Robust Antibacterial Activity of Xanthan-Gum-Stabilized and Patterned CeO2-x-TiO2 Antifog Films.

Increased occurrence of antimicrobial resistance leads to a huge burden on patients, the healthcare system, and society worldwide. Developing antimicrobial materials through doping rare-earth elements is a new strategy to overcome this challenge. To this end, we design antibacterial films containing CeO2-x-TiO2, xanthan gum, poly(acrylic acid), and hyaluronic acid. CeO2-x-TiO2 inks are additionally integrated into a hexagonal grid for prominent transparency. Such design yields not only an antibacterial efficacy of ∼100% toward Staphylococcus aureus and Escherichia coli but also excellent antifog performance for 72 h in a 100% humidity atmosphere. Moreover, FluidFM is employed to understand the interaction in-depth between bacteria and materials. We further reveal that reactive oxygen species (ROS) are crucial for the bactericidal activity of E. coli through fluorescent spectroscopic analysis and SEM imaging. We meanwhile confirm that Ce3+ ions are involved in the stripping phosphate groups, damaging the cell membrane of S. aureus. Therefore, the hexagonal mesh and xanthan-gum cross-linking chains act as a reservoir for ROS and Ce3+ ions, realizing a long-lasting antibacterial function. We hence develop an antibacterial and antifog dual-functional material that has the potential for a broad application in display devices, medical devices, food packaging, and wearable electronics.

Roles of strontium and hierarchy structure on the in vitro biological response and drug release mechanism of the strontium-substituted bioactive glass microspheres.

The strontium (Sr) substituted bioactive glasses (BGs) have inimitable advantages for bone generation, but the influences of Sr substitution on bioactivity and biocompatibility are still in debate. A brand novel porous microstructure of Sr-substituted BG microspheres was prepared by an electro-spraying technique combined with phase inversion, in which in vitro biological response (bioactivity, cell viability, alkaline phosphatase (ALP) activity and extracellular matrix (ECM) mineralization) and drug release were clarified in view of physical chemistry and ionic release behavior. The electro sprayed bioactive glass (ESBG) microspheres involved three characteristic pores: <100 nm, 100-1000 nm and >1000 nm. The Sr substitution on molar basis hindered the bioactivity of the samples in some extent but the cell behavior of the MC3T3-E1 cells was not significantly discouraged. The drug release profile was also controlled by amount of Sr substitution. However, the porous structure of the microspheres conferred improvement in bioactivity and provided a distinct three-stage drug release mode. Therefore, the Sr substituted ESBG microspheres may provide an effective way to deliver a steady supply of therapeutic ions and drugs in bone implantation patients.

Visible Light-Activated Self-Recovery Hydrophobic CeO2/Black TiO2 Coating Prepared Using Air Plasma Spraying.

Hydrophobic coatings are widely used in many areas from home to industry. However, the hydrophobicity can be easily degraded by adsorption of the atmospheric contaminations. In this study, a novel CeO2/black TiO2 hydrophobic coating with self-recovery capability is prepared using air plasma spraying without any chemical modification. The water contact angles (WCAs) of the coatings decreased after oleic acid contamination. Because of the presence of black TiO2, the composite coating has the photodegradation property under irradiation of visible light, and the part of the black TiO2 transforms to be superhydrophilic after irradiation for the generation of the surface oxygen vacancies. The oleic acid was decomposed and the WCAs changed depending on the volume percentage of the CeO2. The coating exhibits hydrophilicity when the volume percentage of the CeO2 is less than 60%, and hydrophobic when higher. After storage in a dark and clean environment, all the coatings can recover their hydrophobicity for the black TiO2 that returned back to its origin state. It is believed that this hydrophobic self-cleaning ceramic coating should have potential in engineering applications.