| Bone is a highly organised and specialised connective tissue with natural ability to self-heal and regain functionality. This capacity is, however, exposed to a great number of threats that can critically damage bone's health and trigger the need for bone substitutes. The present thesis aimed at the production of new bone scaffolds for tissue regeneration using the Inverted Colloidal Crystal (ICC) structure as model system. ICCs are 3D structures, resultant from Colloidal Crystals (CC) inverse replication, that exhibit uniform pore size, interconnected network and whose architectural design enhances the cellular environment and vascular ingrowth. Reported here is the use of organic (chitosan/chitin nanowhiskers) and inorganic (hydroxyapatite) building materials to develop scaffolds comprising ceramic, polymeric and composite matrices. Firstly, polystyrene microspheres are produced by simple microfluidic, assembled in hexagonal close packed CC and then used as templates for all scaffolds production. Ceramic based ICCs were developed using an hydroxyapatite solgel system and sintering route that allowed simultaneous template calcination and matrix formation. Polymeric based ICCs were subjected to hydrolytic degradation after being produced with different molecular weight chitosans in order to understand polymer influence on the scaffolds structural stability. Considering bone's composite nature, ICCs were constructed using hydroxyapatite nanorods suspended in chitosan solutions. Also, structures whose materials have an imprinted liquid crystalline organization provided by chitin nanowhiskers were developed inspired by bone collagen arrangement that contributes to the tissue hierarchical architecture. The morphological, biological and mechanical evaluation of such scaffolds contributes to establish the path for the development of new ICC based products with potential to complement or replace the currently clinically used bone substitutes and in that way constitute valuable solutions for bone tissue regeneration. |
