Polyethylene Glycol Concentration Research Articles

Properties of SiO2-Al2O3 refractories based on silica glass binder suspension and investigation of their printability using the Direct Ink Writing method

The SiO2-Al2O3 refractories and corresponding inks for 3D printing were prepared from silica glass binder suspensions and fused alumina with grain sizes of 75 and 240 μm. Phase analysis (XRD) and morphological studies (SEM) were conducted to investigate the influence of sintering temperature and Al2O3 content on the strength, porosity, and density of the refractories. Rheological studies (rotational viscometry) were carried out determine the effect of polyethylene glycol (PEG) and hydroxypropyl methylcellulose (HPMC) content on the flow behavior of the inks. It was established that firing refractories based on fused silica and fused alumina at 1500 and 1600 °C led to the formation of mullite and aluminosilicate melt on the surface of Al2O3 grains, enhancing the strength of the synthesized materials. Addition of PEG and HPMC to the ink composition was found to improve their rheological properties by increasing yield strength and promoting plastic flow. The ink demonstrated high printability and they are suitable for producing refractories using the Direct Ink Writing method.

Optimization and Characterization of PEG Extraction Process for Tartary Buckwheat-Derived Nanoparticles.

Plant-derived edible nanovesicles serve as crucial nanocarriers for targeted delivery of bioactive substances, including miRNAs and phytochemicals, to specific tissues. They have emerged as a significant focus in precision nutrient delivery research. In this study, Tartary-buckwheat-derived nanoparticles (TBDNs) were isolated and purified using a combination of differential centrifugation and PEG precipitation. A response surface test was employed to optimize the extraction process of TBDNs in terms of yield, total phenol and flavonoid content, as well as antioxidant activity. The results demonstrated that TBDNs exhibited the highest yield and activity at a 10% concentration of PEG, pH 5, and centrifugation temperature of 4 °C. Under these conditions, the measured yield of TBDNs was 1.7795 g/kg, with a total phenol content of 178.648 mg/100 g, total flavonoid content of 145.421 mg/100 g, and DPPH-radical-scavenging rate reaching 86.37%. Characterization through a transmission electron microscope and nanoparticle-size-tracking analyzer revealed that TBDNs possessed a teato-type vesicle structure with dispersed vesicle clusters present within them. Furthermore, the extracted TBDNs were found to have an average particle size of 182.8 nm with the main peak observed at 162.8 nm when tested for particle size distribution analysis. These findings provide a novel method for extracting TBDNs while laying the groundwork for future investigations into their activities.

Enhancing drought resistance in Pinus tabuliformis seedlings through root symbiotic fungi inoculation.

Drought constitutes a major abiotic stress factor adversely affecting plant growth and productivity. Plant-microbe symbiotic associations have evolved regulatory mechanisms to adapt to environmental stress conditions. However, the interactive effects of different fungi on host growth and stress tolerance under drought conditions remain unclear. This study explored the effects of varying polyethylene glycol (PEG-6000) concentrations (0%, 15%, 25%, and 35%) on the growth and physiological responses of two ectomycorrhizal fungi (Suillus granulatus (Sg) and Pisolithus tinctorius (Pt)) and two dark septate endophytes (Pleotrichocladium opacum (Po) and Pseudopyrenochaeta sp. (Ps)) isolated from the root system of Pinus tabuliformis. Specifically, the study aimed to evaluate six inoculation treatments, including no inoculation (CK), single inoculations with Sg, Pt, Po, Ps, and a mixed inoculation (Sg: Pt : Po: Ps = 1:1:1:1), on the growth and physiological characteristics of P. tabuliformis seedlings under different water regimes: well-watered at 70% ± 5%, light drought at 50% ± 5%, and severe drought at 30% ± 5% of the maximum field water holding capacity. All four fungi exhibited the capacity to cope with drought stress by enhancing antioxidant activities and regulating osmotic balance. Upon successful root colonization, they increased plant height, shoot biomass, root biomass, total biomass, and mycorrhizal growth response in P. tabuliformis seedlings. Under drought stress conditions, fungal inoculation improved seedling drought resistance by increasing superoxide dismutase and catalase activities, free proline and soluble protein contents, and promoting nitrogen and phosphorus uptake. Notably, mixed inoculation treatments significantly enhanced antioxidant capacity, osmotic adjustment, and nutrient acquisition abilities, leading to superior growth promotion effects under drought stress compared to single inoculation treatments. All four fungi tolerated PEG-induced drought stress, with increased antioxidant enzyme activities and osmotic adjustment substances and they promoted the growth and enhanced drought resistance of P. tabuliformis seedlings.

