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1.
Molecules ; 29(18)2024 Sep 11.
Artículo en Inglés | MEDLINE | ID: mdl-39339304

RESUMEN

A new class of biologics is obtained using the technologically processed of antibodies (TPA), which are used as the initial substance, and their dilution at each stage is accompanied by a controlled external vibrational (mechanical) treatment. This article focuses on the development and validation of a novel technique that can be applied for assessing the identity of TPA-based drugs. It has previously been found that after such treatment, the resulting solution either acquired new properties that were not present in the initial substance or a quantitative change in properties compared to the initial substance was observed. The use of mechanical treatment during the manufacture of the TPA-based drugs can cause the formation of new bonds between the solvent and antibody molecules. These changes manifest themselves in altered adsorption at the surface of the test solutions, which results in the formation of a near-surface film. One of the indicators of such events is the change in the surface temperature of the solution, which can be analyzed using high-resolution thermography. Unlike other methods, the high-resolution thermography allows the near-surface layer of a heterogeneous aqueous solution to be clearly visualized and quantified. A number of experiments were performed: seven replicates of sample preparations were tested; the influence of factors "day" or "operator" was investigated during 12 days of testing by two operators. The method also allowed us to distinguish between technologically processed antibodies and samples containing technologically processed buffer. The thermographic analysis has proven to be a simple, specific, and reproducible technique that can be used to analyze the identity of TPA-based drugs, regardless of the dosage form tested.


Asunto(s)
Anticuerpos , Termografía , Termografía/métodos , Anticuerpos/química , Soluciones , Agua/química , Propiedades de Superficie , Temperatura
2.
Nat Commun ; 15(1): 7763, 2024 Sep 05.
Artículo en Inglés | MEDLINE | ID: mdl-39237564

RESUMEN

The challenge of transforming organized DNA structures into their metallized counterparts persists in the scientific field. In this context, utilizing DNA molecules modified with 7-deazapurine, provides a transformative solution. In this study, we present the solution structure of a DNA duplex that can be transformed into its metallized equivalent while retaining the natural base pairing arrangement through the creation of silver-modified Watson-Crick base pairs. Unlike previously documented X-ray structures, our research demonstrates the feasibility of preserving the intrinsic DNA self-assembly while incorporating AgI into the double helix, illustrating that the binding of silver does not disrupt the canonical base-pairing organization. Moreover, in our case, the uninterrupted AgI chain deviates from forming conventional straight linear chains; instead, it adheres to a helical arrangement dictated by the underlying DNA structure. This research challenges conventional assumptions and opens the door to precisely design structures based on the organization of highly stable Ag-DNA assemblies.


Asunto(s)
Emparejamiento Base , ADN , Conformación de Ácido Nucleico , Plata , Plata/química , ADN/química , Modelos Moleculares , Soluciones
3.
Q Rev Biophys ; 57: e9, 2024 Sep 03.
Artículo en Inglés | MEDLINE | ID: mdl-39225237

RESUMEN

Structure-switching aptamers have become ubiquitous in several applications, notably in analytical devices such as biosensors, due to their ease of supporting strong signaling. Aside from their ability to bind specifically with their respective target, this class of aptamers also undergoes a conformational rearrangement upon target recognition. While several well-studied and early-developed aptamers (e.g., cocaine, ATP, and thrombin) have been found to have this structure-switching property, the vast majority do not. As a result, it is common to try to engineer aptamers into switches. This proves challenging in part because of the difficulty in obtaining structural and functional information about aptamers. In response, we review various readily available biophysical characterization tools that are capable of assessing structure switching of aptamers. In doing so, we delve into the fundamentals of these different techniques and detail how they have been utilized in characterizing structure-switching aptamers. While each of these biophysical techniques alone has utility, their real power to demonstrate the occurrence of structural change with ligand binding is when multiple techniques are used. We hope that through a deeper understanding of these techniques, researchers will be better able to acquire biophysical information about their aptamer-ligand systems and accelerate the translation of aptamers into biosensors.


