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The inclusion complexation of sulfobutyl ether-β-cyclodextrin sodium salt (SBECD) - ionic liquid (IL) has been investigated by a series of appropriate methods. The stability constant of the complex of SBECD-IL (K = 72.4 m-1) was determined by the method of Higuchi and Connors. An increase in the surface tension of solutions with different SBECD’s content was recorded by using the method of Wilhelm's plate, which could serve as an additional evidence of the formation of inclusion complex between SBECD and IL. Analysis of the TGA results provided for the initial IL and SBECD, their mechanical mixture and the complex elaborated allows us to conclude that the "guest-host" type complexation is emerged. Differential scanning calorimetry (DSC) data also confirmed the formation of inclusion complex between SBECD and IL. While the guest molecule is incorporated into cyclodextrin cavity, its thermal properties are changed. So, the loss of physically bonded water in the complex is equal to 5% by weight, indicating the IL’s molecule being located in the SBECD’s hydrophobic cavity. The thermogram of inclusion complex demonstrates just one endothermic peak at 74 oC. The complex is formed by entering the long alkyl chain of ionic liquid into the hydrophobic cavity of SBECD. Since the bonds of sulfo groups and β-СD’s glucopyran cycles become weaker, this may testify an additional interactions between SBECD and IL. With thermograviometric analysis (TGA) of the original IR and SB-β-CD, their mechanical mixture and the test compound fixed the formation of not a classical complex, but an associated complex of inclusion type "guest-host", which is formed by entering a long alkyl chain IR in the hydrophobic cavity SB-β-CD.

Cellulose is a widespread macromolecule in terrestrial environments and a major architectural component of microbial biofilm. Therefore, cellulose might be considered a biosignature that indicates the presence of microbial life. We present, for the first time, characteristics of bacterial cellulose after long-term spaceflight and exposure to simuled Mars-like stressors. The pristine cellulose-based pellicle membranes from a kombucha microbial community (KMC) were exposed outside the International Space Station, and after their return to Earth, the samples were reactivated and cultured for 2.5 years to discern whether the KMC could be restored. Analyses of cellulose polymer integrity and mechanical properties of cellulose-based pellicle films, as well as the cellulose biosynthesis-related genes' structure and expression, were performed. We observed that (i) the cellulose polymer integrity was not significantly changed under Mars-like conditions; (ii) de novo cellulose production was 1.5 times decreased in exposed KMC samples; (iii) the dry cellulose yield from the reisolated Komagataeibacter oboediens was 1.7 times lower than by wild type; (iv) there was no significant change in mechanical properties of the de novo synthesized cellulose-based pellicles produced by the exposed KMCs and K. oboediens; and (v) the gene, encoding biosynthesis of cellulose (bcsA) of the K. oboediens, was downregulated, and no topological change or mutation was observed in any of the bcs operon genes, indicating that the decreased cellulose production by the space-exposed samples was probably due to epigenetic regulation. Our results suggest that the cellulose-based pellicle could be a good material with which to protect microbial communities during space journeys, and the cellulose produced by KMC members could be suitable in the fabrication of consumer goods for extraterrestrial locations.

Background: Escherichia coli especially its multiresistant strains as the common foodborne pathogens cause bloodstream infections, nosocomial pneumonia, infections of the skin and soft tissues. Therefore, the search for new effective biologically active compounds has been rapidly increasing in recent few decades. In this paper, we describe Quantitative Structure-Activity Relationships (QSAR) studies, molecular docking and in vitro antibacterial activity evaluation of a series of imidazolium-based Ionic Liquids (ILs) against E. coli spp. Methods: M2D fragment-based, classification and regression QSAR models were created using machine learning methods and types of descriptors via the OCHEM server. Biological testing of a series of synthesized imidazolium ILs with predicted activity was performed by the disc diffusion method. The most typical structures of symmetric and asymmetric ILs with high anti-E. coli activity (1e, 1h) were docked into the active site of Enoyl-Acyl Carrier Protein Reductase (ENR) in E. coli. Results: Symmetric imidazolium ILs with C8 alkyl chain length demonstrated the highest antibacterial activity in comparison to the high antibacterial potential of asymmetric ILs with C12 alkyl chain length against drug-sensitive and drug-resistant E. coli strains including hemolytic E. coli. It should be noted that symmetric ILs with C6 or C9 alkyl chain length have a slightly lower activity against certain E. coli strains. The key role in the binding of compounds (1e, 1h) in the E. coli ENR active site is associated with the NAD molecule and the amino acid residue Tyr146. Conclusion: The highly active symmetric and asymmetric imidazolium ILs can be considered as promising drug-candidates effective against E. coli spp. pathogens including multidrug-resistant strains.