Development of shape memory epoxy resin/polyethylene glycol film based on molecular dynamics simulation and performance investigation

AbstractBased on the molecular dynamics (MD) simulation of glass transition temperature (Tg) and hydrogen bonding in the composite system of epoxy resin (Ep) and polyethylene glycol (PEG), this work developed shape memory Ep/PEG (EpP) films with controllable thermal response, recycling and reprocessing functions using melt dispersion and polymerizing‐pressing processes. EpP films with different PEG contents exhibit excellent shape memory performance, among which the shape recovery rate of EpP‐5 film can reach 92.7%, which can recover from complex structures to the initial shape. The PEG in the composite system can effectively regulate the thermal and mechanical properties of EpP, especially increasing the strain at break and reducing the Tg. Compared with EpP‐0 film. The Tg of EpP‐15 film increased by 40°C and the strain at break increased by 18.56%. Furthermore, compared with the EpP‐0 film, the recycling‐reprocessing temperature of EpP‐15 film has been reduced by 75°C. In summary, based on MD simulation, shape memory EpP films with controllable thermal response, recycling, and reprocessing functions have been successfully developed, and have shown considerable application prospects in the field of intelligent materials.

Simulation of UV curing of photosensitive resins with phase change materials

Based on the mechanism of the resin polymerization reaction and free radical diffusion under UV irradiation, here, a mathematical model of the curing process was established for the mixture of photosensitive resin (PAA) and polyethylene glycol (PEG, as the phase change material), and the factor influencing the mechanical performance of the cured samples was analyzed. The yield stress (σs) of the pure resin sample can reach 50 MPa when the monolayer curing depth is 5 mm. σs decreases with the increase in the PEG content and monolayer curing depth. With increasing the monolayer exposure time, the yield stress increases and then decreases, and there is an optimum value. The material has the maximum stress at the monolayer exposure time of 13.5 s when the resin content is 50 %.

Mild osmotic stress offers photoprotection in Chlamydomonas reinhardtii under high light

The exposure of autotrophs to high light intensities significantly impacts their photosynthetic performance. When combined with unpredictable climate changes, the lethality of these effects is exacerbated and, often surpassing the organisms' threshold for tolerance. In this regard, our study centres on examining the mitigating effects of mild osmotic stress induced by 2% Polyethylene Glycol (PEG) in conjunction with high-light conditions, using Chlamydomonas reinhardtii as a model system. Cells were cultivated under low PEG-induced osmotic stress at various light intensities, and their responses were analyzed through biochemical and biophysical approaches. Remarkably, cells grown under lower PEG concentrations exhibited superior growth, increased biomass, and enhanced photosynthetic efficiency under high light compared to non-PEG-treated cells. Surprisingly, their non-photochemical quenching (NPQ) levels were lower, indicating the operation of a distinct photoprotective mechanism in PEG-grown samples. The PEG-grown cells demonstrated higher chlorophyll content but lower carotenoid content, supporting the NPQ data. Circular dichroism analysis suggested that the macro-organization of super-complexes was minimally disrupted in PEG-grown samples, even under high light. This was further supported by Blue native PAGE, which showed greater stability of the super-complexes in PEG-grown cells, implying heightened stability in pigment-protein interactions. Immunoblot analysis revealed minimal differences in core reaction center proteins between PEG-grown and non-PEG cells. Notably, this protective mechanism was absent in the cell wall-deficient mutant CC503. We propose that the partial photoprotection observed is attributed to the PEG shielding the cell wall. This result holds promise for enhancing algal biomass production under natural environmental conditions influenced by fluctuating light intensity.

