Quaternized Amphiphilic Block Copolymers as Antimicrobial Agents

In this study, a novel polystyrene-block-quaternized polyisoprene amphipathic block copolymer (PS-b-PIN) is derived from anionic polymerization. Quaternized polymers are prepared through post-quaternization on a functionalized polymer side chain. Moreover, the antibacterial activity of quaternized polymers without red blood cell (RBCs) hemolysis can be controlled by block composition, side chain length, and polymer morphology. The solvent environment is highly related to the polymer morphology, forming micelles or other structures. The polymersome formation would decrease the hemolysis and increase the electron density or quaternized groups density as previous research and our experiment revealed. Herein, the PS-b-PIN with N,N-dimethyldodecylamine as side chain would form a polymersome structure in the aqueous solution to display the best inhibiting bacterial growth efficiency without hemolytic effect. Therefore, the different single-chain quaternized groups play an important role in the antibacterial action, and act as a controllable factor.

Cytotoxic effect of Myrtus communis, Aristolochia longa, and Calycotome spinosa on human erythrocyte cells

Introduction. Myrtus communis, Aristolochia longa, and Calycotome spinosa are medicinal plants frequently used in Algeria. Some plants can cause a fragility of the erythrocyte membrane and lead to hemolysis. Therefore, we aimed to study the cytotoxicity of aqueous extracts from the aerial part of these species against red blood cells. Study objects and methods. The hemolytic effect was determined spectrophotometrically by incubating an erythrocyte solution with different concentrations of the aqueous extracts (25, 50, 100, and 200 mg/mL) at 37°C during one hour. In addition, we performed phytochemical screening and measured the contents of polyphenols and flavonoids. Results and discussion. After one hour of incubation of human red blood cells with the aqueous extracts at different concentrations, the hemolysis percentage showed a significant leak of hemoglobin with A. longa (68.75 ± 6.11%; 200 mg/mL), the most toxic extract followed by C. spinosa (34.86 ± 5.06%; 200 mg/mL). In contrast, M. communis showed very low cytotoxicity (20.13 ± 3.11%; 200 mg/mL). Conclusion. These plants are sources of a wide range of bioactive compounds but their use in traditional medicine must be adapted to avoid any toxic effect.

Croton cajucara Essential Oil Nanoemulsion and Its Antifungal Activities

The purpose of this study was to develop a stable nanoemulsion (NE) containing Croton cajucara 7-hydroxycalamenene-rich essential oil (NECC) with antifungal activity. The NECCs were prepared using an ultrasonic processor with Pluronic® F-127 as the aqueous phase. In order to evaluate the NECCs, the droplet size, polydispersity index (PdI), percentage of emulsification, and pH were determined along with a stability study. The NECC selected for the study had 15% surfactant, showed 100% emulsification, Pdl of 0.249, neutral pH, droplet diameters of about 40 nm, and remained stable over 150 days at room temperature. In addition, the NECC activity against some species of Zygomycetes and Candida, as well as the potential to inhibit fungal extracellular proteases, were assessed, and, finally, the hemolytic activity was evaluated. The best NECC antifungal activities were against Mucorramosissimus (Minimal inhibitory concentration (MIC) = 12.2 μg/mL) and Candida albicans (MIC = 25.6 μg/mL). The highest extracellular protease activities of M. ramosissimus and C. albicans were detected at pH 3 and 4, respectively, which were totally inhibited after NECC treatment. The NECC showed no hemolytic effect at the highest concentration tested (2 mg/mL).

