Search Results (46)

The bioanalysis of body fluids plays a crucial role in clinical diagnostics, pharmaceutical research, forensic science, and biomarker discovery. Traditional chromatographic techniques are widely used in clinical laboratories but are often costly and time-consuming. Capillary electrophoresis (CE) and its modifications, such as capillary zone electrophoresis, isotachophoresis, and micellar electrokinetic chromatography, have emerged as efficient, cost-effective, and miniaturized alternatives for analyzing small organic and inorganic molecules in biological fluids. This paper deals with the applications of CE-based electromigration techniques in the determination of various analytes in urine, blood, saliva, and cerebrospinal fluid. The study further discusses the advantages and limitations of different detection methods, including ultraviolet-visible spectroscopy, laser-induced fluorescence, mass spectrometry, conductivity, and amperometric detection. A focus is given to the identification and quantification of amino acids and their metabolites as potential biomarkers for metabolic and degenerative disorders. The work highlights recent advancements in CE methodologies and their potential to enhance sensitivity and selectivity in bioanalytical applications. Full article

Efficient biomass harvesting remains one of the primary barriers to the commercial feasibility of large-scale microalgal production. This study investigates the effect of different culture media on the surface physicochemical properties of Tetradesmus sp., with emphasis on their role in natural aggregation. Cultures were grown for 30 days under controlled light and temperature conditions using Blue Green 11 (BG11), Tris–acetate–phosphate (TAP), and deionized water supplemented with Bayfolan^® fertilizer. Surface hydrophobicity was assessed through microbial adhesion to solvents (MATS) and contact angle analysis, electrokinetic properties were evaluated by zeta potential measurements, and cell surface chemistry was characterized by attenuated total reflectance (ATR) sampling methodology for Fourier Transform Infrared (FTIR) spectroscopy. Across all treatments, Tetradesmus sp. exhibited inherent hydrophobicity, but Bayfolan^® supplementation yielded the highest contact angle (49.0 ± 0.9°) and the least negative free energy of interaction (ΔGsws = −26.36 mJ·m⁻²), indicating a stronger tendency toward self-aggregation. Zeta potential values remained consistently negative (−10 to −14 mV), with no significant variation among media, suggesting that hydrophobic interactions rather than electrostatic forces govern aggregation. ATR-FTIR spectra confirmed the presence of lipids, proteins, and carbohydrates, with changes in peak intensities reflecting metabolic adjustments to media composition. These results demonstrate that low-cost Bayfolan^® supplementation enhances surface hydrophobicity and aggregation, providing a sustainable strategy to facilitate biomass recovery and reduce harvesting costs in microalgal biorefineries. Full article

The applications of electromagnetic (EM) field treatment on water in agriculture have garnered increasing attention as a sustainable method to enhance plant growth, water-use efficiency, and metabolic performance. A growing body of evidence suggests that exposure to EM fields can affect water molecules, possibly by influencing hydrogen bonding dynamics, the structuring of water clusters, and electrokinetic properties of the water molecules. These alterations are thought to correlate with plant physiological performance. The methodology of the study was divided into two parts. The first part focused on the preparation of electromagnetically treated water. The second part involved applying this treated water to spinach plants. The present study investigates the physiological responses of Spinacia oleracea L. to irrigation with electromagnetically treated water (EMTW), focusing on elucidating the potential mechanisms that may underlie the observed effects. EMTW was generated using a solenoid-based system operating in dual-frequency ranges (100–1000 Hz and 10–100 kHz), which has been previously shown to influence both the microbiological and electrokinetic properties of aqueous systems. To evaluate the structural and functional implications of EMTW, a combined methodological approach was employed, integrating proton nuclear magnetic resonance (¹H-NMR) spectroscopy, density functional theory (DFT) modeling of water hydrogen bonds and clusters, and comprehensive plant physiological assessments. Plants were cultivated under both controlled and field conditions to assess consistency across environmental settings. Physiological measurements demonstrated that EMTW irrigation increased photosynthetic rate by ~80%, transpiration by 49–67%, stomatal conductance by 78–129%, intercellular CO₂ concentration by 42–80%, and chlorophyll content by 9.3–9.5% compared to control samples. Additionally, phenoloc and flavonoid contents were elevated by 7.4% and 7.6%, respectively, in field-grown plants. These enhancements were statistically significant (p < 0.001 or p < 0.01) under both laboratory and field conditions, confirming the robustness of the observed effects. Full article

