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AbstractWe use the dynamic light scattering technique (DLS) to study the dynamic behavior of complex constituted by weakly charged microemulsion in the presence of polyelectrolyte. We investigated the impact of adding oppositely charged polyacid (PAA), which is a pH-dependent polyelectrolyte, on the dynamics of charged microemulsion nanodroplets in an acidic medium at pH = 4.5 when the polyacrylic acid are partially charged. In a diluted regime, two diffusive relaxation modes are seen when adding (upon addition) the polyacrylic acid PAA to the microemulsion nanodroplets due to collective diffusion and self-diffusion fluctuations. In the concentrated regime, we observed three diffusive relaxation modes when charged microemulsion nanodroplets complexed with oppositely charged polyacrylic acid. We attribute the two first relaxation modes to the collective diffusion (fluctuation of concentration) and self-diffusion of the microemulsion nanodroplets. The third mode which is a slower relaxation mode; we attribute this relaxation process to the motion of the network formed by the polyacid PAA and microemulsion nanodroplets, or “breathing mode” of the network. [ABSTRACT FROM AUTHOR]

Nanoparticles having a radius of ca. 200 nm are prepared from the proteolytic enzyme trypsin (TRY) and the anionic polysaccharide chondroitin sulfate (CS) by electrostatic complexation at pH 4.3 and subsequent thermal treatment. 3D dynamic light scattering and synchrotron small-angle X-ray scattering are used to assess their size distribution and their inner structure in the pH range up to 11.3. They feature a monomodal size distribution up to pH 8, whereas the distribution becomes very broad above. Their inner structure depends strongly on pH, again with a significant change at pH 9. SAXS reveals hierarchical organization within the NPs. At pH 4.3–8.0, compact TRY-CS complexes at intermediate length scales (∼30 nm), whose size increases by thermal treatment, are present within the NPs. At pH 10.1–11.3 the spherical NPs transform into fractal aggregates. The spherical internal substructure vanishes, and only smaller substructures stay present. At low pH values, where TRY is homogeneously positively charged, these results are attributed to the electrostatic interactions of TRY with CS. At intermediate pH values, where the electrostatic surface potential of TRY is patchy, the TRY-TRY interactions seem to play an important role. The morphological properties of the TRY-CS NPs and their length-scale-dependent response to thermal treatment (20 min at 60 °C) and increase of pH are expected to be crucial for the drug/nutrient loading and release properties and the interactions with other biopolymers, proteins, cells, and tissues. They can also be a useful guide for other polysaccharide–protein biocompatible nanocarriers. [ABSTRACT FROM AUTHOR]

In this study, catalytic-degradation of dyes such as methylene blue (MB) and malachite green (MG) was carried out by using silver nanoparticles (AgNPs), obtained by adopting the flower extract of Luffa acutangula (LA). The biogenic synthesised LA-AgNPs were characterised by using UV-Vis spectroscopy, Fourier-transform infrared spectroscopy (FTIR), DLS (dynamic light scattering) with zeta potential analysis, X-ray diffraction (XRD) and high-resolution transmission electron microscopic(HR-TEM) analyses. The typical surface plasmon resonance peak of LA-AgNPs was observed at 428 nm, as confirmed from UV-Vis spectrum. The formation of LA-AgNPs was observed through colour transformation from pale yellow to dark-brown due to the reduction of Ag+. Synthesised LA-AgNPs displayed spherical shape and face-centred cubic structure with an average size of 10–30 nm. The effects of various parameters such as initial extract concentration, time and time process were studied. The degradation reactions of MB and MG are found to follow the Langmuir–Hinshelwood mechanism with a pseudo-first-order kinetic model. Biogenic synthesised LA-AgNPs showed good degradation ability to reduce the MG and MB with NaBH4. [ABSTRACT FROM AUTHOR]

Dynamic light scattering has been employed to investigate aqueous Pluronic P123 solutions at different temperatures and in the presence of different solvents and quercetin additives. Significant changes have been revealed in the average particle size and polydispersity index depending on the conditions. The effect of temperature on micellization of the block copolymer in aqueous solutions has been studied in a range T = 15–45°C, which is most often considered when using P123 in the sol–gel synthesis of silica. The most pronounced effect of temperature on the micellization of the studied surfactant has been observed at T = 15–20°C. In this temperature range, the scattered light intensity distribution over particle sizes has a polymodal character, which indicates the presence of macromolecules, micelles, and their aggregates in the system. A further increase in temperature up to 45°C causes no significant changes in the particle size. In aqueous solutions, micelles with a narrow size distribution (minimum polydispersity index) are formed within temperature ranges of 21–25 and 35–40°C. Substantial effects have been found when adding alkanols and polyphenolic substances as solubilizers capable of influencing the structure of micelles both in their bulk and on the surface of polar moieties of the surfactant. It has been shown that, in the presence of butanol-1, micelles are stabilized at temperatures of 15–20°C. At T > 30°C, the structure of micelles is transformed. As the fraction of butanol-1 in the solution increases, its influence is manifested at lower temperatures. It has been noted that ethanol has a destructive effect on micelles. Additives of quercetin exhibit an opposite effect of micelle stabilization, which leads to the formation of a homogeneous surfactant structure. It has been shown that, by varying solvent composition, the flavonoid–micelle binding can be controlled due to changes in the solvation. The greatest influence of quercetin on the structure formation of P123 has been observed at a solvent composition corresponding to ethanol-to-block copolymer molar ratio of n(EtOH) : n(P123) = 80 : 1. [ABSTRACT FROM AUTHOR]

The potential of using centrifugation in the separation of suspended forms from dissolved and colloidal forms in the chemical analysis of river waters is demonstrated in the case of rivers in the south of the Russian Far East. The concentrations of colloidal and suspended particles in nonfiltered water, as well as in centrifugates and filtrates, were characterized with the use of the method of dynamic light scattering (DLS). The comparison of DLS intensity in centrifugates and 0.45-µm filtrates was used to calculate the native density of pelitic and coarse colloidal particles of river suspension, which made it possible to correlate the centrifugation regimes with the size of settling particles within the range from 0.45 to 3 µm. Chemical analysis of supernatants of river water, obtained at different centrifugation regimes was used to evaluate the distribution of chemical elements between dissolved/colloidal (<0.45 µm), coarse-colloidal (0.45–1 µm), and pelite (1–3 µm) fractions. A significant linear relationship was found between the DLS intensity and the concentrations in centrifugates of Fe, Al, Ti, Th, Sc, REE, i.e., chemical elements with a high fraction of coarse colloidal and suspended forms, which confirms the possibility to assess the concentration of colloidal particles in centrifugates by the intensity of DLS. A disadvantage of centrifugation is that it is difficult to use in the field. [ABSTRACT FROM AUTHOR]

Deamidation frequently is invoked as an important driver of crystallin aggregation and cataract formation. Here, we characterized the structural and biophysical consequences of cumulative Asn to Asp changes in γD‐crystallin. Using NMR spectroscopy, we demonstrate that N‐ or C‐terminal domain‐confined or fully Asn to Asp changed γD‐crystallin exhibits essentially the same 1H‐15N HSQC spectrum as the wild‐type protein, implying that the overall structure is retained. Only a very small thermodynamic destabilization for the overall Asn to Asp γD‐crystallin variants was noted by chaotropic unfolding, and assessment of the colloidal stability, by measuring diffusion interaction parameters, yielded no substantive differences in association propensities. Furthermore, using molecular dynamics simulations, no significant changes in dynamics for proteins with Asn to Asp or iso‐Asp changes were detected. Our combined results demonstrate that substitution of all Asn by Asp residues, reflecting an extreme case of deamidation, did not affect the structure and biophysical properties of γD‐crystallin. This suggests that these changes alone cannot be the major determinant in driving cataract formation. [ABSTRACT FROM AUTHOR]

