Nanocoatings containing sulfated polysaccharides prepared by layer-by-layer assembly as models to study cell–material interactions

The understanding of both cell-extracellular matrix (ECM) and cell-material interactions is crucial for the success of implantable biomaterials including tissue engineering devices. ECM is rich in sulfated and aminated glycosaminoglycans and proteoglycans. The development of synthetic models containing those chemical groups is thus of major interest. Thin coatings of polysaccharides with controlled sulfur and nitrogen contents were developed by layer-by-layer assembly. In particular, the multilayers were prepared by assembling chitosan with κ-, ι- and λ-carrageenan (increasing sulfur content). The nanostructured multilayers were characterized by quartz crystal microbalance with dissipation (QCM-D), atomic force microscopy (AFM), scanning electron microscopy (SEM), water contact angle, X-ray photoelectron spectroscopy (XPS) and used as models to study the effect of the sulfate groups over the behavior of osteoblast-like cells. The biomimetic coatings increased the alkaline phosphatase (ALP) activity and proliferation compared with unmodified polycaprolactone surfaces. Biomineralization increase with the presence of the coatings is significantly higher on ι-carrageenan coatings, suggesting that the sulfate groups may interact positively with molecules involved in the osteoblastic activity as it occurs in the natural ECM. The developed nanocoatings can constitute an interesting model to understand the biological influence of the sulfate and amine groups existing on the surface of biomaterials.