Currently, there is an essential need for bioresorbable bone implants with antibacterial, anti-inflammatory properties as well as osteoinductivity. Considering this, in presented study for the first time hybrid Mg-ZK coatings with polydopamine (PDA), menaquinone-7 (MK-7), zoledronate (ZA) and vancomycin on the hydroxyapatite (HA) containing layer are formed. Porous coatings were obtained by the plasma electrolytic oxidation (PEO) on an Mg alloy, then MK-7 was impregnated into the pores and PDA film with ZA and vancomycin was polymerized on the samples surface. The presence of HA and organic bioactive compounds was confirmed by EDS, Raman spectroscopy, XRD and XPS. Surface free energy values of hybrid coatings are close to optimal for cell adhesion: 75.28 ± 1.35 mJ/m2. Viability tests of the medium, in which Mg-ZK implants were soaked, revealed cytotoxic activity on human osteosarcoma cells with no such an effect on fibroblasts. Antibacterial tests showed an inhibition zone on S. aureus with no viable colonies on the hybrid coatings. The growth inhibition zones for the samples with the hybrid coating were 21 ± 1 mm. Data of electrochemical impedance spectroscopy shows increase of corrosion resistance of samples with hybrid coating by 7 times comparing the Mg alloy without a coating. These properties make the hybrid Mg-ZK coating an attractive modification for bone implants.

The decisive impact of microstructural elements in the Mg–Ca alloy on its overall corrosion degradation trend was shown. The results indicate that the Mg–0.8Ca alloy sample exhibits lower corrosivity in the mammalian cell culture medium when compared to a 0.9% NaCl solution. The influence of corrosion products formed on the material surface on its degradation rate was established. The mechanism of the in vitro bioresorption of the alloy was established.

An increase in the corrosion resistance of magnesium and its alloys is achieved by forming hybrid smart coatings. The introduction of a corrosion inhibitor makes it possible to control the degradation rate of the material due to the self-healing effect of the coating. Additional polymer treatment significantly increases the corrosion resistance and wear resistance of the material. The inhibitor efficiency and the mechanism of anti-corrosion protection of the alloy are established.

A biodegradable matrix with a significant content of bioactive components can be applied for bone tissue replacement, including load-bearing applications in orthopedic surgery. The study outlines the optimized procedure for the production of bioresorbable magnesium-hydroxyapatite (Mg-HA) composites and their corrosion resistance properties. Composites were meticulously crafted by combining pure magnesium with microwavesynthesized hydroxyapatite nanopowder. Sintering occurred via spark plasma sintering technology (SPS). To align the degradation time of the resulting composites with bone remodeling, the corrosion resistance of SPS materials was enhanced through the application of plasma electrolytic oxidation (PEO) and polycaprolactone (PCL) spin-coating methods. The protective properties, morphology dynamics, and composition due to surface treatment and corrosion propagation were investigated using Electrochemical Impedance Spectroscopy (EIS), Potentiodynamic Polarization (PDP), hydrogen evolution tests, Scanning Electron Microscopy (SEM), Energydispersive X-ray (EDX) as well as X-ray diffraction (XRD) analysis. Analytics of the physicochemical properties data of the formed coatings indicate a significant improvement in protective characteristics and deceleration of the corrosive degradation of the samples. The application of polycaprolactone to the PEO coating leads to a decrease in the corrosion current compared to uncoated magnesium composites by more than three orders of magnitude: from 1 10-5 to 2 10-9 A cm- 2. During long-term exposure of samples to 0.9 % NaCl solution, it was found that coating reduced the rate of corrosion degradation of samples from 1.5 to 80 times compared to an unprotected Mg-HA composite and sintered magnesium. Mg-HA composites treated with PEO exhibit potential application as bioactive and biodegradable materials for orthopedic implants and fixation devices.

This paper presents a method for preparing magnetic nanocomposite with hierarchical structure based on Na2Ti3O7 and Fe2O3 (alpha-phase). The nanocomposite was synthesized using hydrothermal technology through combined treatment of TiO2 and various amounts of FeCl3 in a highly alkaline NaOH medium. In this method, Na2Ti3O7 nanotubes and alpha-Fe2O3 nanospheres self-assemble the compositing microparticles. The combining of nanotubular Na2Ti3O7 with nanospherical alpha-Fe2O3 enhances its visible-light sensitization. The band gap decreases across increasing content of the alpha-Fe2O3 phase, up to 2.85 eV (from 3.29 eV). The nanocomposite exhibits superparamagnetic properties. Both blocking temperature and coercive force rise with increasing alpha-Fe2O3 particles content. The obtained results enhance an understanding of how to combine different nanomaterials to design functional nanocomposites.

