Spectral features and antibacterial properties of Cu-doped ZnO nanoparticles prepared by sol-gel method

Zn（1-x）Cux O（x=0.00, 0.01, 0.03, and 0.05） nanoparticles are synthesized via the sol-gel technique using gelatin and nitrate precursors. The impact of copper concentration on the structural, optical, and antibacterial properties of these nanoparticles is demonstrated. Powder x-ray diffraction investigations have illustrated the organized Cu doping into ZnO nanoparticles up to Cu concentration of 5%（x = 0.05）. However, the peak corresponding to CuO for x= 0.01 is not distinguishable. The images of field emission scanning electron microscopy demonstrate the existence of a nearly spherical shape with a size in the range of 30–52 nm. Doping Cu creates the Cu–O–Zn on the surface and results in a decrease in the crystallite size. Photoluminescence and absorption spectra display that doping Cu causes an increment in the energy band gap. The antibacterial activities of the nanoparticles are examined against Escherichia coli（Gram negative bacteria）cultures using optical density at 600 nm and a comparison of the size of inhibition zone diameter. It is found that both pure and doped ZnO nanoparticles indicate appropriate antibacterial activity which rises with Cu doping.

Current Status and Outlook of Porous Zn-based Scaffolds for Bone Applications: A Review

Over the past 5 years,many works have been performed to reveal the potentials of Zinc(Zn)-based materials as temporary bone scaffolds with the expectation that their emergence could address some of the main concerns associated with magnesium-and iron-based materials.Thanks to the emerging Additive Manufacturing(AM)technology,it facilitates the optimization of the design and production of topological porous Zn-based materials suited for bone scaffolds.Since the studies on the porous Zn-based scaffolds are on the rise,we provide the most current progress in the development of porous Zn-based scaffolds for bone applications.The impacts of recently developed topological design from the AM as well as the advanced dynamic-flow corrosion on their corrosion,mechanical properties,and in vitro biocompatibility are also presented.Plus,we identify a number of research gaps and the challenges encountered in adopting porous Zn-based scaffolds for orthopedic applications and suggest some promising areas for future research.