This study investigates how the inclusion of refuse-derived fuel (RDF) alters the surface chemistry and electrostatic behavior of oak-based biochar. Biochars were produced using downdraft gasification at 850 °C from 100% oak (HW) and a ternary blend comprising 50% oak, 30% pine, and 20% RDF (HW/SW/RDF). Characterization using Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), zeta potential, pH, and electrophoretic mobility was conducted to assess surface functionality and colloidal behavior. The RDF-containing biochar exhibited a 43.3% increase in surface nitrogen content (from 0.24% to 0.90%) and a 6.6% rise in calcium content (from 2.07% to 2.27%) alongside the introduction of chlorine (0.20%) and elevated silicon levels (0.69%) compared to RDF-free counterparts. A concurrent reduction in oxygen-containing functional groups was observed, as O1s decreased from 15.75% in HW to 13.37% in HW/SW/RDF. Electrokinetic measurements revealed a notable decrease in zeta potential magnitude from −31.5 mV in HW to −24.2 mV in HW/SW/RDF, indicating diminished surface charge and colloidal stability. Moreover, the pH declined from 10.25 to 7.76, suggesting a loss of alkalinity and buffering capacity. These compositional and electrostatic shifts demonstrate that RDF inclusion significantly modifies the surface reactivity of biochar, influencing its performance in catalysis, ion exchange, and nutrient retention. The findings underscore the need for tailored post-treatment strategies to enhance the functionality of RDF-modified biochars in environmental applications. Full article

Electrokinetic (EK) remediation is a promising approach for the removal of heavy metals from fine-grained soils; however, its efficiency is often hindered by electrode polarization, pH imbalance, and ion accumulation. In this study, we developed a novel hydrogel-based electrode (NH electrode), composed of sodium alginate and multilayer graphene oxide (GO), to enhance the electrokinetic removal of Cu²⁺ and Pb²⁺ from loess. The electrode was systematically characterized by atomic force microscopy (AFM), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS), confirming its structural integrity, electrochemical activity, and interfacial conductivity. The NH electrode exhibited a smooth layered graphene structure with abundant oxygen-containing functional groups (AFM), negligible electrochemical polarization (CV), and low internal resistance with high conductivity (EIS), enabling efficient ion transport and adsorption. Electrokinetic tests revealed that the NH electrode outperformed conventional graphene (Gr) and electrokinetic graphite (EKG) electrodes. Single regulation strategies, including focusing position adjustment and electrode exchange, improved local removal efficiency by mitigating ion accumulation in targeted regions. The combined regulation strategy, integrating both measures, achieved the most uniform Cu²⁺ and Pb²⁺ removal, significantly suppressing hydroxide precipitation in cathodic zones and enhancing ion migration in the mid-section. Compared with literature-reported systems under similar or even more favorable conditions, the NH electrode and combined regulation approach achieved superior performance, with Cu²⁺ and Pb²⁺ removal efficiencies reaching 47.25% and 16.93%, respectively. These findings demonstrate that coupling electrode material innovation with spatial–temporal pH/flow field regulation can overcome key bottlenecks in EK remediation of heavy-metal-contaminated loess. Full article

Fluphenazine (FPZ) is a well-known neuroleptic that has attracted considerable scientific interest due to its biocidal, virucidal, and antitumor properties. Although methods for encapsulating and delivering FPZ to enhance its activity and reduce side effects have been developed, there is still limited knowledge about its conjugates with gold nanoparticles (AuNPs). Therefore, the aim of this research was to develop a preparation method for stable FPZ-AuNP conjugates and to investigate their physicochemical and biological properties. FPZ-AuNP conjugates were synthesized via a ligand exchange process on the surface of gold nanoparticles (AuNPs) with an average size of 17 ± 5 nm. Electrokinetic measurements revealed that the zeta potential of FPZ-AuNPs is affected by both their composition and pH. The FPZ-AuNPs exhibited an isoelectric point due to the acid–base properties of FPZ. Surface-enhanced Raman spectroscopy (SERS), combined with density functional theory (DFT), was used to determine the adsorption structure of FPZ after conjugation. Studies with human neuroblastoma cells (SH-SY5Y) revealed that FPZ-AuNP conjugates more effectively reduced cell viability compared to citrate-stabilized AuNPs alone or free FPZ molecules. The reduction in SH-SY5Y cell viability was found to be dependent on the FPZ-AuNP concentration. Full article