This paper presents the results of an evaluation of corrosion properties of PEO pretreated AlMg3 aluminum alloy samples with polymer coatings obtained by dip-coating in a suspension of superdispersed polytetrafluoroethylene (SPTFE) in a solution of polyvinylidene fluoride (PVDF) in N-methyl-2-pyrrolidone at different PVDF:SPTFE ratios (1:1, 1:3, 1:5, and 1:10). The electrochemical tests showed that samples with a coating formed at a ratio of PVDF to SPTFE of 1:5 possessed the best corrosion properties. The corrosion current density of these samples was more than five orders of magnitude lower than this parameter for bare aluminum alloy. During the 40-day salt spray test (SST) for samples prepared in a suspension at a PVDF:SPTFE ratio of 1:1–1:5, the formation of any pittings or defects was not detected. The PVDF:SPTFE 1:5 sample demonstrated, as a result of the 40-day SST, an increase in corrosion current density of less than an order of magnitude. The evolution of the protective properties of the studied samples was assessed by a two-year field atmospheric corrosion test on the coast of the Sea of Japan. It was revealed that the samples with the PVDF:SPTFE 1:5 coating had electrochemical parameters that remained consistently high throughout the one year of exposure. After this period, the polymer layer was destroyed, which led to a deterioration in the protective characteristics of the coatings.

В работе представлены результаты исследования влияния концентрации пентаоксида тантала в покрытиях, полученных методом плазменного электролитического оксидирования (ПЭО), на их электрохимические свойства и изучена способность данных покрытий к образованию апатитов в условиях in vitro. Согласно результатам анализа электрохимического поведения покрытий в растворе, имитирующем плазму крови человека по минеральному составу (SBF-растворе), модуль импеданса Ta2O5-содержащих ПЭО-покрытий, в среднем более чем на 2 порядка выше по сравнению с модулем импеданса сплава МА8 без покрытия. Введение в состав электролита наночастиц Ta2O5и увеличение содержания пентаоксида тантала в составе ПЭО-покрытий приводит к снижению их защитных свойств, по сравнению с базовым ПЭО-слоем. Установлено, что первые кластеры апатитов появляются на поверхности ПЭО-покрытия уже после 1 дня выдержки в SBF-растворе. Через 28 дней ПЭО-покрытие полностью покрывается слоем апатитов с пластинчатой морфологией. На 21 сутки выдержки Ta2O5-содержащего ПЭО-покрытия в SBF-растворе концентрация ионов Ca2+ в растворе стабилизируется, что обусловлено достижением равновесия окружающего раствора с образовавшимся слоем апатитов.

In the presented study, the corrosion properties of bioactive coatings formed by plasma electrolytic oxidation (PEO) on a MA8 magnesium alloy was studied. Using XRD analysis, it was established that the composition of the coatings includes hydroxyapatite. The presence of this substance significantly increases the biocompatibility of the implant material, since this compound is the main mineral component of bone tissue. Hanks’ solution, which is close to human blood plasma, was used as a corrosive medium for electrochemical studies. The results of the analysis of corrosion of samples without coating and with PEO coating made it possible to establish that the application of a ceramic-like layer reduces the corrosion current density and increases the polarization resistance. Additionally, it was found that applying a protective coating increases the corrosion potential of the samples. This increase in protective properties is due to the creation of a poorly soluble barrier layer between the substrate material and the electrolyte, which, in turn, reduces the likelihood of charge transfer at the electrode/electrolyte interface. Thus, PEO coatings formed on magnesium alloys, in addition to having bioactive properties, can reduce the rate of electrochemical dissolution of the implantation material.

Na2Ti3O7 has attracted attention as an alternative to hard carbon anode for Na-ion batteries due to suitable sodiation potential and, hence, no serious safety issues at high current densities. However, unfavorable electronic transport properties of Na2Ti3O7 need to be addressed to make it applicable for practice. Herein, a hydrothermal method was adopted to fabricate Na2Ti3O7 having a hierarchical micro/nano architecture and to dope it with copper through one stage. As compared to the non-doped Na2Ti3O7, the copper-containing product shows increased electronic conductivity (2.5 times higher) due to a smaller band gap (reduced by similar to 1 eV). Because of Cu-doping, the Na2Ti3O7 crystal structure has evolved, and its unit cell volume has increased by about 9.5 %. Doping with Cu enhances the electrochemical performance of Na2Ti3O7 in Na-ion batteries, which demonstrates higher rate capability (2.0-2.5 times more capacity at high current densities) and remarkable cycleability (85 % capacity retention over 300 cycles at 2C). The calculations show that Cu-doped Na2Ti3O7 is characterized by improved Na+ ion diffusion and increased contribution of the pseudocapacitive current during the sodiation-desodiation process. The research discloses the aspects of copper-doping strategy that enable to unfold the capability of Na2Ti3O7 for energy storage applications.

