RESUMEN
This paper presents a new application of a lanthanum oxide (III)-modified carbon paste electrode (LaOX/CPE) for dopamine (DP) detection in the presence of ascorbic acid (AA). The presence of cetyl trimethyl ammonium bromide (CTAB) facilitated the LaOX/CPE electrode's ability to detect DP amidst AA interference, resulting in a substantial 70.0% increase in the anodic peak current for DP when compared to the unmodified carbon paste electrode (CPE). CTAB enabled clear separation of the anodic peaks for DP and AA by nearly 0.2 V, despite their initially overlapping potential values, through the ion-dipole interaction of AA and CTAB. The electrode was characterized using cyclic voltammetry (CV) and energy-dispersive spectroscopy (EDS). The method demonstrated a detection limit of 0.06 µmol/L with a relative standard deviation (RSD) of 6.0% (n = 15). Accuracy was assessed through the relative error and recovery percent, using urine samples spiked with known quantities of DP.
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Carbono , Cetrimonio , Dopamina , Técnicas Electroquímicas , Electrodos , Lantano , Óxidos , Tensoactivos , Lantano/química , Carbono/química , Dopamina/orina , Dopamina/análisis , Dopamina/química , Óxidos/química , Tensoactivos/química , Cetrimonio/química , Técnicas Electroquímicas/métodos , Ácido Ascórbico/química , Ácido Ascórbico/análisis , Límite de Detección , HumanosRESUMEN
The design of mutifunctional protein films for large-area spatially ordered arrays of functional components holds great promise in the field of biomedical applications. Herein, interfacial electrostatic self-assembly was employed to construct a large-scale protein thin film by inducing electrostatic interactions between three bovine serum albumin (BSA)-coated nanoclusters and cetyltrimethylammonium bromide (CTAB), leading to their spontaneous organization and uniform distribution at the oil-water interface. This protein film demonstrated excellent multienzyme functions, high antibacterial activity, and pH-responsive drug release capability. Therefore, it can accelerate the wound closure process through a synergistic effect that includes reducing local blood glucose levels, regulating cellular oxidative stress, eradicating bacteria, and promoting cell proliferation.
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Antibacterianos , Albúmina Sérica Bovina , Cicatrización de Heridas , Cicatrización de Heridas/efectos de los fármacos , Albúmina Sérica Bovina/química , Animales , Antibacterianos/farmacología , Antibacterianos/química , Cetrimonio/química , Bovinos , Electricidad Estática , Escherichia coli/efectos de los fármacos , Ratones , Proliferación Celular/efectos de los fármacos , Staphylococcus aureus/efectos de los fármacos , Humanos , Concentración de Iones de HidrógenoRESUMEN
Studying the adsorption behavior of cationic surfactants can help to develop more effective strategies to limit their dispersion in the environment. However, there have few studies on the adsorption of cationic surfactants from the perspective of critical micelle concentration (CMC). In this study, with cetyltrimethylammonium bromide (CTAB) and octadecyl trimethylammonium bromide (OTAB) serving as the model cationic surfactants, the effect of CMC on the adsorption behavior of cationic surfactant onto the surface of sodium alginate/silica (SA/SiO2) microspheres was systematically revealed. The adsorption mechanism relative to CMC was investigated under different conditions, including surfactant concentration, pH, temperature, and adsorption time. The results suggest that at identical concentrations, the smaller the CMC value of the cationic surfactants, the greater the adsorption amount (qt). qt for CTAB and OTAB were 583.2 and 678.0 mg/g respectively, with the concentration higher than their CMC value. When the concentration was lower than the CMC value of the cationic surfactants, qt for CTAB and OTAB were 123.2 and 138.7 mg/g, respectively. The CMC value of CTAB was lower than that of OTAB under identical conditions, suggesting that the adsorption of cationic surfactants is related to their CMC. These results are beneficial for the removal of cationic surfactants by adsorption methods.
