Enhanced osteoblasts adhesion and collagen formation on biomimetic polyvinylidene fluoride (PVDF) films for bone regeneration

Bone tissue engineering can be utilized to study the early events of osteoconduction. Fundamental research in cell adhesion to various geometries and proliferation has shown the potential of extending it to implantable devices for regenerative medicine. Following this concept in our studies, first, we developed well-controlled processing of polyvinylidene fluoride (PVDF) film to obtain a surface biomimicking ECM. We optimized the manufacturing dependent on humidity and temperature during spin-coating of a polymer solution. The mixture of solvents such as dimethylacetamide and acetone together with high humidity conditions led to a biomimetic, highly porous and rough surface, while with lower humidity and high temperatures drying allowed us to obtain a smooth and flat PVDF film. The roughness of the PVDF film was biofabricated and compared to smooth films in cell culture studies for adhesion and proliferation of osteoblasts. The bioinspired roughness of our films enhanced the osteoblast adhesion by over 44%, and there was collagen formation already after 7 days of cell culturing that was proved via scanning electron microscopy observation, light microscopy imaging after Sirius Red staining, and proliferation test such as MTS. Cell development, via extended filopodia, formed profoundly on the rough PVDF surface, demonstrated the potential of the structural design of biomimetic surfaces to enhance further bone tissue regeneration.