Effect of zinc oxide micro- and nanoparticles on cytotoxicity, antimicrobial activity and mechanical properties of apatite-polymer osteoplastic material.

This work is devoted to the comparison of the physical and biological properties of synthesized osteoplastic composites with an experimentally determined content (375 μg/g) of the micro (ZnO) and nano (ZnO) particles, immobilized in Hydroxyapatite-Alginate-Chitosan matrix (HA-Alg-CS). ZnO show pronounced antimicrobial activity against E.coli ATCC 25922 and S. aureus ATCC 25923, while ZnO only in the CS presence. Composites containing ZnO do not have a toxic effect on bone-forming cells - osteoblasts, preserving their ability to biomineralization. ZnO and ZnO to varying degrees, but significantly affect composites' swelling, porosity, shape stability, and prolong vitamin D3 release for 120h, compared to Control. Composites do not demonstrate unwanted "burst release." ZnO increase Youngs' modulus of the HA-Alg matrix, namely 348 → 419 MPa (ZnO), 348 → 646 MPa (ZnO), and weaken the plastic (irreversible) deformations. The compressive strength of HA-Alg and HA-Alg/CS matrixes containing ZnO (178 MPa and 251 MPa, respectively) is in the range of values for native cortical bone (170-193 MPa). Biocompatibility and lack of toxic effect give both composites a perspective for osteoplastic application, but composites doped with ZnO are more attractive.