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Cationes , Micelas , Microesferas , Dióxido de Silicio , Tensoactivos , Tensoactivos/química , Adsorción , Dióxido de Silicio/química , Cationes/química , Cetrimonio/química , Compuestos de Cetrimonio/química , Alginatos/química , Concentración de Iones de HidrógenoRESUMEN
BACKGROUND: Post-traumatic distal limb wounds cause discomfort and heal gradually by second intention. The topical application of Tri-Solfen (lidocaine hydrochloride, bupivacaine hydrochloride, adrenaline acid tartrate and cetrimide [LBAC]) produces effective postsurgical cutaneous analgesia in lambs, calves and piglets; however, its effect on wounds in horses is unknown. METHODS: The antinociceptive effect, measured by mechanical threshold (MT), and the wound healing impacts of LBAC compared with saline were investigated on surgically created 20 × 20 mm distal limb wounds in 10 horses. Treatment was applied once daily for 7 days following wounding on day 0. Mechanical thresholds were measured after treatment on days 1, 2 and 3. Healing was observed for 25 days. RESULTS: The topical application of LBAC immediately following wounding and its reapplication 24 hours later increased the average MT on the first post-traumatic day by 3 Newtons. However, no antinociceptive benefit was observed on days 2 or 3. Treatment with LBAC did not adversely affect wound healing when compared with saline. LIMITATIONS: Methodological differences preclude absolute MT comparisons between studies. The experimental design did not include a model of contaminated or naturally occurring wounds. CONCLUSION: LBAC may provide an early antinociceptive benefit when applied to uncontaminated surgically created wounds without compromising healing.
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Bupivacaína , Epinefrina , Lidocaína , Cicatrización de Heridas , Animales , Lidocaína/administración & dosificación , Lidocaína/uso terapéutico , Lidocaína/farmacología , Cicatrización de Heridas/efectos de los fármacos , Caballos , Epinefrina/administración & dosificación , Bupivacaína/administración & dosificación , Masculino , Cetrimonio , Administración Tópica , Femenino , Analgésicos/uso terapéutico , Analgésicos/administración & dosificación , Resultado del Tratamiento , Heridas y Lesiones/veterinaria , Heridas y Lesiones/tratamiento farmacológico , Anestésicos Locales/administración & dosificación , Anestésicos Locales/uso terapéutico , Anestésicos Locales/farmacología , Piel/lesiones , Piel/efectos de los fármacos , Combinación de MedicamentosRESUMEN
SshEstI, a carboxylesterase from the thermoacidophilic archaeon Saccharolobus shibatae, is a member of the hormone-sensitive lipase family that displays slightly alkaliphilic activity with an optimum activity at pH 8.0. In this study, three distinct strategies were explored to confer acidophilic properties to SshEstI. The first strategy involved engineering the oxyanion hole by replacing Gly81 with serine or aspartic acid. The G81S mutant showed optimum activity at pH 7.0, whereas the aspartic acid mutant (G81D) rendered the enzyme slightly acidophilic with optimum activity observed at pH 6.0; however, kcat and kcat/Km values were reduced by these substitutions. The second strategy involved examining the effects of surfactant additives on the pH-activity profiles of SshEstI. The results showed that cetyltrimethylammonium bromide (CTAB) enhanced wild-type enzyme (WT) activity at acidic pH values. In the presence of 0.1 mM CTAB, G81S and G81D were acidophilic enzymes with optimum activity at pH 6.0 and 4.0, respectively, although their enzyme activities were low. The third strategy involved engineering the active site to resemble that of kumamolisin-As (kuma-As), an acidophilic peptidase of the sedolisin family. The catalytic triad of kuma-As was exchanged into SshEstI using site-directed mutagenesis. X-ray crystallographic analysis of the mutants (H274D and H274E) revealed that the potential hydrogen donor-acceptor distances around the active site of WT were fully maintained in these mutants. However, these mutants were inactive at pH 4-8.
