Miroslav M. Pavlović

The study seeks to develop a multifunctional germanium-enriched nanocomposite coating on titanium and to evaluate its ability to modulate early inflammatory responses while promoting osteogenic differentiation in a dental pulp stem cell (DPSC)-based regenerative model. A multifunctional Ti/Coating composed of nanohydroxyapatite (nHAp) particles, chitosan-oligolactate (ChOL), and germanium (Ge) was developed using a combined anodizing/anaphoretic electrodeposition approach. The Ti/Coating system exhibited good biocompatibility, as confirmed by microscopy, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and lactate dehydrogenase (LDH) assays, with cell viability consistently exceeding 90% and moderate LDH release across all time points. Annexin V/PI assay demonstrated a predominance of viable cells (>94%), while intracellular ROS analysis indicated moderate oxidative activity. Gene expression analysis revealed significant downregulation of pro-inflammatory markers (TNF-α, IL-1β, IL-6, COX-2, and MAPK), suggesting attenuation of inflammatory signalling. Flow cytometry further demonstrated reduced CD120b (TNFR2) expression, while intracellular TNF-α levels remained unchanged, indicating selective modulation at the receptor level. In addition, the Ti/Coating promoted osteogenic differentiation, as evidenced by enhanced mineralization, and upregulation of osteogenic genes (ALP, RUNX2, BMP2).

The presented research investigates the corrosion behavior of commercially pure titanium (cp-Ti) and amorphous calcium phosphate–chitosan (ACP@ChOL) coatings enriched with selenium on titanium in simulated body fluid (SBF). Using potentiodynamic polarization techniques, it was sought to derive essential corrosion parameters – corrosion potential, corrosion current density, breakdown potential, and passivation current. This study pioneers a comparative analysis of the corrosion stability of both samples. SEM/EDS analysis of surfaces pre- and postpotentiodynamic measurements offered insights into morphology and elemental composition. The aim was to elucidate the corrosion mechanism by integrating these techniques. Additionally, spontaneous corrosion behavior over 7 days, monitoring changes in open circuit potential, polarization resistance, and impedance were investigated. Furthermore, the antimicrobial efficacy of ACP@ChOL enriched with Se on titanium was assessed against Escherichia coli , Staphylococcus aureus , and Candida albicans , as well as in vitro release of Se. The presented study extends understanding, offering a unique perspective on the corrosion behavior and antimicrobial attributes of ACP@ChOL coatings enriched with Se on titanium. This composite material exhibits promise for medical applications, presenting an innovative avenue for addressing corrosion concerns and potentially reducing antibiotic reliance.

This study explores the electrochemical desulfurization of coal and the recovery of copper (Cu) using dimensionally stable anode (DSA) electrodes. Background: The research addresses the need for effective sulfur removal from coal to reduce emissions. Methods: Electrochemical desulfurization was conducted using DSA and graphite electrodes, evaluating parameters like activation energy, desulfurization rate, and energy consumption. Cyclic voltammetry and linear sweep voltammetry were used to study the electrochemical properties. Results: The DSA electrode demonstrated superior performance with higher desulfurization rates, lower activation energy, and better response to temperature increases compared to the graphite electrode. Optimal desulfurization was achieved at 50 °C with the DSA electrode, balancing efficiency and energy consumption. Copper recovery from the solution post-desulfurization was effective, with an 86.34% recovery rate at −0.15 V vs. (Ag|AgCl). The energy consumption for the Cu recovery was calculated to be 10.56 J, and the total cost for recovering 1 ton of Cu was approximately 781.20 €. Conclusions: The study highlights the advantages of DSA electrodes for efficient sulfur removal and metal recovery, promoting cleaner energy production and environmental sustainability. Future research should focus on optimizing electrochemical conditions and scaling up the process for industrial applications.