Fast lipid vesicles and dielectric particles migration using thermal-gradient-induced forces

Abstract Lipid vesicles are small biological particles that can be used for both targeted drug delivery systems and clinical studies. Their optical manipulation, however, is limited by the small difference in refractive indices with the surrounding medium, as well as the requirement for high laser trapping powers. In this work, we combine gradient force and thermal forces to deliver and trap individual lipid vesicles with low-trapping laser powers. The total optothermal force exerted on liposomes causes them to migrate rapidly toward the laser focus with a high average migration velocity of 1.77 µm s−1 under 7.3% w/v polyethylene glycol (PEG) concentration and low trapping laser power of 1 mW. A high normalized experimental trap stiffness of 0.88 (pN µm) mW−1 was obtained at 7.3% w/v PEG/water solution. This work may open new ways for bioparticle sorting and manipulation with potential applications in cellular studies, drug delivery, biosensing, and medicine.

Electrooxidation of Poly(methyl-methacrylate) and Poly(ethylene glycol): Hydrogen Production from Plastic Wastes Electrolysis

Introduction. Green H2 production by water electrolysis at low temperature has some bottlenecks mostly dealing with the anodic reaction, the oxygen evolution reaction (OER), given its thermodynamic and kinetic limitations [1]. One strategy to reduce the energy requirements for this H2 production route is the replacement of the conventional OER (with a thermodynamic potential of 1.23 V vs. Reversible Hydrogen Electrode (RHE)) by a less-energy intensive reaction like the electrooxidation of organic molecules (in some cases presenting a thermodynamic potential as low as c.a. 0 V vs RHE). This approach also addresses the possibility of converting organic wastes into value-added chemicals avoiding the CO2 emissions derived from conventional treatments (e.g., incineration) [2, 3]. Our research group is focused on the electrochemical valorization of several organic wastes like polyethylene glycol (PEG) or poly(methyl-methacrylate) (PMMA). Both are commonly found in urban and industrial water effluents and concern has been raised about the true fate of these polymers in the environment. Herein, the possibility of generating H2 and value-added organic molecules from these plastic wastes has been explored. Experimental. A binary solvent strategy was followed to dissolve the PMMA polymer, by using 1 M H2SO4 in 80% v/v 2-propanol/water electrolyte. Then the electrooxidation of PMMA was studied in a 2-electrode batch cell at 70ºC with different PMMA concentrations (0.1-2 wt.%). On the other hand, the electrooxidation of ethylene glycol (EG) and PEG with various molecular weights (from 200 to 4000 g mol-1), which are soluble in water, was carried out in aqueous solutions (PEG concentrations from 1 to 20 g/L) between 30 and 80 °C by using a Polymer Electrolyte Membrane (PEM) reactor. Pt/C electrodes were used in all cases. A commercial Pt cathode was employed and the anode material was prepared by the spray-deposition of a Pt(20 wt.%)/C catalyst powder onto a carbon paper gas-diffusion layer. The liquid products at the anodic compartment were analysed by size-exclusion chromatography (SEC) and nuclear magnetic resonance (NMR) spectroscopy while the production of hydrogen in the cathodic compartment was online monitored with a mass spectroscopy. Results and discussion. In the case of PMMA electrooxidation, despite the dissolution challenge, polymer macromolecules showed to partially block the accessibility of the Pt active sites on the electrode and strongly degraded its electrochemical performance [4]. In the case of PEG, it was much more easily electrooxidised, at low cell voltages, from around 0.4 V at 80°C (Figure 1a), near to values recorded with EG, suggesting a first step linked with the electrooxidation of the terminal groups of the macromolecules chain. Current densities larger than 100 mA.cm-2 at 0.8 V and 80°C were achieved for low molecular mass molecules (200 and 400 g/mol). A decrease of the PEG molecular weight in the anodic solution was demonstrated by SEC, confirming that the electro-oxidation process likely follows two main mechanisms, involving the consumption of terminal –OH or intermediate -C-O-C- bonds cleavage (Figure 1b), depending on the polymer molecular weight. This study demonstrates the proof-of-concept of the low-temperature electro-oxidation of polymers containing C-O bonds in their main chain. Conclusions. With a further macroporous electrode enegineering and catalyst development, the electrolysis of plastic wastes stands as a promising technology not only for the production of hydrogen from macromolecules by electrochemical means, but also as a potential pathway to depolymarize plastic wastes, thus increasing their degradability. References. [1]. Y. Cheng, S.P. Jiang, Advances in electrocatalysts for oxygen evolution reaction of water electrolysis-from metal oxides to carbon nanotubes, Prog. Nat. Sci.: Mater. 25 (2015) 545-553.[2]. M. Simões, S. Baranton, C. Coutanceau, Electrochemical valorisation of glycerol, ChemSusChem. 5 (2012) 2106–2124[3]. Y.X. Chen, A. Lavacchi, H.A. Miller, M. Bevilacqua, J. Filippi, M. Innocenti, et al. Nanotechnology makes biomass electrolysis more energy efficient than water electrolysis. Nat. Commun. 5 (2014) 1-6.[4]. N. Grimaldos-Osorio, F. Sordello, M. Passananti, J. González-Cobos, A. Bonhommé, P. Vernoux, A. Caravaca. From plastic-waste to H2: A first approach to the electrochemical reforming of dissolved Poly(methyl methacrylate) particles. Int. J. Hydrogen Energy. 48 (2023) 11899-11913. Acknowledgments The authors gratefully acknowledge the French institution “Ecole Urbaine de Lyon” (EUL - Institut de Convergences) for funding a PhD grant of Dr. N. Grimaldos-Osorio. Figure 1