The current research attempted to address the suitability of bioactive Sambucus nigra extract entrapped in albumin-decorated nanostructured lipid carriers (NLCs) as a promising “adjuvant” in improving tumour penetration for multiple antitumour therapy. The new hybrid albumin-decorated NLCs were characterised based on, e.g., the particle size, zeta electrokinetic potential, SambucusN entrapment efficiency, and fluorescence spectroscopy and tested for different formulation parameters. The antioxidant activity of NLC-SambucusN was significantly enhanced by a bovine serum albumin (BSA) polymer coating. According to the real-time cell analysis (RTCA) results, NLC-I–SambucusN–BSA behaved similarly to the chemotherapeutic drug, cisplatin, with cell viability for LoVo tumour cells of 21.81 ± 1.18%. The new albumin–NLC–SambucusN arrested cancer cells in G1 and G2 cycles and intensified the apoptosis process in both early and late phases. An advanced induction, over 50% apoptosis in LoVo colon cells, was registered for 50 μg/mL of NLC-II-SambucusN-BSA, a fourfold increase compared to that of untreated cells. RTCA and flow cytometry results showed that concentrations of the hybrid NLC–SambucusN up to 50 μg/mL do not affect the proliferation of normal HUVEC cells. This approach provides insightful information regarding the involvement of phytochemicals in future therapeutic strategies. Albumin-decorated NLCs can be considered a noteworthy strategy to be connected to antitumour therapeutic protocols. Full article

Prostate cancer (PCa) remains a significant health threat, with chemoresistance and recurrence posing major challenges despite advances in treatment. The epithelial to mesenchymal transition (EMT), a biochemical process where cells lose epithelial features and gain mesenchymal traits, is linked to chemoresistance and metastasis. Electrical impedance spectroscopy (EIS), a novel label-free electrokinetic technique, offers promise in detecting cell phenotype changes. In this study, we employed EIS to detect EMT in prostate cancer cells (PCCs). PC3, DU145, and LNCaP cells were treated with EMT induction media for five days. EIS characterization revealed unique impedance spectra correlating with metastatic potential, distinguishing DU145 EMT+ and EMT− cells, and LNCaP EMT+ and EMT− cells (in combination with dielectrophoresis), with comparisons made to epithelial and mesenchymal controls. These changes were supported by shifts in electrical signatures, morphologies, and protein expression, including the downregulation of E-cadherin and upregulation of vimentin. No phenotype change was observed in PC3 cells, which maintained a mesenchymal phenotype. EMT+ cells were also distinguishable from mixtures of EMT+ and EMT− cells. This study demonstrates key advancements: the application of EIS and dielectrophoresis for label-free EMT detection in PCCs, characterization of cell electrical signatures after EMT, and EIS sensitivity to EMT transitions. Detecting EMT in PCa is important to the development of more effective treatments and overcoming the challenges of chemoresistance. Full article

Growing volumes of textile waste and heavy metal pollution of water are emerging environmental challenges. In an attempt to tackle these issues, a non-woven sorbent based on jute fibers was fabricated by recycling the textile waste from the carpet industry. The influence of contact time, concentration, pH and temperature on the sorption of lead and copper ions from aqueous solutions was studied. In order to enhance the sorption capacity of the non-woven material, in situ synthesis of polyaniline (PANI) in the presence of TiO₂ nanostructures was performed. The contribution of TiO₂ nanoparticles and TiO₂ nanotubes to the uniformity of PANI coating and overall sorption behavior was compared. Electrokinetic measurements indicated increased swelling of modified fibers. FTIR and Raman spectroscopy revealed the formation of the emeraldine base form of PANI. FESEM confirmed the creation of the uniform nanocomposite coating over jute fibers. The modification with PANI/TiO₂ nanocomposite resulted in a more than 3-fold greater sorption capacity of the material for lead ions, and a 2-fold greater absorption capacity for copper ions independently of applied TiO₂ nanostructure. The participation of both TiO₂ nanostructures in PANI synthesis resulted in excellent cover of jute fibers, but the form of TiO₂ had a negligible effect on metal ion uptake. Full article

