Physicochemical Research Articles

Assessing the Long-term Adverse Effects of Aluminium Nanoparticles on Freshwater Phytoplankton Using Isolated-species and Microalgal Communities.

The physicochemical properties of aluminum oxide nanoparticles (Al2O3-NPs or AlNPs) allow them to remain suspended in water for extended periods. Despite this, AlNPs are one of the least studied types of metal nanoparticles and pose a significant risk to aquatic ecosystems. Therefore, it is essential to understand the toxic mechanisms of AlNPs on microalgae and cyanobacteria, as they can have adverse effects on the entire aquatic food web. Our research aimed to assess the toxicity of continuous exposure to low environmentally relevant concentrations of AlNPs on the growth rate, photosynthetic activity, oxidative stress (ROS), and microcystin production (MC-LR) in a phytoplanktonic community (PCC) consisting of Scenedesmus armatus and Microcystis aeruginosa. Both single and community cultures were exposed to 1.0 μg mL-1 AlNPs for 28 days. The results showed a significant 20-40% inhibition of S. armatus population growth in both individual and community cultures after 28 days of exposure. In contrast, M. aeruginosa exhibited increased survival and cell division rates when exposed to nanoparticles, both individually and within the community. Additionally, S. armatus showed a substantial reduction in gross photosynthesis (Pg) and net photosynthesis (Pn), with less inhibition in respiration (R) after 28 days of exposure. Conversely, M. aeruginosa demonstrated higher rates of photosynthetic productivity in all three parameters (Pg, Pn, and R). In the PCC, respiration was inhibited from 14 to 28 days, and both Pg and Pn were also inhibited. Both S. armatus and M. aeruginosa showed 28-31% levels of ROS generation, while the phytoplanktonic community exhibited no significant ROS production. Moreover, the production and release of MC-LR decreased by 8-38% in M. aeruginosa compared to the control strain. These findings underscore the importance of monitoring the use and application of nanomaterials to mitigate their potential toxic effects on aquatic ecosystems.

Regulation of physicochemical properties of alginate-based hydrogels and preliminary applications in wound healing.

Alginate (Alg) hydrogels have demonstrated great potential in drug delivery, wound dressings, and tissue engineering. However, the practical applications of conventional Alg hydrogels suffer from rapid degradation, insufficient controlled drug release, and poor adhesion to tissues. In this paper, the physicochemical properties of Alg hydrogels were comprehensively modulated through chemical modification and the incorporation of various polymers. The results showed that introducing neutral polymers stabilized Alg hydrogels at room temperature. However, this stabilizing effect did not persist at 37 °C. The cationic chitosan (CS) can bind to Alg through electrostatic interaction. The incorporation of CS substantially improved the stability of Alg hydrogels and remarkably prolonged the release of BSA from hydrogels to 14 days at 37 °C. Meanwhile, introducing dopamine (DA)-modified Alg enhanced the adhesion of hydrogel to porcine skin. The optimized hydrogels were utilized to encapsulate platelet-rich plasma (PRP). The PRP-loaded composite hydrogel (2 wt% Alg, with a Ca2+/carboxyl group molar ratio of 0.2, a DA/carboxyl group molar ratio of 0.2, and a CS content of 30 % of Alg) exhibited an excellent therapeutic effect in the healing of rabbit shoulder cuff injury. These findings provide valuable insights into the modulation of physicochemical properties of hydrogels for biomedical applications.

Volatile constituents, physicochemical properties and antibacterial activity of black and fresh garlic (Allium sativum L.)

