Colloid Journal最新文献

Silver nanoparticles (AgNPs–E) biosynthesized at room and boiling T, stabilized by blackberry plant extracts (E) obtained by maceration at room T and reflux extraction at boiling T, are presented in this work. The obtained AgNPs–E were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), dynamic light scattering (DLS) and zeta-potential measurement. XRD analysis confirmed that the 2θ peak at 38.2°, corresponding to the (111) plane, was the most intense, with the average crystallite size in the range of 18.0 ± 3–21.1 ± 2 nm. SEM spectroscopy showed that spherical shapes of nanoparticles dominate in the reaction mixture. EDX spectroscopy showed the presence of elemental silver in the formed AgNPs–E, along with the presence of C and Mg, which probably originate from the biomolecules of the extracts. DLS provides the size distribution with the average particle size in the range of 50.93 ± 0.83–74.48 ± 1.84 nm, with negative zeta-potential ranged from –25.87 ± 1.63 to –0.3027 ± 0.36 mV indicating the AgNPs stability. The antimicrobial activity of AgNPs–E was tested by microdilution method confirming that both nanoparticles and extracts show the ability to inhibit all the bacteria and a fungus tested. The presented results suggest further investigations of synthesized AgNPs–E for application in topical cosmetic preparations.

Ultra-high molecular weight polyethylene (UHMWPE) has become the preferred material for joint liners due to its excellent wear resistance and chemical stability. This study provides a basic investigation into how water absorption influences the tribological behavior and mechanical characteristics of UHMWPE. The surface plastic deformation layer formed during UHMWPE wear was found to exhibit significant changes after water absorption. Experimental results demonstrate that water absorption not only reduces the friction coefficient of the material by 7.79%, but also exacerbates plastic deformation, resulting in an increase of wear up to 4-fold compared to the control group. Raman spectroscopy analysis further confirmed a notable rise in surface crystallinity after water absorption. Indentation tests show water absorption decreases indentation depth. Molecular simulation results suggest that water absorption in UHMWPE chains tends to reduce the inter-molecular interactions and thereby facilitates the formation of ordered arrangements of surface polyethylene, leading to an anisotropic distribution, i.e., ordered alignment in parallel to the frictional direction, and anisotropic mechanical properties. The anisotropic distribution of surface polymer chains during friction, which was also strengthened after water absorption, in turn increases the resistance to indention. The investigation results of the tribological properties and mechanical characteristics of water-absorbed UHMWPE may provide useful insights for the evaluation and performance of artificial joints.

This study reports the eco-friendly synthesis of silver nanoparticles (AgNPs) using Chenopodium album (CA) leaf extract and evaluates their antifungal efficacy against Rhizoctonia solani. UV–Vis spectroscopy confirmed nanoparticle formation through pH- and extract volume-dependent red-shifts in surface plasmon resonance (SPR) peaks (405–435 nm), indicative of increased particle size and yield. Tauc plot analysis revealed a non-linear band gap variation (2.97 to 2.58 eV), reflecting quantum confinement effects influenced by pH. XRD patterns confirmed the crystalline nature and FCC structure of the AgNPs, while DLS and TEM analyses showed particle growth from 16.36 nm (pH 6) to 78.26 nm (pH 12), accompanied by morphological shifts and aggregation. Zeta potential values decreased from –30.92 to –14.75  mV, indicating reduced colloidal stability under alkaline conditions. In vitro assays demonstrated significant mycelial growth inhibition (MGI), with up to 91% suppression at pH 12 using 1.0 mL of CA extract. EC₅₀ values confirmed enhanced dose- and pH-dependent antifungal potency. Notably, seasonal and temporal cues critically shaped the biosynthesis of CA-AgNPs; spring in Meerut (25°C, 55% RH) yielded ultra-small, stable particles (26 nm, SPR 410 nm) and peak antifungal performance (MGI 89%). These findings reveal how nature’s rhythm–via temperature, humidity, and harvest timing–can be harnessed to fine-tune nanoparticle functionality, presenting a promising green route for antifungal nanomaterial development.

