Colloid and Polymer Science最新文献

Radiation skin injury (RSI) is a common side effect of radiation therapy for cancer patients, and bacterial infection at the RSI site usually hinders the healing process of the radiation skin injury, thus affecting the subsequent treatment regimen of the patient. To address this issue, we developed a dual network hydrogel containing the natural phenolic antioxidant curcumin. The hydrogel possesses good mechanical and swelling properties to effectively isolate radioactive skin wounds from the external environment, while curcumin released from the hydrogel can effectively inhibit bacterial infections in RSI. In addition, curcumin is able to regulate intracellular redox balance by affecting GSH transferase homologs in cell membranes, thereby reducing the inflammatory response at the wound site. The synergistic effect of antibacterial/anti-inflammatory action produced by the hydrogel effectively accelerates the rate of healing of RSI, providing valuable insights into the clinical management of radiation dermatitis.

The reduced graphene oxide (rGO), a two-dimensional nanomaterial with a large aspect ratio, exhibits good chemical stability and electrical conduction. Its applicability could be boosted by making its water-dispersible composite with metallic nanostructures like silver nanoparticles (SNPs). This study focuses on the synthesis and characterization of sustainable SNP-decorated reduced graphene oxide (SNP@rGO) nanosheets for poly(vinyl alcohol) (PVA) nanocomposite films having opto-mechanical potential. The SNP@rGO nanofillers were synthesized using eco-friendly reductants, including sodium citrate and chitosan, through a hydrothermal approach. The resulting nanofillers were characterized using advanced analytical techniques. The XRD analysis revealed that the resultant SNP@rGO nanocomposites retained the face-centered cubic crystal structure for metallic silver. The use of sodium citrate as a reductant resulted in highly crystalline SNP@rGO nanocomposites. SEM images confirmed the successful impregnation of spherical SNPs on the rGO nanosheets. FTIR results indicated interactions between SNPs and residual oxygen functionalities on the rGO nanosheets. The SNP@rGO-mediated PVA nanocomposites demonstrated superior performance, exhibiting up to 97% UV-blockage and a remarkable superoxide dismutase activity of 7.2 U/mg with enhanced mechanical strength and antibacterial properties compared to pristine PVA and SNP-loaded PVA films. Incorporating SNP@rGO into PVA enhanced its optical properties, rendering it suitable for optical applications. This investigation paves the way for using SNP@rGO/PVA nanocomposites in cutting-edge fields such as optical devices, biomedical coatings, and packaging materials.

The escalating release of carcinogenic azo dyes into aquatic environments necessitates the urgent development of efficient adsorbents. This study addresses this challenge by synthesizing two poly(N-vinyl imidazole)-based nanocomposite hydrogels, VMG (non-ionic crosslinking) and VDG (cationic crosslinking via 3, 3′ -divinyl-1, 1′ (1, 6-hexanediyl) di-imidazolium dibromide), incorporating 4.0 wt% of N-doped graphene quantum dots (NGQDs) to potentially enhance adsorption capacity. Characterization was performed using FTIR, XRD, SEM–EDS, BET, TEM, zeta potential (ZP), and swelling tests. VDG was selected for anionic dye adsorption studies due to its higher swelling and porous structure. ZP measurements of the adsorbent indicated that the ZP value was influenced not only by the solution pH but also by the presence of NGQDs in the nanocomposite. BET results indicated that the resulting VDG exhibited a high surface area of 245.02 m²/g. Batch experiments demonstrated highly efficient removal of model anionic dyes, Congo red (CR) and Methyl orange (MO), achieving maximum adsorption capacities of 454.54 and 400.0 mg/g at pH 7.0- and 60-min contact time, conditions likely favoring electrostatic interactions. The adsorption isotherm and kinetic data best fit the Langmuir for both CR and MO, pseudo-first order model for CR and Elovich model for MO, suggesting monolayer adsorption and a predominantly chemisorption-controlled process. The thermodynamic data indicated that dyes adsorption onto the VDG was endothermic and spontaneous. These findings highlight the VDG nanocomposite as a promising and potentially high-capacity adsorbent for the effective removal of anionic dyes from wastewater.