Guanidine salts are promising proton conductors due to the high content of dissociable protons in guanidinium cation that ensure an efficient proton transfer along hydrogen-bonded network formed by proton donor and proton acceptor sites. However, the high melting point of most guanidine salts is a serious drawback for their application as proton conducting electrolytes. Reducing the symmetry of guanidinium cations by the substitution of hydrogen atoms on alkyl radicals reduces the melting points but also leads to decreased proton conductivity. In this study, monosubstituted guanidine salt, N-butylguanidinium bis(trifluoromethylsulfonyl)imide (BG-TFSI), has been synthesized by a simple two-step method. It is water immiscible room temperature protic ionic liquid. The structure of BG-TFSI was confirmed by nuclear magnetic resonance spectroscopy, as well as infrared spectroscopy. According to thermal gravimetric analysis data, the ionic liquid has the thermal degradation point (5% weight loss) of 348 °C which indicates its excellent thermal stability for use in high-temperature fuel cells. The ionic conductivity of BG-TFSI determined by the electrochemical impedance method was found to be 9·10-4 S/cm at room temperature. This value increased by almost one order of magnitude above 100 °C thus reaching an acceptable level for use in fuel cells. The activation energy Ea calculated from the Arrhenius plot for BG-TFSI is found to be 16.4 kJ/mol which is similar to those reported for other guanidine salts. Based on the obtained results one can assume that the proton transport in BG-TFSI is dominated by Grotthus-type (hopping) mechanism. The results of this study indicated that BG-TFSI is a promising proton conducting electrolyte for fuel cells operating at elevated temperatures in water-free conditions. The hydrophobicity of the ionic liquid is an important advantage since it can prevent its leaching from the polymer electrolyte membrane during the operation of a fuel cell.

Background: Currently, a study on the relationship between candidiasis and cancer has been conducted. Until recent years, the opportunistic fungus C. albicans is mainly associated with cancer processes and is able to stimulate carcinogenesis and metastasis. Methods: A number of ionic liquids as potential anticancer and anti-Candida agents have been investigated based on modern theoretical and experimental data about the relationship between oncopathology and candida infection. Results: The analysis of the received experimental results demonstrates that ionic liquid with alkyl chain length of 6 carbon atoms (C6) has not shown anti-Candida activity. The indicators of its cytotoxicity ІС50 (28,617μМ) and MTC (9,050 μМ) against HEP-2 tumor cell line were also very low. Compounds with alkyl chain length C12 have shown high potential of anti-Candida activity and anticancer properties. Conclusion: Based on the obtained results, сompound 4 (C12C1IM-Cl) is proposed for further study as a potential double-acting agent with high anticancer and anti-Candida activities. N-myristoyltransferase is presented and used for docking as a potential molecular target responsible for the dual anti-Сandidа and anticancer activities of studied ionic liquids.

A series of long-chain imidazolium-based ionic liquids (ILs) 1-dodecyl-3-methylimidazolium chloride (1), 1,3-bis(octyloxycarbonylmethyl)imidazolium chloride (2) and 1-dodecyloxycarbonylmethyl-3-methyloxycarbonylmethylimidazolium chloride (3), were synthesized and evaluated as antimicrobials against a wide range of bacteria and fungi. Toxicological risks of selected compounds were assessed using the biomodels of various organizational and functional levels. All compounds demonstrated significant antibacterial and antifungal activity. The toxicity results indicate that ILs containing an ester functional group in the alkyl side chain exhibited much lower toxicity to D. magna and acetylcholinesterase inhibition than ILs with long alkyl chain without polar substituents, while toxicity toward Danio rerio was on a par. The HSA-binding properties of ILs have been investigated by FT-IR spectroscopy technique and the evidences have suggested that the test compounds could induce the protein unfolding and changes in the secondary structure of HSA. The docking studies were carried out to provide structural insights of the ILs–HSA-binding interactions. The docked compounds exhibit a high binding affinity to HSA and the hydrogen bonding, hydrophobic and electrostatic interactions played a major role in the process. ILs 2 and 3 may be perspective for further investigation as potential low-toxic biocides with high antimicrobial activity against reference and clinical multidrug-resistant strains.

