Search Results (184)

We developed a site-directed immobilization strategy exploiting the competitive inhibitor Remazol Brilliant Blue R (RB) to orient horseradish peroxidase (HRP) on functionalized glass surfaces. RB was covalently bound to poly(ethylene-alt-maleic anhydride) (PEMA)-coated substrates, enabling HRP binding via its active site. Subsequent contact with a second PEMA-functionalized surface facilitated covalent immobilization of HRP with controlled orientation. Interfacial layer assembly and the comparative random control were characterized by AFM and XPS analyses, while successful RB acetylation was confirmed by NMR and ATR-IR spectroscopy. Directed contact approaches using stepwise RB and PEMA+RB functionalization yielded HRP loadings with specific activities approximately twofold higher than non-directed immobilization. Our inhibitor-mediated method preserves the native enzyme structure without genetic modification, offering a straightforward platform for enhancing enzyme performance. This strategy is promising for applications in biosensors, biocatalysis, and enzyme-based devices requiring efficient enzyme immobilization. Full article

This work presents an integrated green chemistry and analytical approach for the removal of Brilliant Blue G (BBG) using the non-ionic poly(acrylate) resin Amberlite XAD7HP (XAD7HP), emphasizing structure–property–performance relationships relevant to the resin’s adsorption behavior. The UV–Vis method used for BBG quantification exhibited excellent linearity in the 10–30 mg/L range (R² = 0.9998). Batch adsorption experiments performed over 15–800 mg/L revealed a well-defined saturation profile, with the Langmuir model providing the best fit (R² = 0.9999) and indicating a monolayer capacity of 117 mg/g and highly favorable adsorption (R_L = 0.001). Kinetic evaluation showed rapid initial uptake followed by intraparticle diffusion, with the pseudo-second-order model offering the highest correlation (R² = 0.9811), while Weber–Morris analysis confirmed the contributions of both film and pore diffusion. FTIR-ATR analysis revealed only minor shifts (<10 cm⁻¹) in characteristic bands, confirming physisorption driven by hydrogen bonding, π–π interactions, dipole–dipole forces, and hydrophobic effects, without structural modification of the resin. SEM/EDX imaging demonstrated significant morphological changes after adsorption, including partial pore blockage and deposition of dye aggregates within the meso–macroporous network. XRD patterns confirmed the structural stability of the resin, while TG-DSC analysis highlighted its thermal robustness and suitability for reuse. Desorption studies showed that acidic–alcoholic systems (MeOH–HCl, EtOH–HCl) ensured the highest BBG recovery, supporting the regenerability of XAD7HP. Overall, the combined spectroscopic, kinetic, equilibrium, and morphological evidence demonstrates that XAD7HP is a stable, efficient, and reusable resin for BBG removal, offering a sustainable remediation pathway aligned with green analytical chemistry principles. Full article

The influence of natural and synthetic blue food colorants on the human body, including the cardiovascular system, is a complex and not fully understood topic. Considering that various papers have demonstrated that oxidative stress is a crucial step in the development of cardiovascular diseases (CVDs), our experiments on the pro- or antioxidant action of three blue food colorants (one natural colorant—genipin—and two synthetic colorants—brilliant blue FCF and patent blue V) focused on two aspects that are important for the development of CVDs: the level of biomarkers of oxidative stress induced by H₂O₂/Fe²⁺ (the donor of hydroxyl radicals—one of the most aggressive reactive oxygen species produced in humans) in human blood platelets and human plasma, as well as the arachidonic acid cascade in blood platelets stimulated by thrombin (in vitro). Our results demonstrated that two tested blue colorants—genipin and brilliant blue FCF (at four used concentrations: 2, 10, 20, and 200 µM)—reduced plasma lipid peroxidation induced by H₂O₂/Fe²⁺. Moreover, all tested blue colorants (genipin, brilliant blue FCF, and patent blue V; at the concentrations 2, 10, 20, and 200 µM) inhibited lipid peroxidation in blood platelets treated with H₂O₂/Fe²⁺. In contrast, only genipin (at the highest used concentration—200 µM) statistically significantly reduced plasma protein carbonylation induced by H₂O₂/Fe²⁺ (inhibition of this process: about 25%). However, all tested food colorants decreased blood platelet protein carbonylation stimulated by H₂O₂/Fe²⁺, but their action was not always statistically significant. In addition, we noted that all used blue food colorants (1–200 µM) have protector effects on the change in the level of thiol groups in plasma proteins stimulated by H₂O₂/Fe²⁺, but these tested colorants change the level of thiol groups in blood platelets treated with H₂O₂/Fe²⁺ only at the highest used concentration—200 µM. In conclusion, the present study provides the first data on the antioxidant potential of genipin, brilliant blue FCF, and patent blue V in selected elements of blood treated with H₂O₂/Fe²⁺. Earlier and current studies have indicated the promising potential of these blue food colorants, especially genipin (without cytotoxicity toward human blood platelets), which can modify the oxidative stress of platelets and plasma in vitro at concentrations (1–200 µM) which can be obtained in blood during its administration. However, the presented results have limitations, especially concerning the mechanistic clarity surrounding the antioxidant properties of the tested blue food colorants. Therefore, further in vivo experiments are needed to provide a better understanding of their antioxidant potential. Full article