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Dominio Catalítico , Concentración de Iones de Hidrógeno , Esterol Esterasa/química , Esterol Esterasa/metabolismo , Esterol Esterasa/genética , Cetrimonio/química , Tensoactivos/farmacología , Tensoactivos/química , Tensoactivos/metabolismo , Cinética , Proteínas Arqueales/metabolismo , Proteínas Arqueales/química , Proteínas Arqueales/genética , Mutagénesis Sitio-Dirigida , Carboxilesterasa/metabolismo , Carboxilesterasa/química , Carboxilesterasa/genética , Estabilidad de EnzimasRESUMEN
We report a simple and versatile method for effectively replacing the toxic ligands, such as cetyltrimethylammonium bromide (CTAB) and cetyltrimethylammonium chloride (CTAC), on the surface of Au nanospheres with different sizes by citrate. The method involves the deposition of an ultrathin shell of fresh Au in the presence of sodium citrate at an adequate concentration. After the ligand exchange process, multiple techniques are used to confirm that the surface of the resultant Au nanospheres is covered by citrate while there is no sign of aggregation. We also demonstrate the mitigation of cell toxicity after exchanging the surface-bound CTAB/CTAC with citrate, opening the door to a range of biomedical applications.
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Cetrimonio , Oro , Nanopartículas del Metal , Nanosferas , Oro/química , Cetrimonio/química , Nanosferas/química , Nanopartículas del Metal/química , Humanos , Ácido Cítrico/química , Compuestos de Cetrimonio/química , Tamaño de la Partícula , Ligandos , Propiedades de Superficie , Supervivencia Celular/efectos de los fármacosRESUMEN
A highly sensitive micelle-induced sensory has been developed for detection of long-chain aldehydes as potential biomarkers of respiratory cancers. The micelle-like sensor was fabricated through the partial self-assembly of CTAB and S2 surfactants, containing a fluorescent hydrazine-functionalized dye (Naph-NH2). In principle, long-chain aldehydes with amphiphilic character act as the induced-fit surfactants to form well-entrapped micellar particles, as well as react with Naph-NH2 to form hydrazone derivatives resulting in fluorescent enhancement. The limit of detection (LOD) of micellar Naph-NH2/CTAB/S2 platform was calculated to be â¼ 64.09-80.98 µM for detection of long-chain aldehydes, which showed fluorescent imaging in lung cancer cells (A549). This micellar sensory probe demonstrated practical applicability for long-chain aldehyde sensing in human blood samples with an accepted percent recovery of ~ 94.02-102.4%. Beyond Naph-NH2/CTAB/S2 sensor, the milcellar hybrid sensor was successfully developed by incorporating a micelle-like platform with supramolecular gel regarding to carboxylate-based gelators (Gel1), which showed a tenfold improvement in sensitivity. Expectedly, the determination of long-chain aldehydes through these sensing platforms holds significant promise for point-of-care cancer diagnosis and therapy.
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Aldehídos , Colorantes Fluorescentes , Hidrogeles , Límite de Detección , Micelas , Humanos , Aldehídos/química , Colorantes Fluorescentes/química , Hidrogeles/química , Células A549 , Hidrazinas/química , Cetrimonio/química , Tensoactivos/químicaRESUMEN
Norfloxacin (NOX), a broad spectrum fluoroquinolone (FQ) antibiotic, is commonly detected in environmental residues, potentially contributing to biological drug resistance. In this paper, an aptamer recognition probe has been used to develop a label-free liquid crystal-based biosensor for simple and robust optical detection of NOX in aqueous solutions. Stimuli-receptive liquid crystals (LCs) have been employed to report aptamer-target binding events at the LC-aqueous interface. The homeotropic alignment of LCs at the aqueous-LC interface is due to the self-assembly of the cationic surfactant cetyltrimethylammonium bromide (CTAB). In the presence of the negatively charged NOX aptamer, the ordering changes to planar/tilted. On addition of NOX, the aptamer-NOX binding causes redistribution of CTAB at the LC-aqueous interface and the homeotropic orientation is restored. This results in a bright-to-dark optical transition under a polarized optical microscope (POM). This optical transition serves as a visual indicator to mark the presence of NOX. The devised aptasensor demonstrates high specificity with a minimum detection limit of 5 nM (1.596 ppb). Moreover, the application of the developed aptasensor for the detection of NOX in freshwater and soil samples underscores its practical utility in environmental monitoring. This proposed LC-based method offers several advantages over conventional detection techniques for a rapid, feasible and convenient way to detect norfloxacin.