Asunto(s)
Aptámeros de Nucleótidos , Conformación de Ácido Nucleico , Aptámeros de Nucleótidos/química , Aptámeros de Nucleótidos/metabolismo , Soluciones , Humanos , Fenómenos Biofísicos , Técnicas Biosensibles
4.
Biophys Chem ; 314: 107318, 2024 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-39226875

RESUMEN

The Ebola delta peptide is an amphipathic, 40-residue peptide encoded by the Ebola virus, referred to as E40. The membrane-permeabilising activity of the E40 delta peptide has been demonstrated in cells and lipid vesicles suggesting the E40 delta peptide likely acts as a viroporin. The lytic activity of the peptide increases in the presence of anionic lipids and a disulphide bond in the C-terminal part of the peptide. Previous in silico work predicts the peptide to show a partially helical structure, but there is no experimental information on the structure of E40. Here, we use circular dichroism spectroscopy to report the secondary structure propensities of the reduced and oxidised forms of the E40 peptide in water, detergent micelles, and lipid vesicles composed of neutral and anionic lipids (POPC and POPG, respectively). Results indicate that the peptide is predominately a random coil in solution, and the disulphide bond has a small but measurable effect on peptide conformation. Secondary structure analysis shows large uncertainties and dependence on the reference data set and, in our system, cannot be used to accurately determine the secondary structure motifs of the peptide in membrane environments. Nevertheless, the spectra can be used to assess the relative changes in secondary structure propensities of the peptide depending on the solvent environment and disulphide bond. In POPC-POPG vesicles, the peptide transitions from a random coil towards a more structured conformation, which is even more pronounced in negatively charged SDS micelles. In vesicles, the effect depends on the peptide-lipid ratio, likely resulting from vesicle surface saturation. Further experiments with zwitterionic POPC vesicles and DPC micelles show that both curvature and negatively charged lipids can induce a change in conformation, with the two effects being cumulative. Electrostatic screening from Na+ ions reduced this effect. The oxidised form of the peptide shows a slightly lower propensity for secondary structure and retains a more random coil conformation even in the presence of PG-PC vesicles.


Asunto(s)
Dicroismo Circular , Ebolavirus , Micelas , Estructura Secundaria de Proteína , Ebolavirus/química , Fosfatidilcolinas/química , Soluciones , Fosfatidilgliceroles/química , Péptidos/química , Agua/química , Proteínas Virales/química , Secuencia de Aminoácidos
5.
Int J Mol Sci ; 25(17)2024 Sep 08.
Artículo en Inglés | MEDLINE | ID: mdl-39273676

RESUMEN

Microwaves have been successfully employed in the Lewis acid titanium tetrachloride-assisted synthesis of peptide systems. Dipeptide systems with their amino function differently protected with urethane protecting groups have been synthesized in short periods of time and with high yields. The formation of the peptide bond between the two reacting amino acids was achieved in pyridine by using titanium tetrachloride as a condensing agent and heating the reaction mixture with a microwave reactor. The reaction conditions are compatible with amino acids featuring various side chains and different protecting groups on both the amino function and side chains. Additionally, the substrates retain their chiral integrity after reaction.


Asunto(s)
Dipéptidos , Microondas , Titanio , Dipéptidos/química , Dipéptidos/síntesis química , Titanio/química , Aminoácidos/química , Soluciones
6.
Biosensors (Basel) ; 14(9)2024 Aug 26.
Artículo en Inglés | MEDLINE | ID: mdl-39329788

RESUMEN

Fisetin and Luteolin are important flavonoids produced in plants and known for their antioxidant, anti-inflammatory, neuroprotective, and analgesic properties. They are also good candidates for different types of biosensors. The model used to describe the fluorescence (FL) emission of these flavonoids involves an excited-state intermolecular proton transfer (ESIPT) process that causes a change in the molecule configuration and a corresponding decrease in the emission energy. Due to the different molecular structures of Fisetin and Luteolin, only one possible proton transfer within the molecule is allowed for each of them: transfer of the H3 proton for Fisetin and of the H5 for Luteolin. Here, we compare their calculated emission wavelengths, obtained using TDDFT/M06-2X/6-31++G(d,p), with their FL emission spectra measured on the corresponding powders and solutions and show that the experimental data are consistent with the presence of the ESIPT process. We also compare the emission wavelengths found for Fisetin and Luteolin with those calculated and measured for Quercetin, where, under photoexcitation, the transfers of both H3 and H5 protons are possible. We analyze the difference in the processes associated with the H3 and H5 proton transfers and discuss the reason for the predominance of the H5 proton transfer in Quercetin. Additionally, a new system of notation for flavonoid molecules is developed.


