Colloidal Solution Research Articles

Electrical bioimpedance analysis and comparison in biological tissues through crystalloid solutions implementation

Electrical bioimpedance is a non-invasive and radiation-free technique that was proposed to be used in different clinical areas, however, its practical use is limited due to its low capacity to discriminate between tissues. In order to overcome this limitation, our research group proposes to incorporate the contrast media into the electrical bioimpedance procedure. The main objective of the present study was to assess the crystalloid solutions as a possible contrast media to discriminate between different tissue types in the bioimpedance technique. Two medical-grade crystalloid solutions (Hartmann and NaCl 0.9%) were injected into three biological ex vivo models: kidney, liver, and brain. BIOPAC system was used to acquire bioimpedance data before and after the injections. The data was adjusted to the Debye electrical model. The analysis of measured values showed substantial bioimpedance disparities in tissues subjected to isotonic solutions. The NaCl solution exhibited more pronounced changes in electrical parameters compared to the Hartmann solution. Similarly, NaCl solution displayed superior discriminatory capabilities among tissues, with variations of 465%, 157%, and 206%. Distinct spectral modifications were identified, with tissues demonstrating unique responses at each frequency of analysis relative to untreated tissue. Variations in bandwidth alterations were discernible among tissues, providing clear distinctions. In conclusion, the research showed that the crystalloid solution exhibited greater sensitivity and superior tissue contrast at specific frequencies. This study's findings underscore the feasibility of implementing crystalloid solutions to enhance tissue discrimination, similar to the effects of contrast agents.

A new bodipy/pillar[5]arene functionalized magnetic sporopollenin for the detection of Cu(II) and Hg(II) ions in aqueous solution

In this study, a new bodipy/pillar[5]arene functionalized magnetic MS-Sp-P[5]-bodipy microcapsule sensor was prepared based on the use of environmentally friendly for the selective and sensitive detection of Cu(II) and Hg(II) ions in aqueous media. SEM results used in the characterization process of the materials synthesized at each stage confirmed the structural and morphological changes in the pore structure, while other characterization results (FT-IR and XRD) elucidated the role of pillar[5]arene compound and bodipy dye in the synthesis of magnetic microcapsule sensors. The colloidal solution of MS-Sp-P[5]-bodipy (water/ethanol)) showed two fluorescence bands centered at 402 and 540 nm. The detection limits of MS-Sp-P[5]-bodipy for Hg(II) and Cu(II) were calculated to be 0.06 µM and 2.27 µM, respectively (at 540 nm). The linear range of the magnetic sensor for Hg(II) and Cu(II) was found to be in the range of 1–150 µM and 10–150 µM, respectively. The experimental results (response time, pH, temperature, sensitivity and selectivity) demonstrated the applicability and potential of the prepared magnetic microcapsule sensor for the detection of Cu(II) and Hg(II) in water and tap water samples containing heavy metal ions.

Establishment of a Colloidal Gold Immunochromatographic Method for the Detection of Cypermethrin in Tobacco.

In this study, the establishment of a colloidal gold immunochromatographic method for the detection of cypermethrin in tobacco was achieved by using colloidal gold immunochromatography: strong specificity and high sensitivity of cypermethrin semi-antigens and encapsulants were prepared during the study. The best colloidal gold solution was prepared by spectrophotometer and transmission electron microscope screening; the preparation process of gold-labeled antibodies was optimized, and finally the product of colloidal gold rapid detection test strips for cypermethrin was developed. The results of technical parameters and detection indexes showed that the detection limit of cypermethrin in tobacco was 1 mg/kg, and there was no cross-reaction with bifenthrin, cypermethrin, cyfluthrin and phenothrin, and the detection results of 30 tobacco samples were consistent with those of gas chromatography.

Gold nanoparticles coated with PVP as a novel colorimetric sensor for sensitive and selective determination of Atenolol

In this work, gold nanoparticles coated with polyvinylpyrrolidone (PVP-AuNPs) were used as a colorimetric probe for the sensitive, selective, simple, and rapid determination of atenolol (ATN). Indeed, atenolol triggered the aggregation of PVP-AuNPs via hydrogen bonding, electrostatic interactions, and dipole-dipole forces with PVP on the surface of AuNPs, causing the colloidal solution's color to shift from red to blue. SEM, TEM, FT-IR, UV–Vis, zeta potential, and other methods were used to characterise the PVP-AuNPs that were created as well as their aggregates. An excellent linear relationship between the absorption ratio (A690/A521) and the concentration of ATN in the range of 0.07–3.0 μM with a detection limit of 0.023 μM was discovered by optimising the experimental settings. The influence of potential interfering species on the measurement of ATN was investigated, and it was discovered that the developed colorimetric sensor had satisfactory selectivity. Finally, the presented method was used to measure ATN in tablet and blood plasma samples, and the obtained recovery values showed great promise for the use of the proposed sensor in clinical applications.

