3 research outputs found
Biocompatibility and Antibacterial Properties of ZnO-Incorporated Anodic Oxide Coatings on TiZrNb Alloy
In a present paper, we demonstrate novel approach to form ceramic coatings with incorporated ZnO nanoparticles (NPs) on low modulus TiZrNb alloy with enhanced biocompatibility and antibacterial parameters. Plasma Electrolytic Oxidation (PEO) was used to integrate ZnO nanoparticles (average size 12–27 nm), mixed with Ca(H2PO2)2 aqueous solution into low modulus TiZrNb alloy surface. The TiZrNb alloys with integrated ZnO NPs successfully showed higher surface porosity and contact angle. XPS investigations showed presence of Ca ions and absence of phosphate ions in the PEO modified layer, what explains higher values of contact angle. Cell culture experiment (U2OS type) confirmed that the surface of as formed oxide-ZnO NPs demonstrated hydrophobic properties, what can affect primary cell attachment. Further investigations showed that Ca ions in the PEO coating stimulated proliferative activity of attached cells, resulting in competitive adhesion between cells and bacteria in clinical situation. Thus, high contact angle and integrated ZnO NPs prevent bacterial adhesion and considerably enhance the antibacterial property of TiZrNb alloys. A new anodic oxide coating with ZnO NPs could be successfully used for modification of low modulus alloys to decrease post-implantation complications
Application of Polydopamine Functionalized Zinc Oxide for Glucose Biosensor Design
Zinc oxide (ZnO) nanostructures are widely used in optical sensors and biosensors. Functionalization of these nanostructures with polymers enables optical properties of ZnO to be tailored. Polydopamine (PDA) is a highly biocompatible polymer, which can be used as a versatile
coating suitable for application in sensor and biosensor design. In this research, we have grown
ZnO-based nanorods on the surface of ITO-modified glass-plated optically transparent electrodes
(glass/ITO). Then the deposition of the PDA polymer layer on the surface of ZnO nanorods was
performed from an aqueous PDA solution in such a way glass/ITO/ZnO-PDA structure was formed.
The ZnO-PDA composite was characterized by SEM, TEM, and FTIR spectroscopy. Then glucose
oxidase (GOx) was immobilized using crosslinking by glutaraldehyde on the surface of the ZnOPDA composite, and glass/ITO/ZnO-PDA/GOx-based biosensing structure was designed. This
structure was applied for the photo-electrochemical determination of glucose (Glc) in aqueous
solutions. Photo-electrochemical determination of glucose by cyclic voltammetry and amperometry has been performed by glass/ITO/ZnO-PDA/GOx-based biosensor. Here reported modification/functionalization of ZnO nanorods with PDA enhances the photo-electrochemical performance
of ZnO nanorods, which is well suited for the design of photo-electrochemical sensors and biosensors
Bioactivity Performance of Pure Mg after Plasma Electrolytic Oxidation in Silicate-Based Solutions
The biodegradable metals, including magnesium (Mg), are a convenient alternative to
permanent metals but fast uncontrolled corrosion limited wide clinical application. Formation of a
barrier coating on Mg alloys could be a successful strategy for the production of a stable external layer
that prevents fast corrosion. Our research was aimed to develop an Mg stable oxide coating using
plasma electrolytic oxidation (PEO) in silicate-based solutions. 99.9% pure Mg alloy was anodized
in electrolytes contained mixtures of sodium silicate and sodium fluoride, calcium hydroxide and
sodium hydroxide. Scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy
(EDX), contact angle (CA), Photoluminescence analysis and immersion tests were performed to
assess structural and long-term corrosion properties of the new coating. Biocompatibility and
antibacterial potential of the new coating were evaluated using U2OS cell culture and the grampositive Staphylococcus aureus (S. aureus, strain B 918). PEO provided the formation of a porous
oxide layer with relatively high roughness. It was shown that Ca(OH)2 was a crucial compound for
oxidation and surface modification of Mg implants, treated with the PEO method. The addition of
Ca2+ ions resulted in more intense oxidation of the Mg surface and growth of the oxide layer with a
higher active surface area. Cell culture experiments demonstrated appropriate cell adhesion to all
investigated coatings with a significantly better proliferation rate for the samples treated in Ca(OH)2
- containing electrolyte. In contrast, NaOH-based electrolyte provided more relevant antibacterial
effects but did not support cell proliferation. In conclusion, it should be noted that PEO of Mg alloy
in silicate baths containing Ca(OH)2 provided the formation of stable biocompatible oxide coatings
that could be used in the development of commercial degradable implant