Isolation of Haustorium Protoplasts Optimized by Orthogonal Design for Transient Gene Expression in Phelipanche aegyptiaca.

The efficient protoplast transient transformation system in plants is an important tool to study gene expression, metabolic pathways, and various mutagenic parameters, but it has not been established in Phelipanche aegyptiaca. As a root parasitic weed that endangers the growth of 29 species of plants in 12 families around the world, there is still no good control method for P. aegyptiaca. Even the parasitic mechanisms of P. aegyptiaca and the related genes regulating parasitism are not yet understood. In this study, by comparing the factors related to protoplast isolation and transfection, we developed the optimal protocol for protoplast isolation and transfection in Phelipanche aegyptiaca haustorium. The optimal protoplast yield and activity were 6.2 × 106 protoplasts/g fresh weight [FW] and 87.85%, respectively, by using 0.5 mol/L mannitol, enzyme concentrations of 2.5% cellulase R-10 and 0.8% Macerozyme R-10 at 24 °C for 4 h. At the same time, transfection efficiency of protoplasts was up to 78.49% when using 30 μg plasmid, 40% polyethylene glycol (PEG) concentration, 24 °C incubation temperature, and 20 min transfection time. This is the first efficient protoplasts' isolation and transient transformation system of Phelipanche aegyptiaca haustorium, laying a foundation for future studies on the gene function and mechanisms of haustorium formation in parasitic plants.

Evaluating approach uncertainties of quantitative detection of SARS-CoV-2 in wastewater: Concentration, extraction and amplification

Substantial uncertainties pose challenges to the accuracy of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) quantification in wastewater. We conducted a comprehensive evaluation of two concentration methods, three nucleic acid extraction methods, and the amplification performance of eight primer-probe sets. Our results showed that the two concentration methods exhibited similar recovery rates. Specifically, using a 30 kDa cut-off ultrafilter and a centrifugal force of 2500 g achieved the highest virus recovery rates (27.32 ± 8.06 % and 26.37 ± 7.77 %, respectively), with lower corresponding quantification uncertainties of 29.51 % and 29.47 % in ultrafiltration methods. Similarly, a 15 % PEG concentration with 1.5 M NaCl markedly improved virus recovery (26.76 ± 5.92 % and 28.47 ± 6.74 %, respectively), and reducing variation to 22.16 % and 23.66 % in the PEG precipitation method. Additionally, employing a vigorous bead-beating approach at 6 m/s during viral RNA extraction significantly increased RNA yield, with an efficiency reaching up to 82.18 %. Among the evaluated eight primer-probe sets, the E_Sarbeco primer-probe set provided the most stable and consistent quantitative results across various sample matrices. These findings are crucial for establishing robust viral quantification protocols and enhancing methodological precision for effective wastewater surveillance, enabling sensitive and precise detection of SARS-CoV-2.

Marangoni Droplets of Dextran in PEG Solution and Its Motile Change Due to Coil-Globule Transition of Coexisting DNA.

