Exploring the antimicrobial and antioxidant potential of bacterial cellulose-cerium oxide nanoparticles hydrogel: Design, characterization and biomedical properties.

Bacterial cellulose (BC) is a promising natural polymer prized for its biocompatibility, microporosity, transparency, conformability, elasticity, and ability to maintain a moist wound environment while absorbing exudates. These attributes make BC an attractive material in biomedical applications, particularly in skin tissue repair. However, its lack of inherent antimicrobial activity limits its effectiveness. In this study, BC was enhanced by incorporating cerium (IV)-oxide (CeO2) nanoparticles, resulting in a series of bacterial cellulose-CeO2 (BC-CeO2) composite materials. Characterization via FESEM, XRD, and FTIR confirmed the successful synthesis of the composites. Notably, BC-CeO2-1 exhibited no cytotoxic or genotoxic effects on peripheral blood lymphocytes, and it additionally protected cells from genotoxic and cytotoxic effects in H2O2-treated cultures. Redox parameters in blood plasma samples displayed concentration and time-dependent trends in PAB and LPP assays. The incorporation of CeO2 nanoparticles also bolstered antimicrobial activity, expanding the potential biomedical applications of these composites.

Influence of SiO2 Nanoparticles Extracted from Biomass on the Properties of Electrodeposited Ni Matrix Composite Films on Si(100) Substrate.

Lab-made biosilica (SiO2) nanoparticles were obtained from waste biomass (rice husks) and used as eco-friendly fillers in the production of nickel matrix composite films via the co-electrodeposition technique. The produced biosilica nanoparticles were characterized using XRD, FTIR, and FE-SEM/EDS. Amorphous nano-sized biosilica particles with a high SiO2 content were obtained. Various current regimes of electrodeposition, such as direct current (DC), pulsating current (PC), and reversing current (RC) regimes, were applied for the fabrication of Ni and Ni/SiO2 films from a sulfamate electrolyte. Ni films electrodeposited with or without 1.0 wt.% biosilica nanoparticles in the electrolyte were characterized using FE-SEM/EDS (morphology/elemental analyses, roundness), AFM (roughness), Vickers microindentation (microhardness), and sheet resistance. Due to the incorporation of SiO2 nanoparticles, the Ni/SiO2 films were coarser than those obtained from the pure sulfamate electrolyte. The addition of SiO2 to the sulfamate electrolyte also caused an increase in the roughness and electrical conductivity of the Ni films. The surface roughness values of the Ni/SiO2 films were approximately 44.0%, 48.8%, and 68.3% larger than those obtained for the pure Ni films produced using the DC, PC, and RC regimes, respectively. The microhardness of the Ni and Ni/SiO2 films was assessed using the Chen-Gao (C-G) composite hardness model, and it was shown that the obtained Ni/SiO2 films had a higher hardness than the pure Ni films. Depending on the applied electrodeposition regime, the hardness of the Ni films increased from 29.1% for the Ni/SiO2 films obtained using the PC regime to 95.5% for those obtained using the RC regime, reaching the maximal value of 6.880 GPa for the Ni/SiO2 films produced using the RC regime.

An Extremely Rare Case of Cementless Third Generation Corail Stem Neck Fracture With Fractographic Analysis.

The cementless Corail stem is one of the most frequently implanted stems and has undergone several design changes. Currently in use is the third generation, named Corail AMT. Until now, only one third-generation Corail stem neck fracture has been described in 2020. In our paper, we present an almost identical complication with an additional analysis of the fracture using a scanning electron microscope. The revision surgery consisted of changing the broken implant with a Corail revision stem, along with replacing the polyethylene liner and the femoral head with new one, after which the patient achieved a full recovery. According to the available literature, this is the second case of this extremely rare complication.

Isotherm, Thermodynamic and Kinetic Studies of Elemental Sulfur Removal from Mineral Insulating Oils Using Highly Selective Adsorbent.