Aim. To study the effect of polymeric biocide polyhexamethylene guanidine hydrochloride (PHMG-Cl) on morphophysiological and biochemical parameters of wheat seedlings in the presence of toxic concentration of copper ions. Methods. The growth-stimulating activity of PHMG-Cl in pure state, as well as in the presence of elevated concentrations of copper ions was studied by phytotesting method using wheat seed as a test culture. Physico-chemical interaction between PHMG-Cl and CuSO4 in water solutions was studied by spectrophotometry. Results. Wheat seed treatment with water solutions of polymeric biocide PHMG-Cl in the concentration range of 0.01–0.1 % causes an increase in the length of roots and shoots by over 50 % after 7 days of incubation. The concentration of PHMG-Cl of 1 % was found to have a depressive effect on growth characteristics of the tested plants. This fact indicates that the phytotoxicity of PHMG-Cl is at least two orders of magnitude lower compared with a common pesticide copper sulfate. Thus, wheat seed soaking in 200 μM (0.003 %) water solution of copper sulfate causes reduced length of shoots and roots (by 65 and 34 %, respectively), as well as reduced weight of shoots (by 20 %) and roots (by 74 %) The analysis of green mass showed signifi cantly reduced content of carotenoids (by 26 %) and water soluble fl avonoids (by 37 %), as well as chlorophyll a/b ratio (by 18 %) that indicates decreased plant metabolic activity. However, the toxic effect of copper sulfate ions signifi cantly diminished in the presence of PHMG-Cl (0.01 %). Thus, the length of shoots and roots was found to increase by 24 and 64 %, respectively, compared to the samples treated with CuSO4. Moreover, the content of pigments and fl avonoids in the green mass of seedlings reached the level of control samples. The results of spectrophotometric studies indicate the absence of physico-chemical interaction between PHMG-Cl and copper sulfate in water solutions. Conclusions. The polymeric biocide PHMG-Cl effectively stimulates growth and development of wheat seedlings in the concentration range of its water solutions of 0.01–0.1 %. In the presence of toxic copper sulfate concentration, PHMG-Cl does not possess the growth stimulating activity. However, the polymeric biocide signifi cantly improves copper stress resistance of plants, and normalizes their morpho-physiological indicators, photosynthetic characteristics and secondary exchange.

The growth-promoting activity of poly(DEG-GH) was studied using a test-culture of winter wheat Podolianka. Wheat seeds were soaked in water solutions of cationic polymer for 1 h, placed into Petri dishes and germinated on filters, moistened with distilled water. After seven days, the length of shoots of the seedlings, soaked in poly(DEG-GH) solutions with the concentration of 0.001 % and 0.01 %, was higher compared to control samples (by 6.7 % and 17.8 %, respectively). The maximum increase in the length of seedling roots (14.5 % compared to the control) was established for the lowest cationic polymer concentration of 0.001 %. The concentration of poly(DEG-GH) of 0.1 % inhibited the growth of roots and shoots by 28 % and 18 %, respectively. Thus, the cationic polymer poly(DEG-GH) demonstrates growth-promoting activity on wheat seedlings in the low concentration range of 0.001–0.01 %. Влияние стимулятора роста poly(DEG-GH) исследовали на тест-культуре озимой пшеницы сорта Подолянка. Семена пшеницы замачивали в водных растворах катионного полимера на 1 ч, помещали в чашки Петри и проращивали на фильтрах, смоченных дистиллированной водой. Через семь дней длина побегов проростков, пропитанных растворами poly(DEG-GH) с концентрацией 0,001% и 0,01%, была выше по сравнению с контрольными образцами (на 6,7% и 17,8%, соответственно). Максимальное увеличение длины корней проростков (14,5% по сравнению с контролем) установлено при наименьшей концентрации катионного полимера (0,001%). Таким образом, катионный полимер poly(DEG-GH) демонстрирует стимулирующуй рост эффект на проростках пшеницы в диапазоне низких концентраций 0,001–0,01%. Дію стимулятора роста poly(DEG-GH) досліджували на тест-культурі озимої пшениці сорту Подолянка. Насіння пшениці замочували у водних розчинах катіонного полімеру на 1 год, поміщали в чашки Петрі і пророщували на фільтрах, зволожених дистильованою водою. Через сім діб довжина пагонів, замочених в розчинах poly(DEG-GH) у концентрації 0,001 % та 0,01 %, була вищою порівняно з контрольними зразками (на 6,7 % та 17,8 %, відповідно). Максимальне збільшення довжини коренів проростків (14,5 % порівняно з контролем) встановлено при найменшій концентрації катіонного полімеру (0,001 %). Таким чином, катіонний полімер poly(DEG-GH) в діапазоні низьких концентрацій 0,001–0,01 % демонструє ефект, що стимулюює рост проростків пшениці.

The choice of effective biocides used for routine hospital practice should consider the role of disinfectants in the maintenance and development of local resistome and how they might affect antibiotic resistance gene transfer within the hospital microbial population. Currently, there is little understanding of how different biocides contribute to eDNA release that may contribute to gene transfer and subsequent environmental retention. Here we investigated how different biocides affected the release of eDNA from mature biofilms of two opportunistic model strains Pseudomonas aeruginosa ATCC 27853 (PA) and Staphylococcus aureus ATCC 25923 (SA) and contribute to the hospital resistome in the form of surface and water contaminants and dust particles. The effect of four groups of biocides including alcohols, hydrogen peroxide, quaternary ammonium compounds, and polymeric guanidines were evaluated using PA and SA biofilms. Most biocides, except for PHMG-Cl and 70% ethanol, caused substantial eDNA release and PHMG-Cl was found to block biofilm development when used at concentrations of 0.5% and 0.1%. This might be associated with the formation of DNA-PHMG-Cl complexes as PHMG-Cl is predicted to bind to AT base pairs by molecular docking assays. PHMG-Cl was found to bind high molecular DNA and plasmid DNA and continued to inactivate DNA on surfaces even after four weeks. PHMG-Cl also effectively inactivated biofilm-associated antibiotic resistance gene eDNA released by a pan-drug-resistant Klebsiella strain which demonstrates the potential of PHMG-Cl as a new surface-active agent to combat the spread of antibiotic resistance in hospital settings.