Black garlic is produced from fresh garlic by heat treatment at a controlled temperature and humidity for a certain period of time. The processing conditions are responsible for a series of changes in the plant material that culminate in the alteration of its physicochemical and bioactive properties. This study evaluated the physicochemical properties of fresh and black garlic, as well as the chemical composition and antibacterial activity of their essential oils. Regarding the physicochemical parameters evaluated, there was a significant difference in all parameters, showing that black garlic bulbs had a lower pH, water activity, and L* and b* parameters and higher values of ash, acidity and proteins. The chemical characterization of the essential oils from two batches of fresh garlic (FG1 and FG2) and two batches of black garlic (BG1 and BG2) was carried out using gas chromatography-mass spectrometry and gas chromatography-flame ionization detector. In the case of fresh garlic essential oil, diallyl disulfide and diallyl trisulfide represented more than 70% of the chemical composition of the two batches evaluated. For black garlic essential oils, 4-methyl-1,2,3-trithiolane and 5-methyl-1,2,3,4-tetrathiolane were the main components. Both fresh and black garlic essential oils have been shown to be rich in organosulfur compounds. As for antimicrobial activity, the black garlic essential oil showed greater inhibitory and bactericidal potential against Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa compared to fresh garlic. The black garlic essential oils evaluated are more promising for the microbiological control of food bacteria than those from fresh garlic.

Structural characterization and physicochemical properties of different hydrophilic natural deep eutectic solvents.

To overcome the toxic nature of organic solvents, scientific interest in the use of green solvents, particularly natural deep eutectic solvents (NADES), has increased over the past decade, leading to new applications in the food, nutraceutical, pharmaceutical, and cosmetic industries. Understanding the physicochemical properties and molecular interactions of NADES is essential for uncovering new potential applications in these fields. In this study, several lactic and citric acid-based NADES, as well as chloride choline- and urea-based NADES, were evaluated for their physicochemical properties, including density, pH, viscosity, conductivity, and refractive index. Additionally, nuclear magnetic resonance (NMR), and in particular nuclear Overhauser enhancement spectroscopy (NOESY), was employed to investigate the intermolecular interactions between the NADES components to confirm the formation of the eutectic mixture. The extraction efficiency of the confirmed NADES was tested for extracting polyphenols as a proof of concept to highlight their relationship with the measured properties. Lactic and choline chloride-based NADES provided the highest extraction yields. These results were also compared with the predicted extraction capabilities of each NADES provided by the COSMO-RS software.

Physicochemical and Antimicrobial Properties of Lactic Acid-Based Natural Deep Eutectic Solvents as a Function of Water Content

The interest in natural deep eutectic solvents (NADESs) in green technology as an alternative to organic solvents has grown over the past decades. In this work, for the first time, the effect of dilution with water on the physicochemical and antimicrobial properties of lactic acid-based NADES with choline chloride (NADES1), sorbitol (NADES2), and glucose (NADES3) was systematically studied. According to FTIR data, after the dilution of NADESs with water, the strong hydrogen bonds weakened, however, were not destroyed after dilution of up to 40% water. The dilution of NADES with water resulted in a linear decrease in density and refractive index and in a linear increase in pH. The equations for the prediction of NADES density, pH, and refractive index as a function of water content were calculated. The viscosity decreased by half after adding approximately 10% water. The initial viscosity of NADES2 and NADES3 was significantly different. However, after adding 20% of the water, the viscosity was almost the same. The most pronounced decrease in surface tension (by 46.7%) was found for NADES1. The water activity was decreased in the following order: NADES3 > NADES1 > NADES2. The dilution of NADES with water caused a gradual increase in water activity. NADES1 showed the lowest minimal inhibitory concentrations (MIC) (7.8, 3.9, and 0.98 mg/mL) and minimum bactericidal concentrations (MBC) (15.6, 7.8, and 1.95 mg/mL) for Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus, respectively. The antimicrobial activity was decreased by 2–8 times after the addition of 40% water. The water activity for all tested NADES together with low pH could explain the antimicrobial effect. The revealed regularity can be useful for the prediction of NADES properties and for the selection of green solvents on a laboratory and industrial scale.

