New Interface for Purification of Proteins: One-Dimensional TiO₂ Nanotubes Decorated by Fe₃O₄ Nanoparticles

In this work, a high surface area interface, based on anodic one-dimensional (1D) TiO₂ nanotubes homogeneously decorated by Fe₃O₄ nanoparticles (TiO₂NTs@Fe₃O₄NPs) is reported for the first time for an unprecedented purification of His-tagged recombinant proteins. Excellent purification results were achieved from the model protein mixture, as well as from the whole cell lysate (with His-tagged ubiquitin). Compared to a conventional immobilized-metal affinity chromatography (IMAC) system, specific isolation of selected His-tagged proteins on behalf of other proteins was significantly enhanced on TiO₂NTs@Fe₃O₄NPs interface under optimized binding and elution conditions. The combination of specific isolation properties, magnetic features, biocompatibility, and ease of preparation of this material consisting of two basic metal oxides makes it a suitable candidate for future purification of recombinant proteins in biotechnology. The principally new material bears a large potential to open new pathways for discoveries in nanobiotechnology and nanomedicine

TiO₂ Nanotube/Chalcogenide-Based Photoelectrochemical Cell: Nanotube Diameter Dependence Study

We present photoelectrochemical results for anodic TiO₂ nanotube layers grown with different diameter sizes (21, 35, 56, and 95 nm) with a thickness of approximately 560 nm using a novel anodization protocol. These tube layers were utilized as highly ordered n-type conductive scaffold for the inorganic chromophore Sn–S–Se. While downscaling the nanotube diameter significantly increased the number of nanotubes per square unit (from 5.6 × 10⁹ to 7.2 × 10¹⁰ pcs/cm²) and thus the active surface area increased as well, we found that the photoelectrochemical response in the UV light was identical and thus independent of the TiO₂ nanotube diameter in the range of nanotube diameters from 35 to 95 nm. Further, we demonstrate that a heterostructured photoelectrochemical cell consisting of TiO₂ nanotubes sensitized with crystalline Sn–S–Se chromophore showed higher photocurrent density (from 6 to 32 μA/cm² for the wavelength of 460 nm) with increasing nanotube diameter size. Upon detailed SEM analyses it was revealed that Sn–S–Se was infilled in all nanotube layers approximately to one-third of the thickness. Therefore, this photocurrent increase with increasing tube diameter can be ascribed to better interfacial contact (and improved charge transport) facilitated between the chromophore and nanotube walls

Table1_Photocatalytic degradation of naproxen using TiO2 single nanotubes.DOCX

Herein, TiO2 single-tube (TiO2 ST-NT) powders with and without magnetite Fe3O4 nanoparticles (TiO2 ST-NT@Fe3O4NPs) are presented for the first time as excellent photocatalysts for the degradation of one of the most popular non-steroidal anti-inflammatory drugs (NSAIDs), naproxen (NPX). The TiO2 ST-NT powders were synthesized by anodization followed by etching of the double wall, bending, sonication, ultra-centrifugation, and finally annealing at 600°C. A part of the obtained TiO2 ST-NT powders was decorated with Fe3O4 nanoparticles using a simple one-step decoration process. The best photocatalytic performance of TiO2 ST-NT and TiO2 ST-NT@Fe3O4NPs powders was obtained under the white light (6.2 × 10−4 s-1) and the blue light (2.7 × 10−4 s-1), respectively. During NPX photodegradation using TiO2 ST-NT powders, three main NPX transformation products (P1, P2, and P3) were detected. Upon excitation with the blue light illumination, TiO2 ST-NT@ Fe3O4NPs powders exhibited higher performance (∼80%) than TiO2 ST-NT powders (∼23%) within 1 h, resulting in an approximately three times increased photocatalytic rate constant. Moreover, under simulated sunlight conditions, TiO2 ST-NT powders demonstrated remarkable activity, achieving a 94% NPX degradation within 1 h. TiO2 ST-NT and TiO2 ST-NT@Fe3O4NPs powders represent excellent photocatalysts for NPX degradation.</p

Ultrathin TiO₂ Coatings via Atomic Layer Deposition Strongly Improve Cellular Interactions on Planar and Nanotubular Biomedical Ti Substrates

This work aims to investigate the chemical and/or structural modification of Ti and Ti-6Al-4V (TiAlV) alloy surfaces to possess even more favorable properties toward cell growth. These modifications were achieved by (i) growing TiO2 nanotube layers on these substrates by anodization, (ii) surface coating by ultrathin TiO2 atomic layer deposition (ALD), or (iii) by the combination of both. In particular, an ultrathin TiO2 coating, achieved by 1 cycle of TiO2 ALD, was intended to shade the impurities of F- and V-based species in tested materials while preserving the original structure and morphology. The cell growth on TiO2-coated and uncoated TiO2 nanotube layers, Ti foils, and TiAlV alloy foils were compared after incubation for up to 72 h. For evaluation of the biocompatibility of tested materials, cell lines of different tissue origin, including predominantly MG-63 osteoblastic cells, were used. For all tested nanomaterials, adding an ultrathin TiO2 coating improved the growth of MG-63 cells and other cell lines compared with the non-TiO2-coated counterparts. Here, the presented approach of ultrathin TiO2 coating could be used potentially for improving implants, especially in terms of shading problematic F- and V-based species in TiO2 nanotube layers