Evaluation of the antibacterial properties and in-vitro cell compatibilities of doped copper oxide/hydroxyapatite composites.

Mg, Zn and Ce-doped CuO/HA composites were prepared by a two-step sol-gel and hydrothermal process. SEM images showed a spherical appearance of HA and a needle-like morphology for doped CuO. XRD patterns revealed that all doped CuO/HA composites exhibited a hexagonal crystal structure of HA and a monoclinic crystal structure of CuO with no impurities. ICP analysis indicated that with the increase of loading amount of doped CuO, the concentrations of Cu2+ ions and doping ions released from composites increased. Moreover, CuO/HA composites exhibit improved antibacterial properties against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) as compared with HA. When the loading amount of doped CuO in composites increased to 15 wt%, the composites exhibited the best antibacterial activity and complete bacterial growth inhibition effect. Furthermore, the CCK-8 assay revealed that the doped CuO/HA composites are noncytotoxic and can promote the proliferation of osteosarcoma cells. This work highlights the potential of the doped CuO/HA composites with significant antibacterial activity, bioactivity and cell compatibility for potential biomedical applications in dental implants and bone regeneration.

Synthesis and evaluation of the structural and antibacterial properties of doped copper oxide.

Copper oxide (CuO) nanoparticles (NPs) doped with Mg2+, Zn2+ and Ce4+ ions were prepared by a hydrothermal method. SEM images revealed a spherical surface morphology for all doped CuO NPs. XRD patterns confirm that all doped CuO NPs exhibit a monoclinic structure at a dopant concentration of less than 7%, and when the doping content is up to 10%, MgO, ZnO and CeO2 phases are formed. ICP analysis indicated that these three doping elements have a promoting effect on the release of Cu2+ from the doped CuO NPs. Moreover, investigation of the antibacterial activity of the doped CuO NPs reveals that the doped CuO nanoparticles show effective antibacterial activity against Gram-positive Staphylococcus aureus (S. aureus) compared to the Gram-negative Escherichia coli (E. coli) bacterium. Among them, 5% Mg, 3% Zn and 5% Ce-doped CuO NPs exhibit the best bactericidal effect at a very low concentration of 0.05 mg mL-1, and the highest bacteriostatic rate can reach 99.9%. The improved antibacterial activity of the doped CuO NPs was attributed to the synergetic effect of ROS generation and the inactivation of proteins in the bacterial cells by the binding of the Cu2+ ions to the bacterial cell surface. This work highlights the potential of the doped CuO NPs to replace silver for antibiotic-free antibacterial applications in wound dressings, bone implants and dental fillings.

Porous calcite CaCO3 microspheres: Preparation, characterization and release behavior as doxorubicin carrier.

Porous CaCO3 microspheres are nowadays extensively used as a drug delivery system due to their excellent biocompatibility and degradability. However, the stability of vaterite CaCO3 microspheres is a major problem as a drug carrier. In this work, porous calcite CaCO3 microspheres are fabricated by calcination of gelatin-CaCO3 composite microspheres at 550 °C in air. The size and morphology of CaCO3 microspheres could be well regulated by the addition of gelatin. The structure of the as-prepared porous calcite CaCO3 microspheres is characterized by scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). Compared with vaterite CaCO3 microspheres, porous calcite CaCO3 microspheres are more stable and exhibit good drug-loading and drug release properties for doxorubicin (DOX), an effective anticancer agent. This study provides an easy and novel approach to prepare stable porous calcite CaCO3 microspheres, which show promising potential as a carrier for DOX.