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This study develops an optimized nanoemulsion for efficient oil-based drilling fluid (OBDF) removal, and the unique removal mechanisms of nanoemulsion are studied. Compared to surfactant solutions, the nanoemulsion exhibits enhanced wettability on solid surfaces and lower interfacial tension against oil phases (< 0.1 mN·m⁻¹), synergistically facilitating OBDF detachment through three mechanisms: low interfacial tension, wettability enhancement, and disjoining pressure effects. Enhanced emulsification produced monodisperse micron droplets under shear, overcoming Laplace resistance through pre-organized interfacial films. The synergistic combination of enhanced wettability (contact angle reduction to 25.4°) and nanoscale droplet dimensions (147 nm) significantly improves nanoemulsion permeation through OBDF filter cakes. These combined properties improve the removal effect of OBDF, while interfacial bonding strength at cement-casing (3.02 MPa) and cement-formation (2.74 MPa) interfaces matched pristine samples. These elucidated mechanisms provide theoretical guidance for formulating and optimizing nanoemulsion-based flushing fluids, while also facilitating their broader applications in fields such as enhanced oil recovery and environmental remediation.

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Metal oxide nanoparticles are widely used in various biomedical applications due to their ability to reach unique target positions within the body. In the present work, nickel cobaltite (NiCo₂O₄) nanoparticles (NPs) embedded into sodium alginate/gum arabic polymeric hydrogel beads for controlled release of bioactive agents were prepared. These hydrogel beads are comprehensively examined by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) analysis. XRD confirmed the generation of NiCo₂O₄ NPs and integration of NPs into the hydrogel matrix. The TEM studies revealed that the size of NPs is between 25 and 30 nm. Swelling studies revealed that hydrogel beads exhibit pH-dependent behaviour, which is suitable for controlled drug release in various physiological conditions. In vitro release tests revealed a higher release rate at pH 7.4 compared to pH 2.0. Using doxorubicin as a model drug, cytotoxic effects on human breast cancer cells were examined. The developed NPs-loaded hydrogel beads effectively prevent the growth of breast cancer cells, such as Michigan Cancer Foundation-7 (MCF-7) cells with a viability of 9.5%. Furthermore, the biocompatibility of NPs and sodium alginate/gum arabic hydrogel beads conducted with 3T3 fibroblast cells has shown that cell viability is more than 80%, indicating the biocompatibility of hydrogel beads. These hydrogel beads need to warrant further development as carriers for pH-responsive and controlled release of bioactive agents.

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The study investigates the electrical and dielectric properties of polar and non-polar polymer-based composites and Si-based composite varistors across a range of temperatures. Current-voltage characteristics (CVC) were measured, and the real (ε′) and imaginary (ε″) components of the dielectric constant were calculated at different frequencies. The results show that the CVC exhibits non-linearity over the entire measured temperature range, with the breakdown voltage shifting to lower electric fields as temperature increases. The polar polymer-based composites exhibit a current flow approximately five times higher than non-polar composites under the same applied voltage. For polar polymer composites, the dielectric constant (ε) increases monotonically with rising temperature, whereas non-polar polymer composites show a sharp decline in ε with temperature. A decrease in ε″ and loss tangent (tgδ) was observed with increasing temperature. The electrical conductivity (σ) of polar polymer composites decreases monotonically as temperature increases. In contrast, for non-polar polymer composites, σ decreases sharply at low voltages (<50 V) with increasing temperature, while at higher temperatures, σ increases. These findings highlight the contrasting behaviors of polar and non-polar polymer composites under varying thermal and electrical conditions, offering insights into optimizing materials for advanced dielectric and varistor applications.

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We present a simple analytic expression for the electrophoretic mobility of a weakly charged oil drop in an aqueous electrolyte solution, where the drop acquires its surface charge through ion adsorption. The derivation is based on a simplified Baygents-Saville model, in which no ions are present inside the drop. This model incorporates the Marangoni effect arising from interfacial tension gradients. The resulting analytic expression shows excellent agreement with the numerical results of Baygents and Saville for low zeta potential values, validating the accuracy of the approximation. It is found that, under the assumption of no internal ions, the electrophoretic mobility of the drop is independent of its internal dielectric permittivity. This behavior stands in contrast to the case of an oil drop with a uniform, constant surface charge density, where the mobility depends on the drop's internal dielectric permittivity. However, it is similar to the case of rigid particles, as shown by O’Brien and White. Furthermore, it is found that in the analytic expression for the electrophoretic mobility of a mercury drop, the leading term proportional to κa (where κ is the Debye–Hückel parameter and a is the drop radius) completely cancels out for an oil drop due to the tangential Maxwell stress and the Marangoni effect—both of which are absent in the case of a mercury drop. As a result, the electrophoretic mobility of an oil drop does not increase linearly with increasing κa when plotted at a fixed zeta potential.