The influence of micellar systems based on cationic surfactants—gadolinium(III) and copper(II) complexes with alkylated 1,4-diazabicyclo[2.2.2]octane, 1-hexadecyl-4-aza-1-azoniabicyclo[2.2.2]octane bromide (ligand) and the conventional surfactant cetyltrimethylammonium bromide – on the solubility of the antimalarial drug artemisinin in water was studied by spectrophotometric method. A quantitative assessment of the solubilizing ability of surfactant aggregates was carried out. The value of the solubilization capacity of the systems was determined. The ligand has the greatest influence on the solubility of artemisinin, and, consequently, its bioavailability. The concentration of the drug increases up to 36 times in the presence of a relatively low surfactant content in the aqueous solution. The period of chemical stability of artemisinin in cationic surfactants solutions was determined. Aggregates formed in surfactant-artemisinin systems were characterized by dynamic and electrophoretic light scattering. [ABSTRACT FROM AUTHOR]

Here, we report a novel kind of protein nanoparticles of 11 nm in size, which have a central protein core surrounded by two layers of lipid. One layer of the lipid was covalently attached to the protein, while the other layer has been physically assembled around the protein core. Particle synthesis is highly modular, while both the size and charge of the protein nanoparticles are controlled in a predictable manner. Circular dichroism studies of the conjugate showed that the protein secondary structure is retained, while biophysical characterizations indicated the particle purity, size, and charge. The conjugate had a high thermal stability to steam sterilization conditions at 121°C (17 psi). After labeling the protein core with few different fluorescent dyes, they were strongly fluorescent with the corresponding colors independent of their size, unlike quantum dots. They are readily digested by proteases, and these water‐soluble, non‐toxic, highly stable, biocompatible, and biodegradable conjugates are suitable for cell imaging and drug delivery applications. [ABSTRACT FROM AUTHOR]

A novel construction strategy is introduced for an ultrasensitive dynamic light scattering (DLS) immunosensor targeting alpha fetoprotein (AFP). This approach relies on a self-assembled heptamer fusion protein (A1-C4bpα), incorporating the dual functions of multivalent recognition and crosslinking aggregation amplification due to the presence of seven AFP-specific A1 nanobodies on the A1-C4bpα heptamer. Leveraging antibody-functionalized magnetic nanoparticles for target AFP capture and DLS signal output, the proposed heptamer-assisted DLS immunosensor offers high sensitivity, strong specificity, and ease of operation. Under the optimized conditions, the designed DLS immunosensor demonstrates excellent linear detection of AFP in the concentration range 0.06 ng mL−1 to 512 ng mL−1, with a detection limit of 15 pg mL−1. The selectivity, accuracy, precision, practicability, and reliability of this newly developed method were further validated through an assay of AFP levels in spiked and actual human serum samples. This work introduces a novel approach for constructing ultrasensitive DLS immunosensors, easily extendable to the sensitive determination of other targets via simply replacing the nanobody sequence, holding great promise in various applications, particularly in disease diagnosis. [ABSTRACT FROM AUTHOR]

Nanoparticles are emerging as a fascinating alternative to antibiotics. When stabilized by chemical compounds, magnetite nanoparticles (MagNPs) consistently exhibit bactericidal effects across different types of bacteria. This study describes the synthesis, characterization, and antibacterial properties of magnetite MagNPs prepared by the coprecipitation method under continuous sonication. Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), and Dynamic Light Scattering (DLS) techniques revealed Fe3O4-NPs as spherical, uniform particles with an average size of approximately 16 nm. The antibacterial efficacy of MagNPs was investigated by combining them with methanolic extracts of three medicinal plants known for their antibacterial properties: Aloysia triphylla, Sarcopoterium spinosum, and Urtica pilulifera. The combined effect was assessed against both wild type and resistant strains of Staphylococcus aureus and Escherichia coli. The antibacterial synergistic effect of MagNPs and plant extracts was evaluated by the MIC test, which showed significant inhibitory properties against the growth of the four bacterial strains as compared to control samples of plant extracts alone. Furthermore, the synergistic effect of MagNPs combined with extracts from Rosmarinus officinalis, Anchusa azurea, Quercus infectoria, and Urtica pilulifera significantly prevented biofilm development in both sensitive and resistant strains of Staphylococcus aureus. [ABSTRACT FROM AUTHOR]

Background and Objectives: The development of resistance of microorganisms to existing antibacterial agents requires constant updating of existing drugs and research in the search for alternative sources of active substances. In recent years, the problem of the emergence of microorganisms resistant to all existing antimicrobial drugs has become systematic and requires significant attention from researchers to search for alternative sources of active substances. The main problem in the development of drugs based on antimicrobial peptides is the search for optimal solutions in the preparation of these substances. Therefore, optimization and search for methods of isolation, analysis and control of protein fractions of water-soluble peptides used for the subsequent development of antibacterial drugs based on them is an urgent task. Materials and Methods: Optimal conditions and methods have been selected for the preparative production of water-soluble peptides isolated from the biomass of Hermetia illucens larvae. Optimization and search of methods for isolation, analysis and control of protein fractions of these water-soluble peptides will ensure the accuracy of the results and obtain optimal amounts of protein fractions. Results: It has been found that the use of molecular sieves makes it possible to obtain a mixture of three peptides with a difference in chromatographic retention time of less than 1 minute, which has been confirmed by three parallel experiments on the isolation and purification of peptides. During HPLC it has been noted that protein fractions 1 and 2 have similar values and the first and third protein fractions have a smaller difference in retention time, which is why there is no complete separation of these chromatographic peaks. Comparison of the percentage of the area of the peptides obtained allows us to talk about the possibility of obtaining peptides of the same size from H. illucens larvae by HPLC, and in combination with DLS to obtain protein fractions with very similar physicochemical and physical characteristics, since this type of chromatography separates substances according to their size. Conclusion: The use of high-performance liquid chromatography makes it possible to establish the reproducibility of the method of isolation of antimicrobial peptides by cold extraction with water and further stages of protein purification, salting and molecular sieve chromatography, which, in correlation with DLS analysis, makes it possible to reliably identify the peptides obtained, and the developed technology of isolation and purification makes it possible to produce these proteins on an industrial scale at low cost.