Impact of Exopolysaccharides from Fructilactobacillus sanfranciscensis Ls5 on the Quality of Mantou: A Comparative Study of Fermentation Conditions

Lactic acid bacteria (LAB) and their exopolysaccharides (EPS) have the potential to enhance the quality of flour-based products. This study investigated the effect of EPS produced by Fructilactobacillus sanfranciscensis Ls5 on the quality of Mantou. LAB strains with high EPS production were isolated from traditional fermenters, and their characteristics and EPS properties were examined. Four different fermentation conditions (Blank, Yeast, Ls5-Yeast, and EPS-Yeast) were compared in terms of their effects on the physicochemical properties, in vitro digestion characteristics, and shelf-life of Mantou. The incorporation of Ls5 and its EPS into Mantou resulted in a lower dough fermentation pH, increased organic acid production, and enhanced fermentation activity. Additionally, the incorporation of Ls5 and its EPS led to significant improvements in the quality of the Mantou, including the extension of shelf-life, improved sensory evaluation, and a reduction in the sugar content. Additionally, there was an increase in resistant starch content during digestion in both types of Mantou, which could offer potential benefits to human glycemic health.

Physicochemical Characterization and Kinetics Study of Polymer Carriers with Vitamin C for Controlled Release Applications

This study focuses on the selection and evaluation of a kinetic model for the release of vitamin C from different delivery systems, including microcapsules, hydrogels, and a hybrid system combining both. The microcapsules were synthesized from a 2% sodium alginate solution and with vitamin C incorporated in selected formulations. Hydrogels were obtained through photopolymerization using poly(ethylene glycol) diacrylate and polyvinyl alcohol, with and without the addition of vitamin C. The hybrid system incorporated the vitamin C-containing microcapsules within the hydrogel matrix. Physicochemical properties, such as density, porosity, and water vapor transmission rate (WVTR), were evaluated. Kinetic studies of vitamin C release were conducted under dynamic and static conditions, and the experimental data were fitted to six different kinetic models: zero-order, first-order, second-order, Higuchi, Korsmeyer–Peppas, and Hixson–Crowell. The Higuchi and Korsmeyer–Peppas models provided the best fit for most systems, indicating that the release is predominantly controlled by diffusion and, in dynamic conditions, swelling of the matrix. The hybrid system, while exhibiting slower release than the microcapsules and hydrogel alone, demonstrated more controlled and sustained release, which is advantageous for applications requiring prolonged action.

Impact of water physicochemical properties on the survival of Oncomelania hupensis snails, the intermediate host of Schistosoma japonicum.

Schistosoma japonicum, the causative agent of schistosomiasis, heavily relies on its single intermediate host, the Oncomelania hupensis snail, for its life cycle. Controlling these snails effectively plays a pivotal role in curbing the transmission and prevalence of this disease. While prior research has extensively investigated the impact of environmental factors such as temperature and vegetation on snail survival, growth, and reproduction, the contribution of water physicochemical properties has been notably underexplored. This study presents laboratory experiments designed to comprehensively explore the influence of water physicochemical properties on snail survival, offering valuable insights into environmental factors for more precise predictions of snail distribution. We meticulously conducted laboratory snail survival experiments using water from different sources (river water/tap water), and employed a statistical approach amalgamating principal component analysis with Cox regression to preliminarily investigate the effects of different water physicochemical properties on the survival of snails. Our analysis indicates that after a 6-month laboratory snail survival experiment, the survival rate in the tap water group was significantly higher than that in the river water group for infected snails (χ2 = 7.74, p = 0.005), while the difference in survival rates for non-infected snails was not statistically significant (χ2 = 0.61, p = 0.434). The Principal Component-Cox regression analysis revealed that in the infected snail group, total phosphorus, pH value, five-day biochemical oxygen demand, conductivity, and nitrite were protective factors for snail survival, while phosphate and total nitrogen were risk factors. In the non-infected snail group, total phosphorus, pH value, five-day biochemical oxygen demand, conductivity, and nitrite were protective factors for snail survival, and total nitrogen, ammonia nitrogen, phosphate, and nitrate were risk factors. This study underscores the substantial impact of water quality's physicochemical properties on snail survival. The effects of water quality on snails are complex, and maintaining an appropriate level of organic matter content and controlling the pH value at a weak alkalescency level prove beneficial for snail survival. These findings hold significant promise for advancing our understanding of snail-borne diseases and optimizing control strategies.