Synthetic food dyes represent an important category of chemical contaminants with potential phytotoxic, genotoxic, and ecotoxic effects on living organisms and natural ecosystems. The present study aimed to evaluate the physiological effects induced by three commercial food dyes on the model organism Allium cepa, using the Allium test under hydroponic conditions. A total of 105 bulbs were exposed for 48 h to two different concentrations of each dye, for which gravimetric and physiological parameters, such as biomass, water content, mineral and organic composition, growth inhibition index, tolerance index, and relative growth rate, were subsequently analyzed. Statistical analyses revealed significant differences between batches for all evaluated parameters, indicating effects mainly dependent on the type of dye applied. The results suggest that exposure to synthetic food dyes causes disturbances in water balance, biomass accumulation and mineral homeostasis, confirming the phytotoxic potential of these compounds and the utility of the Allium test in the biomonitoring of chemical contaminants. Full article

Since its introduction in 1976, the Bradford assay has served as a gold standard for protein quantification across a wide range of applications. While its limitations—including protein-to-protein variation in dye binding, challenges in selecting a representative calibration standard, and susceptibility to matrix interferences—are recognized, the relevant information remains scattered throughout the literature, with little quantitative guidance available for assay optimization. Here, we review interfering compounds reported in the literature during nearly 50 years and report a systematic characterization of a panel of potential interfering compounds, evaluating the effects of 29 different substances in the presence or absence of the protein analytes. Our findings revealed that 12 of the tested compounds induce significant artefacts in the Bradford assay, with minimal interfering concentrations varying widely across compounds. Detergents were confirmed as the most problematic interference; furthermore, two novel groups of interfering compounds were identified, represented by the transfection reagents and oligoarginine peptides with molecular weight below 3 kDa. Importantly, the resulting artefacts were also observed in complex biological matrices. While these compounds also affected the Lowry assay, the magnitude of the artefacts was substantially lower than that observed in the Bradford assay. This study will provide a valuable resource for researchers working in proteomics and related fields, offering practical insights for improving the reliability of Bradford-based protein quantification. Full article

Semiconductor photocatalysis technology is a simple, efficient, and low-cost method for environmental pollution remediation. As a promising photocatalyst for oxidative degradation, titanium dioxide (TiO₂) demonstrates the capability to address energy shortages and environmental pollution issues. In this study, orange peel was used as the raw material to synthesize a (TiO₂-CdS-C₃N₄-CDs) TCCC composite photocatalyst containing natural green carbon dots via a one-pot hydrothermal method for the first time. This catalyst was applied to the catalytic degradation of multiple dye molecules (Rhodamine B, Methylene Green, Reactive Brilliant Blue KN-R) and quinolone antibiotic (Ciprofloxacin, CIP) as well as tetracycline antibiotic (Tetracycline, THC). Meanwhile, it provides more adsorption sites for target pollutants and loads electron reservoirs (CDs) on the TCC surface, promoting the separation of photogenerated carriers in pure TiO₂, thereby enhancing the visible light utilization and photocatalytic activity of the material. This work expands the application scope of semiconductor photocatalysis technology and TiO₂-based photocatalytic active substrates. Full article