Cationic polymer polyhexamethylene guanidine hydrochloride (PHMG-Cl) is promising biocide that combines a broad spectrum of antimicrobial activity, mod-erate toxicity, as well as reasonable cost. It is widely used as an effective disinfect-ant in cooling systems, swimming pools, and hospitals, personal hygiene products, etc. Recently PHMG-Cl was found to have pronounced anti-inflammatory and wound healing properties and therefore may be used for the treatment of chronic wounds and thermal burns. This may indicate the antioxidant activity of polymeric biocide. In this study, PHMG-Cl has been synthesized by melt polycondensation of guanidine hydrochloride and 1,6-hexamethylenediamine. The structure of the cati-onic polymer was confirmed by 1H NMR and IR spectroscopy. The viscosity-average molecular weight of PHMG-Cl was found to be 10700. The antioxidant activity of PHMG-Cl has been studied by using different methods. In the methylene blue (MB) dye test, the oxidation of MB by hydroxyl radicals generating in Fenton’s system was found to decrease in the presence of PHMG-Cl in a molar ratio to MB of 5:1 and 10:1 (by 26 % and 38 %, respectively). At the same time, complete dye oxidation was observed when guanidine hydrochloride was used instead of PHMG-Cl. The antioxidant activity of PHMG-Cl has also been studied in the model system of radical chain oxidation of benzyl alcohol (BA). In this system, alkyl and peroxyl radicals are formed. The antioxidant activity was determined by a decrease of the initial rate of oxygen absorption during the initiated oxidation of BA. The introduc-tion of PHMG-Cl into the oxidized system in the concentrations ranged from 1.3·10-3 - 1.6·10-2 mol/l decreased the oxidation rate of BA by 4.5–88 %. This result demonstrates that PHMG-Cl effectively inhibits radical chain oxidation of BA. However, further research is needed to elucidate the mechanism of free radical de-activation by a polymer biocide.

New antimicrobial polymer composite based on commercial polyurethane (PU) Laripur®LPR9020 and polymeric biocide polyhexamethylene guanidine hydrochloride (PHMG-Cl) has been prepared by solvent casting method. Modified PU films containing from 1 to 4 wt% of PHMG-Cl were characterized in terms of mechanical, thermal and surface properties, biocide release behavior, as well as antibacterial activity against Gram-negative (Escherichia coli) and Gram-positive (Bacillus subtilis) bacterial strains. The results of mechanical testing indicate that the introduction of PHMG-Cl did not cause noticeable changes in the tensile strength of PU films, but improved their elasticity by at least 20–30%. The surface of PU/PHMG-Cl films was found to possess significantly higher hydrophobicity than neat polymer that is manifested in sharply increased water contact angle value from 72° for neat PU to 95° for PU/PHMG-Cl (2%). According to thermogravimetric analysis data, PU/PHMG-Cl composites are thermally stable to at least 300 °C which indicate their availability for melt processing by common methods. The results of differential scanning calorimetry showed reduction of both glass transition and melting temperatures of PU by more than 7 °C when contained only 1% of PHMG-Cl. Gradual release of polymeric biocide from modified PU films into water has been detected spectrophotometrically. The total biocide release ratio was found to be in the range from 29% to 48% after 50 hours immersion, depending on its content in polymer composite. PU/PHMG-Cl films showed much lower leaching rate into physiological saline solution compared to pure water (from 10% to 21% after 50 hours), which may be caused by poor solubility of polymeric biocide in sodium chloride solutions. The study of antibacterial activity of modified PU films using both disc agar diffusion and contact methods indicate high efficacy against tested microorganisms when contained 3% of polymeric biocide. So, this approach, based on the modification of PU resin with polymeric biocide PHMG-Cl, has been discussed in terms of potential medical applications when biocide release system or contact active material are necessary.

Four water insoluble room-temperature protic ionic liquids (PILs) based on the N-alkylimidazolium cation with the alkyl chain length from 1 to 4 and bis(trifluoromethylsulfonyl)imide anion were synthesized and their chemical structure was confirmed by the 1H NMR and 19F NMR analysis. PILs were revealed to be thermally stable up to 360 and 400 &deg, C. At the same time, the proton conductivity of PILs was found to be dependent mostly on the temperature and, to a less extent, on the type of the cation, i.e., the increase of the conductivity from ~3 &times, 10&minus, 4 S/cm at 25 &deg, C to 2 &times, 2 S/cm at 150 &deg, C was observed. The water vapour sorption capacity of PILs was evaluated as a function of relative humidity and the influence of the alkyl chain length on the phase behaviour in the PIL-water system was discussed. The composite polyimide/PILs membranes were prepared by the PIL immobilization in the porous polymer (Matrimid&reg, 5218) film. The composite membranes showed a high level of proton conductivity (~10&minus, 3 S/cm) at elevated temperatures (up to 160 &deg, C). The obtained results reveal that the elaborated composite polyimide/PIL membranes are promising candidates for the application as proton exchange membrane at middle and high temperatures.