Novel magnetic organic–inorganic hybrids based on aromatic polyamides and ZnFe2O4 nanoparticles with biological activity

Magnetic nanoparticles were creatively selected as stable, inexpensive, biodegradable, facile recoverable, and functionalizable supports for a variety of synthetic and natural polymers. Herein, for the first time, aromatic polyamide was synthesized on the magnetic core of zinc iron oxide (ZnFe2O4). Terephthaloyl chloride and derivations of phenylenediamine were employed as monomers in this polymerization process. The toxicity of the synthesized hybrid at the highest concentration (1000 μg/ml) is 13.65% and on the other hand, the cell viability percentage is 86.35%. So, the prepared hybrid is biocompatible and non-toxic to Hu02 cells. Also, it has antibacterial ability against gram-positive and gram-negative bacteria. Because the results show that the minimum inhibitory concentration (MIC) of the synthesized polymer for bacteria such as Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 25922, and Pseudomonas aeruginosa ATCC 27853 is in the range of 500–1000 µg/ml. Moreover, the hemolytic effect of ZnFe2O4 based hybrid was below 9% at the concentration of 1000 μg/ml. Therefore, it is compatible with red blood cells.

Exploration its Antioxidant and Immunogenic potential of protein: Calendula officinalis and Dianthus chinensis

Aim and objective: Pollen is reported in flowers and leaves of various medicinal plants and showed its beneficial effect on human health. The objective of our study is to evaluate the antioxidant effect of flowers (Calendula officinalis and Dianthus chinensis) especially pollen protein and also determining its immunogenic effect against specific protein (typhoid vaccine) antigen in human whole blood samples. Methods: In this study, analytical studies were conducted for estimating the protein content using Lowry test and qualitatively determined through high performance thin layer chromatography (HPLC). In addition, immunological studies were also conducted using pollen protein for evaluating its antioxidant potential (using DPPH (2,2-diphenyl-1-picryl-hydrazyl-hydrate) free radical assay) and determined its immunogenic effect using typhoid vaccine antigen and determining its hemolytic effect in human whole blood samples. Results: This work demonstrated that pollen protein content (determined through lowry test) at higher concentrations exhibited a significant declining in antigen specific T cell proliferation using optimized dose of typhoid vaccine antigen in human whole blood samples. In addition, pollen protein showed antioxidant property as well and does not show any hemolytic effect. Conclusion: The current study showed that pollen protein from Calendula officinalis and Dianthus chinensis possesses antioxidant property and less immunogenic in terms of declining in antigen specific T cell proliferation rate.

Hemolysis of Human Erythrocytes by Argovit™ AgNPs from Healthy and Diabetic Donors: An In Vitro Study

The use of nanomaterials is becoming increasingly widespread, leading to substantial research focused on nanomedicine. Nevertheless, the lack of complete toxicity profiles limits nanomaterials’ uses, despite their remarkable diagnostic and therapeutic results on in vitro and in vivo models. Silver nanoparticles (AgNPs), particularly Argovit™, have shown microbicidal, virucidal, and antitumoral effects. Among the first-line toxicity tests is the hemolysis assay. Here, the hemolytic effect of Argovit™ AgNPs on erythrocytes from one healthy donor (HDE) and one diabetic donor (DDE) is evaluated by the hemolysis assay against AgNO3. The results showed that Argovit™, in concentrations ≤24 µg/mL of metallic silver, did not show a hemolytic effect on the HDE or DDE. On the contrary, AgNO3 at the same concentration of silver ions produces more than 10% hemolysis in both the erythrocyte types. In all the experimental conditions assessed, the DDE was shown to be more prone to hemolysis than the HDE elicited by Ag+ ions or AgNPs, but much more evident with Ag+ ions. The results show that Argovit™ is the least hemolytic compared with the other twenty-two AgNP formulations previously reported, probably due to the polymer mass used to stabilize the Argovit™ formulation. The results obtained provide relevant information that contributes to obtaining a comprehensive toxicological profile to design safe and effective AgNP formulations.

