Electrochemical Anodic Synthesis and Analysis of TiO2 Nanotubes for Biomedical Applications

Nowadays, titanium and alloy materials are encouraged for biomedical applications. Fabrication of the passive layer over the titanium materials is limited. Typically, a plain titanium sample is not suitable for bioimplant applications because the adhesion of biological elements like blood cells, tissues, and bones is poor. The use of surface-modified titanium resolves this issue. Surface modifications on titanium by electrochemical methods are simple and cost-effective. The addition of water to the ethylene-based electrolyte-enhanced the oxidation process to increase the length of the nanotubes. Surface morphological analysis shows that the length of the nanotubes has been increased, nanoindentation analysis delivers that increasing the length has been increased the hardness level, and corrosion analysis indicates that the length of nanotubes encouraged the corrosion resistance. Potentiodynamic polarization, Bode and Nyquist plots were models fit analyzed with equivalent electrical circuits. Sample cell viability was characterized with NIH-3T3 cells using an inverted microscopy analyzer.

Anodic synthesis of TiO2 nanotubes by step-up voltages

Fabrication of TiO2 nanotubes (NTs) has extensive application properties due to their high corrosion resistant and compatibility with biomedical applications, the synthesis of TiO2 nanotubes over titanium has drawn interest in various fields. The synthesis of TiO2 NTs using novel in-situ step-up voltage conditions in the electrochemical anodization process is recorded in this work. For manufacturing the NTs at 1 hour of anodization, the input potential of 30, 40 and 50 V was selected. With increasing step-up voltage during the anodization process, an improvement in the NTs was observed, favoring corrosion resistance properties. The surface of NTs enhances the structure of the ribs, raising the potential for feedback over time. XRD was used to analyze phase changes, and HR-SEM analyzed surface topography. Impedance tests found that longer NTs improved the corrosion resistance.

Upscaling Anodic Synthesis of TiO2 Nanotubes Film as Potential Material for Photoelectrocatalytic Applications: Influence of Electrolyte Overheating and Aging on Nanotube Morphology and Stability

Background: Among Advanced oxidation processes, heterogeneous photocatalysis have a great interest, because it uses only light has a source of energy. One of the main limiting processes in photocatalysis is the high probability of electron-hole pair’s recombination in the volume or at the surface of the photocatalyst particles. TiO2 nanotubes grown by anodic synthesis are widely studied because of the large number of potential practical applications especially in photocatalytic or photoelectrochemical applications. However, the preparation of these electrodes at large scale is still challenging due to some technological obstacles such as the electrochemical cell design or the precise control of nanotubes morphology, especially regarding electrolyte ageing and overheating during the synthesis. Objective: This study examines the electrochemical synthesis of TiO2 nanotubes supported on large titanium electrodes. Methods and Results: By understanding heat dissipation phenomenon during the synthesis, an optimized electrochemical cell was designed to prepare 6x4 cm 2 anodes. Then we aimed to control precisely the length of the nanotubes independently of electrolyte ageing. Indeed, It was previously observed that the electrolyte composition evolves (ageing) during the nanotubes synthesis and hence leads to nonreproducible nanotubes morphologies under time-controlled potentiostatic anodization conditions. Conclusion and Perspectives: To overcome this issue, we developed a Coulometric approach that allows to synthesize, reusing the same electrolyte, several electrodes with a great precision and reproducibility on the length of the nanotubes (2,7 μm ± 160 nm) despite electrolyte ageing. Subsequently, these electrodes can be integrated in a photocatalytic or photoelectrocatalytic process in a real wastewater treatment sector would be very relevant.

Assembly of Conducting Polymer and Biohydrogel for the Release and Real-Time Monitoring of Vitamin K3

In this work, we report the design and fabrication of a dual-function integrated system to monitor, in real time, the release of previously loaded 2-methyl-1,4-naphthoquinone (MeNQ), also named vitamin K3. The newly developed system consists of poly(3,4-ethylenedioxythiophene) (PEDOT) nanoparticles, which were embedded into a poly-γ-glutamic acid (γ-PGA) biohydrogel during the gelling reaction between the biopolymer chains and the cross-linker, cystamine. After this, agglomerates of PEDOT nanoparticles homogeneously dispersed inside the biohydrogel were used as polymerization nuclei for the in situ anodic synthesis of poly(hydroxymethyl-3,4-ethylenedioxythiophene) in aqueous solution. After characterization of the resulting flexible electrode composites, their ability to load and release MeNQ was proven and monitored. Specifically, loaded MeNQ molecules, which organized in shells around PEDOT nanoparticles agglomerates when the drug was simply added to the initial gelling solution, were progressively released to a physiological medium. The latter process was successfully monitored using an electrode composite through differential pulse voltammetry. The fabrication of electroactive flexible biohydrogels for real-time release monitoring opens new opportunities for theranostic therapeutic approaches.