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Aptámeros de Nucleótidos , Técnicas Biosensibles , Lagos , Límite de Detección , Cristales Líquidos , Norfloxacino , Norfloxacino/análisis , Norfloxacino/química , Aptámeros de Nucleótidos/química , Cristales Líquidos/química , Lagos/análisis , Lagos/química , Técnicas Biosensibles/métodos , Suelo/química , Antibacterianos/análisis , Antibacterianos/química , Contaminantes Químicos del Agua/análisis , Contaminantes Químicos del Agua/química , Cetrimonio/químicaRESUMEN
Several studies have demonstrated that air-bubbling and foam fractionation techniques can efficiently remove long-chain PFAS from contaminated water. However, removing short-chain PFAS is challenging due to its lower surface activity and inability to form self-assembly structures at the air-water interface. In this study, we tested various additives, including salts, surfactants, and polymers, to improve short-chain PFAS (e.g., perfluorobutanesulfonic acid (PFBS) and perfluorobutanoic acid (PFBA)) removal in non-foaming solutions using a bench-scale system. We found that in the presence of cetyltrimethylammonium chloride (CTAC) and salt, air-bubbling can significantly remove 0.5 µg L-1 of PFBS and PFBA in deionized water by >99% (15 min) and 81% (60 min), respectively. The decline of surface tension and the formation of thin foam-like layers during bubbling, controlled by the concentration of CTAC, significantly improved the removal of short-chain PFAS. Adding anionic and neutral surfactants showed no removal of short-chain PFAS during bubbling, suggesting the importance of the electrostatic interactions between short-chain PFAS and the cationic CTAC. We observed a 1:1 M ratio between CTAC and PFBS removed from the solution, suggesting the formation of ion pairs in the solution and enhancing the surface activity of the overall neutral (PFAS-CTAC) complex. A mass balance of the system revealed that the primary mechanism by which PFAS was removed from non-foaming waters was through aerosol generation (70-100%). Using the optimized condition, PFAS mixtures (short- and long-chain PFAS, including five recently regulated PFAS by USPEA, 2 nM each) in deionized water and natural groundwater were successfully removed to below detection (>99% removal; <2 ng L-1), except for PFBA (25-73% removal). These results provide an improved understanding of the mechanism by which PFAS is removed during foam fractionation and highlight the need for capturing aerosols enriched with PFAS to prevent secondary contamination.
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Fluorocarburos , Tensoactivos , Contaminantes Químicos del Agua , Fluorocarburos/química , Tensoactivos/química , Contaminantes Químicos del Agua/química , Cationes/química , Fraccionamiento Químico/métodos , Cetrimonio/química , Purificación del Agua/métodos , Agua/química , Ácidos SulfónicosRESUMEN
AIM: The antifungal activity was studied on sessile and persister cells (PCs) of Candida tropicalis biofilms of gold nanoparticles (AuNPs) stabilized with cetyltrimethylammonium bromide (CTAB-AuNPs) and those conjugated with cysteine, in combination with Amphotericin B (AmB). MATERIALS/METHODS: The PC model was used and synergistic activity was tested by the checkerboard assay. Biofilms were studied by crystal violet and scanning electron microscopy. RESULTS/CONCLUSIONS: After the combination of both AuNPs and AmB the biofilm biomass was reduced, with significant differences in architecture being observed with a reduced biofilm matrix. In addition, the CTAB-AuNPs-AmB combination significantly reduced PCs. Understanding how these AuNPs aid in the fight against biofilms and the development of new approaches to eradicate PCs has relevance for chronic infection treatment.