Taghrid S Alomar,1 Najla AlMasoud,1 Manal A Awad,2 Reem S AlOmar,3 Nada M Merghani,4 Mohamed El-Zaidy,5 Ajaya Bhattarai6 1Department of Chemistry, College of Science, Princess Nourah Bint Abdulrahman University, Riyadh, 11671, Saudi Arabia; 2King Abdullah Institute for Nanotechnology, King Saud University, Riyadh, 11451, Saudi Arabia; 3Department of Family and Community Medicine, College of Medicine, Imam Abdulrahman Bin Faisal University, Dammam, 32210, Saudi Arabia; 4Central Research Laboratory, Vice Rectorate for Studies and Scientific Research, King Saud University, Riyadh, 11451, Saudi Arabia; 5Department of Botany and Microbiology, Faculty of Science, King Saud University, Riyadh, 11459, Saudi Arabia; 6Department of Chemistry, Mahendra Morang Adarsh Multiple Campus, Tribhuvan University, Biratnagar, 56613, NepalCorrespondence: Ajaya Bhattarai; Manal A Awad, Email ajaya.bhattarai@mmamc.tu.edu.np; mawad@ksu.edu.saIntroduction: Researchers are increasingly favouring the use of biological resources in the synthesis of metallic nanoparticles. This synthesis process is quick and affordable. The current study examined the antibacterial and anticancer effects of silver nanoparticles (AgNPs) derived from the Neurada procumbens plant. Biomolecules derived from natural sources can be used to coat AgNPs to make them biocompatible.Methods: UV-Vis spectroscopy was used to verify the synthesis of AgNPs from Neurada procumbens plant extract, while transmission electron microscopy (TEM), photoluminescence (PL) spectroscopy, dynamic light scattering (DLS), and Fourier transform infrared spectroscopy (FTIR) were used to characterize their morphology, crystalline structure, stability, and coating.Results: UV-visible spectrum of AgNPs shows an absorption peak at 422 nm, indicating the isotropic nature of these nanoparticles. As a result of the emergence of a transmission peak at 804.53 and 615.95 cm− 1 in the spectrum of the infrared light emitted by atoms in a sample, FTIR spectroscopy demonstrated that the Ag stretching vibration mode is metal-oxygen (M-O). Electron dispersive X-ray (EDX) spectral analysis shows that elementary silver has a peak at 3 keV. Irradiating the silver surface with electrons, photons, or laser beams triggers the illumination. The emission peak locations have been found between 300 and 550 nm. As a result of DLS analysis, suspended particles showed a bimodal size distribution, with their Z-average particle size being 93.38 nm.Conclusion: The findings showed that the antibacterial action of AgNPs was substantially (p≤ 0.05) more evident against Gramme-positive strains (S. aureus and B. cereus) than E. coli. The biosynthesis of AgNPs is an environmentally friendly method for making nanostructures that have antimicrobial and anticancer properties.Keywords: Silver nanoparticles, UV-Vis spectroscopy, transmission peak, dynamic light scattering

In this paper, we present an efficient and rapid method for synthesizing perovskite nanoparticles (PeNPs) using ultrasonic spray techniques. The synthesized PeNPs are notably larger than the exciton Bohr radius of perovskite, avoiding the quantum confinement effect, and exhibit a size distribution of around 61.6 ± 30 nm. They show an exceptionally narrow full width at half-maximum of approximately 21.8 nm and a high exciton binding energy (Eb) of approximately 204 meV. Furthermore, the physically restrained reprecipitation method not only effectively transforms perovskite precursor droplets into solid PeNPs at the interface of an antisolvent but also concurrently achieves ligand passivation. This dual-action mechanism promotes their dispersion in various organic solvents and highly concentrated solutions, thus significantly expanding the scope of potential optoelectronic applications such as light-emitting diodes and photodetectors. [ABSTRACT FROM AUTHOR]

Plastic materials are used in various domains, such as constructions, textile, or medical applications, due to their durability and versatility. Despite plastics contribution to human wellbeing, these materials can also have a negative impact on ecosystems, leading to water pollution and loss of aquatic life. However, no study has been made, so far, to determine the impact of plastic products on natural particle size distribution in water systems. The aim of this study is to evaluate if plastic affects aquatic particulate matter of different size ranges, from 0.3 to 16 000 nm. Three types of plastics (polystyrene [PS], polypropylene [PP], and low‐density polyethylene [LDPE]) have been added to lake water samples and incubated for nine months at room temperature. Results show that the average particle size increases toward the end of the experiment indicating that small particles (<1200 nm) adhere to plastic surfaces, while medium and large particles sediment in the water sample. Also, substances migrating from plastic may alter the aggregating properties of particles. However, the influence may be less substantial in the environment, as plastic types and concentrations differ. Moreover, more studies are needed to establish additional implications in relation to bacterial communities, transport of pollutants, or chemical composition. [ABSTRACT FROM AUTHOR]

Rieske oxygenases (ROs) are a diverse metalloenzyme class with growing potential in bioconversion and synthetic applications. We postulated that ROs are nonetheless underutilized because they are unstable. Terephthalate dioxygenase (TPADO PDB ID 7Q05) is a structurally characterized heterohexameric α3β3 RO that, with its cognate reductase (TPARED), catalyzes the first intracellular step of bacterial polyethylene terephthalate plastic bioconversion. Here, we showed that the heterologously expressed TPADO/TPARED system exhibits only ~300 total turnovers at its optimal pH and temperature. We investigated the thermal stability of the system and the unfolding pathway of TPADO through a combination of biochemical and biophysical approaches. The system's activity is thermally limited by a melting temperature (Tm) of 39.9°C for the monomeric TPARED, while the independent Tm of TPADO is 50.8°C. Differential scanning calorimetry revealed a two‐step thermal decomposition pathway for TPADO with Tm values of 47.6 and 58.0°C (ΔH = 210 and 509 kcal mol−1, respectively) for each step. Temperature‐dependent small‐angle x‐ray scattering and dynamic light scattering both detected heat‐induced dissociation of TPADO subunits at 53.8°C, followed by higher‐temperature loss of tertiary structure that coincided with protein aggregation. The computed enthalpies of dissociation for the monomer interfaces were most congruent with a decomposition pathway initiated by β‐β interface dissociation, a pattern predicted to be widespread in ROs. As a strategy for enhancing TPADO stability, we propose prioritizing the re‐engineering of the β subunit interfaces, with subsequent targeted improvements of the subunits. [ABSTRACT FROM AUTHOR]

A lot of literature sources discuss diseases associated with the hemoglobin protein [1-2]. In the modern world, more than 800 million people suffer from anemia [3]. Assessing the level of hemoglobin in the circulatory system is one of the ways to diagnose anemia. Hemoglobin protein is also a promising source of bioactive peptides [4]. The aim of the work was to identify the reasons leading to conformation changes of this protein. It still remains unclear what exactly causes disruption of its functionality. Human hemoglobin from Sigma H7379 was studied in the work; all experiments were conducted on a dynamic light scattering spectrometer—Photocor Complex. Experimental data were obtained using optical methods of static and dynamic light scattering. The work included an analysis of the behaviour of hemoglobin protein molecules in aqueous and aqueous-saline solutions with changes in solution parameters (pH, addition of iron chloride III). At values of pH and pH , the hemoglobin molecule underwent conformational changes, resulting in the disintegration of the quaternary structure into -dimers and individual - and -globules. As a result of the study, it was found that the addition of FeCl to aqueous solutions of hemoglobin increases the size and mass of scattering particles, which can be explained by the adsorption of Fe ions on the protein surface. However, upon reaching a certain concentration of FeCl , the pH of the solution was lowered to such an extent that it caused conformational changes in hemoglobin, leading to the disintegration of its quaternary structure. These results can be taken into account when creating medicinal drugs for the treatment of anemia and other diseases associated with the hemoglobin protein. [ABSTRACT FROM AUTHOR]