Effect of Perilla Seeds Pretreatment on the Volatile Profile and Flavor Characteristics of Perilla Oil: Comparison of Oven, Infrared, and Microwave Heating

ABSTRACTThe effects of microwave (MW), infrared (IF), and oven heating (OH) on the volatile profile and flavor of perilla oil were investigated in this study. Physicochemical properties and Maillard reaction products of perilla oil were measured to investigate the potential pathway of flavor formation. Sensory evaluation, combined with headspace‐solid‐phase microextraction‐gas chromatography‐mass spectrometry (HS‐SPME‐GC‐MS) and electronic nose (E‐nose) techniques, was employed to determine the categories and contents of volatile compounds in perilla oil. Three heating treatments all effectively increased the content of odor‐active volatile compounds in perilla oil. Samples treated by MW contained higher concentration of heterocyclics, while samples treated using IF and OH contained more aldehydes. The content of (E,E)‐2,4‐heptadienal were highly correlated to P‐AV. The contents of pyrazines and furans were positively correlated with A420nm, particularly 2,5‐dimethyl‐pyrazine, trimethyl‐pyrazine, and 2‐pentylfuran. The content of hexanal and (E)‐2‐hexenal showed a negative correlation with the content of heterocyclic compounds. Consequently, the volatile compounds in perilla oils were generated through three potential mechanisms: lipid oxidation, the Maillard reaction, and their synergistic effect.

Principles and Biomedical Applications of Self-Assembled Peptides: Potential Treatment of Type 2 Diabetes Mellitus

Type 2 diabetes mellitus (T2DM) is the most prevalent metabolic disorder worldwide. There have been tremendous efforts to find a safe and prolonged effective therapy for its treatment. Peptide hormones, from certain organisms in the human body, as the pharmaceutical agents, have shown outstanding profiles of efficacy and safety in plasma glucose regulation. Their therapeutic promises have undergone intensive investigations via examining their physicochemical and pharmacokinetic properties. Their major drawback is their short half-life in vivo. To address this challenge, researchers have recently started to apply the state-of-the-art molecular self-assembly on peptide hormones to form nanofibrillar structures, as a smart nanotherapeutic drug delivery technique, to tremendously enhance their prolonged bioactivity in vivo. This revolutionary therapeutic approach would significantly improve patient compliance. First, this review provides a comprehensive summary on the pathophysiology of T2DM, various efforts to treat this chronic disorder, and the limitations and drawbacks of these treatment approaches. Next, this review lays out detailed insights on various aspects of peptide self-assembly: adverse effects, potential applications in nanobiotechnology, thermodynamics and kinetics of the process, as well as the molecular structures of the self-assembled configurations. Furthermore, this review elucidates the recent efforts on applying reversible human-derived peptide self-assembly to generate highly organized smart nanostructured drug formulations known as nanofibrils to regulate and prolong the bioactivity of the human gut hormone peptides in vivo to treat T2DM. Finally, this review highlights the future research directions to advance the knowledge on the state-of-the-art peptide self-assembly process to apply the revolutionary smart nanotherapeutics for treatment of chronic disorders such as T2DM with highly improved patient compliance.

Physicochemical and ecosystem properties of the Middle to Lower Xingu River, Brazil, prior to the operation of the Belo Monte Dam Complex

Physicochemical and ecosystem properties of the Middle to Lower Xingu River, Brazil, prior to the operation of the Belo Monte Dam Complex

Crucial aspects for maintaining rAAV stability.