White‐Color Generation Using Blue Top‐Emission Organic Light‐Emitting Diode and Nanocrystalline Materials

White light is of great technical interest in many photonic applications. In this work, colloidal solutions containing mutually immiscible green perovskite nanocrystals and red InP quantum dots are developed as color‐conversion (CC) materials for generating white light. By combining the green/red CC materials and a blue top‐emission organic light‐emitting diode as an excitation source, it is possible to generate white light with a range of color temperatures (CTs). The technical approach can be extended to a wide variety of photonic applications where controllable CT is desirable.

Ultrathin nanolayer constituted by a natural polysaccharide achieves “egg-box” structured SnO2 nanoparticles toward efficient and stable perovskite solar cells

Notorious nonradiative recombination and retarded charge dynamics corrodes the performance of perovskite solar cells (PSCs). Accordingly, a natural polysaccharide sodium alginate (SA) is introduced into SnO2 colloid solution, developing “egg-box” structured SnO2 nanoparticles wrapped by ultrathin SA nanolayer to achieve a bottom-up holistic passivation strategy. The active oxygen-containing functional groups with lone pair electrons of SA can coordinate with uncoordinated Sn4+/Pb2+. Meanwhile, hydroxyl groups can form hydrogen bonds with I of perovskite. Additionally, Na+ can fill the cation vacancies in perovskite and electrostatically interacts with the halogen ions, hindering the formation of iodine Frenkel defects. Based on the synergistic effects of various functional groups, SA-modification can simultaneously inhibit the agglomeration of SnO2 nanoparticles, improve carrier dynamics, release tensile stress and promote crystallization of perovskite. Finally, the SA-optimized methylammonium-free (MA-free) device fabiricated entirely in ambient air achieves a champion efficiency up to 23.61%. The optimized devices without encapsulation exhibit better thermal and moisture stability, with the PCE retaining 80.2% of its initial efficiency after 1080 h of thermal aging at 60 °C and 91.1% of its initial efficiency after 1440 h at 25% relative humidity, respectively.

Silane-modified bentonite clay-coated membrane development on ceramic support for oil/water emulsion separation using tuning of hydrophobicity

Bentonite clay-coated and silane-modified hydrophobic composite membranes were prepared on the ceramic support by facile sol-gel deposition route to effectively separate various oil-water colloidal solutions. This study explores the correlation of silane content involved in optimizing and modifying surface hydrophobicity, membrane pore characteristics, and the solvent permeation properties in terms of oil permeation rate and water rejection (%) in oil-water emulsion solutions. Membrane surface modifications with relatively higher silane content (∼15%) reduced the membrane pores extensively, increasing the water rejection properties but the oil flux was reduced modestly. The oil flux increases with the introduction of reduced silane content (∼2%) but the water rejection properties were compromised. Silane: solvent ratio of 1:100 (silane loading ∼10%) proved to be efficient for the separation (94–99%) of various hydrocarbons such as hexane, toluene, cyclohexane, and heptane from emulsified solutions with permeate flux of 25–40 Lm−2h−1. Cake filtration model was found suitable to explain the membrane fouling. The optimized membrane also recorded a minimal loss of hydrophobicity and mechanical strength enduring oil atmosphere and corrosive environments. The overall study supported by suitable physicochemical material characterizing techniques reveals that optimizing silane concentration in bentonite-based clay composite membrane surface modification can be an effective oil/water separation strategy.

Revisiting the Use of Normal Saline for Peritoneal Washing in Ovarian Cancer.

The omentum is the predominant site of ovarian cancer metastasis, but it is difficult to remove the omentum in its entirety. There is a critical need for effective approaches that minimize the risk of colonization of preserved omental tissues by occult cancer cells. Normal saline (0.9% sodium chloride) is commonly used to wash the peritoneal cavity during ovarian cancer surgery. The omentum has a prodigious ability to absorb fluid in the peritoneal cavity, but the impact of normal saline on the omentum is poorly understood. In this review article, we discuss why normal saline is not a biocompatible solution, drawing insights from clinical investigations of normal saline in fluid resuscitation and from the cytopathologic evaluation of peritoneal washings. We integrate these insights with the unique biology of the omentum and omental metastasis, highlighting the importance of considering the absorptive ability of the omentum when administering agents into the peritoneal cavity. Furthermore, we describe insights from preclinical studies regarding the mechanisms by which normal saline might render the omentum conducive for colonization by cancer cells. Importantly, we discuss the possibility that the risk of colonization of preserved omental tissues might be minimized by using balanced crystalloid solutions for peritoneal washing.