Knowledge of diffusion in water or aqueous solutions of sodium chloride with dissolved hydrogen and methane is important for geological hydrogen storage. This study examines the accessibility of diffusivities in the corresponding mixtures through dynamic light scattering at macroscopic thermodynamic equilibrium and provides corresponding data for hydrogen-storage-relevant temperatures T up to 393 K and pressures up to 20 MPa. The thermal and mutual diffusivities are simultaneously accessible in mixtures of water and hydrogen. Moreover, for water with dissolved mixtures of hydrogen and methane, the thermal diffusivity and an apparent diffusivity related to the diffusion of the gas mixture can be accessed. In aqueous solutions of sodium chloride at T > 300 K, a strong molecular association leading to a quasi-static light-scattering pattern in the liquid sample was observed, which hindered the determination of the molecular gas diffusivities. However, the salt diffusion coefficient was accessible for all T values. [Display omitted] •First-time application of dynamic light scattering to H 2 O/brine-H 2 /CH 4 systems. • Experimental diffusivity data up to 393 K and 20 MPa. • Presence of sodium chloride does not influence gas diffusion significantly. • Correlation for estimating the mass diffusivity of dissolved H 2 /CH 4 in H 2 O/brine. [ABSTRACT FROM AUTHOR]

[Display omitted] Surfactants are inexpensive chemicals with promising applications in virus inactivation, particularly for enveloped viruses. Yet, the detailed mechanisms by which surfactants deactivate coronaviruses remain underexplored. This study delves into the virucidal mechanisms of various surfactants on Feline Coronavirus (FCoV) and their potential applications against more pathogenic coronaviruses. By integrating virucidal activity assays with fluorescence spectroscopy, dynamic light scattering and laser Doppler electrophoresis, alongside liposome permeability experiments, we have analyzed the effects of non-ionic and ionic surfactants on viral activity. The non-ionic surfactant octaethylene glycol monodecyl ether (C 10 EO 8) inactivates the virus by disrupting the lipid envelope, whereas ionic surfactants like Sodium Dodecyl Sulfate and Cetylpyridinium Chloride predominantly affect the spike proteins, with their impact on the viral membrane being hampered by kinetic and thermodynamic constraints. FCoV served as a safe model for studying virucidal activity, offering a faster alternative to traditional virucidal assays. The study demonstrates that physicochemical techniques can expedite the screening of virucidal compounds, contributing to the design of effective disinfectant formulations. Our results not only highlight the critical role of surfactant-virus interactions but also contribute to strategic advancements in public health measures for future pandemic containment and the ongoing challenge of antimicrobial resistance. [ABSTRACT FROM AUTHOR]

Pretransitional behaviour, with strong softening of the bend or splay elastic constants, is characteristic of two of the nematic to nematic phase transitions reported in the last decade. Such softening is strongly reflected in the pretransitional behaviour of the thermally excited director fluctuations. Here we give a comprehensive overview of the cross-Differential Dynamic Microscopy (c-DDM) method and its application to the investigation of thermal director fluctuations and phase transitions. For this, we build on the potentialities of the method for the investigation of the standard nematic phase of E7 to compare with the pretransitional behaviour of the nematic to twist bend nematic phase transition as well as the nematic to ferroelectric nematic transition. [ABSTRACT FROM AUTHOR]

A dynamic light-scattering method for qualitative analysis was developed and used in production and quality control of hydrolyzed collagen (HC). A semiquantitative analytical method based on ultrafiltration coupled with spectrophotometry was proposed for the peptide fraction with molecular mass <10 kDa, which determines the most significant properties of HC. [ABSTRACT FROM AUTHOR]

Biological nanoparticles (NPs), such as extracellular vesicles (EVs), exosome-mimetic nanovesicles (EMNVs) and nanoghosts (NGs), are perspective non-viral delivery vehicles for all types of therapeutic cargo. Biological NPs are renowned for their exceptional biocompatibility and safety, alongside their ease of functionalization, but a significant challenge arises when attempting to load therapeutic payloads, such as nucleic acids (NAs). One effective strategy involves fusing biological NPs with liposomes loaded with NAs, resulting in hybrid carriers that offer the benefits of both biological NPs and the capacity for high cargo loads. Despite their unique parameters, one of the major issues of virtually any nanoformulation is the ability to escape degradation in the compartment of endosomes and lysosomes which determines the overall efficiency of nanotherapeutics. In this study, we fabricated all major types of biological and hybrid NPs and studied their response to the acidic environment observed in the endolysosomal compartment. In this study, we show that EMNVs display increased protonation and swelling relative to EVs and NGs in an acidic environment. Furthermore, the hybrid NPs exhibit an even greater response compared to EMNVs. Short-term incubation of EMNVs in acidic pH corresponding to late endosomes and lysosomes again induces protonation and swelling, whereas hybrid NPs are ruptured, resulting in the decline in their quantities. Our findings demonstrate that in an acidic environment, there is enhanced rupture and release of vesicular cargo observed in hybrid EMNVs that are fused with liposomes compared to EMNVs alone. This was confirmed through PAGE electrophoresis analysis of mCherry protein loaded into nanoparticles. In vitro analysis of NPs colocalization with lysosomes in HepG2 cells demonstrated that EMNVs mostly avoid the endolysosomal compartment, whereas hybrid NPs escape it over time. To conclude, (1) hybrid biological NPs fused with liposomes appear more efficient in the endolysosomal escape via the mechanism of proton sponge-associated scavenging of protons by NPs, influx of counterions and water, and rupture of endo/lysosomes, but (2) EMNVs are much more efficient than hybrid NPs in actually avoiding the endolysosomal compartment in human cells. These results reveal biochemical differences across four major types of biological and hybrid NPs and indicate that EMNVs are more efficient in escaping or avoiding the endolysosomal compartment. [ABSTRACT FROM AUTHOR]

Polysaccharide-based systems have very good emulsifying and stabilizing properties, and starch plays a leading role. Their modifications should add new quality features to the product to such an extent that preserves the structure-forming properties of native starch. The aim of this manuscript was to examine the physicochemical characteristics of the combinations of starch with phospholipids or lysozymes and determine the effect of starch modification (surface hydrophobization or biological additives) and preparation temperature (before and after gelatinization). Changes in electrokinetic potential (zeta), effective diameter, and size distribution as a function of time were analyzed using the dynamic light scattering and microelectrophoresis techniques. The wettability of starch-coated glass plates before and after modification was checked by the advancing and receding contact angle measurements, as well as the angle hysteresis, using the settle drop method as a complement to profilometry and FTIR. It can be generalized that starch dispersions are more stable than analogous n-alkane/starch emulsions at room and physiological temperatures. On the other hand, the contact angle hysteresis values usually decrease with temperature increase, pointing to a more homogeneous surface, and the hydrophobization effect decreases vs. the thickness of the substrate. Surface hydrophobization of starch carried out using an n-alkane film does not change its bulk properties and leads to improvement of its mechanical and functional properties. The obtained specific starch-based hybrid systems, characterized in detail by switchable wettability, give the possibility to determine the energetic state of the starch surface and understand the strength and specificity of interactions with substances of different polarities in biological processes and their applicability for multidirectional use. [ABSTRACT FROM AUTHOR]