The sorption of thiocyanate ions under various conditions on a Cr–polymer composite and, for comparison, on a strongly basic anion exchanger Purolite A-400(Cl) was studied. Temperature has a significant effect on sorption on the composite and a minor effect on Purolite A-400(Cl). The sorption of thiocyanate ions on both sorbents practically does not depend on the pH of the solution in the range 2–12. The rate of thiocyanate ion sorption is limited by mixed intra-particle and boundary layer diffusion. The sorption isotherms obtained at 18 and 60°C on Purolite A-400 are well described by the Langmuir sorption model, and on the Cr–polymer composite – by the Freundlich model. The difference in the magnitude of sorption on these composites is explained by the fact that on Purolite A-400(Cl) the retention of thiocyanate ions occurs as a result of ion exchange, while on the Cr–polymer composite it occurs as a result of ion exchange and complex formation. The Cr–polymer composite loaded with thiocyanate ions becomes a sorbent with selective sorption properties in relation to heavy metal cations, which is confirmed by the retention of Hg²⁺ ions from solution.

This study investigates the formulation and characterization of curcumin-loaded microemulsions using linseed oil (LDME) and fish oil (FDME) to enhance the solubility, stability, and bioavailability of curcumin, a hydrophobic polyphenol with potent antioxidant and anti-inflammatory properties. The microemulsions were prepared using Tween 20 as a surfactant and ethanol as a co-surfactant. The solubility of curcumin in linseed oil (2.301 mg/mL) and fish oil (2.078 mg/mL) were significantly (p < 0.05) higher compared to other oils, making them suitable carriers. Thermodynamic stability studies revealed that FDME formulations exhibited superior stability, with four out of ten formulations passing centrifugation, heating-cooling, and freeze-thaw cycles, while only two LDME formulations remained stable. Particle size analysis showed that curcumin-loaded FDME and LDME had mean diameters of 264.02 nm and 214.7 nm, respectively, with polydispersity indices (PDI) of 21.7 and 21.01%, indicating monodisperse distributions. Zeta potential values ranged from –11.3 to –17.8 mV, ensuring colloidal stability. Encapsulation efficiency was 97.05% for LDME and 93.95% for FDME, demonstrating effective curcumin retention. Further, in vitro drug release studies revealed sustained release profiles, with LDME releasing 43.98% and FDME releasing 34.39% of curcumin over 3 h, following zero-order kinetics. Antioxidant assays demonstrated enhanced ABTS and DPPH radical scavenging activities for curcumin-loaded microemulsions, with FDME showing 98.2% and LDME 95.63% ABTS inhibition at 2.5 mg/mL. These findings highlight the potential of curcumin-loaded microemulsions as effective delivery systems for improving the therapeutic efficacy of curcumin and omega-3 fatty acids in nutraceutical and pharmaceutical applications.

eLiposomes are oil-in-water nanoemulsions encapsulated in the internal pool of liposomes. When creating such systems, the main challenge is understanding the conditions for the formation of various structures in the confined space of liposomes. In this study, we propose a method for calculating the attractive and repulsive forces between an oil droplet and the internal surface of a hollow sphere with the purpose to simulate the nanoemulsion stability in the interior of eLiposomes. The motion of oil droplets and their interaction with the internal surface of a liposome are simulated using Langevin dynamics. At a low liposome charge of –10 mV, oil droplets are adsorbed on the internal surface of liposomes to form structures that may be referred to as inverted colloidosomes. If the charge of the oil droplets in the nanoemulsion is also low and equal to –10 mV, the adsorbed oil droplets form regions with a dense hexagonal packing on the internal surface of the liposomes. When the charge on the oil droplets in the nanoemulsion is high and equal to –50 mV, the droplets repulse each other and are located at some distance, thereby forming a layer with a loose packing. Such multicompartment systems (inverted colloidosomes) are promising carriers for hydrophobic, hydrophilic, and amphiphilic drug compounds.

