Search Results (430)

Bacterial membrane vesicle (BMV) nanoparticles are secreted naturally by bacteria throughout their lifecycle and are a rich source of biomarkers from the parent bacteria, but they are currently underutilized for clinical diagnostic applications, such as pathogen identification, due to the time-consuming and low-yield nature of traditional recovery methods required for analysis. The recovery of BMVs is particularly difficult from complex biological fluids. Here, we demonstrate a recovery method that uses dielectrophoretic (DEP) forces generated on electrokinetic microfluidic chips to isolate and analyze BMVs from human plasma. DEP takes advantage of the natural difference in dielectric properties between the BMVs and the surrounding plasma fluid to quickly and consistently collect these particles from as little as 25 µL of plasma. Using DEP and immunofluorescence staining of the LPS biomarker carried on BMVs, we have demonstrated a lower limit of detection of 4.31 × 10⁹ BMVs/mL. The successful isolation of BMVs from human plasma using DEP, and subsequent on-chip immunostaining for biomarkers, enables the development of future assays to identify the presence of specific bacterial species by analyzing BMVs from small amounts of complex body fluid. Full article

Disease’s severity, mortality rates, and common failures to achieve clinical improvement during the unprecedented COVID-19 pandemic exposed the emergency need for new antiviral therapeutics with higher efficacy and fewer adverse effects. This study explores the potential to encapsulate multi-component plant extracts in liposomes as optimized delivery systems and to verify if they exert inhibitory effects against human seasonal betacoronavirus OC43 (HCoV-OC43) in vitro. The selection of Sambucus nigra, Potentilla reptans, Allium sativum, Aesculus hippocastanum, and Glycyrrhiza glabra L. plant extracts was based on their established pharmacological and antiviral properties. The physicochemical characterization of extract-loaded liposomes was conducted by DLS and electrokinetics. Encapsulated amounts of the extract were evaluated based on the total flavonoid content (TFC) and total polyphenol content (TPC) by colorimetric methods. The BALB 3T3 neutral red uptake (NRU) phototoxicity/cytotoxicity assay was used to estimate compounds’ safety. Photo irritation factors (PIFs) of the liposomes containing extracts were <2 which assigned them as non-phototoxic substances. The antiviral capacities of liposomes containing medicinal plant extracts against HCoV-OC43 were measured by the cytopathic effect inhibition test in susceptible HCT-8 cells. The antiviral activity increased by several times compared to “naked” extracts’ activity reported previously. A. hippocastanum extract showed 16 times higher inhibitory properties reaching a selectivity index (SI) of 58.96. Virucidal and virus-adsorption effects were investigated using the endpoint dilution method and ∆lgs comparison with infected and untreated controls. The results confirmed that nanoparticles do not directly affect the viral surface or cell membrane, but only serve as carriers of the active substances and the observed protection is due solely to the intracellular action of the extracts. Full article

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

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

A method to determine aceclofenac, ketorolac, and sulindac in human urine samples using microemulsion electrokinetic chromatography (MEEKC) has been developed in this study. The optimization of MEEKC conditions was carried out by changing the microemulsion compositions including the buffer pH, borate salt concentration, surfactant concentration, co-surfactant concentration, organic modifier concentration, and oil droplet concentration. The optimum separation of selected drugs was obtained with a composition of microemulsion containing 10 mM borate buffer pH 9, 0.5% sodium dodecyl sulphate (SDS), 6.6% n-butanol, 6.0% acetonitrile, and 0.8% ethyl acetate. Excellent linearity was obtained in the range concentration of 25 to 200 ppm with r² > 0.999. Limits of detection (LOD, S/N = 3) and limits of quantification (LOQ, S/N = 10) were 2.72 to 4.75 and 9.08 to 15.85 ppm, respectively. The solid-phase extraction (SPE) method using C-18 as an adsorbent and the solid phase micro-tip extraction (SPMTE) method using multiwalled carbon nanotubes (MWCNTs) as an adsorbent were used to clean-up and pre-concentrate the urine samples prior to the MEEKC analysis. The best recoveries of the selected drugs in the spiked urine sample were 91 to 103% with RSD of 1.26 to 4.03% (n = 3) using the SPE-MEEKC method. Full article