Asunto(s)
Flavonoides , Flavonoles , Luteolina , Quercetina , Luteolina/química , Quercetina/química , Flavonoles/análisis , Flavonoides/análisis , Flavonoides/química , Fluorescencia , Protones , Polvos , Espectrometría de Fluorescencia , Soluciones
7.
Org Lett ; 26(38): 8206-8210, 2024 Sep 27.
Artículo en Inglés | MEDLINE | ID: mdl-39269272

RESUMEN

A novel chemoselective peptide conjugation via late-stage N-alkylation of pyridyl-alanine (PAL) in the solution and solid phase, namely, NAP, is demonstrated. The method constructs functionally diverse and highly stable N-alkylated conjugates with various peptides. Notably, conjugations in the solid phase offered a more economical process. The method can provide the opportunity for dual labeling along with a cysteine handle in a peptide chain. Finally, we showcased that the antiproliferative activities of the p53 peptide (MDM2 inhibitor) could be 2-fold enhanced via NAP conjugation with the RGD peptide (selective integrin binder).


Asunto(s)
Alanina , Péptidos , Alquilación , Alanina/química , Estructura Molecular , Péptidos/química , Péptidos/farmacología , Péptidos/síntesis química , Humanos , Oligopéptidos/química , Oligopéptidos/farmacología , Proteínas Proto-Oncogénicas c-mdm2/antagonistas & inhibidores , Proteínas Proto-Oncogénicas c-mdm2/química , Proteínas Proto-Oncogénicas c-mdm2/metabolismo , Soluciones , Técnicas de Síntesis en Fase Sólida , Proteína p53 Supresora de Tumor/química , Proteína p53 Supresora de Tumor/antagonistas & inhibidores , Proteína p53 Supresora de Tumor/metabolismo , Proliferación Celular/efectos de los fármacos , Piridinas/química , Piridinas/farmacología
8.
Biomed Khim ; 70(5): 273-286, 2024 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-39324193

RESUMEN

The review considers the possibility of using atomic force microscopy (AFM) as a basic method for protein detection in solutions with low protein concentrations. The demand for new bioanalytical approaches is determined by the problem of insufficient sensitivity of systems used in routine practice for protein detection. Special attention is paid to demonstration of the use in bioanalysis of a combination of AFM and fishing methods as an approach of concentrating biomolecules from a large volume of the analyzed solution on a small surface area.


Asunto(s)
Microscopía de Fuerza Atómica , Proteínas , Microscopía de Fuerza Atómica/métodos , Proteínas/análisis , Proteínas/química , Humanos , Animales , Soluciones
9.
J Phys Chem B ; 128(38): 9086-9093, 2024 Sep 26.
Artículo en Inglés | MEDLINE | ID: mdl-39268801

RESUMEN

Misfolding of antibody light chains can lead to systemic light chain amyloidosis, which is associated with misfolding and aggregation. The antibody light chain may engage in 3D domain swapping within the variable region (#4VL) through hydrogen bonding (HB) interactions, potentially forming the tetramer, as revealed in solution and crystal structures. However, the 3D-domain swapping (3D-DS) dimers could not be detected experimentally. This study investigates the absence of 3D-DS using computational approaches, focusing on structural dynamics, solvation effects, and stability relevant to the loss of 3D-DS. Microscale molecular dynamics simulations of #4VL and 3D-DS confirm that native HB interactions are essential to maintain ß-sheet structures in both #4VL and 3D-DS. A flickering native HB interaction in the 3D-DS system, caused by repulsive interaction with water molecules in the hydrophobic region, leads to intramolecular breathing motions and oligomerization in another 3D-DS. Structural dynamics of the 3D-DS dimer in long-run simulations were analyzed using the newly developed integrated solvation-based principal component analysis (3D-RISM/PCA) and density-based spatial clustering of applications with noise, confirm that if the 3D-DS cannot form the tetramer within the breathing motion process, the 3D-DS will collapse. This finding provides insights into why the 3D-DS dimer is missing from the solution and can be used to design and develop 3D-DS in other antibodies.