International audience; Filamentous fungi are present everywhere in our environment and can grow on almost any substance in presence of moisture. Protecting the indoor environment against microbial growth remains a complex issue especially in sanitary applications or where protection against moulds is critical. Silicone samples containing 2% or 5% (w/w) of the cationic biocides polyhexamethylene guanidine dodecylbenzenesulfonate (PHMG-DBS), 1-octyl-3-me-thylimidazolium tetrafluoroborate (OMIM-BF 4) or 1-dodecyl-3-methylimidazolium tetrafluoroborate (DMIM-BF 4) were tested against a series of fungal species implicated in indoor fungal contamination. Our investigations were conducted according to the international standard ISO 16869 i.e. with a carbon-poor Nutrient-Salt-Agar (NSA) culture medium, and also with a carbon-rich Peptone-Dextrose-Agar (PDA) culture medium composed of pancreatic peptone, glucose and agar-agar as the spore suspension agar overlay. The experimental protocol using the PDA medium proved to be the most efficient procedure for discriminating, in a week only, the control analysis and those using modified silicones. Our results demonstrate that silicones containing 5% of polymeric biocide PHMG-DBS present higher antifungal activity on the filamentous fungi than longchain imidazolium ionic liquids-containing silicones. The possible mechanisms of antifungal action of cationic biocides are discussed. The efficacy of PHMG-DBS demonstrates that such modified-silicones can prevent microbial growth and silicone deterioration by microorganisms in areas with high humidity levels such as kitchens and bathrooms as well as hospitals and microbiology laboratories.

The use of graphene for ‘conducting phase + glass’ thick films that are screen-printed onto an alumina ceramic substrate and then heat-treated in a vacuum furnace has been studied. Quantitative microanalysis of carbon and glass elements has been carried out and the microstructure and electrical properties of the films have been examined. The film surface layer shows an increased carbon content, the current–voltage curve is linear, indicating that Ohm’s law is obeyed, and resistivity decreases with increasing temperature. The temperature resistance coefficient is negative. It has been concluded that graphene can be used as a conducting phase in thick films.

New protic ionic liquid N-butylguanidinium tetrafluoroborate (BG-BF4) has been synthesized by single-step method. The ionic liquid is thermally stable to at least 300 °C and has ionic conductivity value of 8⋅10−3 S/cm at room temperature increasing to 0.18 S/cm at 180 °C. To develop a new proton conducting membrane, the nano-fibrillar matrix of bacterial cellulose (BC) has been impregnated with BG-BF4. The composite BC/BG-BF4 membrane containing 80 wt% of ionic liquid was found to have tensile strength of 35 MPa and ionic conductivity of 4.5⋅10−4 S/cm at 180 °C. The high saturation of BC with protic ionic liquid to 95 wt% allowed obtain composite membrane with reduced tensile strength of 6 MPa but excellent ionic conductivity of 5.2⋅10−2 S/cm at 180 °C. The deposition of polyaniline (PANI, emeraldine base) into BC matrix by oxidative polymerization of aniline on the surface of cellulose nanofibrils was found to improve the ionic conductivity of BC/BG-BF4 system significantly, reaching the value of 4⋅10−3 S/cm at 180 °C for cellulose film containing 80 wt% of ionic liquid. According to results of dynamical mechanical analysis (DMA), both BC/BG-BF4 and BC/PANI/BG-BF4 composites keep excellent storage modulus values at 180 °C (1000 MPa and 835 MPa, respectively). Due to the excellent holding capacity of BC matrix to ionic liquid, as well as good thermal and mechanical properties of BC/BG-BF4 composite it can be promising material for the fabrication of proton conducting membranes for fuel cells operating at elevated temperatures in water free conditions.

The interaction between human serum albumin (HSA) and synthesized imidazolium and pyridinium based ionic liquids (ILs), as good potential microbial growth inhibitors, was investigated by spectroscopic techniques combined with molecular docking analysis. All compounds were significant active against the tested bacterial and fungal strains. FT-IR spectroscopy indicated that the interaction of HSA with ILs generates considerable changes in protein secondary structure. The results of the molecular docking study showed that the studied ILs are able to firmly bind in the subdomain IIA of HSA with almost equal binding affinity (about −6.23 kcal/mol). Investigated HSA–ILs complex binds through hydrogen bonding or/and cation-π interactions. This study provides a better understanding of the binding of imidazolium and pyridinium based ILs to HSA and opens the way for their further biological and pharmaceutical investigations as candidates with antimicrobial properties.