The storage of rAAV vectors for gene therapy applications is critical for ensuring a constant product quality and defined amount of medication at the time of administration. Therefore, we determined the influence of different storage conditions on the physicochemical and biological properties of rAAV8 and rAAV9 preparations. Particular attention was paid to short-term storage, which plays a crucial role in both the manufacturing process and in clinical applications. Additionally, we addressed the question, of viability of rAAV8 and rAAV9 when subjected to very low-temperature storage conditions (below -65°C) or lyophilization. To determine the impact on rAAV vectors, various analyses were used, including the quantification of capsid and genome titers, as well as biopotency assessments, which are pivotal determinants in characterizing vector behavior and efficacy. Our data showed that freeze/thaw cycles hardly affected the functionality of rAAV9-aGAL vectors. In contrast, prolonged storage at room temperature for several days, resulted in a discernible decrease in biopotency despite consistent capsid and genome titers. When the storage temperature was further increased, the rAAV8-aGAL decay accelerated. For example, a short-term exposure of + 40°C and more, led to a reduction in the physical viral titer and to an even faster decline in efficacy determined by biopotency. However, the addition of sucrose and sorbitol to the rAAV9-aGAL and rAAV9-GAA preparations reduced the temperature sensitivity of rAAV and improved its stability. Furthermore, exposure of rAAV9-aGAL to highly acidic conditions (pH 2.5) dramatically reduced its biopotency by 70% or more. Most interestingly, a long-term storage of rAAV9-aGAL and rAAV8-FVIII vectors over 12 and 36months, respectively, demonstrated exceptional stability at storage temperatures below -65°C. Also, lyophilization conserved functionality for at least 10months. Our data showed how to maintain rAAV biopotency levels over the time without substantial loss. Storage at very low temperatures (below -65°C) preserved its effectiveness over years. Overall, pH and temperature conditions during the manufacturing process, storage and clinical application are worth considering. Consistency in the rAAV capsid titer determination did not necessarily indicate the preservation of biopotency. In conclusion, our approach determined several options for maximizing rAAV stability.

PENGARUH PENGGUNAAN KOAGULAN ALAMI SARI BELIMBING WULUH PADA TAHU PUTIH BERDASARKAN PERBEDAAN KONSENTRASI DAN LAMA PENGGUMPALAN

Tofu is a food whose process involves agglomerating soybean curd using coagulants, one of which is vinegar. In addition, from the other side, vinegar acid has shortcomings so that a natural coagulant substitute such as starfruit wuluh is needed. Belimbing wuluh one of the fruits that contains citric acid so that it can be used as a natural coagulant to replace vinegar, besides that it also contains oxalic acid, acetic acid, malic acid, formic acid, ascorbic acid and other compound components. This study aims to determine the effect of star fruit juice concentration and clotting time on the physicochemical and organoleptic properties of white tofu using star fruit as a coagulant. The method used was Randomized Group Design (RGD) using two factors, namely the concentration of Wuluh starfruit juice (factor 1) consisting of 4%, 5% and 6% and the coagulation activity (factor 2) consisting of 20 minutes, 30 minutes and 40 minutes. The testing parameters include protein content, fat content, moisture content, ash content, carbohydrate content, chewiness and organoleptic (scent, taste, color, texture and liking). The results of the analysis showed that there was an effect of the use of star fruit juice concentration and clotting time on protein in white tofu, which ranged from 3.50% - 6.77%; the range of water content ranged from 85.79% - 89.89%, chewiness was 3.08 N - 16.03 N. However, there was no significant effect on ash, fat and carbohydrates. As for the organoleptic test, the results showed a significant effect for scent parameters ranging from 2.80 (somewhat fragrant) - 4.05 (fragrant), color ranging from 2.45 (not bright white) - 3.45 (slightly bright white), texture ranging from 2.85 – 3,65 (slightly chewy) and liking ranging from 3.05 (slightly like) - 3.7 (like).

Development and quality evaluation of a finger millet (Eleusine coracana (L.) Gaertn.) flour incorporated set yoghurt.