Primary amine citrate-based supramolecular designer solvent: Preconcentration of ochratoxin A for determination in foods by liquid chromatography

BackgroundSupramolecular solvents are nanostructured liquids that are separated from colloidal solutions of amphiphilic compounds as a result of self-assembly of amphiphiles and coacervation under changing conditions. They are considered to be designer solvents as their properties can be tailored to a specific analytical task by controlling the conditions of their formation (amphiphile, coacervation inducer, medium, concentration of components). The discovery of new extraction systems based on supramolecular solvents and their application to relevant analytical tasks are of great importance for the advancement of environmentally-friendly sample preparation. ResultsA novel green liquid-phase microextraction approach involving in situ formation of 1-octylamine citrate followed by preconcentration of ochratoxin A from aqueous extract of food sample in supramolecular solvent droplets was developed. The extraction system was carefully characterized. The density of the solvent allowed it to be to retrieved from the extraction system by its solidification. The alkaline nature of the obtained extract allowed the use of acetic acid for its dissolution instead of more toxic organic solvents followed by high-performance liquid chromatography with fluorometric detection. An excellent extraction recovery of 99 % and a satisfactory enrichment factor of 8.3 were achieved. The limit of detection was 0.5 μg kg−1, while the calibration plot was linear over the range of 1.5–50 μg kg−1. Cereal and roasted coffee bean samples were successfully analyzed with a relative bias less than 20 %. SignificanceIn the present work, a phenomenon of supramolecular solvent formation based on primary amine citrate was presented for the first time. Tetrabutylammonium bromide was investigated as a coacervation agent in an extraction system, and possible interactions responsible for its ability to induce phase separation in a micellar solution of primary amine citrate were described. The critical micelle concentration of 1-octylamine citrate in aqueous solution of tetrabutylammonium bromide was firstly determined.

AN IMPACT OF THE LASER IRRADIATION TIME ON PROPERTIES OF COLLOIDAL SOLUTIONS OF SILICON NANOPARTICLES

The design of semiconductor-metallic nanostructures using pulsed laser ablation in liquids (PLAL) is a very demanding task for biomedical applications being at an early stage of its development. Only few recent papers show the possibility of such a synthesis of composite nanoparticles as well as their perspectives for biosensing applications. However, mechanisms of the laser-stimulated formation of semiconductor-metallic nanoparticles involving several processes are not clarified yet being considerably depended on experimental conditions. In this work, we demonstrated an impact of the laser irradiation of colloidal solutions of silicon nanoparticles at different exposure time in the presence/absence of a gold target. In particular, longer ablation of the metal led to a stronger plasmonic maximum in silicon nanoparticles at around 520 nm. It also decreased the hydrodynamic size from 165 nm to 85 nm as well as the ξ-potential from –46 mV to –30 mV by increasing the ablation time from 0 s to 600 s. At the same time, the lowest electrical conductivity value (~1.5 µS/cm) of the plasmonic nanocomposites was detected at 120 s irradiation time. The highest concentration of synthesized composite nanoparticles (~3·1011 NPs/mL) was achieved at 180 s ablation time. Another purpose of the paper was to reveal an influence of the used laser irradiation on properties of the colloidal solutions of silicon nanoparticles themselves. It was found a considerable decrease of their absorbance with the increase of the laser exposure time that can be associated with the change of their properties (e.g. concentration, size, oxidation state etc.). Thus, the laser irradiation strongly affects properties of colloidal solutions of silicon nanoparticles that must also be taken into account considering possible mechanisms of the formation of composite nanostructures. Presented in the paper fast optical diagnostic can help to determine properties of colloidal solutions of nanocomposites formed by PLAL prior their biomedical or catalytic applications.

Emergence and inversion of chirality in hierarchical assemblies of CdS nanocrystal fibers.