Motile droplets using Marangoni convection are attracting attention for their potential as cell-mimicking small robots. However, the motion of droplets relative to the internal and external environments that generate Marangoni convection has not been quantitatively described. In this study, we used an aqueous two-phase system [poly(ethylene glycol) (PEG) and dextran] in an elongated chamber to generate motile dextran droplets in a constant PEG concentration gradient. We demonstrated that dextran droplets move by Marangoni convection, resulting from the PEG concentration gradient and the active transport of PEG and dextran into and out of the motile dextran droplet. Furthermore, by spontaneously incorporating long DNA into the dextran droplets, we achieved cell-like motility changes controlled by coexisting environment-sensing molecules. The DNA changes its position within the droplet and motile speed in response to external conditions. In the presence of Mg2+, the coil-globule transition of DNA inside the droplet accelerates the motile speed due to the decrease in the droplet's dynamic viscosity. Globule DNA condenses at the rear part of the droplet along the convection, while coil DNA moves away from the droplet's central axis, separating the dipole convections. These results provide a blueprint for designing autonomous small robots using phase-separated droplets, which change the mobility and molecular distribution within the droplet in reaction with the environment. It will also open unexplored areas of self-assembly mechanisms through phase separation under convections, such as intracellular phase separation.

3D Printed Drug Delivery Systems in Action-Magnetic Resonance Imaging and Relaxometry for Monitoring Mass Transport Phenomena.

The hypothesis of the study was that (1) 3D printed drug delivery systems (DDS) could be characterized in situ during drug release using NMR/MRI techniques in terms of mass transport phenomena description (interfacial phenomena), particularly for systems dealing with two mobile phases (e.g., water and low molecular weight liquid polymer); (2) consequently, it could be possible to deduce how these interfacial mass transport phenomena influence functional properties of 3D printed DDS. Matrix drug delivery systems, prepared using masked stereolithography (MSLA), containing poly(ethylene glycol) diacrylate (PEGDA) and low molecular weight polyethylene glycol (PEG) with ropinirole hydrochloride (RH) were studied as example formulations. The PEGDA to PEG (mobile phase) concentration ratio influenced drug release. It was reflected in spatiotemporal changes in parametric T2 relaxation time (T2) and amplitude (A) images obtained using magnetic resonance imaging (MRI) and T1-T2 relaxation time correlations obtained using low-field time-domain nuclear magnetic resonance (LF TD NMR) relaxometry during incubation in water. For most of the tested formulations, two signal components related to PEG and water were assessed in the hydrated matrices by MRI relaxometry (parametric T2/A images). The PEG component faded out due to outward PEG diffusion and was gradually replaced by the water component. Both components spatially and temporally changed their parameters, reflecting evolving water-polymer interactions. The study shows that dynamic phenomena related to bidirectional mass transport can be quantified in situ using NMR and MRI techniques to gain insight into drug release mechanisms from 3D printed DDS systems.

Activation of the antioxidant system and transduction of the mediated by exogenous calcium improve drought resistance in tobacco

Drought stress is one of the most important stresses in plants. The important role of calcium signal as a second messenger in alleviating drought stress is still unclear. We used tobacco as test material to simulate drought stress with 20 % PEG concentration. Physiological and transcriptome techniques were used to study how the model plant tobacco protects itself from drought stress by examining the mechanism used by exogenous calcium ions to respond to the antioxidant and hormone signals that indicate drought stress. Exogenous calcium was shown to increase the levels of expression of the proteins CDPK, CBL/CIPK and AQPs that respond to signaling by calcium under drought stress. The cis-acting elements of the promoters of the genes related to signals primarily focused on hormone and drought-related elements, which suggests that the exogenous calcium may mediate the transduction of hormone signals in response to drought stress. The results of physiological and transcriptional data showed that oxidative damage occurred in the tobacco leaves under drought stress. Under drought stress, exogenous calcium can enhance the activities of SOD (4.75 %), POD (42.33 %) and APX (512.43 %), up-regulate the expression of the genes that encode antioxidant enzymes to eliminate excessive reactive oxygen species (ROS), and alleviate the oxidative damage to tobacco leaves under drought stress. The calcium produced during drought stress increased the content of auxin (IAA), decreased that of abscisic acid (ABA) and downstream gene expression, and prevented excessive amplification of the ABA signal. Exogenous calcium enhanced the crosstalk between cytokinin, gibberellin and ABA signals.In summary, exogenous calcium can stimulate the synergistic effect of calcium and hormone signals and the antioxidant system, eliminate ROS, improve the crosstalk between plant hormones, and improve the drought resistance of tobacco.