Asunto(s)
Enlace de Hidrógeno , Simulación de Dinámica Molecular , Multimerización de Proteína , Cadenas Ligeras de Inmunoglobulina/química , Soluciones , Interacciones Hidrofóbicas e Hidrofílicas
10.
J Extra Corpor Technol ; 56(3): 84-93, 2024 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-39303129

RESUMEN

BACKGROUND: The del Nido cardioplegia solution is a widely used method for myocardial protection in various settings. However, there is limited evidence of its effectiveness in adult cardiac surgery, and the baseline solution, Plasma Lyte A, is not readily available, leading to the use of alternative baseline solutions. This study aims to investigate the effectiveness of routine del Nido cardioplegia in adult cardiac surgery and the impact of different baseline solutions on myocardial protection and other perioperative outcomes. METHODS: This study was a prospective, double-blind randomized parallel group clinical trial conducted at a single tertiary care hospital in Iran. A total of 187 adult patients were evaluated for eligibility, of which 120 met the inclusion criteria for elective isolated CABG surgery. The patients were randomly assigned to three groups, with each group consisting of 40 patients. The control group received a normal saline-based routine del Nido cardioplegia, Intervention Group A received Ringer lactate-based del Nido cardioplegia, and Intervention Group B received plain Ringer-based del Nido cardioplegia. The levels of Creatine Kinase-MB (CK-MB), Troponin T, Troponin I, and lactate were primarily assessed at four different times: after anesthesia induction (Baseline), 2 h, 12 h, and 24 h. RESULTS: Preoperative demographic and clinical characteristics were the same among groups with insignificant differences (p > 0.05). There was no significant difference among groups based on CK-MB, Troponin T, Troponin I, and lactate levels (p = 0.078, 0.143, 0.311, and 0.129 respectively). However, there was a significant difference in the time effect of Troponin T and Lactate (p = 0.034, p = <0.001). CONCLUSION: Normal saline, Ringer lactate, and plain Ringer provide comparable myocardial protection in adult-isolated CABG surgery with modified del Nido cardioplegia. Larger studies are needed to identify the best alternative to Plasma Lyte A while maintaining del Nido cardioplegia as the control.


Asunto(s)
Soluciones Cardiopléjicas , Puente de Arteria Coronaria , Paro Cardíaco Inducido , Humanos , Masculino , Método Doble Ciego , Femenino , Puente de Arteria Coronaria/métodos , Puente de Arteria Coronaria/efectos adversos , Persona de Mediana Edad , Paro Cardíaco Inducido/métodos , Soluciones Cardiopléjicas/uso terapéutico , Anciano , Estudios Prospectivos , Cloruro de Potasio/uso terapéutico , Resultado del Tratamiento , Manitol , Lidocaína , Soluciones , Electrólitos , Sulfato de Magnesio , Bicarbonato de Sodio
11.
Medicine (Baltimore) ; 103(36): e39453, 2024 Sep 06.
Artículo en Inglés | MEDLINE | ID: mdl-39252294

