Characterization of esterified hyaluronan-gelatin polymer composites suitable for chondrogenic differentiation of mesenchymal stem cells

Composite scaffolds of homogeneously mixed esterified hyaluronan (HY) and gelatin (G) were manufactured with variable component compositions (HY100%; HY95%/G5%; HY70%/G30%). The goals of this study were to analyze the produced composite scaffolds using physical and chemical methods, for example, scanning electron microscopy, IR-spectroscopy, water contact angle, protein assay, and tensile testing as well as to assess the effects of adding gelatin to the composite scaffolds on attachment, proliferation, and chondrogenic differentiation of human mesenchymal stem cells. Numbers of attached cells were significantly higher on the composite material compared to pure hyaluronan at different time points of two-dimensional or three-dimensional cell culture (p < 0.02). In composite scaffolds, a significantly greater amount of cartilage-specific extracellular matrix components was deposited after 28 days in culture (glycosaminoglycan: p < 0.001; collagen: p < 0.001) as compared with 100% hyaluronan scaffolds. Additionally, gelatin-containing composite scaffolds displayed stronger promotion of collagen type II expression than pure hyaluronan scaffolds. The mechanism, based on which gelatin influences cell adhesion, was examined. The effect was inhibited by collagenase treatment of the composites or by addition of α5β1-integrin blocking antibodies to the cell suspension. In summary, the results describe the establishment of a class of composite polymer scaffolds, consisting of esterified hyaluronan and gelatin, which are potentially useful for cell-based tissue engineering approaches using mesenchymal stem cells for chondrogenic differentiation.