Bioresorbable Polyester Coatings with Antifouling and Antimicrobial Properties for Prevention of Biofilm Formation in Early Stage Infections on Ti6Al4V Hard-Tissue Implants.

Implants made from titanium are used as prostheses because of their biocompatibility and their mechanical properties close to those of human bone. However, the risk of bacterial infection is always a major concern during surgery, and the development of biofilm can make these infections difficult to treat. A promising strategy to mitigate against bacterial infections is the use of antifouling and antimicrobial coatings, where bioresorbable polymers can play an important role due to their controlled degradability and sustained drug release, as well as excellent biocompatibility. In the present study, poly(d,l-lactide) (PDLLA) and poly[d,l-lactide-co-methyl ether poly(ethylene glycol)] (PDLLA-PEG) were studied, varying the PEG content (20-40% w/w) to analyze the effectiveness of PEG as an antifouling molecule. In addition, silver sulfadiazine (AgSD) was used as an additional antimicrobial agent with a concentration ≤5% w/w and incorporated into the PEGylated polymers to create a polymer with both antifouling and antimicrobial properties. Polymers synthesized were applied using spin coating to obtain homogeneous coatings to protect samples made from titanium/aluminum/vanadium (Ti6Al4V). The polymer coatings had a smoothing effect in comparison to that of the uncoated material, decreasing the contact area available for bacterial colonization. It was also noted that PEG addition into the polymeric chain developed amphiphilic materials with a decrease in contact angle from the most hydrophobic (Ti6Al4V) to the most hydrophilic PDLLA-PEG (60/40), highlighting the increase in water uptake contributing to the hydration layer formation, which confers the antifouling effect on the coating. This study demonstrated that the addition of PEG above 20% w/w and AgSD above 1% w/v into the formulation was able to decrease bacterial adherence against clinically relevant biofilm former strains Staphylococcus aureus and Pseudomonas aeruginosa.

Impact of PEG Content on Doxorubicin Release from PLGA-co-PEG Nanoparticles.

Nanoparticles (NPs) have become attractive vehicles for drug delivery in cancer therapy due to their ability to accumulate in tumours and mitigate side effects. This study focuses on the production of doxorubicin (DOX)-loaded NPs comprising Poly (lactic-co-glycolic acid)-Polyethylene glycol with varying PEG proportions and the examination of their impact on drug release kinetics. DOX-loaded NPs, composed of PLGA-co-PEG with PEG contents of 0%, 5%, 10%, and 15%, were synthesized by the solvent evaporation technique, exhibited spherical morphology, and had sizes ranging from 420 nm to 690 nm. In vitro drug release studies revealed biphasic profiles, with higher PEG contents leading to faster and more extensive drug release. The Baker-Lonsdale model demonstrated the best fit to the drug release data, indicating that the release process is diffusion-controlled. The diffusion coefficients for DOX determined ranged from 6.3 × 10-18 to 7.55 × 10-17 cm2s-1 and exhibited an upward trend with increasing PEG content in the polymer. In vitro cytotoxicity tests with CHO cells showed that unloaded NPs are non-toxic, while DOX-loaded PLGA-PEG 15% NPs induced a greater decrease in cellular viability compared to their PLGA counterparts. A mathematical relationship between the diffusion coefficient and PEG percentage was derived, providing a practical tool for optimizing DOX release profiles.

Study on the Biological Characteristics of Dark Septate Endophytes under Drought and Cadmium Stress and Their Effects on Regulating the Stress Resistance of Astragalus membranaceus.