Soil restoration by exploiting the principles and basics of electrokinetic (EK) has been extended to involve several categories, such as electrokinetic remediation in soil (SEKR), soil consolidation, the prevention of soil pollution, reclaiming salt-affected soil, the dewatering/dryness of wet soils, water reuse, seed germination, sedimentation, etc. As an extension of our recently published review articles on the soil electrokinetic (SEK) process intensification/optimization, the present review illustrates the effect of a reverse-polarity mode (RPM) on the efficiency of the SEK. Based on several searches of six database search engines, we did not find any relevant reviews focused on SEK improvements using the RPM. The influences of the RPM are described by various features, including (a) pollutant removal (organic, inorganic, and mixed pollutants) and (b) integration with other processes (phyto/bioremediation and Fenton oxidation), geosynthetics (consolidation, stabilization, and sedimentation), SEK operation conditions, and soil properties. Most of the RPM studies have focused on the remediation of organic pollutants. Several benefits can be gained from applying the RPM, such as (a) controlling the soil’s temperature, pH, and moisture values at desirable levels, (b) reducing a large number of chemical additives, (c) high remediation efficiency, (d) maintaining the indigenous fungal community’s appropriate diversity and abundance, (e) a stable and higher electric current, (f) enhancing microbial growth, etc. However, the hindrances to applying the RPM are (a) reducing the electroosmosis flow, (b) relatively high energy consumption, (c) reducing the diversity of soil microbes with a prolonged experiment period, (d) providing oxygen for a microbial community that may not be desirable for anaerobic bacteria, etc. Finally, the RPM is considered an important process for improving the performance of the SEK, according to experimental endeavors. Full article

Electrokinetic remediation (EKR) has shown great potential for the remediation of in situ contaminated soils. For heavy metal-contaminated soft clay with high moisture content and low permeability, an electrokinetic remediation method with electrolytes placed above the ground surface is used to avoid issues such as electrolyte leakage and secondary contamination that may arise from directly injecting electrolytes into the soil. In this context, using this novel experimental device, a set of citric acid (CA)-enhanced EKR tests were conducted to investigate the optimal design parameters for Cu- and Zn-contaminated soft clay. The average removal rates of heavy metals Cu and Zn in these tests were in the range of 27.9–85.5% and 63.9–83.5%, respectively. The results indicate that the Zn removal was efficient. This was determined by the migration intensity of the electro-osmotic flow, particularly the volume reduction of the anolyte. The main factors affecting the Cu removal efficiency in sequence were the effective electric potential of the contaminated soft clay and the electrolyte concentration. Designing experimental parameters based on these parameters will help remove Cu and Zn. Moreover, the shear strength of the contaminated soil was improved; however, the degree of improvement was limited. Low-concentration CA can effectively control the contact resistance between the anode and soil, the contact resistance between the cathode and soil, and the soil resistance by increasing the amount of electrolyte and the contact area between the electrolyte and soil. Full article

The toxicity of silver nanoparticles (AgNPs) depends on their physicochemical properties. The ongoing research aims to develop effective methods for modifying AgNPs using molecules that enable control over the processes induced by nanoparticles in both normal and cancerous cells. Application of amino acid-stabilized nanoparticles appears promising, exhibiting tunable electrokinetic properties. Therefore, this study focused on determining the influence of the surface charge of cysteine (CYS)-stabilized AgNPs on their toxicity towards human normal B (COLO-720L) and T (HUT-78) lymphocyte cell lines. CYS-AgNPs were synthesized via the chemical reduction. Transmission electron microcopy (TEM) imaging revealed that they exhibited a quasi-spherical shape with an average size of 18 ± 3 nm. CYS-AgNPs remained stable under mild acidic (pH 4.0) and alkaline (7.4 and 9.0) conditions, with an isoelectric point observed at pH 5.1. Following a 24 h treatment of lymphocytes with CYS-AgNPs, concentration-dependent alterations in cell morphology were observed. Positively charged CYS-AgNPs notably decreased lymphocyte viability. Furthermore, they exhibited grater genotoxicity and more pronounced disruption of biological membranes compared to negatively charged CYZ-AgNPs. Despite both types of AgNPs interacting similarly with fetal bovine serum (FBS) and showing comparable profiles of silver ion release, the biological assays consistently revealed that the positively charged CYS-AgNPs exerted stronger effects at all investigated cellular levels. Although both types of CYS-AgNPs have the same chemical structure in their stabilizing layers, the pH-induced alterations in their surface charge significantly affect their biological activity. Full article