RESUMEN

BACKGROUND: Del Nido cardioplegia (DNC) has extensively been used for pediatric population undergoing cardiac surgery. However, its use in adult cardiac surgeries have been limited thus, its benefits are not yet fully known. This analysis was performed to evaluate the impact of DNC versus any other type of cardioplegia in adult patients who are undergoing cardiac surgery. METHODS: We systematically searched PubMed, Cochrane Library, and Scopus from database inception till March 2023, and moderate to high-quality randomized controlled trials were included which compared DNC to other cardioplegia. The primary outcome was postoperative stroke and/or transient ischemic attack (TIA). Secondary outcomes included spontaneous rhythm return, postoperative myocardial infarction, all-cause mortality, postoperative atrial fibrillation, defibrillation after coronary reperfusion, postoperative intra-aortic balloon pump, postoperative kidney injury, postoperative low cardiac output syndrome, inotropic support, cardiopulmonary bypass time, cross-clamp time, blood transfusion, cardioplegia volume, hospital stay, intensive care unit stay, mechanical ventilation stay, postoperative left ventricular ejection fraction, and cardiac markers. RESULTS: In this meta-analysis, 13 studies were included with a patient population of 2207. Stroke and/or TIA studies (risk ratio [RR]: 0.54, 95% CI [0.29, 1.00]) and all-cause mortality studies (RR: 1.30, 95% CI [0.66, 2.56]) were insignificant. From the secondary outcomes, spontaneous rhythm return (RR: 1.58, 95% CI [1.02, 2.45]), defibrillation after coronary reperfusion (RR: 0.49, 95% CI [0.30, 0.79]), inotropic support (RR: 0.70, 95% CI [0.57, 0.85]), composite risk of stroke and/or TIA and/or acute kidney injury and mortality (RR: 0.72, 95% CI [0.53, 0.99]), cross-clamp time (mean difference [MD]: -6.01, 95% CI [-11.14, -0.89]), blood transfusion (RR: 0.73, 95% CI [0.60, 0.90]), cardioplegia volume (MD: -537.17, 95% CI [-758.89, -315.45]), troponin T (MD: -1.71, 95% CI [-2.11, -1.32]), creatine phosphokinase-MB (MD: -2.96, 95% CI [-5.84, -0.07]) were significant. Whereas all other secondary outcomes were found to be insignificant. CONCLUSION: No significant difference was observed between patients undergoing Del Nido administration in comparison to other cardioplegia solutions for the primary outcome, stroke or/and TIA.


Asunto(s)
Procedimientos Quirúrgicos Cardíacos , Paro Cardíaco Inducido , Complicaciones Posoperatorias , Ensayos Clínicos Controlados Aleatorios como Asunto , Humanos , Paro Cardíaco Inducido/métodos , Procedimientos Quirúrgicos Cardíacos/métodos , Adulto , Complicaciones Posoperatorias/epidemiología , Complicaciones Posoperatorias/prevención & control , Soluciones Cardiopléjicas/uso terapéutico , Cloruro de Potasio , Manitol , Lidocaína , Soluciones , Electrólitos , Sulfato de Magnesio , Bicarbonato de Sodio
12.
PLoS One ; 19(9): e0309544, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-39231150

RESUMEN

This study examines the corrosion characteristics of weakly cemented sandstone under alkaline conditions, evaluating the effects of varying pH levels on its macroscopic degradation, micro-porosity, and mechanical properties, notably uniaxial compressive strength. Findings reveal that heightened alkalinity exacerbates rock damage, although a temporary alleviation in mass loss occurs between pH 9 and 11 due to pore clogging by complexes formed from cations like Ca2+ and Mg2+.Increased alkalinity induces marked changes in pore features, with an observed rise in pore numbers, transformation of pore shapes from elongated to more spherical, and adjustments in porosity, pore size, and roundness. Furthermore, the study confirms a decline in both the rock's compressive strength and elastic modulus as pH rises. These revelations shed light on the role of pH in the corrosion behavior of weakly cemented sandstone under alkaline conditions, providing a fresh perspective for understanding its corrosion mechanisms in such environments.


Asunto(s)
Fuerza Compresiva , Corrosión , Concentración de Iones de Hidrógeno , Porosidad , Soluciones , Álcalis/química , Módulo de Elasticidad
13.
Carbohydr Polym ; 345: 122567, 2024 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-39227104

RESUMEN

Solution blowing process was used to prepare cellulose nonwovens, by using N-methyl morpholine-N-oxide (NMMO) as solvent, and salicylic acid (SA) microcapsules as antibacterial additives. The structure and properties of cellulose nonwovens modified with different SA microcapsules contents were compared and evaluated. The results showed that more uniform and denser web structure was formed with the increase of SA microcapsules content, the average fiber diameter of cellulose nonwoven increased from 1.99 µm to 2.65 µm. The air flow resistance and filtration efficiency of cellulose nonwovens increased with addition of SA microcapsules, whereas the mechanical properties, and wearing comfort including air permeability, moisture vapor transfer rate, and softness of cellulose nonwovens decreased slightly, under the same basis weight. SA microcapsules modified cellulose nonwovens exhibited good sustained-release behavior and antimicrobial activity against Escherichia coli. The higher SA microcapsules content in cellulose nonwovens, the faster release rate and the higher antimicrobial activity. The cellulose solution-blown nonwovens modified with SA microcapsules are expected to find applications in medical and healthcare fields due to its antibacterial activity and biodegradability.