Astragalus membranaceus is a famous traditional medicinal plant. However, drought and cadmium (Cd) pollution are the main abiotic stress factors that affect plant growth and yield and the ability to improve the host's stress resistance through the use of beneficial endophytic fungi. To evaluate the tolerance of dark septate endophytes (DSE) to various abiotic stresses, 10 DSE strains [Microsphaeropsis cytisi (Mc), Alternaria alstroemeriae (Aa), Stagonosporopsis lupini (Sl), Neocamarosporium phragmitis (Np), Paraphoma chlamydocopiosa (Pc), Macrophomina phaseolina (Mp'), Papulaspora equi (Pe), Alternaria tellustris (At), Macrophomina pseudophaseolina (Mp), and Paraphoma radicina (Pr)] were investigated under different drought and Cd stressors in vitro by using solid-plate cultures and liquid-shaker cultures in the current study. The experiments involved using varying concentrations of PEG (0, 9, 18, and 27%) and Cd2+ (0, 25, 50, and 100 mg/L) to simulate different stress conditions on DSE. Additionally, the effect of DSE (Np and At) on the growth of A. membranaceus at different field water capacities (70% and 40%) and at different CdCl2 concentrations (0, 5, 10, and 15 mg Cd/kg) in soil was studied. The results demonstrated that the colony growth rates of Aa, Np, Pc, Mp', and Mp were the first to reach the maximum diameter at a PEG concentration of 18%. Aa, Np, and At remained growth-active at 100 mg Cd/L. In addition, Aa, Np, and At were selected for drought and Cd stress tests. The results of the drought-combined-with-Cd-stress solid culture indicated that the growth rate of Np was significantly superior to that of the other strains. In the liquid culture condition, the biomasses of Np and Aa were the highest, with biomasses of 1.39 g and 1.23 g under the concentration of 18% + 25 mg Cd/L, and At had the highest biomass of 1.71 g at 18% + 50 mg Cd/L concentration, respectively. The CAT and POD activities of Np reached their peak levels at concentrations of 27% + 50 mg Cd/L and 27% + 25 mg Cd/L, respectively. Compared to the control, these levels indicated increases of 416.97% and 573.12%, respectively. Aa, Np, and At positively influenced SOD activity. The glutathione (GSH) contents of Aa, Np, and At were increased under different combined stressors of drought and Cd. The structural-equation-modeling (SEM) analysis revealed that Aa positively influenced biomass and negatively affected Cd content, while Np and At positively influenced Cd content. Under the stress of 40% field-water capacity and the synergistic stress of 40% field-water capacity and 5 mg Cd/kg soil, Np and At significantly increased root weight of A. membranaceus. This study provides guidance for the establishment of agricultural planting systems and has good development and utilization value.

Effect of Changing the Concentration of Zinc Oxide Nanoparticles on the Viscosity of the Polyacrylamide / Polyethylene Glycol Solutions

In this work, Polyacrylamide/ Polyethylene glycol solutions of different molecular weights for Polyethylene glycol and different concentrations (17, 29, 38, 45, and 57 %) of ZnO nanoparticles were prepared by dissolving 0.5g of Polyethylene glycol in 20mL Polyacrylamide, then adding different concentrations of ZnO nanoparticles. Relative viscosity values are calculated by using the efflux time of the solutions, the viscosities(relative viscosity (ƞr), specific viscosity (ƞsp), reduced viscosity (ƞred) and inherent viscosity (ƞint) were calculated for all solutions, where measurements indicated an increase in these properties with increased concentration of ZnO nanoparticles and increased molecular weight of Polyethylene glycol. Viscosity is a significant parameter during the electrospinning process, and if the molecular weight increases, the viscosity of the solutions increases, making subsequent synthesis and purification more difficult. the constants KH and KK were calculated from the slopes of the viscosity values related to the Huggins and Kramer equations. These results can be used in many applications and scientific studies.

Enhancing camptothecin loading and release control through physical surface modification of organosilica nanoparticles with polyethylene glycol

The surface modification of nanoparticles holds the potential to enhance the loading capacity of drug molecules and regulate their release, making it possible to exploit the differences between tumor and normal cells. To this end, the surfaces of tetrasulfide-based phenylene-containing biodegradable periodic mesoporous organosilica (BPMO) nanoparticles (designated P4S) are modified herein with a hydrophilic and biocompatible polyethylene glycol (PEG) polymer. The PEG coating is optimized by adjusting the PEG concentration during synthesis, thus resulting in a significant increase in the nanoparticle stability. Furthermore, PEG modification enhances the nanoparticles' camptothecin (CPT) loading capacity. Drug release assessments under physical and acidic pH conditions demonstrate the pH-responsive properties of the P4S nanoparticles upon PEG functionalization, which results in increased drug release at low pH, along with enhanced cellular uptake potential. Notably, the cytotoxicity of CPT against HepG2 cancer cells is significantly improved when loaded into the P4S-PEG nanoparticles. These findings reveal the efficacy of PEG surface modification of the drug-delivery material in augmenting the activity of CPT, with promising prospects for clinical applications.