Elemental sulfur (S8) is a corrosive sulfur compound which was found to be extremely reactive to silver, causing intensive silver sulfide (Ag2S) deposition on on-load tap changer (OLTC) contacts in power transformers. A highly selective adsorbent (HSA), called Tesla'Ssorb, for the removal of S8 from mineral insulating oils was prepared from raw material (RM) using the novel procedure. In this study, the adsorption properties of HSA for the removal of S8 from the oil were determined. RM and HSA were characterized using various techniques, such as field-emission scanning electron microscopy (FESEM), energy-dispersive X-ray (EDX), and X-ray diffraction (XRD). The performance of HSA was determined by adsorption equilibrium, thermodynamic, and kinetic study through batch experiments, at various temperatures and initial concentrations of S8. The obtained results were analyzed by Langmuir and Freundlich adsorption isotherms and it was found that equilibrium data were fitted better with the Langmuir isotherm model. The maximum adsorption capacity was 4.84 mg of S8/g of HSA at 353 K. Thermodynamic parameters, such as enthalpy (ΔH°), Gibbs free energy (ΔG°), and entropy (ΔS°), were calculated and it was found that the sorption process was spontaneous (ΔG° < 0) and endothermic in nature (ΔH° > 0). It was found that the adsorption of S8 follows pseudo-second-order kinetic model, and the activation energy indicated the activated chemisorption process.

Enhanced antimicrobial properties and bioactivity of 3D-printed titanium scaffolds by multilayer bioceramic coating for large bone defects.

The restoration of large bone defects caused by trauma, tumor resection, or infection is a major clinical problem in orthopedics and dentistry because postoperative infections, corrosion, and limited osteointegration of metal implants can lead to loosening of the implant. The aim of this study was to improve the surface properties of a 3D-printed (electron beam melting) Ti6Al4V-based macroporous scaffold by multilayer coating with bioactive silicate glasses (BAGs) and hydroxyapatite doped with a silver (AgHAP) or AgHAP additionally sonochemically modified with ZnO (ZnO-AgHAP). The coated scaffolds AgHAP_BAGs_Ti and ZnO-AgHAP_BAGs_Ti enhanced cytocompatibility in L929 and MRC5 cell lines and expressed bioactivity in simulated body fluid. A lower release of vanadium ions in coated samples compared to bare Ti scaffold indicates decreased dissolution of Ti alloy in coated samples. The coated samples reduced growth ofEscherichia coliandStaphylococcus aureusfor 4-6 orders of magnitude. Therefore, the 3D-printed Ti-based scaffolds coated with BAGs and (ZnO-)AgHAP have great potential for application as a multifunctional implant with antibacterial properties for the restoration of defects in load-bearing bones.

A novel chitosan/tripolyphosphate/L-lysine conjugates for latent fingerprints detection and enhancement.

Most chemical and physical methods employed in visualizing latent marks have shown detrimental effects on human health and, therefore, some research groups have directed their attention to the utilization of various (bio)polymers with the aforementioned purpose. Although chitosan is widely used in medicine, pharmacy, food, and drug delivery systems, there are very few studies that address this biopolymer utilization in forensic applications, such as the detection of latent fingerprints. We used chitosan crosslinked with sodium tripolyphosphate and conjugated with L-lysine to enhance the visualization of latent fingerprints, due to its ability to interact with fingerprint sweat residues. These conjugates were prepared using different (w/w) amounts of chitosan and tripolyphosphate (6/1; 4/1; 1/1; 1/4; and 1/6), and those with the most promising results (i.e., 6/1 formulation) were investigated in detail. Fourier transform infrared (FT-IR) spectroscopy confirmed interactions between components of the systems. Optical microscopy and scanning electron microscope (SEM) analysis showed that prepared powder formulations were uniform in size and confirmed that chitosan/tripolyphosphate/lysine conjugates bind easily to the sweat and lipid residues present in the latent fingerprints. The testing of prepared conjugates demonstrated the potential of these systems as bio-based powder substitution for commercially available powders.