The aim of the study was to compare the effects and mechanism of tetrasodium pyrophosphate (TSPP) and sodium tripolyphosphate (STPP) as dispersants on the selective flotation of arsenopyrite from muscovite. The results of single-mineral flotation showed that the recovery of arsenopyrite was 81.4% when no dispersant was added. The recovery of arsenopyrite slightly decreased with increasing dosage of TSPP. When the dosage of STPP was 6 × 10⁻⁵ mol/L, the recovery of arsenopyrite was only 28.6%. Neither of the dispersants had significant influence on the muscovite flotation (<10%). However, in a mixed-mineral system, the recovery of arsenopyrite dropped significantly, and then under the action of dispersants, its recovery back up. The RPM results showed that the dispersion effect of TSPP was superior to that of STPP. The electrokinetic potential showed that the potential change value of muscovite with TSPP was −17.37 mV, while that of muscovite with STPP was −8.33 mV (pH = 8). The adsorption of TSPP onto muscovite was stronger than that of STPP. FTIR and XPS analysis confirmed that dispersants exhibited chemical adsorption with the Al atoms on muscovite and that dispersant STPP exhibited stonger adsorption than TSPP on arsenopyrite, which was consistent with flotation experiments. Full article

The kinetics of amyloid aggregation was studied indirectly by monitoring the changes in the polydispersity of mixed dispersion of amyloid β peptide (1-40) and composite liposomes. The liposomes were prepared from the 1,2-dioleoyl-sn-glicero-3-phoshocholine (DOPC) phospholipid and stabilised by the electrostatic adsorption of κ-carrageenan. The produced homotaurine-loaded and unloaded liposomes had a highly negative electrokinetic potential and remarkable stability in phosphate buffer (pH 4 and 7.4). For the first time, the appearance and evolution of the aggregation of Aβ were presented through the variation in the standard percentile readings (D10, D50, and D90) obtained from the particle size distribution analysis. The kinetic experiments indicated the appearance of the first aggregates almost 30 min after mixing the liposomes and peptide solution. It was observed that by adding unloaded liposomes, the size of 90% of the particles in the dispersion (D90) increased. In contrast, the addition of homotaurine-loaded liposomes had almost minimal impact on the size of the fractions of larger particles during the kinetic experiments. Despite the specific bioactivity of homotaurine in the presence of natural cell membranes, this study reported an additional inhibitory effect of the compound on the amyloid peptide aggregation due to the charge effects and ‘molecular crowding’. Full article

Human serum albumin (HSA) corona formation on polymer microparticles of a spheroidal shape was studied using dynamic light scattering and Laser Doppler Velocimetry (LDV). Physicochemical characteristics of the albumin comprising the zeta potential and the isoelectric point were determined as a function of pH for various ionic strengths. Analogous characteristics of the polymer particles were analyzed. The adsorption of albumin on the particles was in situ monitored by LDV. The stability of the HSA-functionalized particle suspensions under various pHs and their electrokinetic properties were also determined. The deposition kinetics of the particles on mica, silica and gold sensors were investigated by optical microscopy, AFM and quartz microbalance (QCM) under diffusion and flow conditions. The obtained results were interpreted in terms of the random sequential adsorption model that allowed to estimate the range of applicability of QCM for determining the deposition kinetics of viruses and bacteria at abiotic surfaces. Full article

Label-free optical biosensors, such as interferometers, can provide a comparable limit of detection to widely used enzyme-linked immunosorbent assays while minimizing the number of steps and reducing false positives/negatives. In 2020, the authors reported on a novel optofluidic Young interferometer (YI) that could provide real-time spatial information on refractive index changes occurring along the length of the sensor and reference channels. Herein, we exploit these features of the YI to study interactions of biomolecules with recognition elements immobilized in selected regions of agarose gel in the sensor channel. We show that the YI is well suited for the biosensing of an exemplar biomolecule, streptavidin, in the absence and presence of the bovine serum albumin interferent. Equally, we couple the YI with electrokinetic transport to reduce the time needed for biosensing. Full article

