No abstract

Biomimetic mineralization of collagen is an advantageous method to obtain resorbable collagen/hydroxy-apatite composites for application in bone regeneration. In this report, established procedures for mineralization of bovine collagen were adapted to a new promising source of collagen from salmon skin challenged by the low denaturation temperature. Therefore, in the first instance, variation of temperature, collagen concentration, and ionic strength was performed to reveal optimized parameters for fibrillation and simultaneous mineralization of salmon collagen. Porous scaffolds from mineralized salmon collagen were prepared by controlled freeze-drying and chemical cross-linking. FT-IR analysis demonstrated the mineral phase formed during the preparation process to be hydroxyapatite. The scaffolds exhibited interconnecting porosity, were sufficiently stable under cyclic compression, and showed elastic mechanical properties. Human mesenchymal stem cells were able to adhere to the scaffolds, cell number increased during cultivation, and osteogenic differentiation was demonstrated in terms of alkaline phosphatase activity.

We introduce a novel Bombyx mori silk-based composite material developed for bone tissue engineering. Three-dimensional scaffolds were fabricated by embedding of natural degummed silk fibers in a matrix of regenerated fibroin, followed by freeze-drying. Different ratios of fibers to fibroin were investigated with respect to their influence on mechanical and biological properties. For all scaffold types, an interconnected porous structure suitable for cell penetration was proven by scanning electron microscopy. Compressive tests, carried out in static and cyclic mode under dry as well as wet conditions, revealed a strong impact of fiber reinforcement on compressive modulus and compressive stress. Cell culture experiments with human mesenchymal stem cells demonstrated that the fiber/fibroin composite scaffolds support cell attachment, proliferation, as well as differentiation along the osteoblastic lineage. Considering the excellent mechanical and biological properties, novel fiber/fibroin scaffolds appear to be an interesting structure for prospect studies in bone tissue engineering.