The effect of chitosan on the in vitro biological performance of chitosan-poly(butylene succinate) blends

Chitosan blends with synthetic biodegradable polymers have been proposed for various biomedical applications due to their versatile mechanical properties and easier processing. However, details regarding the main surface characteristics that may benefit from the blending of these two types of materials are still missing. Hence, this work aims at investigating the surface properties of chitosan-based blends, illustrating the way these properties determine the material-proteins interactions and ultimately the behavior of osteoblast-like cells. The surface characteristics of modified and nonmodified blends were assessed using complimentary techniques such as optical microscopy, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR-ATR), X-ray photoelectron spectroscopy (XPS), contact angle measurements and surface energy calculations. The adsorption of human serum albumin (HSA) and human plasma fibronectin (HFN) onto the different surfaces was quantified by association of an indirect method with a colorimetric assay. It was found that the presence of chitosan on the surface promoted the adsorption of proteins. Moreover, a preferential adsorption of albumin over fibronectin was registered. The in vitro biological performance of the studied materials was further investigated by a direct contact assay with an osteoblastic-like cell line (SaOs-2). A synergistic effect of the two components of the blend was observed. While the synthetic polyester promoted the adhesion of SaOs-2, the presence of chitosan significantly enhanced the osteoblastic activity of these cells. This work further confirmed the interest in designing polymeric blends with natural polymers as a successful strategy to enhance the biological performance of a biomaterial.