The integrating sphere with sample inside (ISSI) method is useful for absorption spectroscopy of scattering samples, but the measured absorbance ($A_{\mathit{meas}}$) becomes nonlinear with dye concentration (c) because the sample is placed inside the sphere. This study modeled the $A_{\mathit{meas}}-c$ relationship for ISSI using a cylindrical cell (CC) and a Brewster cell (BC) with simple analytical expressions based on the fraction of light not passing through the sample and the effective weights of light passing through it multiple times. Four aqueous dye solutions—Trypan Blue, Brilliant Blue FCF, Tartrazine, and New Coccine—were used as non-scattering samples. For CC, a single-pass model reproduced the measured relationship well for all dyes, and linearity was maintained in the low-absorbance region (up to approximately half of the saturation absorbance, $A_{\max }/2\approx 0.67$ Abs). For BC, the same low-absorbance region (up to approximately $A_{\max }/2\approx 1.21$ Abs) also exhibited practical linearity, but the full relationship including saturation required a multiple-pass model. Model selection based on adjusted RMSE and AICc identified the 3-pass model as the minimum sufficient model for BC. The saturation absorbance $A_{\mathit{max}}$ was on average 1.81 times higher for BC than for CC (corresponding to an approximately 12-fold expansion in linear intensity ratio), and the upper concentration limit of the linear approximation was on average 1.85 times higher. These results demonstrate that BC extends the measurable concentration range while preserving practical low-absorbance linearity. In addition, the wavelength dependence of $A_{\mathit{max}}$ observed at short wavelengths is attributed primarily to the reduced reflectance of the BaSO₄ integrating-sphere wall rather than to the refractive-index dispersion of the quartz cell. Full article

Background: Prophylactic human papillomavirus (HPV) vaccines are crucial for preventing HPV-related cancers. This study aimed to preclinically evaluate a novel recombinant 9-valent HPV vaccine produced in Escherichia coli (E. coli), which targets HPV types 6, 11, 16, 18, 31, 33, 45, 52, and 58, and is based on virus-like particles (VLPs) of the HPV major capsid protein L1. Methods: The molecular weight and purity of HPV L1 protein bands were assessed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) with Coomassie Brilliant Blue staining. The morphology and size distribution of VLPs were characterized using cryo-electron microscopy and DLS. The immunogenicity and durability of the recombinant 9-valent HPV vaccine were evaluated in BALB/c mice and Wistar rats. Mice received single or triple immunizations (2-week intervals) of two vaccine batches or Gardasil^®9 (MSD, USA) control at 1/20 human dose. Antibody responses were monitored via ELISA and pseudovirus neutralization assays over 24 weeks. Rats were administered single or triple immunizations (2-week intervals) of high- (1/10), medium- (1/20), or low-dose (1/40) vaccine or Gardasil^®9 control (1/20), with neutralizing antibodies tracked for 16 weeks. Results: Cryo-electron microscopy and DLS revealed that VLPs of each type appeared as uniformly distributed, spherical or ellipsoidal hollow intact particles with a diameter of approximately 45–65 nm. This vaccine demonstrated robust immunogenicity and long-lasting efficacy in BALB/c mice and Wistar rats, with effects comparable to those of the commercially available vaccine Gardasil^®9. Conclusions: The 9-valent HPV vaccine induces robust and persistent immune responses in mice and rats, strongly supporting further clinical trials. It is expected to be an alternative to marketed vaccines and ease the global supply shortage of 9-valent HPV vaccines. Full article

This study investigated the bactericidal effect and examined the associated cellular damage of low temperature plasma (LTP) combined with slightly acidic electrolyzed water (SAEW) against Listeria monocytogenes. Single-factor experiments were conducted to assess the bactericidal efficacy under individual treatment conditions, followed by the evaluation of three different combination sequences. An orthogonal experimental design was performed to optimize the key parameters, and the optimal treatment conditions were determined as LTP at 45 W with an electrode spacing of 1 mm for 2 min, combined with SAEW at an available chlorine concentration (ACC) of 30 mg/L. Under these conditions, confocal laser scanning microscopy (CLSM) with SYTO 9/PI staining confirmed that the combined treatment caused cell death, as indicated by loss of membrane integrity in treated cells. A resuscitation assay further ruled out the viable but non-culturable (VBNC) state, as no bacterial growth was detected after 48 h of enrichment. The leakage of intracellular proteins and nucleic acids was measured using the Coomassie Brilliant Blue method combined with a microplate reader, and changes in cellular morphology were observed by scanning electron microscopy (SEM). The results demonstrated that SAEW+LTP treatment exerted a distinct effect, significantly disrupting bacterial cell membrane integrity, inducing the leakage of intracellular contents, and causing obvious morphological damage to the bacterial cells. In conclusion, the combined treatment of LTP and SAEW significantly improved the bactericidal efficiency against L. monocytogenes, which may be due to the combined disruptive effects on membrane integrity and subsequent structural and functional damage to the cells. Future investigations are needed to unravel the precise mechanisms, establish the efficacy against a wider panel of strains, and explore the potential for practical application in food matrices. Full article

