synthesis of a biomimetic hydrogel based on complex coacervate as a bone adhesive

Median sternotomy surgery is one of the most common access methods in heart and chest surgery. sternotomy wound healing may be associated with sternal wound infection, osteomyelitis, or mediastinitis. although there is currently no suitable bone adhesive to control bleeding from the edges of the sternum after sternotomy, inspired by marine organisms in water, the aim of this research is to develop biomimetic adhesive based on chitosan and hydroxyapatite nanoparticles substituted with zinc and gallium. adhesive was synthesized based on quaternized chitosan (qch) and cellulose/polyphosphodopamide interpenetrating polymer network (ipn) with edta/fecl3 complex as a crosslinker. then coacervate adhesive was composited with mesoporous hydroxyapatite nanoparticles substituted with zinc and gallium. in order to evaluate the adhesiveness of the synthesized adhesive, the adhesive strength was tested by the astm f2255-05 adhesive strength test. in the results of the adhesive strength on the glass substrate, by adding 2% by weight of nanoparticles to the c2 adhesive, the shear strength was 900.4±38 kpa. the shear strength of this adhesive was 19.647±9 kpa and 27.8±2 kpa on sheep sternum bone and cow skin substrate, respectively, which showed the high ability of this adhesive to adhere to different substrates. also, in order to evaluate the adhesive strength in wet environment, c2 adhesive showed shear strength of 144±1.12 kpa on bone substrate and 18±1.2 kpa for skin substrate. also, to evaluate the adhesion strength in wet environment, c2 adhesive showed shear strength of 144±1.12 kpa on bone substrate and 18±1.2 kpa for skin substrate in wet conditions. in all adhesives, cell growth and proliferation were high, so that in sample c2, after 72 hours of culture, 149.5±5 percent cell viability was observed. the addition of mesoporous hydroxyapatite nanoparticles substituted with zinc and gallium in coacervate adhesives increased osteogenesis and the expression of bone genes alkaline-phosphatase, osteocalcin, collagen i and runx2 resulting from the differentiation of mesenchymal cells. histological evaluation of composite coacervate adhesive in rabbit sternum showed bone healing and the presence of osteoblast cells in the wound site.