Novel amino-functionalized lignin microspheres: High performance biosorbent with enhanced capacity for heavy metal ion removal.

Novel highly effective amino-functionalized lignin-based biosorbent in the microsphere geometry (A-LMS) for removal of heavy metal ions, was synthesized via inverse suspension copolymerization of kraft lignin with poly(ethylene imine) grafting-agent and epoxy chloropropane cross-linker. Optimization of A-LMS synthesis, performed with respect to the quantity of sodium alginate emulsifier (1, 5 and 10 wt%), provides highly porous microspheres A-LMS_5, using 5 wt% emulsifier, with 800 ± 80 µm diameter, 7.68 m2 g-1 surface area and 7.7 mmol g-1 of terminal amino groups. Structural and surface characteristics were obtained from Brunauer-Emmett-Teller method, Fourier Transform-Infrared spectroscopy, scanning electron microscopy, X-ray photoelectron spectroscopy and porosity determination. In a batch test, the influence of pH, A-LMS_5 dose, temperature, contact time on adsorption efficiency of Ni2+, Cd2+, As(V) and Cr(VI) ions were studied. The adsorption is spontaneous and feasible with maximum adsorption capacity of 74.84, 54.20, 53.12 and 49.42 mg g-1 for Cd2+, Cr(VI), As(V) and Ni2+ ions, respectively, obtained by using Langmuir model. Modeling of kinetic data indicated fast adsorbate removal rate with pore diffusional transport as rate limiting step (pseudo-second order model and Weber-Morris equations), thus further confirming high performances of produced bio-adsorbent for heavy metal ions removal.

Antibacterial activity of Cu-based nanoparticles synthesized on the cotton fabrics modified with polycarboxylic acids.

The fabrication of antimicrobial textile nanocomposite by in situ synthesis of Cu-based nanoparticles on cotton fabrics modified with different polycarboxylic acids was discussed in this study. In order to evaluate the influence of carboxyl group content on Cu2+-ions adsorption, their subsequent reduction with sodium borohydride and formation of Cu-based nanoparticles, cotton fabrics were modified with succinic, citric and 1,2,3,4-butanetetracarboxylic acids. It was shown that the larger the number of carboxyl groups in applied acid, the larger the content of free carboxyl groups on the fibers and consequently, the larger the Cu2+-ions uptake and total amounts of Cu-based nanoparticles. On the basis of the XPS and XRD measurements, it was suggested that synthesized nanoparticles were mixture of Cu2O and CuO. Fabricated nanocomposites provided maximum reduction of Gram-negative bacterium E. coli and Gram-positive bacterium S. aureus and controlled release of Cu2+-ions in physiological saline solution which are necessary prerequisites for infection prevention.

Pectin-based nanocomposite aerogels for potential insulated food packaging application.

Environmental-friendly pectin-TiO2 nanocomposite aerogels were prepared via sol-gel process and subsequent drying under supercritical conditions. The first step includes dissolution of pectin in water, addition of proper amount of TiO2 colloid and crosslinking reaction induced in the presence of tert-butanol and zinc ions. Then, the gels are subjected to the solvent exchange and supercritical CO2 drying. The influence of TiO2 nanoparticles on the textural, mechanical, thermal and antibacterial properties of aerogels was investigated. Results indicate that in the presence of TiO2 nanoparticles (NPs) mechanical, thermal and antimicrobial properties of pectin-based aerogels are improved in comparison to the control pectin aerogels. It should be emphasized that the thermal conductivity of pectin-based aerogels (0.022-0.025 W m-1 K-1) is lower than the thermal conductivity of air. Generally, the results propose that the pectin-TiO2 nanocomposite aerogels, as bio-based material, might have potential application for the storage of temperature-sensitive food.