The method for modifying the surface of a bioresorbable magnesium alloy (MA8 – Mg-Mn-Ce system) using formation of the hybrid coatings containing an organic biocompatible corrosion inhibitor and a bioresorbable polymer material was developed. The anticorrosion properties of the formed coatings were studied in physiological solution (0.9 wt.% NaCl and HBSS). Such layers reduce the rate of alloy degradation due to the active protection function.

The biocompatible protective coating was formed using the plasma electrolytic oxidation (PEO) on a bioresorbable Mg–0.8Ca alloy. The electrochemical properties and the mechanism of material bioresorption were established. The model of the biodegradation process of the alloy with a hydroxyapatite-containing PEO-coating in mammalian cell culture medium was proposed.

The present study investigates the physical and chemical characteristics, behavior in vitro and in vivo, and biocompatibility of coatings containing Ta2O5, which are obtained by plasma electrolytic oxidation (PEO) on MA8 magnesium alloy. The obtained coatings demonstrate in vivo biocompatibility and in vitro bioactivity. Compared to the base PEO coating, the layers containing Ta2O5 facilitate the development of apatite in simulated body fluid, suggesting that the inclusion of nanoparticles improves bioactivity of the coatings. It was found that incorporation of Ta2O5 nanoparticles increases roughness and porosity of the formed layers by increasing particle concentration in electrolytes for the PEO process contributing to sufficient soft tissue ingrowth in vivo. Based on in vivo studies, these coatings also provide favorable tissue response and minimal inflammatory reaction in comparison with the bare magnesium alloy due to protection of living tissues from deleterious corrosion events of magnesium implant such as local alkalization and intense hydrogen evolution. The results obtained in the present study concluded biocompatibility, tissue integration of the PEO coatings containing Ta2O5 nanoparticles making them a promising protective layer for biodegradable magnesium implants.

The efficiency of the green inhibitors (sodium salts of fumarate, glycolate and gluconate) in suppressing corrosion of the structural MA8 magnesium alloy (MgMnCe) and the biomedical Mg0.8Ca alloy was studied using the hydrogen evolution measurements, mass loss test, EIS, PDP, SVET/SIET. The analysis of the morphology, chemical composition, and growth kinetic of corrosion films formed in 0.9 wt% NaCl solution with and without corrosion inhibitors was carried out. The most compact surface film with the smallest thickness was formed in a saline solution with sodium fumarate. The Mg alloy samples exhibited the highest polarization resistance, the lowest localized electrochemical activity, and the lowest corrosion rate in saline with the addition of sodium fumarate and sodium glycolate. The efficiency of the applied inhibitors was up to 81 %. The model of the corrosion mechanism based on the sorption of molecules of organic inhibitors is proposed. The results show the high compatibility of the used inhibitors with the calcium-phosphate PEO-matrix, indicating the possibility of forming a self-healing coating by means of these active substances.

Sodium trititanate, Na2Ti3O7 is of interest as a negative electrode material for designing high-power and safe sodium-ion batteries due to the suitable potential of electrochemical sodium intercalation. Nevertheless, Na2Ti3O7 requires qualitative modification to improve its conductive properties, for example, doping with other elements or morphology optimization. Within the scope of this work, sodium trititanate doped with copper in various quantities, consisting of "microflowers" formed by nanotubes and nanosheets, was prepared via a one-stage hydrothermal treatment of titanium and copper salts in 10M sodium hydroxide solution. It was found that, in comparison with the undoped sample, the Cu-doped Na2Ti3O7 shows a narrowed band gap (by 1.1 eV) and increased electronic conductivity (by 2.5 times). The electrochemical insertion and extraction of Na+ + ions into copper-doped sodium trititanate were investigated. It was found that the specific capacity of doped Na2Ti3O7 at high current densities of 3C and 4C is 2.0-2.5 - 2.5 times higher as compared to the undoped sample. At low current densities (up to 0.5C), undoped and copper-doped Na2Ti3O7 samples have similar electrochemical performance. The kinetics of charge carriers in electrodes based on such materials in (de-)sodiation processes has been studied. It was shown that Cu-doped Na2Ti3O7 possesses a lower charge transfer resistance and higher Na+ + diffusion coefficient. This promotes a decrease in the polarization of the electrode during charge and discharge processes, providing increased specific capacity at high current loads.

