Farnaz Dehghani Firoozabadi - Biomedical Engineering (Biomaterials) Department, Islamic Azad University - Science and Research Branch, Tehran, Iran
Ahmad Ramazani Saadatabadi - Department of Chemical and Petroleum Engineering, Sharif University of Technology, Tehran, Iran
Azadeh Asefnejad - Biomedical Engineering (Biomaterials) Department, Islamic Azad University - Science and Research Branch, Tehran, Iran

Fabrication of fully optimized tissue-engineered materials in order to simulating the natural structure, and enhancing the biological properties of damaged tissue is one of the major challenges in biomedical engineering and regeneration medicine. Although polymeric based membranes have revealed noticeable advancements in bone regeneration, their mechanical stiffens, electrical conductivity and bioactivity need to be tolerated.  Therefore, the present study is designed to generate a multifunctional biomaterial based on polylactic acid (PLA)/ polycaprolactone (PCL)/hydroxyapatite (HA) nanocomposite containing zinc oxide (ZnO) and Graphene (Gr) nanoparticles employing solvent casting combined with die cast techniques for using as absorbable joint implants in bone tissue regeneration. The physical, chemical, mechanical and biological properties of the produced nanocomposite biomaterials were analyzed in vitro. A detailed experimental evaluation between the nanocomposite coatings was carried out to shed light on the effect of ZnO and Gr nanoparticles on the properties. It was found that the nanocomposite contained ۱% ZnO and ۱% graphene with a Young's modulus of ۱۵۴۰.۵ ± ۱۶۹.۴۲۶MPa and the pure sample had a Young's modulus of ۱۱۹۴.۸۱±۲۱۵.۳۴۲MPa. The rate of elongation at break of the nanostructure contained ۱% graphene was ۵.۱±۰.۸۱۶%. This value was ۳.۸±۰.۹۴۴% for the pure sample. The improvement in elongation at break is due to the presence of polycaprolactone in the polymer matrix. The optimal sample with ۱% zinc oxide and ۱% graphene had antibacterial properties more than other samples. Also, the survival rate of fibroblasts cell in the vicinity of the optimal matrix was significantly different from other samples. The obtained results revealed that the incorporation of the nanoparticles improved physico-chemical features and mechanical strength with enhanced biological properties and its anti-bacterial performance makes this material a promising candidate for further bone regeneration studies.

polylactic acid, hydroxyapatite, graphene, zinc oxide, polylactic acid