Chronic alcohol exposure disrupts blood–brain barrier (BBB) integrity and promotes neuroinflammation, with P2X7 receptor (P2X7R) signaling playing a critical role. Our prior work in male mice linked P2X7R inhibition to reduced extracellular adenosine triphosphate (eATP) release, modulated extracellular vesicle (EV) cargo, and attenuated neuroinflammation in chronic intermittent ethanol (CIE)-exposed mice. However, sex-specific roles of P2X7R signaling and EV-mediated mechanisms in alcohol-induced neuroinflammation remain unclear. Male and female mice were exposed to ethanol vapor for three weeks and treated with Brilliant Blue G (BBG), a P2X7R inhibitor. Compared to their respective CIE-unexposed controls, brain gene expression of tumor necrosis factor–α (Tnf-α), interleukin-1 beta (Il-1b), interleukin-6 (Il-6), monocyte chemoattractant protein-1 (Mcp-1), and Fas ligand (Fasl) significantly increased in CIE-exposed males, while only Il-1b increased in females. P2X7R inhibition significantly reduced these cytokines. Pericyte immunostaining was decreased by CIE (indicating BBB injury) in male mice only and was restored by P2X7R inhibition with no difference between groups in females. Occludin staining (another BBB marker) did not differ between the treatment groups in male and female animals. Circulating cytokines (Macrophage inflammatory protein-1 alpha (MIP-1α), tumor necrosis factor–α (TNF-α), interleukin-1 beta (IL-1β), and interleukin-27 subunit p28/interleukin-30 (IL-27p28/IL-30) were significantly elevated in CIE-exposed males but not in females, with BBG treatment reducing cytokines in males. Circulating eATP, P2X7Rs, P-glycoprotein (P-gp), EVs, and EV-mtDNA, which we identified in our previous study, were increased in both sexes and partially decreased by P2X7R blockade. Spatial memory was impaired by CIE exposure in males but not females, and this deficit was reversed by BBG treatment. Our findings reveal sex differences in CIE-induced circulating cytokines, neuroinflammation, and memory impairment, with a stronger response in males. However, other markers of cell injury associated with CIE exposure were upregulated in both sexes; P2X7R inhibition effectively mitigated these effects, highlighting the functional relevance of targeting the P2X7R in alcohol-induced injury. Full article

In recent years, photocatalysis based on metal oxides has gained significant attention as an effective and environmentally sustainable strategy for the degradation of dye pollutants under mild operating conditions. Among the various metal oxide photocatalysts, zinc oxide (ZnO) is particularly attractive due to its appropriate band gap, excellent chemical stability, low cost, and capability to operate under visible light. In this work, ZnO nanoparticles (NPs) were green-synthesized using Livistona chinensis leaf extract and subsequently assessed for their photocatalytic performance in the degradation of the synthetic dye Brilliant Blue FCF. The synthesized ZnO NPs achieved approximately 76% dye removal within 90 min of visible light irradiation. These findings demonstrate the potential of ZnO NPs as an efficient, economical, and eco-friendly visible-light-driven photocatalyst, supporting their application in sustainable wastewater remediation. Full article

Brilliant blue G is a chemical compound with many important applications in various domains, from dye manufacturing to biotechnologies and medicine. Despite the fact that it is used mainly in solutions, a solvatochromic study of this compound has never been reported, while the value of the electrical dipole moment in the excited state is unknown. Here, a solvatochromic study of brilliant blue G is described, and the data is analyzed by three models, allowing for the estimation of the intermolecular interactions involved, as well as their contribution to the total shift in the visible electronic absorption spectral band. Two models provide a predominance of the non-specific (universal) intermolecular interactions, while the third model overestimates the weight of the specific interactions. The spectral data also allow for the comparative estimation of the electrical dipole moment in the first excited state of brilliant blue G molecule by two methods. The values obtained are very close, confirming the good agreement between the two approaches. One of these methods also estimates the angle between the electrical dipole moments in the ground and excited states of brilliant blue G molecule, respectively. Full article