Additive manufacturing has revolutionized implantology by enabling the fabrication of customized, highly porous implants. Surface modifications using electrochemical methods can significantly enhance the bioactivity and biocompatibility of biomaterials, including 3D-printed implants. This study investigates novel coatings on 3D titanium (Ti) samples. Mesh Ti samples were designed and subjected to plasma electrolytic oxidation (PEO) to form a calcium phosphate coating. Subsequently, a layer of polydopamine (PDA) was applied. The electrochemical properties and morphology of the coatings were analyzed. Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) revealed well-developed coatings containing calcium phosphates (including hydroxyapatite), titanium dioxide, and polymerized dopamine, suggesting promising bioactive potential. Composite layers incorporating PDA exhibited superior protective properties compared to base PEO coatings.

Today a lot of attention is paid to the formation of thermosensitive systems for biomedical and industrial applications. The development of new methods for synthesis of such systems is a dynamically developing direction in chemistry and materials science. In this regard, this paper presents results of the studies of a new synthesized supramolecular polymer system based on polyethylene glycol and tetrafluoroethylene telomers. The films formed from the polymer substance have the property of switching wettability depending on temperature after heating activation. It has been established that the wettability changes at 60 °C. The contact angle of activated hydrophobic polymer film reaches 143°. Additionally, the system exhibits its properties regardless of the pH of the environment. Based on data obtained by the methods of infrared and x-ray photoelectron spectroscopy, differential thermal analysis and thermal analysis in conjunction with wettability and morphology, a model of the behavior of molecules in a polymer system was built that ensures switching of the hydrophilic/hydrophobic surface state. The resulting polymer system, as well as films based on it, can be used in targeted drug delivery, implantation surgery, as sensors, etc.

В работе двухстадийным методом получен композиционный материал на основе волокон твердого углерода, модифицированных нанолистами дисульфида молибдена. Твердый углерод, используемый в качестве основы, получен термообработкой вискозы при 810 °С. Осаждение на волокнах наночастиц MoS2 выполнено гидротермальным способом. Структура и состав композита установлены с использованием методов рентгеновской дифракции, малоуглового рентгеновского рассеяния, спектроскопии комбинационного рассеяния света, сканирующей электронной микроскопии, энергодисперсионной спектроскопии, спектрофотометрии и рентгеновской фотоэлектронной спектроскопии. Исследованы электрохимические характеристики композита как анодного материала для натрий-ионных аккумуляторов. Обнаружено, что за счет эффекта синергизма композиционный материал обладает преимуществами над твердым углеродом и нанокристаллическим MoS2 в отдельности. По сравнению с твердым углеродом композит демонстрирует более высокие значения удельной емкости, в том числе при высоких плотностях тока. Так, при 1000 и 2000 мА/г композиционный материал показал удельную емкость 139 и 84 мА·ч/г, тогда как твердый углерод при тех же плотностях тока обеспечивает только 73 и 45 мА·ч/г. По отношению к MoS2 композит демонстрирует лучшую циклируемость. Для MoS2 наблюдается деградация энергозапасающих свойств уже после 90 цикла. Композиционный материал, напротив, сохраняет стабильность даже на 150 цикле с емкостью 204 мА·ч/г при 200 мА/г.

In this study, a calcium-phosphate coating was formed on a Mg–Mn–Ce alloy by the plasma electrolytic oxidation (PEO). The antibiotic vancomycin, widely used in the treatment of infections caused by Staphylococcus aureus (S. aureus), was impregnated into the coating. Samples with vancomycin showed high bactericidal activity against S. aureus. The mechanical and electrochemical properties of the formed coatings were studied, as well as in vitro cytotoxicity tests and in vivo tests on mature male rats were performed. According to SEM, EDS, XRD and XPS data, coatings had a developed morphology and contained hydroxyapatite, which indicates high biocompatibility. The analysis of roughness of coatings without and with vancomycin did not reveal any differences, confirming the high roughness of the samples. During electrochemical tests, an increase in corrosion resistance by more than two times after the application of PEO coatings was revealed. According to the results of an in vivo study, after 28 days of the implantation of samples with calcium phosphate PEO coating and vancomycin, no signs of inflammation were observed, while an inflammatory reaction developed in the area of implantation of bare alloy, followed by encapsulation. Antibiotic release tests from the coatings show a sharp decrease in the concentration of the released antibiotic on day 7 and then a gradual decrease until day 28. Throughout the experiment, no significant deviations in the condition and behavior of the animals were observed; clinical tests did not reveal a systemic toxic reaction.