Nutritional and therapeutic properties of yoghurts can be enhanced by incorporating bioactive food components. The present study was focused on formulating a finger millet flour incorporated set yoghurt to deliver the inherent health benefits of finger millet to consumers in a ready-to-eat way. Ten yoghurt samples were formulated incorporating different percentages of finger millet flour. Physicochemical and microbiological properties of the yoghurts were evaluated. When considering organoleptic properties, 7% finger millet flour incorporated yoghurt was selected as the most preferable yoghurt among the tested finger millet flour incorporated yoghurts. It was complying with the physicochemical requirements and microbiological limits mentioned in the Sri Lanka Standard - Specification for yoghurts. Incorporation of 7% finger millet flour enhanced the nutritional composition of the yoghurt in terms of total dietary fibers (1.04%), total phenolic content (54.09 mg Gallic acid equivalents/100 g of yoghurt), total flavonoid content (8.00 mg Quercetin equivalents/100 g of yoghurt) and antioxidant properties including ABTS radical scavenging activity (190.81 mg Trolox equivalents/100 g of yoghurt) without affecting the sensory properties. Since it was formulated without adding gelatine, the 7% finger millet flour incorporated yoghurt is suitable for lacto-vegetarians. When stored in a refrigerator at 4 °C, the 7% finger millet flour incorporated yoghurt could be stored satisfactorily for four weeks. The finger millet flour incorporated yoghurt is capable of not only fulfilling the consumer demands for finger millet-based ready-to-eat foods and diversified yoghurt products, but also delivering additional health benefits, beyond the basic nutritional functions of a yoghurt, to consumers.

Atractylodes macrocephala Root Rot Affects Microbial Communities in Various Root-Associated Niches

Atractylodes macrocephala, a perennial herb widely used in traditional Chinese medicine, is highly prone to root rot, which significantly reduces its yield and quality. This study compared the physicochemical properties of soil from healthy and diseased A. macrocephala plants and analyzed the microbial diversity in the endophytic, rhizosphere, and root zone soils. The results showed that the diseased plants had higher levels of available potassium and electrical conductivity in the rhizosphere, both positively correlated with the severity of root rot, while soil pH was negatively correlated. The diversity and richness of endophytic bacterial and fungal communities were significantly reduced in diseased plants. Additionally, root rot led to major changes in the rhizosphere microbial community, with an increased abundance of Proteobacteria and Ascomycota, and a decrease in Firmicutes, Bacteroidetes, Actinobacteria, and Basidiomycota. Fusarium oxysporum, Fusarium solani, and Fusarium fujikuroi were identified as key pathogens associated with root rot. This study enhances our understanding of the microbial interactions in soils affected by root rot, offering a foundation for developing soil improvement and biological control strategies to mitigate this disease in A. macrocephala cultivation.

Adsorbed microdroplets are mobile at the nanoscale

The extraordinary chemistry of microdroplets has reshaped how we as a community think about reactivity near multiphase boundaries. Even though interesting physico-chemical properties of microdroplets have been reported, "sessile" droplets' inherent mobility, which has been implicated as a driving force for curious chemistry, has not been well established. This paper seeks to answer the question: Can adsorbed microdroplets be mobile at the nanoscale? This is a tantalizing question, as almost no measurement technique has the spatiotemporal resolution to answer it. Here, we demonstrate a highly sensitive technique to detect nanometric motions of insulating bodies adsorbed to electrified microinterfaces. We place an organic droplet atop a microelectrode and track its dissolution by driving a heterogeneous reaction in the aqueous continuous phase. As the droplet's contact radius approaches the size of the microelectrode, the current versus time curve remarkably displays abrupt changes in current. We used finite element modeling to demonstrate these abrupt steps are due to nanometric movements of the three-phase boundary, where the nonaqueous droplet meets the aqueous phase and the electrode. Furthermore, the velocity with which the liquid interface moves can be estimated to tens-to-hundreds of nanometers per second. Our results indicate that processes that are driven by contact electrification and the frictional movement of bodies on a surface may be at play even when a droplet seems quiescent.

Exploring Pt-Impregnated CdS/TiO2 Heterostructures for CO2 Photoreduction

This work focuses on the production of methane through the photocatalytic reduction of carbon dioxide using Pt-doped CdS/TiO2 heterostructures. The photocatalysts were prepared using P25 commercial titania and CdS synthesized through a solvothermal methodology, followed by the impregnation of Pt onto the surface to enhance the physicochemical properties of the resulting photocatalysts. The pure and heterostructure-based materials were characterized using X-ray diffraction (XRD), inductively coupled plasma optical emission spectroscopy (ICP-OES), scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), ultraviolet-visible spectroscopy (UV-Vis), ultraviolet photoelectron spectroscopy (UPS), and photoluminescence spectroscopy (PL). The obtained results show the successful synthesis of the heterostructure impregnated with Pt. Moreover, the observed key role of CdS and Pt nanoparticles in the final semiconductor is to reduce the electron-hole pair recombination rate by acting as an electron sink, which slows down the recombination process and increases the photocatalyst efficiency. Thus, Pt-doped CdS/TiO2 heterostructures with the best observed composition presents better catalytic activity than P25 titania with methane production values being 460 and 397 µmol CH4/g·h, respectively.