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Anfotericina B , Antifúngicos , Biopelículas , Candida tropicalis , Sinergismo Farmacológico , Oro , Nanopartículas del Metal , Pruebas de Sensibilidad Microbiana , Candida tropicalis/efectos de los fármacos , Oro/química , Oro/farmacología , Biopelículas/efectos de los fármacos , Anfotericina B/farmacología , Anfotericina B/química , Nanopartículas del Metal/química , Antifúngicos/farmacología , Antifúngicos/química , Cetrimonio/química , Compuestos de Cetrimonio/farmacología , Compuestos de Cetrimonio/químicaRESUMEN
This study explores the dual applications of a greenly synthesized ZnO@CTAB nanocomposite for the efficient remediation of Rhodamine B (RhB) and lead (Pb). The synthesis method involves a sustainable approach, emphasizing environmentally friendly practices. FT-IR, XRD, FESEM, zeta potential, and particle size analyzer (PSA), BET, and UV-VIS were used to physically characterize the zinc oxide and CTAB nanocomposite (ZnO@CTAB). The size and crystalline index of ZnO@CTAB are 77.941 nm and 63.56% respectively. The Zeta potential of ZnO@CTAB is about - 22.4 mV. The pore diameter of the ZnO@CTAB was 3.216 nm, and its total surface area was 97.42 m2/g. The mechanism of adsorption was investigated through pHZPC measurements. The nanocomposite's adsorption performance was systematically investigated through batch adsorption experiments. At pH 2, adsorbent dose of 0.025 g, and temperature 50 °C, ZnO@CTAB removed the most RhB, while at pH 6, adsorbent dose of 0.11 g, and temperature 60 °C, ZnO@CTAB removed the most Pb. With an adsorption efficiency of 214.59 mg/g and 128.86 mg/g for RhB and Pb, the Langmuir isotherm model outperforms the Freundlich isotherm model in terms of adsorption. The pseudo-2nd-order model with an R2 of 0.99 for both RhB and Pb offers a more convincing explanation of adsorption than the pseudo-1st-order model. The results demonstrated rapid adsorption kinetics and high adsorption capacities for RhB and Pb. Furthermore, there was minimal deterioration and a high reusability of ZnO@CTAB till 4 cycles were observed.
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Plomo , Nanocompuestos , Rodaminas , Contaminantes Químicos del Agua , Óxido de Zinc , Plomo/química , Óxido de Zinc/química , Rodaminas/química , Nanocompuestos/química , Contaminantes Químicos del Agua/química , Adsorción , Cetrimonio/química , Restauración y Remediación Ambiental/métodos , Tecnología Química Verde , Nanoestructuras/químicaRESUMEN
Although rare, amoebic keratitis (AK) is a disease caused by Acanthamoeba spp. that can lead to blindness. The drugs currently available for its treatment are very toxic, which has motivated the investigation for more effective and safe therapeutic options. In this study, the in vitro activity of ß-caryophyllene (BCP) was exploited taking into account its action against other protozoans as well as its well-known healing and anti-inflammatory properties (aspects relevant for the AK pathogenesis). On the other hand, high volatilization and oxidation phenomena are found for this compound, which led to its incorporation into nanoemulsions (NEs). Two emulsifying agents were tested, resulting in monodisperse systems with reduced droplet size (<265 nm) and high surface charge (positive and negative for NEs prepared with cetrimonium bromide -CTAB and Phosal® 50+, respectively). NEs prepared with CTAB were shown to be more stable after long-term storage at 4 and 25 °C than those prepared with Phosal®. Pure BCP, at the highest concentration (500 µM), resulted in a level of inhibition of Acanthamoeba trophozoites equivalent to that of reference drug (chlorhexidine). This activity was even greater after oil nanoencapsulation. The reduced droplet size could improve the interaction of the oil with the microorganism, justifying this finding. Changes in surface charge did not impact the activity. Positively charged NEs improved the interaction and retention of BCP in the cornea and thus should be prioritized for further studies.