Asunto(s)
Antibacterianos , Cápsulas , Celulosa , Escherichia coli , Ácido Salicílico , Solventes , Celulosa/química , Ácido Salicílico/química , Ácido Salicílico/farmacología , Antibacterianos/farmacología , Antibacterianos/química , Escherichia coli/efectos de los fármacos , Solventes/química , Liberación de Fármacos , Óxidos N-Cíclicos/química , Soluciones , Pruebas de Sensibilidad Microbiana
14.
Nat Commun ; 15(1): 7740, 2024 Sep 04.
Artículo en Inglés | MEDLINE | ID: mdl-39231922

RESUMEN

The physical characterization of proteins in terms of their sizes, interactions, and assembly states is key to understanding their biological function and dysfunction. However, this has remained a difficult task because proteins are often highly polydisperse and present as multicomponent mixtures. Here, we address this challenge by introducing single-molecule microfluidic diffusional sizing (smMDS). This approach measures the hydrodynamic radius of single proteins and protein assemblies in microchannels using single-molecule fluorescence detection. smMDS allows for ultrasensitive sizing of proteins down to femtomolar concentrations and enables affinity profiling of protein interactions at the single-molecule level. We show that smMDS is effective in resolving the assembly states of protein oligomers and in characterizing the size of protein species within complex mixtures, including fibrillar protein aggregates and nanoscale condensate clusters. Overall, smMDS is a highly sensitive method for the analysis of proteins in solution, with wide-ranging applications in drug discovery, diagnostics, and nanobiotechnology.


Asunto(s)
Proteínas , Imagen Individual de Molécula , Imagen Individual de Molécula/métodos , Proteínas/química , Proteínas/análisis , Soluciones , Difusión , Microfluídica/métodos , Hidrodinámica , Técnicas Analíticas Microfluídicas/métodos
15.
J Chem Phys ; 161(9)2024 Sep 07.
Artículo en Inglés | MEDLINE | ID: mdl-39225532

RESUMEN

The diffusion of proteins is significantly affected by macromolecular crowding. Molecular simulations accounting for protein interactions at atomic resolution are useful for characterizing the diffusion patterns in crowded environments. We present a comprehensive analysis of protein diffusion under different crowding conditions based on our recent docking-based approach simulating an intracellular crowded environment by sampling the intermolecular energy landscape using the Markov Chain Monte Carlo protocol. The procedure was extensively benchmarked, and the results are in very good agreement with the available experimental and theoretical data. The translational and rotational diffusion rates were determined for different types of proteins under crowding conditions in a broad range of concentrations. A protein system representing most abundant protein types in the E. coli cytoplasm was simulated, as well as large systems of other proteins of varying sizes in heterogeneous and self-crowding solutions. Dynamics of individual proteins was analyzed as a function of concentration and different diffusion rates in homogeneous and heterogeneous crowding. Smaller proteins diffused faster in heterogeneous crowding of larger molecules, compared to their diffusion in the self-crowded solution. Larger proteins displayed the opposite behavior, diffusing faster in the self-crowded solution. The results show the predictive power of our structure-based simulation approach for long timescales of cell-size systems at atomic resolution.


Asunto(s)
Método de Montecarlo , Difusión , Proteínas/química , Soluciones , Simulación del Acoplamiento Molecular , Escherichia coli/química , Simulación de Dinámica Molecular , Cadenas de Markov
16.
Sensors (Basel) ; 24(17)2024 Sep 04.
Artículo en Inglés | MEDLINE | ID: mdl-39275661