Dual Responsive Emulsions Based on Amphiphilic Elastin-like Polypeptide Bioconjugates.

To achieve the desired therapeutic response, drug delivery systems must ensure the controlled release of the loaded content at the targeted site. One possible strategy relies on the improvement of conventional drug delivery systems. To do so, smart polymers, able to change their behavior upon chemical, physical, or biological stimuli, can be used. In this context, this study aims to evaluate the potential of natural amphiphilic smart elastin-like polypeptides grafted with alkyl chains (ELP-g-Bu) to stabilize conventional oil-in-water emulsions and trigger the release of loaded molecules upon dual stimuli. With butyl pendant chains and methionine residues, the macromolecular surfactant ELP-g-Bu demonstrated a modification of physicochemical properties, looking at critical aggregation concentration, upon both temperature and oxidation stimuli. The macromolecular surfactant was then able to stabilize a paraffin-oil-in-water emulsion. The ELP-g-Bu emulsion presented a droplet size of 9 ± 1 μm and stability for at least a month at 4 and 25 °C. After successful loading of a fluorescent lipophilic molecule used as a drug model, a complete destabilization of the ELP-g-Bu emulsion and burst release of the content was achieved with thermal triggering at 42 °C. In oxidative conditions, a partial release was measured, which can be improved by increasing the number of oxidable thioether groups. Overall, these dually responsive amphiphilic ELP-g-Bu demonstrated their potential for smart-polymer-based drug delivery systems that can be promising for inflammatory disease treatment as increased temperature and radical oxygen species are present in such cases.

Role of cavity strong coupling on single electron transfer reaction rate at electrode-electrolyte interface.

The physicochemical properties of molecules can be modulated through polariton formation under strong electromagnetic confinement. Here, we discuss the possibility of exploiting this phenomenon to increase the electron transfer rate at an electrode-electrolyte interface. Electron transfer theory under strong electromagnetic confinement can be extended to the electrode-electrolyte interface, and single-electron transfer reactions can be simulated using Gerischer's theory. Although single electron transfer in free space is well described using Marcus theory, the vacuum electric field can facilitate an additional electron transfer pathway via virtual photon excitation under cavity strong coupling conditions. Therefore, this binary reaction pathway for single electron transfer can yield a quasi-two-particle electron transfer process. This quantum behavior can dominate when the mode volume is small and when there are a large number of molecules in the vacuum electric field. Exploitation of polaritons in single electron transfer reactions can lead to enhanced electrochemical energy conversion systems.

Synthesis of cefixime loaded PCL/HPMC blend nanoparticles: a controlled release study and in vitro anti-bacterial evaluation

Aim To enhance cefixime’s effectiveness and address drug delivery challenges like concentration at the site, dose, and time, present study investigated the impact of polymer blends on cefixime’s in vitro release profile. Methods Cefixime-loaded nanoparticles were prepared via a modified solvent evaporation method, forming a W/O/W double emulsion. Characterisation included FT-IR, zeta potential, TGA, TEM, and XRD, with in vitro studies and kinetic models used to analyse the release mechanism. Results The PH-4 nanoparticle formulation (80:20 PCL/HPMC, 0.5% PVA) achieved an 81% loading rate, no adverse effects, and a controlled release of 84.66%±2.53 over 30 days. It showed stable physicochemical properties, with in vitro antibacterial tests revealing inhibition zones of 27.4 ± 2.12 mm for E. coli and 17.2 ± 2.23 mm for S. aureus at 12 hours. Conclusion Based on the findings, developed nanoparticulate system containing PCL/HPMC demonstrates its efficacy and safety as a controlled drug delivery method for antibiotics like cefixime.