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Queratitis por Acanthamoeba , Emulsiones , Sesquiterpenos Policíclicos , Queratitis por Acanthamoeba/tratamiento farmacológico , Queratitis por Acanthamoeba/parasitología , Sesquiterpenos Policíclicos/química , Nanopartículas , Administración Oftálmica , Cetrimonio/química , Animales , Acanthamoeba/efectos de los fármacos , Estabilidad de Medicamentos , Tamaño de la Partícula , Soluciones Oftálmicas , HumanosRESUMEN
In this study, UV-vis spectroscopy was employed to investigate the interaction between formylphenoxyacetic acid (FPAA) and its derivatives (chalcone and flavones) with ionic surfactants (SDS, CTAB, and DTAB) in different physiological environments. Changes in the physiochemical properties of FPAA chalcone and flavones including binding constants, partitioning constants, and Gibbs free energy were observed which were influenced by the presence of ionic surfactants computed using mathematical models. The solubilization of the targeted compounds in the ionic surfactants was determined through the binding constant (Kb). The results of the present study indicated that electrostatic interactions played a significant role in the solubilization of the targeted compounds in SDS, CTAB, and DTAB. At pH 4.1, FPAA chalcone exhibited stronger binding affinity with SDS compared to CTAB and DTAB. However, at pH 7.4, chalcone showed stronger binding with DTAB compared to SDS, while negligible interaction with CTAB was observed at pH 7.4. The flavones demonstrated stronger binding with DTAB at pH 7.4 compared to SDS and CTAB and it exhibited strong bonding with CTAB at pH 4.1. The negative values of the Gibbs free energy for binding (ΔGbË) and partitioning (ΔGpË) constants displayed the spontaneity of the process. However, FPAA chalcone with SDS and FPAA flavones with DTAB furnished positive ΔGbË, indicating a non-spontaneous process.
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Flavonas , Solubilidad , Tensoactivos , Tensoactivos/química , Flavonas/química , Flavonas/metabolismo , Concentración de Iones de Hidrógeno , Cetrimonio/química , Termodinámica , Iones/química , Chalcona/química , Chalconas/química , Chalconas/metabolismo , Dodecil Sulfato de Sodio/química , Electricidad EstáticaRESUMEN
The surfactant cetyltrimethylammonium bromide (CTAB) induces the aggregation of gold nanoclusters (GNCs), leading to the development of a proposed fluorometric technique for detecting thiocyanate (SCN-) ions based on an anti-aggregation mechanism. This approach is straightforward to execute, highly sensitive, and selective. A significant quenching effect occurs in fluorescence upon using the aggregation agent CTAB in GNCs synthesis, resulting in a transition from intense red fluorescence to dim red. The decrease in fluorescence intensity of GNCs in the presence of CTAB is caused by the mechanism of fluorescence quenching mediated by aggregation. As the levels of SCN- rise, the fluorescence of CTAB-GNCs increases; this may be detected using spectrofluorometry or by visually inspecting under UV irradiation. The recovery of red fluorescence of CTAB-GNCs in the presence of SCN- enables the precise and discerning identification of SCN- within the concentration range of 2.86-140 nM. The minimum detectable concentration of the SCN- ions was 1 nM. The selectivity of CTAB-GNCs towards SCN- ions was investigated compared to other ions, and it was demonstrated that CTAB-GNCs exhibit exceptional selectivity. Furthermore, we believe that CTAB-GNCs have novel possibilities as favorable sensor candidates for various industrial applications. Our detection technique was validated by analyzing SCN- ions in milk samples, which yielded promising results.
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Cetrimonio , Oro , Nanopartículas del Metal , Tiocianatos , Oro/química , Nanopartículas del Metal/química , Cetrimonio/química , Espectrometría de Fluorescencia , Industria de Alimentos , Técnicas Biosensibles , IonesRESUMEN
Arsenic contamination in soils poses a critical global challenge, yet the influence of surfactants on arsenic adsorption behavior is often underestimated. This study aims to investigate the effects of three representative surfactants, namely cetyltrimethylammonium bromide (CTAB), sodium dodecyl sulfate (SDS), and polyethylene glycol anhydrous sugar alcohol monooleate (Tween 80), on arsenic adsorption behavior in soils. The adsorption isotherm shifts from a single Temkin model without surfactants to both the Langmuir and Temkin models in the presence of surfactants, indicating the simultaneous occurrence of monolayer and multilayer adsorption for arsenic in soils. Moreover, the surfactants can inhibit the adsorption and hasten the attainment of adsorption equilibrium. SDS displayed the most inhibitory effect on arsenic adsorption, followed by Tween 80 and CTAB, due to the competitive adsorption, electrostatic interaction, and hydrophobic interaction. Variations in zeta potential with different surfactants further elucidate this inhibitory phenomenon. Through orthogonal experiment analyses, pH emerges as a primary factor influencing arsenic adsorption in soils, with surfactant concentration and type identified as secondary factors. Temperature notably affects CTAB, with the adsorption inhibition rate plummeting to a mere 0.88% at 50 °C. Sequential extraction analysis revealed that surfactants enhanced the bioavailability of arsenic. The FTIR, XRD, SEM, and CA analyses further support the mechanism underlying the effect of surfactants on arsenic adsorption in soil. These analyses indicate that surfactants modify the composition and abundance of functional groups, hinder the formation of arsenic-containing substances, and improve soil compactness, smoothness, and hydrophilicity. This study provides valuable insights into the effect of surfactants in arsenic-contaminated soils, which is often ignored in previous work.