Arranging semiconducting nanocrystals into ordered superstructures is a promising platform to study fundamental light-matter interactions and develop programmable optical metamaterials. We investigated how the geometrical arrangement of CdS nanocrystals in hierarchical assemblies affects chiroptical properties. To create these structures, we controlled the evaporation of a colloidal CdS nanocrystal solution between two parallel plates. We combined in situ microscopy and computational modeling to establish a formation mechanism involving the shear-induced alignment of nanocrystal fibers and the subsequent mechanical relaxation of the stretched fibers to form Raman noodle-type band textures. The high linear anisotropy in these films shares many similarities with cholesteric liquid crystals. The films deposited on top and bottom surfaces exhibit opposite chirality. The mechanistic insights from this study are consequential to enable future advances in the design and fabrication of programmable optical metamaterials for further development of polarization-based optics toward applications in sensing, hyperspectral imaging, and quantum information technology.

Blood cardioplegia may be better than crystalloid cardioplegia during cardiac surgery for infective endocarditis

Abstract Background Cardioplegia is an indispensable element in cardiac surgery for left sided infective endocarditis (IE). Crystalloid cardiolegia (CC) as a single or dual-dose is more attractive in complicated IE surgery than repeated, every 15-20 min, administration of blood cardioplegia (BC). Recently, blood cardioplegia was shown to reduce the systemic inflammatory response to cardiopulmonary (CPB) compared to crystalloid cardioplegia. As the systemic inflammatory response after surgery for IE endocarditis is more exaggerated than in non-IE valve surgery, it is important to investigate impact of the two solutions on outcome after IE surgery. Methods We retrospectively analyzed data of all patients (n=581) with endocarditis who underwent cardiac valve surgery at our institution between January 2007 and March 2018. The primary endpoint was 30-day mortality, secondary endpointwas the length of intensive care unit (ICU) stay. Nearest neighbor propensity matching with a caliper of 0.01 was performed to adjust for differences in basal characteristics between patients who received Calafiore BC vs Bretschneider CC. Results Patients who received CC were older (67 vs 63, p<0.01) had greater incidence of large vegetations (42.7% vs 32.3%, p<0.01), prosthetic valve endocarditis (30.8% vs 17.3%, p<0.01) and mitral valve endocarditis (54.6 vs 43.6 p<0.01). Logistic regression in the raw data revealed a higher mortality rate and longer LOS in ICU for the patients who received CC. After matching, CC was still associated with higher 30-day mortality (24.4% vs 15.9%, p=0.01) and longer ICU-stay (median: 6, IQR: 9 vs median: 3, IQR: 6, p<0.01). Conclusions Administration of blood cardioplegia during cardiac surgery for infective endocarditis may be associated with lower 30-day mortality and shorter ICU-stay compared to using crystalloid solution.

Taming the coffee-ring effect on solid surface by localized heating upon the suspension droplet

Coffee-ring effect is a very common phenomenon in our daily life, especially in the evaporation process of colloidal solutions on solid surfaces. However, in processes such as inkjet printing, this effect can change the uniformity of the deposited film, thus affecting the quality of the printed products. In this paper, a facile and convenient method of localized heating of liquid droplets by using a tiny steel wire is proposed. The results indicated that this method can effectively suppress the generation of coffee-ring effect, and the deposition morphology of the suspended particles can be adjusted by controlling the applied temperature, wire diameter and the distance from the wire to the droplet. And it was found that the heated wire-induced inward flows caused by the temperature gradient of the droplet are the main reason for adjusting the deposition morphology. The coffee-ring effect is mainly controlled by the free convection from the edge to the center caused by the evaporation loss of the solution, so as to adjust the distribution of suspended particles in the evaporating droplet and thus achieve the goal of suppressing the coffee-ring effect. This method has no special requirements for the substrate and droplet solution, and it is expected to be universally applicable to uniform deposition of colloidal solutions.

Influence of shear direction on gelation ability of colloidal chitosan solutions

Influence of shear direction on gelation ability of colloidal chitosan solutions

Lamellar particle self-assembling of graphene oxide into continuous thin and thick films by automated atmospheric pressure plasma jet deposition

This work shows the achievement of obtaining graphene oxide coatings deposited under ambient conditions using the plasma jet technique at atmospheric pressure in an automated system with robotic arms. Graphene oxide nanoparticles in an aqueous solution were sonicated to obtain a colloidal solution. This was projected in an ultrasonic mist perpendicularly through an air plasma of about 260 °C. The primary process parameters were deposition time, speed, concentration, and distance to obtain coating thickness from about 100 nm to microns. These were homogeneous and adherent coatings on aluminum, steel, glass, and polymers (PMMA and polycarbonate), showing similar characteristics on all these substrates. The highlight of this contribution is transforming nanometric thickness flakes into continuous layers with chemical bonding to surfaces with contrasting characteristics such as those mentioned. The GO obtained layer differs from those obtained by spin-coating, dipping, drop-casting, or electrophoretic deposition. We propose that APPJ eliminates OH radicals around the particles, allowing them to self-assemble by connecting them through bonds. This work probes the feasibility of depositing horizontally/vertically self-assembled GO on polymers and aluminum in a modular industrial facility. This achievement opens the possibility of transferring the characteristics of graphene oxide to surfaces for industrial use, making nanotechnology accessible for social benefit.