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One way to mitigate microplastic pollution from pharmaceutical and cosmetic products is to develop nature-based ‘green’ microcapsules. This study involves in situ microencapsulation of therapeutic tea tree essential oil by brown algae-derived alginate biopolymer using classic external ionotropic gelation. The effects of type of divalent crosslinkers (calcium and barium ions), presence/absence of surfactant in oil-in-water (o/w) emulsion and molecular weight of alginate were investigated using gravimetry, scanning electron microscopy (SEM), shear rheometry, ultraviolet (UV) and infrared spectroscopy. Microcapsules were ~ 1 mm in diameter. Barium chloride crosslinker showed highest gel strength (8396 ± 306 Pa) and large pores on surface (59.9 ± 9.1 µm). Presence of surfactant lowered the gel strength (182.6 ± 100.5 Pa) and had smaller pore size (20.3 ± 2.6 µm). Microcapsules with no surfactant, calcium chloride crosslinker and low viscosity alginate showed optimum gel strength (3620.8 ± 141.5 Pa) and smooth surface. An interplay exists between loading capacity (proportional to pore size) and encapsulation efficiency (compromised by surface oil and water-soluble oil components). Life cycle analysis (LCA) shows significant reduction in global warming and ecotoxicity. This project supports eight Sustainable Development Goals (SDG) of United Nations and promotes blue economy.

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Gene therapy holds promise for a wide range of diseases, including Alzheimer’s, diabetes, and cancer, and requires the efficient transfer of nucleic acids into cells. However, transfection in primary cells is still problematic and requires the development of new transfection agents. Poly (β-amino ester) (PBAE) has attracted great attention in transfection research due to their low toxicity, high gene loading capacity, endosomal escape ability, and biodegradability properties. In this study, two new PBAEs with different molecular weights are synthesized that could provide high viability and transfection efficiency in primary cells. They are characterized using FTIR and ¹H NMR analysis. GPC-SEC system is also used to calculate the average molecular weight (M_w) and polydispersity index. PBAE nanoparticle preparation is carried out using the nanoprecipitation technique. The gene loading capacity, protective ability against nuclease degradation, and proton buffering capacity of nanoparticles are determined. Additionally, the morphology of PBAE_A:pEGFN1 complexes was investigated by STEM analysis. Finally, their cytotoxicity and transfection efficiency in primary ovine fibroblast (POF) cells are also investigated. The results reveal that the new PBAE with higher M_w achieves quite high transfection efficiency of about 87% and did not show any cytotoxic effects on these cells. These findings suggest that PBAE is a promising option to achieve high transfection efficiency in primary cells.

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This study focused on the development and characterization of chlorquinaldol (CQD)-loaded nanogels for effective topical application. CQD, a hydrophobic antimicrobial agent, was encapsulated using polymers like carbopol 940 and gellan gum through high-pressure homogenization to enhance its solubility and stability. The prepared nanogels exhibited a particle size of 143.56 ± 2.34 nm and a zeta potential of − 0.1 mV, ensuring stability and uniform dispersion. The pH of the formulation was optimized to 6.43, which is compatible with skin applications. The nanogels demonstrated sustained drug release, achieving 87.09 ± 1.08% release over 48 h, following first-order kinetics. Antimicrobial studies against Staphylococcus aureus and Pseudomonas aeruginosa showed superior efficacy, with zones of inhibition measuring 20.5 ± 1.2 mm and 18.3 ± 1.4 mm, respectively, compared to free CQD (15.2 ± 1.1 mm and 13.5 ± 1.0 mm). Furthermore, the nanogel formulations exhibited excellent spreadability (13.3 g cm/s) and were non-irritant, as confirmed by skin irritation tests on animal models. These findings suggest that CQD-loaded nanogels are a promising platform for enhanced topical drug delivery, offering sustained release, improved stability, and superior antimicrobial activity.

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