Enhancing growth and bioactive metabolites characteristics in Mentha pulegium L. via silicon nanoparticles during in vitro drought stress

The development and production of secondary metabolites from priceless medicinal plants are restricted by drought stress. Mentha pulegium L. belongs to the Lamiaceae family and is a significant plant grown in the Mediterranean region for its medicinal and aesthetic properties. This study investigated the effects of three polyethylene glycol (PEG) (0, 5, and 10%) as a drought stress inducer and four silicon nanoparticle (SiNP) (0, 25, 50, and 100 ppm) concentrations as an elicitor to overcome the adverse effect of drought stress, on the growth parameters and bioactive chemical composition of M. pulegium L. plants grown in vitro. The experiment was performed as a factorial experiment using a completely randomized design (CRD) consisting of 12 treatments with two factors (3 PEG × 4 SiNPs concentrations), 6 replicates were used for each treatment for a total of 72 experimental units.The percentage of shoot formation was inversely proportional to the PEG concentration; for the highest PEG concentration, the lowest percentage of shoot formation (70.26%) was achieved at 10% PEG. SiNPs at 50 ppm enhanced shoot formation, the number of shoots, shoot height, fresh and dry weight, rosmarinic acid, total phenols, and 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity. The methanol extract from M. pulegium revealed the presence of significant secondary metabolites using gas chromatography‒mass spectrometry (GC–MS). The principal constituents of the extract were limonene (2.51, 2.99%), linalool (3.84, 4.64%), geraniol (6.49, 8.77%), menthol (59.73, 65.43%), pulegone (3.76, 2.76%) and hexadecanoic acid methyl ester or methyl palmitate (3.2, 4.71%) for the 0 ppm SiNPs, PEG 0% and 50 ppm SiNPs, and PEG 10%, respectively. Most of the chemical components identified by GC‒MS in the methanol extract were greater in the 50 ppm SiNP and 10% PEG treatment groups than in the control group. SiNP improves drought tolerance by regulating biosynthesis and accumulating some osmolytes and lessens the negative effects of polyethylene glycol-induced drought stress.Based on the results, the best treatment for most of the parameters was 50 ppm SiNPs combined with 10% PEG, the morphological and chemical characteristics were inversely proportional to the PEG concentration, as the highest PEG concentration (10%) had the lowest results. Most parameters decreased at the highest SiNP concentration (100 ppm), except for the DPPH scavenging percentage, as there was no significant difference between the 50 and 100 ppm SiNPs.

Effect of PEG concentration on drug release from PLA-PEG copolymers: A molecular dynamics simulation study

Mercaptopurine (6-MP), a cancer medication limited by its hydrophobic properties, was studied using molecular dynamics simulations with biodegradable copolymers (PLA-PEG, PLA-PEG-PLA, PEG-PLA-PEG) as drug carriers. The influence of PEG concentration in copolymers on drug release was examined. Results revealed that blending PEG with PLA or copolymerizing them affected hydrogen bond numbers and mixing energy in the drug carrier, dependent on copolymer type and PEG concentration. Introducing PEG into PLA chains increased hydrogen bonds and energy, but copolymerizing PLA and PEG did not consistently enhance hydrogen bond energy (PLA-PEG-PLA > PEG-PLA-PEG > PLA-PEG). Mixing energy was consistently elevated by PEG-PLA copolymerization, ranked PEG-PLA-PEG > PLA-PEG > PLA-PEG-PLA. The fastest drug release was observed with the PLA&PEG-10.9 carrier, attributed to weak PLA-PEG chain connections facilitating water access to PEG. Increasing PEG content reduced chain mixing energy, slowed drug release via stronger chain hydrogen bonding. Notably, PEG-PLA-PEG-8.7 exhibited the highest drug release rate due to quicker water penetration. The copolymer type and chain length were found to impact water molecule access to PEG and drug release rate significantly.