The performance of an orthopedic procedure depends on several tandem functionalities. Such characteristics include materials’ surface properties and subsequent responses. Implant surfaces are typically roughened; this roughness can further be optimized to a specific morphology such as nanotubular roughness (ZrNTs) and the surfaces can further be used as static drug reservoirs. ZrNTs coatings are attracting interest due to their potential to improve the success rate of implant systems, by means of better physical affixation and also micro/nano physio-chemical interaction with the extracellular matrix (ECM). Effective control over the drug release properties from such coatings has been the subject of several published reports. In this study, a novel and simple approach to extending drug release time and limiting the undesirable burst release from zirconia nanotubes (ZrNTs) via structural modification was demonstrated. The latter involved fabricating a double-layered structure with a modulated diameter and was achieved by varying the voltage and time during electrochemical anodization. The structurally modified ZrNTs and their homogenous equivalents were characterized via SEM and ToF-SIMS, and their drug release properties were monitored and compared using UV–Vis spectroscopy. We report a significant reduction in the initial burst release phenomenon and enhanced overall release time. The simple structural modification of ZrNTs can successfully enhance drug release performance, allowing for flexibility in designing drug delivery coatings for specific implant challenges, and offering a new horizon for smart biomaterials based on metal oxide nanostructures.

The outcome of an implant procedure largely depends on the implant's surface properties. Biomaterials are now designed to have surfaces with multifunctionality, such as favorable tissue integration and the ability to combat bacterial adhesion and colonization. Herein, we report on a simple approach to improve the antibacterial properties of zirconia nanotubes (ZrNTs) coatings by decorating with silver nanoparticles (AgNP), achieved through electrochemical anodization of a zirconium–silver alloy (Zr–Ag). The AgNPs were shown to partially consist of Ag₂O, potentially enhancing the availability of Ag⁺ ions for antibacterial activity. The modified ZrNTs were characterized using SEM, EDS, ToF-SIMS, and XPS to determine their structural morphology and chemical composition, and were further subjected to antibacterial testing. The silver and zirconium ion release behavior was monitored via ICP-MS. ZrNTs decorated with AgNP exhibit strong antimicrobial activity (>99% bacterial killing) against both S. aureus and E. coli. Antimicrobial tests indicate that the antibacterial activity against the Gram-positive pathogen S. aureus was improved by a factor of 100 compared to unmodified ZrNTs, while unmodified ZrNTs already showed a comparable reduction of viable Gram-negative E. coli. This strategy illustrates a straightforward and effective modification that optimizes the interface between the host environment and the biomaterial surface to meet the very important criteria of biocompatibility and active antibacterial response.

The analysis and characterization of hybrid organic-inorganic metal oxide nanomaterials is of huge interest nowadays, due to their vastly increased use in current-issue applications reaching from solar energy conversion to catalysis or medical applications. Common to all, those hybrid materials are backboned by nanostructured metal oxides which contain modifications like self-assembled monolayers or molecule (e.g., drug) loadings leading to complex functional composite materials. While the chemical composition analysis or morphological studies of such structures can be performed superficially for example with time-of-light secondary ion mass spectrometry (TOF-SIMS) or scanning electron microscopy (SEM) respectively, a proper and efficient way for gathering depth information of such a composite material with appropriate resolution and measurement time has not yet been developed. Depth analysis by common sputtering techniques may lead to artefacts and destruction of molecular information during the analysis and, thereto, in a loss of signal. To overcome these issues in in-depth characterization of interlaced organic-inorganic nanostructures, this study presents the possibilities given by use of time-of-flight secondary ion mass spectrometry (TOF-SIMS) alone and in combination with cross-section-polishing (CSP) or focused-ion-beam (FIB) milling. A correlation in-between those methods is demonstrated on a model zirconium dioxide nanostructure-based material and a complex model consisting of encapsulated dye sensitized solar cells based on titanium dioxide nanotubes.

The surface charge of metal oxides is an important property that significantly contributes to a wide range of phenomena, including adsorption, catalysis and material science. The surface charge can be predicted by determining the isoelectric point (IEP) of a material and the pH of a solution. Although there have been several studies about the IEP of metal oxide (nano)particles, only few of them have reported the IEP of metal oxide films. The IEP of various compact metal oxide films such as TiO2, Nb2O5, WO3, ZrO2, NiO and Al2O3 formed via electrochemical anodization was determined in this project using the streaming potential technique. Nanostructured TiO2 and NiO were additionally produced using a single-step anodization technique and their IEPs were compared with the compact ones. The surface morphology and wettability of the oxides were studied by scanning electron microscopy (SEM) and contact angle (CA) measurements. X - ray powder diffraction (XRD) and X - Ray photoelectron spectroscopy (XPS) measurements were carried out to detect the elemental composition and phase analysis. The IEPs of compact anodic oxides are deviating from their nanoparticular and atomic layer deposited (ALD) counterparts. When comparing compact and nanostructured anodic oxides, the latter show even higher IEPs, emphasizing the dependency of the IEP on the method of oxide production.

Self-assembled monolayers (SAMs) on metal oxides play a pivotal role in tailoring surfaces for advanced hybrid and nanoscale architectures; however, their adsorption behavior is strongly governed by the interfacial chemistry of the underlying oxide. In this study, we systematically investigate the adsorption characteristics of two model acidic and basic SAM molecules with identical 12-carbon alkyl chains, tridecanoic acid (TDA) and dodecylamine (DDA), on WO3, TiO2, and NiO surfaces. These organics exhibit distinct dissociation mechanisms and surface affinities, enabling a detailed comparison across oxides with markedly different isoelectric points (IEPs). WO3 and TiO2 possess low IEPs (~3 and ~4), whereas NiO shows a significantly higher IEP (~10), providing a well-defined platform for probing the influence of surface charge on SAM adsorption. Leveraging these insights, we further fabricated TiO2-NiO composite substrates to assess the potential for area-selective SAM functionalization driven by IEP contrast. Comprehensive characterization combining contact angle measurements, XPS and ToF-SIMS was employed to quantify surface coverage and elucidate chemical and elemental compositions. The findings show that each SAM exhibits a clear preference for particular oxide surfaces based on surface charge interactions, enabling selective molecular modification of composite-oxide substrates and providing new opportunities for constructing advanced three-dimensional hybrid organic-inorganic architectures.

The outcome of an implant procedure largely depends on the implant's surface properties. Biomaterials are now required to have surfaces with multifunctionality such as favorable tissue integration and the ability to combat bacterial adhesion and colonization. Herein, we report on a simple approach to improving the antibacterial properties of zirconia nanotubes (ZrNT) coatings via decoration with silver nanoparticles (AgNp/Ag2O). This was done by electrochemical anodization of Zr-Ag alloy at a constant voltage in a fluoride-containing electrolyte. The modified ZrNTs were characterized using SEM, EDS, ToF – SIMS, and XPS to determine their structural morphology and chemical composition, and were further subjected to antibacterial testing The silver and zirconium ion release behavior was also monitored via ICP-MS. ZrNT decorated with AgNp/Ag2O exhibited strong antimicrobial activity (> 99 % bacterial killing) against both S. aureus and E. coli. Antimicrobial tests indicated that the antibacterial activity against the Gram-positive pathogen S. aureus could be improved by a factor of 100 compared to unmodified ZrNT while the unmodified ZrNT showed already a comparable reduction of viable Gram-negative E. coli achieved with the additional AgNp/Ag2O decoration. This modification strategy illustrates a simplified and effective approach toward optimizing the interface between the host environment and the biomaterial surface to meet the very important criteria of biocompatibility and antibacterial properties.