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Arsénico , Tensoactivos , Tensoactivos/química , Suelo/química , Polisorbatos , Cetrimonio , Adsorción , Arsénico/química , Monitoreo del AmbienteRESUMEN
Gold nanorods (AuNRs) with unique optical properties play a pivotal role in applications in plasmonic imaging, small molecule detection, and photothermal therapy. However, challenges in DNA functionalization of AuNRs hinder their full potential due to the presence of a dense cetyltrimethylammonium bromide (CTAB) bilayer, impeding close DNA contact. In this study, we introduced a convenient approach for the rapid assembly of polyadenine (polyA) tailed DNA on AuNRs with control of DNA density, rigidity, and valence. We explored the impact of DNA with designed properties on the construction of core-satellite structures by employing AuNRs as cores and spherical gold nanoparticles (AuNSs) as satellites. Density, rigidity, and valence are identified as crucial factors for efficient construction. Specifically, polyA-tailed DNA modulated DNA density and reduced spatial hindrance and electrostatic repulsion, thereby facilitating the construction. Enhancing the rigidity of DNA and incorporating multiple binding sites can further improve the efficiency.
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ADN , Oro , Nanotubos , Poli A , Oro/química , Nanotubos/química , ADN/química , Poli A/química , Nanopartículas del Metal/química , Cetrimonio/químicaRESUMEN
Wastewater-based epidemiology has allowed tracking the magnitude and distribution of SARS-CoV-2 in communities, allowing public health officials to prepare for impending outbreaks. While many factors influence recovery of SARS-CoV-2 from wastewater, proper extraction, concentration, and purification of RNA are key steps to ensure accurate detection of viral particles. The aim of this study was to compare the efficiency of four commonly used RNA extraction methods for detection of the SARS-CoV-2 RNA genome in sewage samples artificially inoculated with the virus, in order to identify a protocol that improves viral recovery. These methods included CTAB-based, TRIzol-based, and guanidinium thiocyanate (GTC)-based extraction procedures coupled with silica spin column-based purification, and an automated extraction/purification protocol using paramagnetic particles. Following RNA extraction, virus recovery rates were compared using RT-qPCR-based detection. The CTAB-based approach yielded the highest recovery rates and was the only method to consistently demonstrate stable virus recovery percentages regardless of the specific physicochemical characteristics of the samples tested. The TRIzol method proved to be the second most effective, yielding significantly higher recovery rates compared to both the GTC-based and the automated extraction methods. These results suggest that the CTAB-based approach could be a useful tool for the recovery of viral RNA from complex wastewater matrices.
