Ceramics have historically been used for repair of hard tissues, however, more recently, promising applications in soft tissue engineering have also been reported for this group of biomaterials. Nonetheless, these inorganic scaffolds lack the ability to provide biochemical cues, which becomes an absolute necessity when orchestrating cell-ligand interactions during multicellular tissue repair. Collagen and fibrinogen are two essential proteins involved in tissue regeneration and have been extensively used for the design of biomaterials for soft tissue repair. Therefore, we studied how functionalization of porous ceramics with physiologically relevant proteins, such as collagen and fibrinogen nanofibres, influences cell interaction and bacterial growth. In this work we analysed the interaction of 3T3 fibroblasts, HaCaT keratinocytes and E. Coli bacteria with protein-modified alumina nanopores and microporous alumina textiles for a potential regenerative therapy of the largest organ in the human body - the skin. Alumina nanopores and microporous alumina textiles were silanized followed by modification with self-assembled collagen [1,2] and fibrinogen nanofibers, respectively.[3-4] Interestingly, collagen-modified alumina nanopores were able to prevent bacterial penetration through them. This ultimately led to death of the bacteria as they were unable to travel across the membranes and reach their nutrient source (agar). In case of fibrinogen-modified alumina textiles a completely different behaviour was observed whereby the textile surfaces were capable of acting as bacteria capture agents. Therefore, despite their microporous scaffold architecture, these textiles prevented bacterial infiltration, which is very interesting for protein-modified ceramics to be used as wound dressing materials that can promote adequate gas exchange and nutrient supply.  The interaction of skins cells, such as 3T3 fibroblasts and HaCaT keratinocytes, with protein-modified ceramics revealed the ability of both cell types to grow on these ceramics up to a period of 72h. In particular, the keratinocytes showed a tendency to grow in cell clusters on alumina nanopores whereas a distinct change in morphology was observed on the microporous alumina textiles. Fibroblasts were also found to adhere well to the ceramics without any distinct change in their morphology.

In summary, our results indicate future possibilities of exploring ceramics with tailored protein nanofiber modifications further to better mimic the microenvironment of native skin and other soft tissues.