) and 52° (GM₄) without alteration of the surface roughness determined by AFM. Protein adsorption taking place on the coated surfaces was measured during contact of the surfaces with fetal calf serum by SPRS. Protein adsorption on the coated surfaces was reduced by the factor of 6.4 (uG), 5.4 (GM_1.5), and 4.6 (GM₄) compared to gold surfaces. Human fibroblasts cultured on the surfaces showed excellent viability shown by water soluble tetrazolium salt assay as well as live/dead staining with propidium iodide and fluorescein diacetate. No cytotoxic effects of the GM coated surfaces were observed, giving rise to the conclusion that GMs are suitable materials as coatings in cell culture.