Hybrid nano-composites for the regeneration of multi-functional anatomical regions

3D hybrid biomimetic and bio-resorbable scaffolds for the complete regeneration of multi-functional regions like osteochondral and periodontal sites are developed by a well-established bio-inspired synthesis mimicking the biologic neo-ossification process, thus providing the new devices with very high regenerative ability. The scaffolds are based on Type I collagen fibers that assemble, organize and mineralize with biomimetic, ion-substituted hydroxyapatite nano-nuclei upon pH variation at body temperature. The extent of mineralization can be varied from zero (i.e. cartilage-like constructs) to 70 wt% (i.e. bone-like), therefore 3D scaffolds with graded composition and morphology can be developed to mimic the multifunctional tissues of osteochondral and periodontal regions (sub-chondral bone, mineralized cartilage, hyaline cartilage, dentine, enamel, cement, etc), thus triggering relevant cell phenotypes (i.e. osteoblasts, chondrocytes, dentinoblasts, etc). In addition self assembling collagen fibers can be mineralized by nano-crystals of hydroxyapatite doped with Fe2+/Fe3+ ions so that the final hybrid composites are endowed with super-paramagnetic properties. Self-assembling polymeric blends (collagen, gelatine, cellulose, chitosan, alginate, etc.) are investigated to increase the chemical stability, mechanical performances as well as to modify the pore size and distribution.
The orientation of collagen fibres, pore size and interconnection is tailored by controlled freeze-drying and chemical cross-linking, to promote fast cell colonization, formation of new bone and controlled bio-degradation in vivo, in compliance with the kinetics of bone regeneration.