In this study, a series of four surface-active compounds—N-alkyl betaine ethyl ester chlorides, CnBetC2Cl—were synthesized and characterized in aqueous solutions. As with other alkyl betaines, these amphiphiles can be practically used, for example, as co-surfactants and/or solubility enhancers acting according to hydrotropic or micellar mechanisms, depending on the alkyl chain length in the amine. We focused on the representatives of the medium alkyl chain length (C6–C12) to find the dependence between the alkyl chain length in N-alkyl betaine ethyl ester chlorides and the surface, volumetric, acoustic, and viscometric properties of their solutions. Ethyl esters, the derivatives of amino acids, were chosen to increase functionality and take advantage of possible hydrolysis in solutions at higher pH, which is also a key parameter in biodegradability. The micellization parameters were calculated based on the physicochemical characteristics. We focused our interest on the ester with a dodecyl substituent since we can compare and discuss its properties with some other C12 representatives that are available in literature. Surprisingly, its micellization characteristic is almost temperature-independent in the investigated temperature range, t = (15–45) °C. Particularly interesting are the results of dynamic light scattering (DLS), which show that the changes in physicochemical parameters of the C12 homolog around the CMC are caused by the two types of micelles of different sizes present in solutions. [ABSTRACT FROM AUTHOR]

Nanodiamonds (NDs) are promising carriers of radionuclides in radiopharmaceuticals for the use in nuclear medicine. In this work, we investigated the influence of the properties of NDs suspensions, including the sizes of their aggregates, in aqueous solutions with different pH on their binding of medical isotopes 90Y and 177Lu and determination of conditions for fabricating promising conjugates for further in vivo studies. It was shown that sorption is influenced by the composition of the solution, which determines the properties of the NDs surface, while the forms of cations of the studied nuclides in the solution do not affect the sorption value. [ABSTRACT FROM AUTHOR]

The present article summarizes experimental and theoretical considerations required for a proper use of dynamic light scattering (DLS) for the measurement of transport properties of fluids. It addresses not only recent advancements of the method, but also aims to provide recommendations to researchers who intend to apply the technique in the future. As outlined in this study, DLS is based on the analysis of scattered light governed by microscopic statistical or periodic fluctuations that originate from the thermal movement of molecules and/or particles at macroscopic thermodynamic equilibrium. The dynamics of these hydrodynamic fluctuations in the bulk of fluids or at their phase boundaries are related to the underlying diffusive processes and, thus, to the associated transport properties, and are reflected by the time-dependent correlation function of the scattered light intensity. The fundamentals of this type of detection, known as photon correlation spectroscopy (PCS), will be discussed in the present contribution in some more detail. It is emphasized that the experiments need to be designed carefully in accordance with theory in order to assign the measurement signals to the corresponding hydrodynamic fluctuations. If the necessary conditions are fulfilled, DLS allows the accurate determination of several transport properties including kinematic and dynamic viscosity, thermal diffusivity, mutual diffusivity, and sound attenuation, which may be accessed together with other thermophysical properties such as speed of sound and surface or interfacial tension. In some instances, also the simultaneous determination of several transport properties is possible. With the exception of the sound attenuation, expanded uncertainties for the mentioned transport properties down to 1 % can be achieved for various types of fluid systems over a wide range of thermodynamic states up to elevated temperatures and pressures as well as in the vicinity of critical points. This performance and versatility of the DLS technique is documented in the present study by highlighting measurement examples from recent thermophysical property research on different classes of working fluids relevant for process and energy technology. [ABSTRACT FROM AUTHOR]

Monoclonal antibodies represent the rapidly expanding class of biotherapeutics having applications in the treatment of cancer, autoimmune disorders, metabolic disorders, and infectious diseases. One of the major challenges in mAb-based therapeutics development lies in the significant issue of aggregation which in turn has an impact on the quality, safety, and efficacy of the antibody drug. The presence of aggregates in the drug substance or final drug product potentially affects its biological activity thereby making it a critical quality attribute to be assessed. State-of-the-art analytical techniques are required for quality control and detailed characterization. This review provides insight into monoclonal antibody aggregation and the analytical techniques used to detect and quantify these aggregates. [ABSTRACT FROM AUTHOR]

Polymer nanocomposite materials with catalytic activity were designed via modification of MF-4SK ion-exchange membranes with Au and Ag nanoparticles obtained according to various synthetic methods in reverse micellar solutions. A sufficient transparency of the films allowed us to detect nanoparticles in the films using UV–Vis spectrophotometry, monitoring changes in the content of metal nanoparticles in the reverse micellar solution. A different mechanism of interaction of Au and Ag nanoparticles obtained by the same synthetic method with the MF-4SK film upon their contact with its surface was discovered, the destruction of nanoparticles was observed, and the influence of mechanism of primary acts in the formation of metal nanoparticles in reverse micellar solutions on their adsorption properties was confirmed. The highest concentration of gold nanoparticles was found in films immersed in reverse micellar solutions at the time of their exposure to ionizing radiation. [ABSTRACT FROM AUTHOR]

Dynamic light scattering (DLS) measurements have been performed on the polyacrylic acid (PAA) to investigate the polyelectrolyte effect on its solution dynamics. Viscosity measurements confirm the solution to be in the nondilute regime. The polyelectrolyte impacts are contrasted by using two solution pHs, five electrolyte concentrations, and in each with four different polymer concentrations. An interesting ergodic → nonergodic → ergodic transitions are being observed with variation in solution pH and electrolyte concentrations, which is directly coupled to a similar transition between bi‐modal and triple mode relaxation. The partial heterodyne method is used to analyze the DLS data exhibiting nonergodicity; otherwise, the standard Siegert relation is being employed. For the new third mode of relaxation, in addition to the conventional fast and slow mode, a novel term of nonergodic mode being coined because of a direct association between its presence with the sample becoming nonergodic. The fast relaxation time being analyzed through Rouse model and both the nonergodic and slow relaxation time show a monotonous increase with rise in polymer concentration. The stretched exponent β, a measure of inhomogeneity, decreases with increase in solution pH and polymer concentration while increases with the addition of salt to the solution. [ABSTRACT FROM AUTHOR]

The possibility of synthesizing nanoparticles by pulsed laser ablation of thin cobalt films in water is shown. The average size of the formed nanoparticles varies in the range of 70–1020 nm depending on the thickness of the ablated film. At film thicknesses less than 35 nm, the size dispersion of the nanoparticles is minimum. The produced nanoparticles are characterized by magnetic response and structurally most closely correspond to cobalt oxide Co3O4. [ABSTRACT FROM AUTHOR]

This paper presents the study of the effect of multiple ultrasonic impacts on submicron asphaltene aggregates in a toluene/heptane solution, conducted with dynamic light scattering technique. The objects of the study were four samples of asphaltenes obtained from four different oils. For all samples, the change in the average size of the asphaltene submicron aggregates with time was measured after the addition of a precipitant (heptane) to a solution of asphaltenes in toluene at an amount above the threshold concentration. Asphaltene aggregates formed in solution after the addition of the precipitant and were subjected to ultrasonic treatment, which led to the destruction of the asphaltene aggregates. Aggregation of destroyed asphaltenes was observed. The kinetics of this aggregation were similar to the kinetics of aggregation of asphaltenes after the addition of a precipitant. Multiple iterations of asphaltene aggregate destruction in the sample led to a significant change in the kinetics of aggregation: the growth of aggregates slowed and stabilized at a size of approximately 200 nm and 30 nm for the different studied samples.