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Cetrimonio , ARN Viral , SARS-CoV-2 , Aguas Residuales , Aguas Residuales/virología , ARN Viral/aislamiento & purificación , ARN Viral/genética , SARS-CoV-2/aislamiento & purificación , SARS-CoV-2/genética , Cetrimonio/química , Humanos , Compuestos de Cetrimonio/química , COVID-19/virología , COVID-19/diagnóstico , Tiocianatos , Aguas del Alcantarillado/virología , GuanidinasRESUMEN
This study aims to design an artificial metalloprotease based on a Zr-containing polyoxometalate Na8[Zr(W5O18)2] [Zr(W5)2] for the hydrolysis of ovalbumin (OVA) in the presence of different surfactants, which can be used in many areas of the biological and medical sciences, particularly for targeted proteolytic drug design. For this reason, parameters, including the free energy of binding, the chemical nature of amino acid residues, secondary structures, and electrostatic potentials, of Zr(W5)2-OVA and Zr(W5)2-OVA-surfactant were analyzed by molecular docking simulations. The investigations showed that the presence of surfactants decreases the binding affinity of Zr(W5)2 for OVA amino acids, and hydrogen bonds and van der Waals interactions are formed between Zr(W5)2 and OVA amino acids. Additionally, GROMACS further illustrated the significance of SDS and CTAB surfactants in influencing the conformational changes of the OVA that lead to selective protein hydrolysis. In agreement with molecular dynamics simulation results, the experimental analysis showed more protein hydrolysis for the Zr(W5)2-OVA-surfactant systems. For instance, circular dichroism spectroscopy indicated that Zr(W5)2-OVA-CTAB and Zr(W5)2-OVA-TX-100 were more hydrolytically efficient due to the increased level of ß-structures rather than α-chains, which showed that surfactants can facilitate the accessibility of Zr(W5)2 to the cleavage sites by inducing partial unfolding of the OVA structure.
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Aminoácidos , Tensoactivos , Tensoactivos/química , Ovalbúmina/química , Hidrólisis , Cetrimonio , Simulación del Acoplamiento Molecular , Aminoácidos/químicaRESUMEN
The interaction between fluorescently labeled hyaluronan and cationic surfactants was studied using Fluorescence Correlation Spectroscopy. The hyaluronan was selected at two different molecular weights - specifically, 274 kDa and 710 kDa. Cetyltrimethylammonium bromide and Septonex® were chosen as cationic surfactants to interact with the negatively charged biopolymer. The study focused on changes in the diffusive behavior of a biopolymer that interacts with surfactant molecules in an aqueous environment. Various methods were applied to evaluate the obtained data, these including, among others, the Maximum Entropy Method, which provides the distributional dependences of diffusion coefficients. Without the surfactant, the studied biopolymers showed diffusion behavior comparable to that found in previously published studies. In the presence of surfactants, more intense interaction was observed between Cetyltrimethylammonium bromide and Septonex®. Comparing the molecular weights, the retention of intermolecular aggregates after the precipitation region for the lower weight and the disintegration of these aggregates for the higher weight were observed; moreover, they showed diffusion behavior comparable to the samples without the presence of the surfactant.
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Ácido Hialurónico , Compuestos de Amonio Cuaternario , Tensoactivos , Tensoactivos/química , Ácido Hialurónico/química , Cetrimonio , Espectrometría de Fluorescencia , BiopolímerosRESUMEN
Conformational changes play a seminal role in modulating the activity of proteins. This concept becomes all the more relevant in the context of metalloproteins, owing to the formation of specific conformation(s) induced by internal perturbations (like a change in pH, ligand binding, or receptor binding), which may carry out the binding and release of the metal ion/ions from the metal binding center of the protein. Herein, we investigated the conformational changes of an iron-binding protein, monoferric human serum transferrin (Fe-hTF), using several spectroscopic approaches. We could reversibly tune the cetyltrimethylammonium bromide (CTAB)-induced conformation of the protein, exploiting the concept of mixed micelles formed by three sequestrating agents: (3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate) hydrate (CHAPS) and two bile salts, namely, sodium cholate (NaC) and sodium deoxycholate (NaDC). The formation of mixed micelles between CTAB and these reagents (CHAPS/NaC/NaDC) results in the sequestration of CTAB molecules from the protein environment and aids the protein in reattaining its native-like structure. However, the guanidinium hydrochloride-induced denatured Fe-hTF did not acquire its native-like structure using these sequestrating agents, which substantiates the exclusive role of mixed micelles in the present study. Apart from this, we found that the conformation of transferrin (adopted in the presence of CTAB) displays pronounced esterase-like activity toward the para-nitrophenyl acetate (PNPA) substrate as compared to native transferrin. We also outlined the impact of the iron center and amino acids surrounding the iron center on the effective catalytic activity in the CTAB medium. We estimated â¼3 times higher specific catalytic efficiency for the iron-depleted Apo-hTF compared to the fully iron-saturated Fe2-hTF in the presence of CTAB.