The sedimentation of a soft particle composed of an uncharged hard sphere core and a charged porous surface layer inside a concentric charged spherical cavity full of a symmetric electrolyte solution is analyzed in a quasi-steady state. By using a regular perturbation method with small fixed charge densities of the soft sphere and cavity wall, a set of linearized electrokinetic equations relevant to the fluid velocity field, electrical potential profile, and ionic electrochemical potential energy distributions are solved. A closed-form formula for the sedimentation velocity of the soft sphere is obtained as a function of the ratios of core-to-particle radii, particle-to-cavity radii, particle radius-to-Debye screening length, and particle radius-to-porous layer permeation length. The existence of the surface charge on the cavity wall increases the settling velocity of the charged soft sphere, principally because of the electroosmotic enhancement of fluid recirculation within the cavity induced by the sedimentation potential gradient. When the porous layer space charge and cavity wall surface charge have the same sign, the particle velocity is generally enhanced by the presence of the cavity. When these fixed charges have opposite signs, the particle velocity will be enhanced/reduced by the presence of the cavity if the wall surface charge density is sufficiently large/small relative to the porous layer space charge density in magnitude. The effect of the wall surface charge on the sedimentation of the soft sphere increases with decreases in the ratios of core-to-particle radii, particle-to-cavity radii, and particle radius-to-porous layer permeation length but is not a monotonic function of the ratio of particle radius-to-Debye length. Full article

The preparation of pellets using a high-shear granulator in a rapid single-step is considered a good economic alternative to the extrusion spheronization process. As process parameters and material attributes greatly affect pellet qualities, successful process optimization plays a vital role in producing pellet dosage forms with the required critical quality attributes. This study was aimed at the development and optimization of the pelletization technique with the Pro-CepT granulator. According to the quality by design (QbD) and screening design results, chopper speed, the volume of the granulating liquid, binder amount, and impeller speed were selected as the highest risk variables for a two-level full factorial design and central composite design, which were applied to the formula of microcrystalline cellulose, mannitol, and with a binding aqueous polyvinylpyrrolidone solution. The design space was estimated based on physical response results, including the total yield of the required size, hardness, and aspect ratio. The optimized point was tested with two different types of active ingredients. Amlodipine and hydrochlorothiazide were selected as model drugs and were loaded into an optimized formulation. The kinetics of the release of the active agent was examined and found that the results show a correlation with the electrokinetic potential because amlodipine besylate can be adsorbed on the surface of the MCC, while hydrochlorothiazide less so; therefore, in this case, the release of the active agent increases. The research results revealed no significant differences between plain and model drug pellets, except for hydrochlorothiazide yield percent, in addition to acceptable content uniformity and dissolution enhancement. Full article

In recent years, with the escalation of food waste generation, stringent legal constraints on landfill usage and incineration have necessitated the exploration of alternative disposal methods, augmenting interest in diverse recycling strategies. Notably, carbonized food waste (CFW), a byproduct of food waste carbonization, has emerged as an efficacious adsorbent for pollutant removal. This study focuses on the application of in situ remediation techniques, specifically electrokinetic (EK) remediation combined with enhancers, to decontaminate soil afflicted with single or multiple heavy metals. The utilization of a permeable reactive barrier (PRB) infused with CFW aims to mitigate secondary environmental repercussions, including the propagation of contaminants in soil and groundwater. Experiments were conducted on clay samples contaminated with copper, lead, or a combination thereof. Observations revealed that the current density peaked during the initial 1–2 days of the experiment, experienced a resurgence post-electrode exchange, and subsequently diminished. The efficacy of metal removal was predominantly pronounced for copper, with remediation rates ranging from 85% to 92% in singly contaminated samples and 75% to 89% in dually contaminated samples after a 10-day treatment period, incorporating an electrode exchange on the eighth day. Conversely, the efficacy of lead removal was markedly lower, with rates of 0.6% to 33% in singly contaminated samples and 14% to 25% in combined contamination scenarios, suggesting the necessity for extended treatment durations. The post-experimental moisture content indicated successful enhancer injection. Additionally, pH measurements affirmed that heavy metals migrated effectively within the sample matrix, facilitated by the EK phenomenon after the electrode exchange. This study highlights the potential of CFW within PRBs for the remediation of heavy metal-contaminated soils, although the removal efficiencies between different metals is variable, emphasizing the need for tailored approaches in the treatment of lead-contaminated environments. Full article