The function of immune complexes in rheumatoid arthritis (RA) is related to their composition and size. Using dynamic light scattering (DLS), we investigated the link between the RA circulating immune complex (CIC) particles' size and the CIC immunoglobulin level. In this study, 30 RA patients and 30 healthy individuals were included. IgA, IgG, and IgM were found in all analyzed CICs, but more IgA and IgG were found in RA than in control CICs. In both control and RA CICs, DLS detected 50 particles that differed in size and clustered around two size groups: with a 7.5–164 nm radius and with a 342–1718 nm radius. An increased level of IgA in RA CICs, compared to control ones, was associated with more than 50% of CIC particles. In RA, compared to the control, a higher number of CICs with 28.2 nm, 531 nm, 712 nm, and 1718 nm particles and a lower number of CICs with 78.8 nm particles were detected. This particle distribution pattern did not reflect the changes in the CIC immunoglobulin level. Thus, RA elevated CIC IgA was linked with all these particles (except the 1718 nm particle), the IgM increase was linked with 43.8 nm and 712 nm particles, and the IgG increase was linked with the 712 nm particle only. This study provides the very first data on the association between CIC particles' size, CIC immunoglobulin level, and RA. It opens the possibility that the size of CICs determined by DLS can be used as a criterion in RA diagnosis or monitoring after a large-scale study confirmation. [ABSTRACT FROM AUTHOR]

To clarify the effect of proteins on the charging and aggregation–dispersion characteristics of oxidized carbon nanohorn (CNHox), we measured the electrophoretic mobility and stability ratios as a function of concentrations of a model protein, lysozyme (LSZ), and KCl. The zeta potential from the electrophoretic mobility of CNHox was neutralized and reversed by the addition of oppositely charged LSZ. Electrical and hydrophobic interactions between CNHox and LSZ can be attributed to the adsorption and charge reversal of CNHox. The stability ratio of CNHox in the presence or absence of LSZ showed Derjaguin–Landau and Verwey–Overbeek (DLVO) theory-like behavior. That is, the slow aggregation regime, fast aggregation regime, and critical coagulation concentration (CCC) were identified. At the isoelectric point, only the fast aggregation regime was shown. The existence of patch-charge attraction due to the charge heterogeneity on the surface was inferred to have happened due to the enhanced aggregation of CNHox at high LSZ dosage and low electrolyte concentration. The relationship between critical coagulation ionic strength and surface charge density at low LSZ dosage showed that the aggregation of CNHox is in line with the DLVO theory. An obvious decrement in the Hamaker constant at high LSZ dosage can probably be found due to an increased interaction of LSZ-covered parts. [ABSTRACT FROM AUTHOR]

Understanding the impact of lipid nanoparticle size on immunogenicity represents an important step for enabling the rapid development of novel vaccines against known or emergent diseases. Dynamic light scattering, also known as quasi-elastic light scattering or photon correlation spectroscopy, has established itself as an optimal analytical method to determine particle size due to its in-situ approach and fast measurements. However, its application to many systems of industrial relevance has been hindered due to artifacts arising from multiple scattering. Result interpretation becomes severely compromised depending on the concentration of the system and the size of the particles. In this context, strong sample dilution is often required, bringing additional uncertainties to the formulation development process. Here, we show how advanced dynamic light scattering technology can filter out multiple scattering from the signal and yield fully accurate sizing measurements regardless of the sample concentration. We illustrate this in a comparative study with standard dynamic light scattering using polystyrene beads as model suspension as well as a concentrated commercial lipid nanoparticle adjuvant (AddaVax™). [ABSTRACT FROM AUTHOR]

Using spectral ensemble methods (DLS, optical and luminescence spectroscopy) and the transmission electron microscopy as reference method, the dynamics of selenium nanoparticles synthesis from sodium bis(2-phenylethyl)diselenophosphinate (DSePhNa) organophosphorus precursor in aqueous solution of polysaccharide matrix arabinogalactan (Ar-Gal) was studied. It was shown that the addition of hydrogen peroxide to the aqueous solution of DSePhNa initiates its oxidation with release of Se0 atoms with formation of selenium nanoparticles already by 10 s of synthesis. This stage identified by isolation of a fraction corresponding to nanoparticles in the size distribution. Full involvement of Ar-Gal macromolecules in the stabilization of formed selenium nanoparticles is completed by 8 min of the synthesis, which is accompanied by a narrowing of the size distribution of the formed nanoparticles. All basic stages of the particle formation and growth, as well as Ostwald ripening, in the case of long-term sample storage have been recorded by both TEM and the spectral ensemble methods. In the paper the most probable mechanism of selenium nanoparticle formation under the selected synthesis conditions is explained based on all the data obtained on the nature of nanoparticle size distribution. Besides, the possibility of using these spectral methods to estimate the dynamics of nanoparticle synthesis is discussed. Highlights: Spectral ensemble methods (DLS, optical and luminescence spectroscopy) can be used to evaluate the dynamics of nanoparticle synthesis in solution. The formation of nanoparticles is identified almost instantly (by 10 s of synthesis) by the separation of the small particle fraction, in the size distributions obtained from all spectral methods and confirmed by TEM. The nature (symmetry, modality) of the size distribution of Ar-Gal-stabilized SeNPs depends on the synthesis step and varies strongly over time until the completion stage of the process is reached. Prolonged storage of aqueous solution of Ar-Gal-stabilized SeNPs is characterized by non-stationary of state and is accompanied by a number of processes typical of Ostwald ripening leading also to changes in the character of disperse distribution of particles identified by all used spectral and TEM methods. [ABSTRACT FROM AUTHOR]

The associative behavior of n-alkanes in petroleum dispersed systems and its changes under different temperature conditions were studied using dynamic light scattering, as well as optical, electron, and atomic force microscopy. Within the framework of the previously proposed hypothesis about the presence of associates (coacervates) of n-alkanes in crude oil systems, i.e., microparticles with a shell and a specific internal composition and structure, studies of the sizes of the existing structures were carried out at two different temperatures. It was shown that in the studied paraffinic oil system the associates remained even at elevated temperatures. [ABSTRACT FROM AUTHOR]

In the pursuit of identifying the novel resin glycoside modulators glucose-6-phosphatase and α-glucosidase enzymes, associated with blood sugar regulation, methanol-soluble extracts from the flowers of Ipomoea murucoides (cazahuate, Nahuatl), renowned for its abundance of glycolipids, were employed. The methanol-soluble extracts were fractionated by applying the affinity-directed method with glucose-6-phosphatase enzymes from a rat's liver and α-glucosidase enzymes from its intestines. Mass spectrometry and nuclear magnetic resonance were employed to identify the high-affinity compound as a free ligand following the release from the enzymatic complex. Gel permeation through a spin size-exclusion column allowed the separated high-affinity molecules to bind to glucose-6-phosphatase and α-glucosidase enzymes in solution, which led to the identification of some previously reported resin glycosides in the flowers of cazahuate, where a glycolipid mainly structurally related to murucoidin XIV was observed. In vitro studies demonstrated the modulating properties of resin glycosides on the glucose-6-phosphatase enzyme. Dynamic light scattering revealed conformational variations induced by resin glycosides on α-glucosidase enzyme, causing them to become more compact, akin to observations with the positive control, acarbose. These findings suggest that resin glycosides may serve as a potential source for phytotherapeutic agents with antihyperglycemic properties. [ABSTRACT FROM AUTHOR]