Nanogold-Bound Copper Complexes and Their Various Applications: A Review Article

The term "nano gold," also known as "gold nanoparticles," is commonly used. These particles are extremely small, with a diameter of less than 100 nm, which is only a fraction of the width of a human hair. Due to their tiny size, nano gold particles are often found in a colloidal solution, where they are suspended in a liquid stabilizer. This colloidal gold is essentially another name for nano gold. The main method for producing gold nanoparticles in a colloidal solution is the citrate synthesis technique, which involves combining different solutions to precipitate the gold nanoparticles[1-5]. In biological systems, copper complexes play a significant role at the active sites of many metalloproteins. These complexes have potential applications in various catalytic processes that occur in living organisms, such as electron transfer reactions and the activation of specific antitumor substances. These processes are relevant in the fields of medicinal chemistry and bioinorganic chemistry. The interaction of copper chelates with biological systems and their noteworthy activities against neoplastic, bacterial, fungal, and cancerous cells are also important. Many copper (II) N, S, O / N, N-donor chelators function as effective anticancer agents due to their ability to bind with DNA base pairs[6-10]. Using hydrophilic gold nanoparticles (AuNPs) as carriers for copper complexes is a novel and purposeful strategy that Could raise these compounds' stability and solubility in H2O aqueous., thus enhancing their bioavailability. The regulated release of Cu-complexes made possible by this method also creates the possibility for fruitful in vivo and in vitro tests. The definition, significance, and numerous applications of copper complexes in connection to nanogold are presented in this review study[11-15].

High-Precision Optical Excited Heaters Based on Au Nanoparticles and Water-Soluble Porphyrin

Gold nanoparticles are widely used as local heaters under optical excitation. Hybrid molecular-plasmon nanostructures based on gold nanoparticles and water-soluble porphyrin have been developed. A colloidal solution of gold nanoparticles was obtained by laser ablation of metallic gold in water, ensuring its highest chemical purity. The hybrid nanostructures formation was performed due to the Coulomb interaction of cationic porphyrin and gold nanoparticles. The revealed functional properties of hybrid nanostructures make them promising for controllable nano-heater applications (for example, photothermal therapy). Gold nanoparticles act as heaters, whereas porphyrin serves as a fluorescent thermometer with a single optical excitation.

Viscoelastic effect on the triple diffusive oscillatory flow in a fluid-saturated porous layer

The combined heat and mass transfer, the so-called thermosolutal convective problem, has become an attractive field of research in many diversified areas. In this paper, for the first time, oscillatory flow analysis has been carried out for triple diffusive viscoelastic fluid flow in a porous medium. A comprehensive model is developed for the modified Darcy–Brinkman–Oldroyd-B fluid, porous medium, Boussinesq approximation, heat and mass transfer across a finite temperature and concentration difference in the chemical potential of two salts. Triple diffusive viscoelastic fluid flows through porous media have grown significantly as this situation occurs in more than a few applications such as improved oil recovery filtration, liquid complex molding, solidification of liquid crystals, cooling of metallic plate in a bath, exotic lubricants and colloidal solutions, polymer processing, chemical and bioengineering industries, among others. The governing coupled nonlinear partial differential equations with boundary constraints represent the modeled flow problem. In addition, these equations are converted into non-dimensional form by employing suitable non-dimensionalizing quantities. The impacts of the pertinent parameters and related dimensionless numbers on the dimensionless velocity, temperature, concentrations, shear stress, heat and mass transfer are examined for both suction and injection cases. It has been found that when the injection level on the heated plate is increased, the shear rate increases for each channel plate. Furthermore, we recognized that the viscoelastic parameters exhibit an opposite kind of behavior on the velocity, temperature, and concentrations fields.

Experimental aggregative stability study of Ag/PVP nanoparticles in colloidal solutions, based on the water, propylene glycol-water, and isopropanol systems

Experimental aggregative stability study of Ag/PVP nanoparticles in colloidal solutions, based on the water, propylene glycol-water, and isopropanol systems

Modeling the Formation of Noble Metal Nanocluster Systems during Deposition from a Colloid Solution

Modeling the Formation of Noble Metal Nanocluster Systems during Deposition from a Colloid Solution