A new polymeric biocide polyhexamethylene guanidine (PHMG) molybdate has been synthesized. The obtained cationic polymer has limited water solubility of 0.015 g/100 mL and is insoluble in paint solvents. The results of acute toxicity studies indicate moderate toxicity of PHMG molybdate, which has a median lethal dose at 48 h of 0.7 mg/L for Daphnia magna and at 96 h of 17 mg/L for Danio rerio (zebrafish) freshwater model organisms. Commercial ship paint was then modified by the addition of a low concentration of polymeric biocide 5% (w/w). The painted steel panels were kept in Dnipro River water for the evaluation of the dynamics of fouling biomass. After 129-d exposure, Bryozoa dominated in biofouling of tested substrates, forming 86% (649 g/m2 ) of the total biomass on control panel surfaces. However, considerably lower Bryozoa fouling biomass (15 g/m2 ) was detected for coatings containing PHMG molybdate. Dreissenidae mollusks were found to form 88% (2182 g/m2 ) of the fouling biomass on the control substrates after 228 d of exposure, whereas coatings containing PHMG molybdate showed a much lower biomass value of 23.6 g/m2 . The leaching rate of PHMG molybdate in water was found to be similar to rates for conventional booster biocides ranging from 5.7 μg/cm2 /d at the initial stage to 2.2 μg/cm2 /d at steady state. Environ Toxicol Chem 2017;36:2543-2551. © 2017 SETAC.

New hydrophobic protic ionic liquid, 2-butylaminoimidazolinium bis(trifluoromethylsulfonyl)imide (BAIM-TFSI), has been synthesized. The ionic liquid showed good thermal stability to at least 350 °C. The conductivity of BAIM-TFSI determined by electrochemical impedance method was found to be 5.6 × 10−2 S/cm at 140 °C. Homogeneous composite films based on commercial polyimide (PI) Matrimid and BAIM-TFSI containing 30–60 wt% of ionic liquid were prepared by casting from methylene chloride solutions. Thermogravimetric analysis data indicated an excellent thermal stability of PI/BAIM-TFSI composites and thermal degradation points in the temperature range 377 °C–397 °C. The addition of ionic liquid up to 50 wt% in PI films does not lead to any significant deterioration of the tensile strength of the polymer. The dynamic mechanical analysis results indicated both an increase of storage modulus E′ of PI/BAIM-TFSI composites at room temperature and a significant E′ decrease with temperature compared with the neat polymer. The cross-linking of the PI with polyetheramine Jeffamine D-400 allowed to prepare PI/Jeffamine/BAIM-TFSI (50%) membrane with E′ value of 300 MPa at 130 °C. The ionic conductivity of this cross-linked composite membrane reached the level of 10−2 S/cm at 130 °C, suggesting, therefore, its potential use in medium-temperature fuel cells operating in water-free conditions.

Quantitative structure-activity relationships (QSAR) of imidazolium ionic liquids (ILs) as inhibitors of C. albicans collection strains (IOA-109, KCTC 1940, ATCC 10231) have been studied. Predictive QSAR models were built using different descriptor sets for a set of 88 ionic liquids with known minimum inhibitory concentrations (MIC) against C. albicans. We applied the state-of-the-art QSAR methodologies such as WEKA Random Forest (RF) as a binary classifier, Associative Neural Networks (ASNN) and k-Nearest Neighbors (k-NN) to build continuum non-linear regression models. The obtained models were validated using a 5-fold cross-validation approach and resulted in the prediction accuracies of 80% ± 5.0 for the classification models and q2 = 0.73-0.87 for the non-linear regression models. Biological testing of newly synthesized 1,3-dialkylimidazolium ionic liquids with predicted activity was performed by disco-diffusion method against C. albicans ATCC 10231 M885 strain and clinical isolates C. albicans, C. krusei and C. glabrata strains. The high percentage of coincidence between the QSAR predictions and the experimental results confirmed the high predictive power of the developed QSAR models within the applicability domain of new imidazolium ionic liquids.

International audience

Online Chemical Modeling Environment (OCHEM) was used for QSAR analysis of a set of ionic liquids (ILs) tested against multi-drug resistant (MDR) clinical isolate Acinetobacter baumannii and Staphylococcus aureus strains. The predictive accuracy of regression models has coefficient of determination q2 = 0.66 &minus, 0.79 with cross-validation and independent test sets. The models were used to screen a virtual chemical library of ILs, which was designed with targeted activity against MDR Acinetobacter baumannii and Staphylococcus aureus strains. Seven most promising ILs were selected, synthesized, and tested. Three ILs showed high activity against both these MDR clinical isolates.