The emergence of antimicrobial resistance due to antibiotics in the environment presents significant public health, economic, and societal risks. This study addresses the need for effective strategies to reduce antibiotic residues, focusing on ciprofloxacin degradation. Magnetic iron oxide nanoparticles (IO NPs), approximately 13 nm in size, were synthesized and functionalized with branched polyethyleneimine (bPEI) to obtain a positive charge. These IO-bPEI NPs were combined with negatively charged titanium dioxide NPs (TiO₂@CA) to form magnetically photocatalytic IO-TiO₂ nanocomposites. Characterization techniques, including X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), infrared spectroscopy (IR), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), electrokinetic measurements, and a vibrating sample magnetometer (VSM), confirmed the successful formation and properties of the nanocomposites. The nanocomposites exhibited a high specific surface area, reduced mobility of photogenerated charge carriers, and enhanced photocatalytic properties. Testing the photocatalytic potential of IO-TiO₂ with ciprofloxacin in water under UV-B light achieved up to 70% degradation in 150 min, with a degradation rate of 0.0063 min⁻¹. The nanocomposite was magnetically removed after photocatalysis and successfully regenerated for reuse. These findings highlight the potential of IO-TiO₂ nanocomposites for reducing ciprofloxacin levels in wastewater, helping curb antibiotic resistance. Full article

Labradorite is a beautiful and popular mineral known for its iridescent play of colour. It is commonly found in igneous rocks and belongs to the feldspar group of minerals which are common in sulfidic Cu-Ni-PGM ores in South Africa. Labradorite primarily consists of calcium, sodium, aluminum, and silicon. There are various uses for labradorite, these range from its use as an ornamental stone to being an additive in ceramics and in glassmaking. Therefore understanding its behaviour under various water conditions is therefore important not only for froth flotation where process water of high ionic strength is used but also important for the question of how ceramics with labradorite as an additive would be affected when subjected to water of high ionic strength and water containing Ca²⁺, Mg²⁺, Cl⁻ and SO₄²⁻ ions in significant quantities. This study therefore examined the behaviour of labradorite in changing water quality, specifically of increasing ionic strength. Labradorite particles were investigated for their behaviour under varying ionic strength of water using two techniques, namely the zeta potential analyser and UV-vis spectroscopy in order to understand the impact of water quality on surface chemistry of labradorite. The zeta potential analyser was used to understand effects on the surface charge of the mineral whilst UV-vis spectroscopy was used to determine the adsorption of sodium carboxymethyl cellulose (CMC) at the mineral surface. CMC was important in this study not only because of its use in flotation as a depressant but also due to its role in materials manufacturing as a binder and rheology modifier, both of which are significant properties in the production of ceramics and pellets. The results of this study showed that the adsorption of CMC, is enhanced in water of high ionic strength. It was also shown that the electrokinetic potential of labradorite increased and became less nagative in water of higher ionic strength, thus demonstrating a passivation effect at the labradorite mineral surface. The findings of this study imply that gangue minerals associated with or of a similar nature to labradorite, such as the feldspar group of minerals in sulfide ore flotation, are likely to be depressed in flotation. Furthermore, the results from this study may be valuable for the ceramics and glassmaking industries, where labradorite is used as an additive, especially in cases where their products are exposed to harsh water conditions. Full article

Many bio-applicable materials, medical devices, and prosthetics combine both polymer and metal components to benefit from their complementary properties. This goal is normally achieved by their mechanical bonding or casting only. Here, we report an alternative easy method for the chemical grafting of a polymer on the surfaces of a metal or metal alloys using alkoxy amine salt as a coupling agent. The surface morphology of the created composites was studied by various microscopy methods, and their surface area and porosity were determined by adsorption/desorption nitrogen isotherms. The surface chemical composition was also examined by various spectroscopy techniques and electrokinetic analysis. The distribution of elements on the surface was determined, and the successful bonding of the metal/alloys on one side with the polymer on the other by alkoxy amine was confirmed. The composites show significantly increased hydrophilicity, reliable chemical stability of the bonding, even interaction with solvent for thirty cycles, and up to 95% less bacterial adhesion for the modified samples in comparison with pristine samples, i.e., characteristics that are promising for their application in the biomedical field, such as for implants, prosthetics, etc. All this uses universal, two-step procedures with minimal use of energy and the possibility of production on a mass scale. Full article