A three-dimensional Ag/TiO₂/Ti foam was fabricated via thermal annealing followed by pulsed laser deposition (PLD), providing a simple and scalable fabrication strategy. The porous Ti foam framework allows for the uniform dispersion of Ag nanoparticles (NPs), while the thermally formed TiO₂ interlayer promotes synergistic electromagnetic and chemical enhancement mechanisms. The localized electromagnetic field amplification at Ag-TiO₂ interfaces was simulated using the finite-difference time-domain (FDTD) method. Density functional theory (DFT) calculations confirmed that TiO₂ enhances both rhodamine 6G (R6G) adsorption on the substrate and charge transfer (CT) between the substrate and R6G, increasing the SERS activity. The optimized substrate demonstrates exceptional surface-enhanced Raman scattering (SERS) performance with an enhancement factor of 1.9 × 10⁷ and a detection limit of 2.24 × 10⁻¹¹ M for rhodamine 6G, with good reproducibility (RSD = 8.4%). Practical applicability is validated through sensitive detection of food colorants (brilliant blue and allura red). The synergistic combination of CT and electromagnetic enhancement in the easily fabricated Ag/TiO₂/Ti foam enables its application as a promising platform for food safety monitoring, effectively bridging laboratory innovation and practical applications. Full article

Brilliant blue, as a pigment food additive, has all the characteristics of printing and dyeing wastewater and belongs to persistent and refractory organic compounds. The photocatalysis–Fenton reaction system consists of two parts: photocatalytic reaction and Fenton reaction. Electrons promote the decomposition of H₂O₂ to produce •OH. In addition, the effective separation of e- and h⁺ by light strengthens the direct oxidation of h⁺, and h⁺ reacts directly with OH⁻ to produce •OH, which can further promote the removal of organic pollutants. In this paper, g-C₃N₄ and Fe/g-C₃N₄ photocatalysts were prepared by the thermal polycondensation method. Fe/g-C₃N₄ of 15 wt% can reach 98.59% under the best degradation environment, and the degradation rate of g-C₃N₄ is only 7.6% under the same conditions. The photocatalytic activity of the catalysts was further studied. Through active species capture experiments, it is known that •OH and •O₂⁻ are the main active species in the system, and the action intensity of •OH is greater than that of •O₂⁻. The degradation reaction mechanism is that H₂O₂ combines with Fe²⁺ in Fe/g-C₃N₄ to generate a large amount of •OH and Fe³⁺, and the combination of Fe-N bonds accelerates the cycle of Fe³⁺/Fe²⁺ and promotes the formation of •OH, thereby accelerating the degradation of target pollutants. •O₂⁻ can reduce Fe³⁺ to Fe²⁺, Fe²⁺ reacts with H₂O₂ to produce •OH, which promotes degradation, and •O₂⁻ itself also plays a role in degradation. In addition, under the optimal experimental conditions obtained by response surface experiments, the fitting degree of first-order reaction kinetics is 0.96642, and the fitting degree of second-order reaction kinetics is 0.57884. Therefore, this reaction is more in line with first-order reaction kinetics. The adsorption rate is only proportional to the concentration of Fe/g-C₃N₄. Full article

The main goal of this study is to address the problem of environmental water pollution caused by organic dyes through waste valorization by synthesizing geopolymer-based adsorbents. In this work, geopolymers were synthesized using fly ash modified with chitosan and polyvinyl alcohol as a starting material. The obtained materials were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, and determination of the point of zero charge. We examined the adsorption potential for organic dye (methylene blue, brilliant green, crystal violet) removal through the influence of contact time, initial pH and concentration of adsorbate solution, and temperature on adsorption. The obtained results were analyzed using theoretical kinetics and isotherm models. Interpretation of the obtained results was performed using the Box–Behnken design and chemometric methods of multivariate analysis. The findings showed that modification with chitosan significantly enhanced the adsorption efficiency of the synthesized materials up to 95.9% for methylene blue adsorption. The parameters identified as having the greatest influence on the adsorption process were contact time, pH-value, initial dye concentration, and the type of dye being adsorbed. Full article