The choice of efficient antimicrobial additives for polyamide resins is very difficult because of their high processing temperatures of up to 300 &deg, C. In this study, a new, thermally stable polymeric biocide, polyhexamethylene guanidine 2-naphtalenesulfonate (PHMG-NS), was synthesised. According to thermogravimetric analysis, PHMG-NS has a thermal degradation point of 357 &deg, C, confirming its potential use in joint melt processing with polyamide resins. Polyamide 11 (PA-11) films containing 5, 7 and 10 wt% of PHMG-NS were prepared by compression molding and subsequently characterised by FTIR spectroscopy. The surface properties were evaluated both by contact angle, and contactless induction. The incorporation of 10 wt% of PHMG-NS into PA-11 films was found to increase the positive surface charge density by almost two orders of magnitude. PA-11/PHMG-NS composites were found to have a thermal decomposition point at about 400 &deg, C. Mechanical testing showed no change of the tensile strength of polyamide films containing PHMG-NS up to 7 wt%. Antibiofilm activity against the opportunistic bacteria Staphylococcus aureus and Escherichia coli was demonstrated for films containing 7 or 10 wt% of PHMG-NS, through a local biocide effect possibly based on an influence on the bacterial eDNA. The biocide hardly leached from the PA-11 matrix into water, at a rate of less than 1% from its total content for 21 days.

International audience; A strong catalytic effect of 1.0 wt% ionic liquids (ILs) on kinetic parameters of dicyanate ester of bisphenol E (DCBE) polycyclotrimerization was evidenced, and structure-property relationships of resulting densely cross-linked cyanate ester resins (CERs) were investigated. Three different ILs with contrasted reactivity were employed as a catalysts: an aprotic IL, i.e. 1-octyl-3-methyl imidazolium tetrafluoroborate ([OMIm][BF4]), a protic IL, i.e. 2-(hydroxyethylamino) imidazolinium chloride ([HEAIm][Cl]), and a protic polymeric IL, i.e. poly(hexamethylene guanidine) toluene sulfonate ([PHMG][TS]). Both [HEAIm][Cl] and [PHMG][TS] were reactive towards DCBE monomer, whereas [OMIm][BF4] was chemically inert, as confirmed by Fourier Transform Infrared (FTIR) spectroscopy. Noticeably, the conversion (αc) of cyanate groups in the presence of ILs dramatically increased, and a significant dependence of αc values on IL chemical structure was found. The corresponding mechanisms of DCBE polycyclotrimerization in the presence of different ILs were proposed. All the CER/IL networks exhibited a high thermal stability inherent to neat CER, as shown by TGA, whereas unexpected significant changes of the viscoelastic characteristics for CER/IL networks compared to pure CER analogue were observed using DMTA.

Several model plants are known to respond to bacterial quorum sensing molecules with altered root growth and gene expression patterns and induced resistance to plant pathogens. These compounds may represent novel elicitors that could be applied as seed primers to enhance cereal crop resistance to pathogens and abiotic stress and to improve yields. We investigated whether the acyl-homoserine lactone N-hexanoyl-L-homoserine lactone (C6-HSL) impacted winter wheat (Triticum aestivum L.) seed germination, plant development and productivity, using two Ukrainian varieties, Volodarka and Yatran 60, in both in vitro experiments and field trials. In vitro germination experiments indicated that C6-HSL seed priming had a small but significant positive impact on germination levels (1.2x increase, p < 0.0001), coleoptile and radicle development (1.4x increase, p < 0.0001). Field trials over two growing seasons (2015-16 and 2016-17) also demonstrated significant improvements in biomass at the tillering stage (1.4x increase, p < 0.0001), and crop structure and productivity at maturity including grain yield (1.4 – 1.5x increase, p < 0.0007) and quality (1.3x increase in good grain, p < 0.0001). In some cases variety effects were observed (p ≤ 0.05) suggesting that the effect of C6-HSL seed priming might depend on plant genetics, and some benefits of priming were also evident in F1 plants grown from seeds collected the previous season (p ≤ 0.05). These field-scale findings suggest that bacterial acyl-homoserine lactones such as C6-HSL could be used to improve cereal crop growth and yield and reduce reliance on fungicides and fertilisers to combat pathogens and stress.