Aptamers are currently being investigated for their potential to improve virotherapy. They offer several advantages, including the ability to prevent the aggregation of viral particles, enhance target specificity, and protect against the neutralizing effects of antibodies. The purpose of this study was to comprehensively investigate an aptamer capable of enhancing virotherapy. This involved characterizing the previously selected aptamer for vaccinia virus (VACV), evaluating the aggregation and molecular interaction of the optimized aptamers with the recombinant oncolytic virus VV-GMCSF-Lact, and estimating their immunoshielding properties in the presence of human blood serum. We chose one optimized aptamer, NV14t_56, with the highest affinity to the virus from the pool of several truncated aptamers and built its 3D model. The NV14t_56 remained stable in human blood serum for 1 h and bound to VV-GMCSF-Lact in the micromolar range (Kd ≈ 0.35 μM). Based on dynamic light scattering data, it has been demonstrated that aptamers surround viral particles and inhibit aggregate formation. In the presence of serum, the hydrodynamic diameter (by intensity) of the aptamer–virus complex did not change. Microscale thermophoresis (MST) experiments showed that NV14t_56 binds with virus (EC50 = 1.487 × 109 PFU/mL). The analysis of the amplitudes of MST curves reveals that the components of the serum bind to the aptamer–virus complex without disrupting it. In vitro experiments demonstrated the efficacy of VV-GMCSF-Lact in conjunction with the aptamer when exposed to human blood serum in the absence of neutralizing antibodies (Nabs). Thus, NV14t_56 has the ability to inhibit virus aggregation, allowing VV-GMCSF-Lact to maintain its effectiveness throughout the storage period and subsequent use. When employing aptamers as protective agents for oncolytic viruses, the presence of neutralizing antibodies should be taken into account. [ABSTRACT FROM AUTHOR]

Lipopolysaccharides (LPSs) are major components of the outer membranes of Gram-negative bacteria. In this work, the structure of the O-polysaccharide of Ochrobactrum quorumnocens T1Kr02 was identified by nuclear magnetic resonance (NMR), and the physical–chemical properties and biological activity of LPS were also investigated. The NMR analysis showed that the O-polysaccharide has the following structure: →2)-β-d-Fucf-(1→3)-β-d-Fucp-(1→. The structure of the periplasmic glucan coextracted with LPS was established by NMR spectroscopy and chemical methods: →2)-β-d-Glcp-(1→. Non-stoichiometric modifications were identified in both polysaccharides: 50% of d-fucofuranose residues at position 3 were O-acetylated, and 15% of d-Glcp residues at position 6 were linked with succinate. This is the first report of a polysaccharide containing both d-fucopyranose and d-fucofuranose residues. The fatty acid analysis of the LPS showed the prevalence of 3-hydroxytetradecanoic, hexadecenoic, octadecenoic, lactobacillic, and 27-hydroxyoctacosanoic acids. The dynamic light scattering demonstrated that LPS (in an aqueous solution) formed supramolecular particles with a size of 72.2 nm and a zeta-potential of –21.5 mV. The LPS solution (10 mkg/mL) promoted the growth of potato microplants under in vitro conditions. Thus, LPS of O. quorumnocens T1Kr02 can be recommended as a promoter for plants and as a source of biotechnological production of d-fucose. [ABSTRACT FROM AUTHOR]

Complexes ofN‐heterocyclic carbenes have become an irrefutable class of molecules for the researchers in the field of organocatalysis. They rank as one of the potent tools in organic chemistry, which have a wide range of uses in various commercially important processes. Palladium(II) mesoionic carbene (MIC) complexes embedded with PPh3 as an ancillary ligand appeared to be efficient catalysts for the aforementioned purpose. Two new triazolylidene‐based palladium(II) complexes bearing either Py or PPh3 as an ancillary ligand were synthesized, with chirality present at one of the nitrogen atoms of the triazolylidene moiety. The MIC unit in these complexes possesses a mesityl group at the C‐wingtip and 1‐(1‐naphthyl)ethyl substitution at the N‐wingtip. NMR spectroscopy and ESI mass spectrometry were utilized to analyze these complexes. For the determination of the structure of the palladium(II) complex possessing mixed MIC and PPh3 donor ligands, single crystal X‐ray diffraction was utilized. The new complexes were employed in α‐arylation reaction and Sonogashira coupling reactions under copper‐free conditions. While studying their catalytic activity, it was brought to the conclusion that the PdII MIC complex having PPh3 as an ancillary ligand surpassed the complex with Py as an ancillary ligand.The catalytic results of these complexes are also correlated with cyclic voltammetric (CV) data. [ABSTRACT FROM AUTHOR]

Dynamic light scattering (DLS) is a well known experimental approach uniquely suited for the characterization of small particles undergoing Brownian motion in randomly inhomogeneous turbid scattering medium, including water suspension, polymers in solutions, cells cultures, and so on. DLS is based on the illuminating of turbid medium with a coherent laser light and further analyzes the intensity fluctuations caused by the motion of the scattering particles. The DLS‐based spin‐off derivative techniques, such laser Doppler flowmetry (LDF), diffusing wave spectroscopy (DWS), laser speckle contrast imaging (LSCI), and Doppler optical coherence tomography (DOCT), are exploited widely for non‐invasive imaging of blood flow in brain, skin, muscles, and other biological tissues. The recent advancements in the DLS‐based imaging technologies in frame of their application for brain blood flow monitoring, skin perfusion measurements, and non‐invasive blood micro‐circulation characterization are overviewed. The fundamentals, breakthrough potential, and practical findings revealed by DLS‐based blood flow imaging studies, including the limitations and challenges of the approach such as movement artifacts, non‐ergodicity, and overcoming high scattering properties of studied medium, are also discussed. It is concluded that continued research and further technological advancements in DLS‐based imaging will pave the way for new exciting developments and insights into blood flow diagnostic imaging. [ABSTRACT FROM AUTHOR]

Demetallization pretreatment is of great significance for the re-refining of used lubricating oil (ULO) by catalytic hydrogenation. Calcium-containing detergents colloidal stability, pyrolysis properties and kinetics studies have great significance for the demetallization pretreatment, re-refining, and resource utilization of ULO. The present study is focused on the pyrolysis mechanism and determining an accurate pyrolysis kinetic model for the removal of calcium from ULO using vulcanized calcium alkylphenolate (T-115B) colloidal as a model compound. Colloidal stability, pyrolysis process and thermal decomposition products have been studied by DLS, TEM, FTIR spectroscopy and XPS. The reaction energy for primary and secondary dissociation is calculated using the B3LYP-D3(BJ)/6-31g* method. The pyrolysis characteristics at different heating rates have been investigated by TG/DTA, and based on iso-conversional and master plot methods, E and kinetic equation have been determined, which revealed that the process can be divided into two distinct phases and the pyrolysis mechanism and function are necessarily described by a two-step model. The colloid was relatively stable when the temperature is lower than 395 K. When the temperature rises, compounds occur thermal decomposition, alkyl-CH2–S bond may be the trigger bond in the initiation process, and CaCO3 is the main degradation product. Based on iso-conversional methods (KAS and FWO) and master plot methods, values of E are determined as 96.67 and 100.78 kJ mol−1, respectively. And the pyrolysis reaction in stage 1 indicated that the most probable kinetic model followed an Fn mechanism with n = 1.39, and the second stage was also controlled by an Fn mechanism, but with n = 0.86. [ABSTRACT FROM AUTHOR]