This study evaluates the effectiveness of KMnO4, MK3 and 1-butanol inhibitors on corrosion of AISI 314 and AISI 304 stainless steels using linear and potentiodynamic polarization in 0.1 M HNO3. The metrics like corrosion potential (Ecorr), current density (jcorr) and polarization resistance (Rp) influence the inhibitor efficacy. The inhibitors improved electrochemical parameters significantly, indicating strong anti-corrosive properties. 1-Butanol had the strongest effect, enhancing corrosion potential and drastically reducing corrosion current density, demonstrating superior protection. The results indicated that without inhibitors, both steels showed higher corrosion rates and more negative potentials, reflecting their susceptibility to corrosion. The introduction of inhibitors markedly improved these parameters, particularly with 1-butanol, which significantly enhanced the polarization resistance and shifted the corrosion potential towards less negative values. The potentiodynamic results highlighted the dynamic effectiveness of inhibitors, reinforcing their role in mitigating corrosion under varied conditions. The study underscores the importance of selecting the appropriate inhibitors to enhance the durability and longevity of stainless steels in acidic environments, with 1-butanol showing the potential for industrial applications requiring high corrosion resistance. This necessitates comprehensive testing to accurately measure inhibitor capabilities in different conditions.

The aim of this work is in situ anodization/anaphoretic deposition of a nano amorphous calcium phosphate (ACP)/chitosan oligosaccharide lactate (ChOL) multifunctional hybrid coating decorated with selenium (Se) on a titanium substrate and in vivo investigation of its immunomodulatory and anti-inflammatory effect. Investigating phenomena at the implant–tissue interface of interest for controlled inflammation and immunomodulation was also the aim of the research. In our earlier research, we designed coatings based on ACP and ChOL on titanium with anticorrosive, antibacterial and biocompatible properties, while in the presented results we show that selenium addition makes this coating an immunomodulator. The immunomodulatory effect of the novel hybrid coating is characterized by the examination of the functional aspects in the tissue around the implant (in vivo): proinflammatory cytokines’ gene expression, M1 (iNOS) and M2 (Arg1) macrophages, fibrous capsule formation (TGF-β) and vascularization (VEGF). The EDS, FTIR and XRD analyses prove the formation of a ACP/ChOL/Se multifunctional hybrid coating on Ti and the presence of Se. A higher M2/M1 macrophage ratio in the ACP/ChOL/Se-coated implants compared to pure titanium implants (a higher level of Arg1 expression) is noted at all time points examined (after 7, 14 and 28 days). Lower inflammation measured by gene expression of proinflammatory cytokines IL-1β and TNF, lower expression of TGF-β in the surrounding tissue and higher IL-6 expression (solely at day 7 post-implantation) is noted in presence of the ACP/ChOL/Se-coated implants.

Electrophoretic deposition (EPD) occurs as a cataphoretic deposition ? the coating is deposited on the cathode, and anaphoretic deposition ? the coating is deposited on the anode. The primary purpose of EPD is to obtain compact and uniform organic/inorganic coatings of the desired thickness and adhesion on metal surfaces by applying an electric field to the particles of coating precursor. EPD basic principles for coatings deposition concerning fundamental explanations and considerations of practical parameters of the process are presented. Cataphoretic deposition has become popular because it can apply organic coatings to complex structures that are otherwise very difficult to coat. These coatings were found to improve the characteristics of the substrate, such as biocompatibility, appearance and resistance to the corrosion processes. The key EPD parameters are composition, pH value and viscosity of deposition medium, as well as zeta potential of the particles, electric field strength, etc. A special survey is given to the process of anaphoretic deposition, which is relatively new, and its advantages over cataphoretic deposition are discussed. Through the process of joint anaphoresis/substrate anodization process, the surface of the substrate is simultaneously anodized and modified by incorporation of the foreign particles into the anodic layer. The coatings of mixed composition of better adhesion and corrosion resistance with respect to cataphoretically- deposited coatings are obtained as result.