RESUMEN

The accurate determination of the post-dilution concentration of biological buffers is essential for retaining the necessary properties and effectiveness of the buffer to maintain stable cellular environments and optimal conditions for biochemical reactions. In this work, we introduce a silicon-based impedance chip, which offers a rapid and reagent-free approach for monitoring the buffer concentrations after dilution with deionized (DI) water. The impedance of the impedance chip is measured, and the impedance data are modeled using a multiparameter equivalent circuit model. We investigated six aqueous biological buffers with pH values above and below the physiological pH for most tissues (pH ~ 7.2-7.4) following dilution with DI water by factors of 2.0, 10.0, 20.0, 100.0, and 200.0. The impedance measurement is then performed for the frequency spectrum of 40 Hz to 1 MHz. From the interpretation of the impedance measurement using the multiparameter equivalent circuit model, we report a buffer-sensitive equivalent circuit parameter RAu/Si of the silicon-based impedance chip showing a linear trend on a logarithmic scale with the buffer concentration change after dilution. The parameter RAu/Si is independent of the buffer pH and the added volume. The results demonstrate the efficacy of the silicon-based impedance chip as a versatile tool for precise post-dilution concentration determination of diverse biologically relevant buffers. The presented impedance chip offers rapid, accurate, and reliable monitoring, making it highly suitable for integration into automated liquid-handling systems to enhance the efficiency and precision of biological and chemical processes.


Asunto(s)
Impedancia Eléctrica , Concentración de Iones de Hidrógeno , Tampones (Química) , Silicio/química , Soluciones/química , Técnicas Biosensibles/métodos , Agua/química
17.
Bioresour Technol ; 412: 131387, 2024 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-39214180

RESUMEN

Due to the serious threat posed by tebuconazole to the aquatic ecosystem, it is imperative to develop a highly efficient adsorbent material for the sustainable remediation of tebuconazole-contaminated water. Herein, a phosphorus (P)-doped biochar from corn straw and H3PO4 was fabricated by one-step pyrolysis for tebuconazole adsorption. Results showed that the P-doped biochar produced at 500℃ (PBC500) possesses a large specific surface area (SSA=869.6 m2/g), abundant surface functional groups, and the highest tebuconazole adsorption capacity (429.6 mg/g). The adsorption of tebuconazole on PBC500 followed pseudo-second-order kinetics and Langmuir adsorption isotherm models. Thermodynamic calculations indicated that the adsorption of tebuconazole by PBC500 was a spontaneous, endothermic process with a random increase. Adsorption mechanism mainly involves pore filling, π-π interactions, hydrogen bonding, and hydrophobic interaction. Moreover, PBC500 demonstrated robust anti-interference capabilities in adsorbing tebuconazole from diverse water sources and exhibited excellent reusability, underscoring its potential for a broad array of practical applications.


Asunto(s)
Carbón Orgánico , Triazoles , Contaminantes Químicos del Agua , Zea mays , Zea mays/química , Carbón Orgánico/química , Triazoles/química , Adsorción , Contaminantes Químicos del Agua/aislamiento & purificación , Cinética , Purificación del Agua/métodos , Termodinámica , Fósforo , Soluciones , Concentración de Iones de Hidrógeno
18.
Int J Biol Macromol ; 278(Pt 3): 134847, 2024 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-39168190

RESUMEN

Ciprofloxacin (CIP) is one of the most widely used antibiotics to treat bacterial infections. Consequently, there is concern that it may contaminate water resources due to its high usage level. It is therefore necessary to monitor, trace, and reduce exposure to these antibiotic residues. In the current study, the extraction of CIP from water was performed using a green adsorbent material based on cellulose/polyvinyl alcohol (PVA) decorated with mixed metal oxides (MMO). This cellulose/MMO/PVA adsorbent was synthesized using a simple sol-gel method. The prepared adsorbent materials were then characterized using a range of methods, including scanning electron microscopy, energy-dispersive X-ray spectroscopy, gas adsorption analysis, X-ray diffraction, and Fourier Transform infrared. The impact of pH, adsorbent dose, contact time, and CIP concentration on ciprofloxacin extraction were examined. The equilibrium and kinetic adsorption data were well described using the Freundlich model (R2 = 0.965). The optimum conditions for CIP adsorption were: pH = 4.5; adsorbent dosage = 0.55 g·L-1; contact time = 83 min; and initial CIP concentration = 2 mg·L-1. The adsorption capacity of the cellulose/MMO/PVA adsorbent for CIP removal was ∼19 mg·g-1 (CIP removal = 86.48 %). This study shows that cellulose/MMO/PVA adsorbents have potential for removing contaminants from aqueous environments.