Skin disorders, including acne vulgaris, atopic dermatitis, and rosacea, are characterized by the presence of biofilms, which are communities of microorganisms. The mechanical stability of biofilms is attributed to one of their constituents--polysaccharides--which are secreted by microorganisms. Sophorolipids are biosurfactants with biofilm disruption and removal abilities and are expected to become alternatives for classical petrochemical-based surfactants in cosmetics. In this study, we investigated the influence of sophorolipids on β-glucan such as dispersion status, interaction mechanism, and configuration change as a model polysaccharide of biofilm in aqueous solution. Dynamic light scattering measurements showed that sophorolipids interfere with the aggregation of β-glucan in aqueous solutions. In contrast, sodium dodecyl sulfate (SDS), which is used as a typical surfactant reference, promotes the aggregation of β-glucan. The interaction between sophorolipids and β-glucan were investigated using surface tension measurements and isothermal titration calorimetry (ITC). Surface tension increased only near critical micelle concentration (CMC) region of sophorolipids in the presence of β-glucan. This suggests that the interaction occurred in the solution rather than at the air-liquid interface. Moreover, the results of ITC indicate that hydrophobic interactions were involved in this interaction. In addition, the results of optical rotation measurements indicate that sophorolipids did not unfold the triple helical structure of β-glucan. β-glucan dispersion was expected to be caused steric hindrance and electrostatic repulsion when sophorolipids interacted with β-glucan via hydrophobic interactions owing to the unique molecular structure of sophorolipids attributed by a bulky sugar moiety and a carboxyl functional group. These results demonstrated unique performances of sophorolipids on β-glucan and provided more insights on the efficacy of sophorolipids as good anti-biofilms. [ABSTRACT FROM AUTHOR]

The introduction of zinc oxide nanoparticles (ZnOn) in sunscreens solved the issue of poor spreadability of these formulations, which often left a white film on the skin. However, safety concerns have arisen regarding the topical application of ZnOn. Some studies employed commercial sunscreens to address the safety issues of the topical application of ZnOn; however, commercial formulations are often complex and contain a wide range of ingredients that could attenuate the potential damage caused by the ZnOn. Therefore, in this study we aimed to develop a simple stable formulation containing 20% of coated and uncoated ZnOn, characterize the formulations and the nanoparticles, and assess the skin penetration in a Franz diffusion cell. The Feret's diameter for the uncoated and coated ZnOn was 137 nm and 134 nm, respectively. For the uncoated ZnOn the hydrodynamic size in water was 368 nm and for the coated ZnOn, the average hydrodynamic size in ethyl acetate was 135 nm. The incorporation of ZnOn led to formulations more consistent and easier to spread, as suggested by the lower work of shear and higher values of firmness, cohesiveness, consistency and index of viscosity compared with the vehicle. The stability assessment at 45 °C suggested that the formulations containing the ZnOn were stable for 30 days and the vehicle was stable for 90 days. The assessment of the skin penetration by reflectance confocal laser microscopy indicated that the ZnOn did not permeate into the deepest layers of the skin, but accumulated on the skin furrows, hair and hair follicles. [ABSTRACT FROM AUTHOR]

Manganese oxide nanoparticles (MnOx NPs) are finding applications in several environmentally important areas such as farming and energy storage. MnOx NPs span a range of metal oxidation states that open up a wide range of applications in catalysis as well. As a result, it is important to understand how such materials can impact human health through incidental exposure. In this study, we examined a range of commercially available Mn2O3 NPs and compared our characterization data to those supplied by manufacturers. Discrepancies were noted and then measured values were used to assess the biological impact of these materials on three mammalian cell lines—A549, HepG2 and J774A.1 cells. Cell toxicity assays showed that all Mn2O3 particles exhibited cytotoxic effects that may be correlated, at least in part, to the production of reactive oxygen species. All eight nanoforms also activated caspase 3 but not caspase 1, although the magnitude of these changes varied greatly between materials. [ABSTRACT FROM AUTHOR]

The geochemical behavior of microplastics (MPs) and nanoplastics (NPs) in the environment has become a global hot topic. Aggregation effect is an important factor controlling the geochemical behavior of NPs, yet there is conflicting evidence regarding the dependence of aggregation on NPs size. Investigating the general patterns and dominant mechanisms governing the aggregation behavior of different-sized NPs under various environmental conditions, will provide help in understanding and predicting the fate of NPs with different sizes. The study has shown that NPs with the same chemical composition but different sizes have different stability and mobility under the same conditions. The critical coagulation concentration (CCC) for NPs increases with the decrease in particle size at a fixed surface ζ potential (CCC=325mmol/L, 296mmol/L, 264mmol/L for 50nm, 100nm, and 200nm, respectively); indicating smaller NPs may transport longer distances. As the pH increased from 5.5 to 7, the negative surface charge of 100 and 200nm NPs allowed them to remain stable even at higher ionic strength. However, 50 nm NPs underwent rapid aggregation because of its smaller ζ potential. Therefore, the effects of pH, ionic strength and NPs sizes should be considered comprehensively in predicting and evaluating the geochemical behavior of NPs in the natural environment. [ABSTRACT FROM AUTHOR]

In the previously published results, we studied the effect of flavin mononucleotide (FMN), sodium halides NaF and NaBr, iron chloride FeCl3 and aluminum chloride AlCl3 on zigzag patterns of films obtained from saline solutions of bovine serum albumin (BSA). Changes in the properties of the biopolymer and its aqueous environment in solutions were monitored by UV absorption and fluorescence spectroscopy, microwave dielectrometry and dynamic light scattering. This work summarizes the obtained results on the influence of components of various nature on BSA and its film textures. Changes in the parameters of zigzag patterns are associated with polydispersity due to the presence of colloidal particles, aggregates and FMN associates, as well as a decrease in the surface potential and BSA hydration. The possibility of predicting the character of the influence of the studied biologically active substances on BSA is analyzed. [ABSTRACT FROM AUTHOR]

Particulate matter emissions from conventional automobiles are of great concern due to their significant health impacts. Upgradation of fuel has become essential for the reduction of these emissions. The study focuses on the effect of the size of aggregated Alumina (Al2O3) nanoparticles dispersed as nano-fuel on the emission and performance characteristics of a Compression Ignition engine. The size distribution of the dispersed nanoparticles significantly affects various physicochemical and transport properties of the nanofluids. In this work, effect of the size reduction of dispersed Alumina particles using mechanical methods like ball milling and ultra-sonication, on the emission and performance characteristics of a compression ignition engine, is studied in detail. The long-term dispersibility of the nano-fuel was studied using the Dynamic Light Scattering (DLS) technique. The particle stabilization through the inhibition of agglomerate formation was achieved with the surfactant Span80. The DLS analysis showed improvement in the long-term stability of dispersed particles when ball milling and bath sonication were combined with the surfactant. It was observed that the ball-milled Al2O3 particles remained dispersed even after 24 days of preparation. The nano-fuel sample with an Al2O3 concentration of 50 ppm and 100 ppm prepared using mechanical methods showed improved engine and emission characteristics. The results show a significant difference in the emission characteristics compared to neat diesel and nano-fuel prepared without ball milling. The maximum improvement in brake-specific fuel consumption, hydrocarbon emissions, nitrogen oxide emissions, and smoke opacity was found to be 16.8%, 27.4%, 25.1%, and 14.8%, respectively. [ABSTRACT FROM AUTHOR]