The main objective of this study was to discover new packaging materials that could integrate one of the most expected properties, such as UV protection, with a self-cleaning ability defined as photocatalytic performance. Accordingly, new hybrid additives were used to transform LDPE films into materials with complex performance properties. In this study, titanium dioxide–lignin (TL) hybrid systems with a weight ratio of inorganic to organic precursors of 5-1, 1-1, and 1-5 were prepared using a mechanical method. The obtained materials and pristine components were characterized using measurement techniques and research methods, such as Fourier-transform infrared spectroscopy (FTIR), thermal stability analysis (TGA/DTG), measurement of the electrokinetic potential as a function of pH, scanning electron microscopy (SEM), and particle size distribution measurement. It was found that hydrogen bonds were formed between the organic and inorganic components, based on which the obtained systems were classified as class I hybrid materials. In the next step, inorganic–organic hybrid systems and pristine components were used as fillers for a low-density polyethylene (LDPE) composite, 5 and 10% by weight, in order to determine their impact on parameters such as tensile elongation at break. Polymer composites containing titanium dioxide in their matrix were then subjected to a test of photocatalytic properties, based on which it was found that all materials with TiO₂ in their structure exhibit photocatalytic properties, whereby the best results were obtained for samples containing the TiO₂–lignin hybrid system (1-1). The mechanical tests showed that the thin sheet films had a strong anisotropy due to chill-roll extrusion, ranging from 1.98 to 3.32. UV–Vis spectroscopy revealed four times higher light absorption for composites in which lignin was present than for pure LDPE, in the 250–450 nm range. On the other hand, the temperature at 5% and 30% weight loss revealed by TGA testing increased the highest performance for LDPE/TiO₂ materials (by 20.4 °C and 8.7 °C, respectively). Full article

An object of the present study was the development of liposomes loaded with the medicine Veklury^® (remdesivir) stabilized by electrostatic adsorption of polysaccharide film formed from chitosans with different physicochemical characteristics and hyaluronic acid. The functionalization of the structures was achieved through the inclusion of an aptamer (oligonucleotide sequence) with specific affinity to the spike protein of the human coronavirus HCoV-OC43. The hydrodynamic size, electrokinetic potential and stability of the structures were evaluated at each step in the procedure. The encapsulation efficiency and loaded amount of remdesivir (99% and 299 µg/mL) were estimated by UV–vis spectroscopy. Our investigations showed manifestation of promising tendencies for prolonged periods of the drug release and increased effectiveness of its antiviral action. Among all studied versions of the delivery system, the most distinguished and suitable in a model coronavirus therapy are the liposomes formed from chitosan oligosaccharides. The cytotoxicity of the liposomes was determined against the HCT-8 cell line. A cytopathic effect inhibition test was used for the assessment of the antiviral activity of the compounds. The virucidal activity and the effect on the viral adsorption of the samples were reported by the end-point dilution method, and the alteration in viral titer was determined as Δlgs compared to untreated controls. The redox-modulating properties of the nanoparticles were studied in vitro in certain/several/a few chemical model systems. Our investigations showed a manifestation of promising tendencies for a prolonged effect of the drug release and increased effectiveness of its antiviral action. Full article

Negatively charged carbon dots (Cdots) were successfully impregnated into chitosan/alginate film formed on model colloidal particles as a result of the attractive interactions with the chitosan molecules. The electrical properties of the produced films were studied by electrokinetic spectroscopy. In this study, the electric light scattering method was applied for first the time for the investigation of suspensions of carbon-based structures. The electro-optical behavior for the suspension of polymer-coated particles showed that the electric polarizability of the particle-covered layer from alginate was significantly higher compared to that of the layer from chitosan due to the higher charge density of alginate. The presence of a low concentration of Cdots in the film results in partial charge screening. It was confirmed that the polarizability of counterions with lower mobility along the adsorbed polyion chains was responsible for the registered electro-optical effect from the suspension of polymer-coated particles and that the participation of diffuse H⁺ counterions of Cdots in the creation of the electro-optical effect was negligible. The observed oscillation behavior in the evolution of the film thickness was interpreted through the participation of compensatory effects due to the additional adsorption/desorption of polyelectrolyte complexes from the film surface. The concentration of Cdots in the film was determined, and the loaded amount was ca. 6.6 µg/mL per layer. Full article