Asunto(s)
Celulosa , Ciprofloxacina , Contaminantes Químicos del Agua , Purificación del Agua , Ciprofloxacina/química , Ciprofloxacina/aislamiento & purificación , Celulosa/química , Adsorción , Contaminantes Químicos del Agua/química , Contaminantes Químicos del Agua/aislamiento & purificación , Purificación del Agua/métodos , Cinética , Concentración de Iones de Hidrógeno , Agua/química , Alcohol Polivinílico/química , Transición de Fase , Soluciones , Espectroscopía Infrarroja por Transformada de Fourier
19.
Int J Biol Macromol ; 278(Pt 3): 134876, 2024 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-39168218

RESUMEN

To enhance the stability and adsorption performance of chitosan in Cr(VI)-contaminated acidic wastewater, a novel EDAC-modified-EDTA-crosslinked chitosan derivative (CSEC) was synthesized via a one-pot method with chitosan, 1-Ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDAC), and Na2EDTA as raw materials. To further improve the mechanical strength and separation performance of CSEC, a novel composite bead (CSEP) of CSEC and imidazolium-functionalized polysulfone (IMPSF) was prepared through a phase inversion method. The chemical composition and microstructure of CSEC and CSEP were characterized by FESEM, FTIR, NMR and XPS techniques. The maximum adsorption capacities of CSEC and CSEP for Cr(VI) were 145.96 and 135.82 mg g-1 at pH 3, respectively, and the equilibrium time for Cr(VI) adsorption by CSEC and CSEP was 5 min and 8 h, respectively. The adsorption process of Cr(VI) by both CSEC and CSEP was exothermic and spontaneous. Compared to CSEC, CSEP has significantly enhanced resistance to interference from coexisting anions. The removal mechanism of Cr(VI) by CSEP might involve redox reaction as well as electrostatic attraction between Cr(VI) oxyanions and various nitrogen cations, including protonated amino groups, guanidinium groups, protonated tertiary amine groups, and imidazolium cations. The CSEP beads have potential application value in the treatment of acidic wastewater containing Cr(VI).


Asunto(s)
Quitosano , Cromo , Imidazoles , Polímeros , Sulfonas , Contaminantes Químicos del Agua , Purificación del Agua , Quitosano/química , Cromo/aislamiento & purificación , Cromo/química , Sulfonas/química , Adsorción , Contaminantes Químicos del Agua/química , Contaminantes Químicos del Agua/aislamiento & purificación , Imidazoles/química , Polímeros/química , Purificación del Agua/métodos , Concentración de Iones de Hidrógeno , Cinética , Aguas Residuales/química , Carbodiimidas/química , Agua/química , Soluciones , Microesferas
20.
Talanta ; 280: 126748, 2024 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-39180875

RESUMEN

This study reports for the first time the phenomenon of supramolecular solvent formation based on alkyl polyglucoside as an amphiphile and primary alcohol as a coacervation agent. The physical properties (density, kinematic viscosity, phase diagram for ternary system) of the supramolecular solvent were investigated, and a mechanism for its formation was proposed. A green and simple microextraction procedure for preconcentration and determination of phthalates in baby foods packaged in plastic packaging was developed as proof-of-concept example. The microextraction procedure assumed separation of analytes from solid phase sample in micellar solution of decyl glucoside and in situ formation of supramolecular solvent for analytes preconcentration after addition of n-heptanol. The determination of phthalates in obtained extracts was implemented by high-performance liquid chromatography with UV-Vis detection. The limits of detection, calculated from a blank test based on 3σ, were determined to be 10 µg kg-1 for dimethyl phthalate, diethyl phthalate, di-n-butyl phthalate, and di-n-octyl phthalate. The developed procedure did not require filtration of sample suspension, and assumed the use of green and biodegradable substances for the supramolecular solvent formation across a wide pH range.


Asunto(s)
Alimentos Infantiles , Micelas , Ácidos Ftálicos , Solventes , Ácidos Ftálicos/análisis , Ácidos Ftálicos/química , Solventes/química , Cromatografía Líquida de Alta Presión/métodos , Alimentos Infantiles/análisis , Glucósidos/análisis , Glucósidos/química , Glucósidos/aislamiento & purificación , Microextracción en Fase Líquida/métodos , Humanos , Alcoholes/análisis , Alcoholes/química , Soluciones , Contaminación de Alimentos/análisis
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