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In the past decades, iron has been one of the intensively studied biodegradable metals due to its suitable mechanical properties, but it suffers from slow degradation in a physiological environment and low bioactivity. In this work, the beneficial properties of ceramic and polymer coatings were merged to enhance the corrosion properties and biological compatibility of Fe-based biomaterials. A new bilayer coating for Fe-based biomaterials that speeds up degradation while offering controlled, localized drug release to prevent infections was prepared. In addition, bioactive coatings with an incorporated antibiotic (gentamicin, Ge) were produced to introduce antibacterial properties into the prepared biomaterials and thus increase their bioactivity. The calcium phosphate (CaP) coating layer as well as a bioactive coating layer of CaP doped with gentamicin was electrochemically deposited onto an iron substrate. A layer of poly(ethylene glycol) was subsequently applied to the selection of prepared specimens to create a bilayer ceramic/polymer coating. Electrochemical and immersion corrosion tests revealed that the application of a bilayer coating allowed achieving the desired acceleration of degradation, while the application of only a ceramic coating led to a reduction in the corrosion rate. A slight increase in the corrosion rate was observed for samples with bioactive drug-containing coatings compared to samples with drug-free coatings. Higher viability of human fibroblastic cells cultured in the extracts of the tested samples was noted for samples with a bilayer coating compared to a ceramic coating. The addition of gentamicin in the bioactive coatings had no significant effect on the viability value. Antibacterial tests proved the antibacterial activity of samples with a gentamicin-loaded coating layer against Escherichia coli and Staphylococcus aureus strains. A detailed study of the release of gentamicin from the prepared coatings revealed a different mechanism of drug release from the ceramic and the ceramic/polymer coating. Furthermore, it was found that the drug was released more slowly and uniformly from the bilayer coating. It is therefore possible to adjust the amount and duration of drug release from the bioactive coating by the thickness of the upper polymer layer. Incorporation of an antibiotic in a combined ceramic/polymer coating enabled the creation of a high-performance bioactive coating for Fe bone implants with the possibility to release a drug in the vicinity of the implant in a controlled manner to address the needs of the patient., Competing Interests: The authors declare no competing financial interest., (© 2024 The Authors. Published by American Chemical Society.)

The work is focused on the degradation, cytotoxicity, and antibacterial properties, of iron-based biomaterials with a bioactive coating layer. The foam and the compact iron samples were coated with a polyethylene glycol (PEG) polymer layer without and with gentamicin sulfate (PEG + Ge). The corrosion properties of coated and uncoated samples were studied using the degradation testing in Hanks' solution at 37 °C. The electrochemical and static immersion corrosion tests revealed that the PEG-coated samples corroded faster than samples with the bioactive PEG + Ge coating and uncoated samples. The foam samples corroded faster compared with the compact samples. To determine the cytotoxicity, cell viability was monitored in the presence of porous foam and compact iron samples. The antibacterial activity of the samples with PEG and PEG + Ge against Escherichia coli CCM 3954 and Staphylococcus aureus CCM 4223 strains was also tested. Tested PEG + Ge samples showed significant antibacterial activity against both bacterial strains. Therefore, the biodegradable iron-based materials with a bioactive coating could be a suitable successor to the metal materials studied thus far as well as the materials used in the field of medicine., Competing Interests: The authors declare no competing financial interest., (© 2024 The Authors. Published by American Chemical Society.)

In this study, a highly sensitive, fast, and selective enzyme-free electrochemical sensor based on the deposition of Ni cavities on conductive glass was proposed for insulin detection. Considering the growing prevalence of diabetes mellitus, an electrochemical sensor for the determination of insulin was proposed for the effective diagnosis of the disease. Colloidal lithography enabled deposition of nanostructured layer (substrate) with homogeneous distribution of Ni cavities on the electrode surface with a large active surface area. The morphology and structure of conductive indium tin oxide glass modified with Ni cavities (Ni-c-ITO) were characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The diameter of the resulting cavities was approximately 500 nm, while their depth was calculated at 190 ± 4 nm and 188 ± 18 nm using AFM and SEM, respectively. The insulin assay performance was evaluated by cyclic voltammetry. Ni-c-ITO exhibited excellent analytical characteristics, including high sensitivity (1.032 µA µmol -1 dm 3 ), a low detection limit (156 µmol dm -3 ), and a wide dynamic range (500 nmol dm -3 to 10 µmol dm -3 ). Finally, the determination of insulin in buffer with interferents and in real blood serum samples revealed high specificity and demonstrated the practical potential of the method., (© 2022. The Author(s).)

Polymer-coated metals may act as biodegradable orthopedic implants with adjustable corrosion rates. Metallic surfaces represent a dynamic system with specific interactions occurring after the material is implanted into the human body. An additional layer, in the form of polymeric thin film, changes the nature of this metal-body fluids interface. Moreover, the interaction between polymer and metal itself can differ for various systems. Iron-based material modified with a thin layer of polyethyleneimine (PEI) coating was prepared and studied as potential absorbable implant. Computational methods were employed to study the interaction between the metallic surface and polymer functional monomer units at atomic levels. Various spectroscopical and optical methods (SEM, AFM, Confocal, and Raman spectroscopy) were also used to characterize prepared material. Electrochemical measurements have been chosen to study the polymer adsorption process onto the iron surface and corrosion behavior which is greatly influenced by the PEI presence. The adsorption mechanism of PEI onto iron was proposed alongside the evaluation of Fe and Fe-PEI degradation behavior studied using the impedance method. Bonding via amino -NH 2 group of PEI onto Fe and enhanced corrosion rate of coated samples were observed and confirmed., (© 2022. The Author(s).)

Diabetes mellitus represents one of the most widespread diseases in civilization nowadays. Since the costs for treating and diagnosing of diabetes represent several billions of dollars per year, a cheap, fast, and simple sensor for diabetes diagnosis is needed. Electrochemical insulin sensors can be considered as a novel approach for diabetes diagnosis. In this study, carbon electrode with electrodeposited NiO nanoparticles was selected as a suitable electrode material for insulin determination. The morphology and surface composition were studied by scanning electron microscopy (SEM), energy dispersive X-ray (EDX) spectroscopy, and X-ray photoelectron spectroscopy (XPS). For a better understanding of insulin determination on NiO-modified electrodes, the mechanism of electrochemical reaction and the kinetic parameters were studied. They were calculated from both voltammetric and amperometric measurements. The modified carbon electrode displayed a wide linear range from 600 nM to 10 µM, a low limit of detection of 19.6 nM, and a high sensitivity of 7.06 µA/µM. The electrodes were stable for 30 cycles and were able to detect insulin even in bovine blood serum. Additionally, the temperature stability of this electrode and its storage conditions were studied with appropriate outcomes. The above results show the high promise of this electrode for detecting insulin in clinical samples.