Alginate matrixed bone scafolds enriched with mineral doped hydroxyapatite

In the field of tissue engineering and regenerative medicine, the need for innovative biomimetic and bioactive biomaterials for repair and regeneration of damaged bone tissues is increasing. Among the biomaterials used for this purpose, natural polymer-based hydrogels and scaffolds stand out due to their biocompatibility and biodegradability as well as their properties supporting cell proliferation and tissue integrity. The produced scaffolds should be porous and have a structure similar to natural bone tissue which is suitable for vital continuity, such as cell adhesion, proliferation and blood flow. Hydroxyapatite (HA), a calcium phosphate compound found in the inorganic composition of bone, is a bioceramic material frequently used as a filler material and scaffold for repair and regeneration of bone tissue due to its biocompatibility and bioactive properties. However, the high crystalline stability of synthetically produced HA limits its biodegradability and causes tissue repair to be prolonged. Therefore, various ion-doped HA forms containing ions found in natural bone structure to increase the biodegradability of HA are being investigated. Within the scope of this thesis study, hydrogel scaffolds based on alginate (Alg), a natural polysaccharide due to its biocompatible structure, extracellular matrix (ECM)-like morphology and gel-forming ability, were investigated for bone regeneration and drug delivery applications as a suitable matrix material. Alginate polymer matrix scaffolds were doped with hydroxyapatite-based bioceramics. In order to increase the biodegradability and bioactivity of hydroxyapatite, an alumina silicate mineral, natural pumice (PM) mineral containing rich silicate ions was doped into HA and used in scaffold forms. 7.5% PM-doped HA and pure HA powders were synthesized and sintered at 1100℃. Sintered bioceramic powders were combined with alginate polymer matrix by freeze-gelation method to synthesize cross-linked porous scaffolds. Targocid drug containing Teicoplanin active ingredient as an antibacterial agent was composed into scaffolds integrated with PM doped HA. These Teicoplanin loaded alginate matrix mineral doped scaffolds were developed with antibacterial properties for bone regeneration and treatments with a gradual drug release mechanism. The developed composite scaffolds were characterized by morphological, chemical, thermal and biological (in-vitro swelling behavior, bioactivity, antibacterial activity and biocompatibility) analyses. Interconnected porous structure supporting cellular activities was observed in alginate matrixed pumice doped hydroxyapatite (Alg-HA-PM) scaffolds. Pumice addition decreased the high crystalline stability of HA and increased its remineralization ability. Teicoplanin integrated scaffolds have shown antibacterial activity against gram negative: Escherichia coli (E. coli) and gram positive: Staphylococcus aureus (S. Aureus) bacterial species in antibacterial tests performed by disk diffusion method. These developed scaffolds are expected to have high potential for use in the applications promoting tissue regeneration by providing drug release in the treatments of bone infections due to their high bioactivity, suitable morphological structure, low cytotoxicity and antibacterial activity.