Traditional methods for quantitative identification of bacteria require long time, which substantially limits their operational efficiency. This paper proposes a rapid and simple method for counting S. aureus 209p and E. coli K12 bacterial cells on the basis of indirect surface-enhanced Raman scattering (SERS) using gold nanostar and nanorod tags conjugated with 4-nitrothiophenol. An increase in the SERS signal has been shown to depend on the number of nanoparticle-labeled bacterial cells. The developed procedure has appeared to be efficient both for the direct measurement of the signal from the freshly prepared complex and for measuring the signal from the cellular precipitate after centrifugation. The most statistically reliable results have been obtained using gold nanostars under the conditions of the direct precipitate-free measurement of the SERS signal from the bacteria complex.

Biocompatible nanosystems of various types, such as polymersomes based on amphiphilic di- and triblock poly(ethylene glycol)–poly(propylene sulfide) (PEG–PPS) copolymers, liposomes, and solid lipid nanoparticles containing an enzyme, phosphotriesterase (PTE) mutant obtained from Saccharolobus solfataricus hyperthermophilic archaea, can be used as biocatalytic nanoscavengers for detoxification of an organophosphorus compound, paraoxon. The characteristics of the PTE-containing nanosystems determined by dynamic light scattering, namely, a diameter of about 100 nm, a polydispersity of no higher than 0.3, and a negative surface potential, indicate that they can be used for detoxification therapy. Determination of the concentration of polymer nanoparticles in a solution by ultramicroscopy has made it possible to calculate the concentration of the enzyme inside of the nanoparticles, which has appeared to be much higher than the concentration of the toxicant (paraoxon). Membrane permeability for the paraoxon hydrolysis product, para-nitrophenol, and PTE enzyme has been estimated by dialysis. The kinetic study of paraoxon hydrolysis catalyzed by the free PTE and PTE-containing nanosystems has shown that the enzyme encapsulation and the type of nanoparticles do not change the Michaelis–Menten reaction mechanism. The catalytic activity of PTE in the nanosystems has been found to be higher than that of its nonencapsulated form and to depend on the type of nanoparticles. Of the series of the studied nanosystems, polymersomes based on PEG–PPS are most promising for further testing and detoxification therapy.

Modern photonics technologies are increasingly dealing with nanostructures of different chemical composition and morphology. DNA-origami is one of the most promising methods of colloidal synthesis since its self-assembling allows creating organic nanoparticles with controlled geometry. Yet the issue remains how to hybridize them with single emitters of light for photonics applications. In the paper we investigate an opportunity of spontaneous interaction of DNA-origami in the form of parallelepiped tiles (61 × 52 × 5.8 nm) containing rectangle apertures (15 × 9 nm) with colloidal core-shell quantum dots (CdSe/CdS/ZnS/oleic acid). We characterize the attachment probability (~25%) as well as consider single DNA/QD hybrid geometry with atomic force microscopy using deep 2D deconvolution post-processing analysis for correction.

Colloidal systems used as templates in the sol–gel synthesis are of great interest owing to their structural diversity; however, they are very sensitive to experimental conditions. The introduction of a precursor; the release of an organic solvent during hydrolysis; the addition of a catalyst, e.g., an acid or an alkali; and heating lead to rearrangements and phase transformations. As a result, the final state turns out to be significantly changed compared to the initial one, and such changes cannot be predicted a priori. This review is devoted to precursors containing ethylene glycol residues. In contrast to tetraethoxysilane, which is used in the traditional sol–gel synthesis, such precursors are hydrophilic, soluble in water, undergo hydrolysis in neutral aqueous solutions, and do not require the addition of a catalyst and heating. Moreover, unlike ethanol, ethylene glycol present in the amounts in which it is released during hydrolysis causes no transformations in colloidal systems. The review covers the preparation of the precursors, the issues of sol–gel chemistry, and examples of the formation of various functional materials that are synthesized using a simpler protocol in a single step under conditions that are determined by a template being mineralized rather than the sol–gel process. Many of the mentioned silica materials can be synthesized only using ethylene glycol-containing silanes.