MEDICAL AND VETERINARY SIGNIFICANCE OF BLOOD-SUCKING MOSQUITOES (REVIEW)

This article presents an analysis of studies on harmful effects of blood-sucking mosquitoes (Diptera: Culicidae), which are one of the components of the gnat complex. Many individuals of this family are vectors of pathogens for a number of invasive and infectious diseases that are dangerous for animals and humans. The relevance of this study lies in the fact that today, climate warming and urbanization lead to expansion of the area of mosquitos, increase in their number, and as a result, the spread of diseases to new territories of Russia. Mosquito bites are accompanied by damage to the skin of a victim, a feeder, and introduction of toxic saliva which has a strong anticoagulant and hemolytic effect. Erythema, inflammation and itching are developed at the place of the insect bite. Multiple bites cause edema, and increased body temperature and local inflammation. It is difficult to estimate losses caused by mosquitoes to agriculture due to the fact that mosquitoes attack cattle together with other blood-sucking dipterans: horseflies, blackflies and sandflies. A massive attack of insects causes anxiety in cattle, disrupts normal grazing of livestock, and results in injuries caused by movements to protect themselves from insects, which leads to disruption of normal grazing and a decrease in their productivity.

Synthesis, Study of Dielectric Properties, Thermogravimetric Analysis and Hemolytic Effect of Copolymers Based on Various Derivatives of Styrene and α-Methylstyrene

The paper describes the synthesis of three new copolymers based on styrene and α-methylstyrene derivatives by radical emulsion copolymerization in an aqueous medium in the presence of an ammonium persulfate initiator and potassium stearate emulsifier. In early study, it was found that copolymers based on methoxy derivatives of styrene have the advanced dielectric properties, as compared to polystyrene and a copolymer of styrene and α-methylstyrene. In addition, the latest scientific literature provides data on the biological activity of styrene copolymers. Thus, the synthesis and study of the properties of new copolymers based on styrene and α-methylstyrene creates a prospect for establishing materials with a unique set of properties differing from their previously studied analogues. The structure of synthesized copolymers is confirmed by IR spectroscopy. Along with this, the paper provides the curves of thermogravimetric analysis, data on dielectric constant and tangent of a dielectric loss angle. A hemolytic effect of copolymers is determined, which indicates biocompatibility and further research perspectives towards their suitability for medical use. A copolymer of sodium 4-styrenesulfonate and α-methylstyrene (the molar ratio of starting monomers is 7:3) is soluble in an aqueous medium, which makes it of higher priority in terms of further study into biological activity.

Self-Assembled Cationic-Covered Nanoemulsion as A Novel Biocompatible Immunoadjuvant for Antiserum Production Against Tityus serrulatus Scorpion Venom

This study assesses the efficacy of different nanoemulsion formulations as new and innovative adjuvants for improving the in vivo immunization against the Tityus serrulatus scorpion venom. Nanoemulsions were designed testing key-variables such as surfactants, co-solvents, and the influence of the temperature, which would be able to induce the phase transition from a liquid crystal to a stable nanoemulsion, assessed for four months. Additionally, cationic-covered nanoemulsion with hyper-branched poly(ethyleneimine) was prepared and its performance was compared to the non-cationic ones. The physicochemical properties of the selected nanoemulsions and the interactions among their involved formulation compounds were carefully monitored. The cytotoxicity studies in murine macrophages (RAW 264.7) and red blood cells were used to compare different formulations. Moreover, the performance of the nanoemulsion systems as biocompatible adjuvants was evaluated using mice immunization protocol. The FTIR shifts and the zeta potential changes (from −18.3 ± 1.0 to + 8.4 ± 1.4) corroborated with the expected supramolecular anchoring of venom proteins on the surface of the nanoemulsion droplets. Cell culture assays demonstrated the non-toxicity of the formulations at concentrations less than 1.0 mg/mL, which were able to inhibit the hemolytic effect of the scorpion venom. The cationic-covered nanoemulsion has shown superior adjuvant activity, revealing the highest IgG titer in the immunized animals compared to both the non-cationic counterpart and the traditional aluminum adjuvant. In this approach, we demonstrate the incredible potential application of nanoemulsions as adjuvants, using a nanotechnology platform for antigen delivery system on immune cells. Additionally, the functionalization with hyper-branched poly(ethyleneimine) enhances this recognition and improves its action in immunization.