Zn/Na Co-Doped Hydroxyapatites: Synthesis, Antibacterial, and Bioactivity Studies

Abstract

The most crucial challenge of post-orthopedic surgery is related to bacterial film formation, which leads to implant failure. In this work, zinc/sodium (Zn/Na) co-doped hydroxyapatite nanoparticles (HA NPs) with different Zn/Na concentrations, including 1, 3, and 5 mol.% were synthesized using a hydrothermal method. Several analyses such as X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Energy Dispersive X-ray Spectroscopy (EDX), Scanning Electron Microscopy (SEM), and N2 ad/desorption were used to pinpoint the properties of as-prepared materials. Field Emission Scanning Electron Microscopy (FE-SEM) and EDX analysis demonstrated that the HA NPs possess an average size of about 30-40 nm and hexagonal morphology with no impurity. XRD patterns confirm that by the increasing amounts of Zn/Na, the crystal size of samples was decreased. FT-IR affirms the correct doping of metal ions. Brunauer-Emmett-Teller (BET) results of co-doped samples demonstrated a microporous structure, which can improve fluid flow in the inner structure of implants. The colony-forming unit (CFU) method conducted the antibacterial test, which confirmed that 5 mol.% Zn/Na co-doped HA NPs showed the highest antibacterial properties against Escherichia coli (PTCC 1276) (E. coli). Cytotoxicity results affirmed that 1 and 3mol.% Zn/Na co-doped HA NPs demonstrated low toxicity. Bioactivity tests revealed that the Zn/Na co-doped samples showed a higher ability to facilitate bone marrow stem cells; thus, improving the proliferation after the immersion in simulated body fluid (SBF). Therefore, Zn/Na co-doped HA NPs could be a promising candidate for bone tissue engineering applications.