Ester-functionalized pyridinium ionic liquids (ILs), 1-decyloxycarbonylmethylpyridinium chloride (PyrСOOC10-Cl), and 1-dodecyloxycarbonylmethylpyridinium chloride (PyrСOOC12-Cl) have been synthesized and studied for their environmental toxicity. Simple long-chain pyridinium ILs, 1-dodecylpyridinium chloride (PyrC12-Cl), and commercial disinfectant cetylpyridinium chloride (CPC) were used as reference compounds. Both ester-functionalized ILs and CPC showed significantly reduced antibacterial activity compared to PyrC12-Cl. However, ester-functionalized ILs were found to have excellent antifungal activity towards Candida albicans fungus strains, similar to PyrC12-Cl and much higher than for CPC. The molecular docking of ILs in the active site of the known antifungal target N-myristoyltransferase (Nmt) C. albicans has been conducted. The obtained results indicate the possibility of ILs binding into the Nmt pocket. The high stability of the complexes, especially for PyrCOOC10-Cl, is ensured by hydrogen bonding, electrostatic anion-pi interactions, as well as hydrophobic pi-alkyl and alkyl interactions that was confirmed by calculated binding energy values. The acute toxicity studies of ester-functionalized ILs on D. rerio (zebrafish) hydrobiont have shown their dramatically reduced ecotoxicity compared to PyrC12-Cl and CPC. Thus, LD50 values of 15.2 mg/L and 16.8 mg/L were obtained for PyrCOOC10-Cl and PyrCOOC12-Cl, respectively, whereas CPC had LD50 value of 0.018 mg/L. The primary biodegradation test CEC L-33-A93 of ILs indicated an improved biodegradability of ester-functionalized compounds compared to simple long-chain ILs. Based on the obtained results, PyrCOOC10-Cl may be considered as very promising cationic biocide due to the combination of soft antimicrobial activity and reduced ecotoxicity, as well as improved biodegradability.

Novel thermosetting systems based on cyanate ester resins (CERs) have been created through the polycyclotrimerization reaction of dicyanate ester of bisphenol E (DCBE) in the presence of different amounts of 1-heptyl pyridinium tetrafluoroborate [HPyr][BF4] Ionic Liquid (IL). A significant accelerating effect on the curing kinetics of DCBE was found by FTIR analysis. The reaction mechanism for the [HPyr][BF4]-catalyzed polycyclotrimerization of DCBE was newly proposed via the formation of a [CN]δ+–[HPyr]δ− complex as a key intermediate. Structure–properties relationships for the thermostable CER/IL networks were investigated by using DSC, DMTA, dielectric spectroscopy, tensile testing, quasi-dc measurements (I-V characteristics), and TGA. All the nanocomposites showed excellent thermal stability up to 300 °C, indicating the formation of a densely crosslinked network even at high IL content (40 wt%), and they could be used at high temperatures above their Tg without significant thermal degradation. Nanoscale phase separation led to the creation of ionic channels within the CER matrix to ensure photosensitivity properties.

© 2018 Moshynets O. V. et al. Bacterial success in colonizing complex environments requires individual response to micro-scale conditions as well as community-level cooperation to produce large-scale structures such as biofilms. Connecting individual and community responses could be achieved by linking the intracellular sensory and regulatory systems mediated by bis-(3′-5′)-cyclic dimeric guanosine monophosphate (c-di-GMP) and other compounds of individuals with intercellular quorum sensing (QS) regulation controlling populations. There is growing evidence to suggest that biofilm formation by many pseudomonads is regulated by both intra and intercellular systems, though in the case of the model Pseudomonas fluorescens SBW25 Wrinkly Spreader in which mutations increasing c-di-GMP levels result in the production of a robust cellulose-based air-liquid interface biofilm, no evidence for the involvement of QS regulation has been reported. However, our recent review of the P. fluorescens SBW25 genome has identified a potential QS regulatory pathway and other QS–associated genes linked to c-di-GMP homeostasis, and QS signal molecules have also been identified in culture supernatants. These findings suggest a possible link between c-di-GMP and QS regulation in P. fluorescens SBW25 which might allow a more sophisticated and responsive control of cellulose production and biofilm formation when colonising the soil and plant-associated environments P. fluorescens SBW25 normally inhabits.

International audience

The polycyclotrimerization reaction of dicyanate ester of bisphenol E (DCBE) in the presence of varying amounts (from 0.5 to 5 wt%) of 1-octyl-3-methylimidazolium tetrafluoroborate ((OMIm)(BF4)) ionic liquid has been investigated using differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR) techniques, after a curing stage at 150 °C for 6 h. It is noteworthy that an amount of (OMIm)(BF4) as low as 0.5 wt% accelerates dramatically the ther- mal curing process leading to the formation of a polycyanurate network. The conversion of DCBE increased with increasing (OMIm)(BF4) content in the temperature range studied. A reaction mechanism associated with the ionic liquid-catalyzed DCBE polycyclotrimerization is newly proposed via the involvement of a (CN) δ+ -(OMIm) δ- complex as a key intermediate.

Water immiscible ionic liquid 1-dodecyl-3-methylimidazolium tetrafluoroborate (DMIM-BF 4 ) and its inclusion complex with β-cyclodextrin (β-CD) in molar ratio 1:1 have been synthesized. The formation of DMIM-BF 4 /β-CD complex was confirmed by FT-IR analysis, 1 H NMR analysis, and differential scanning calorimetry data. Our results indicate that the aliphatic tail of DMIM-BF 4 is included into β-CD inner cavity whereas imidazolium ring is located outside the torus. Moreover, the weak interaction between polar components of ionic liquid and hydrophilic outer surface of β-CD has also been detected. The standard agar disk diffusion method was performed to evaluate antimicrobial efficiency of the obtained compounds against Staphylococcus aureus (ATCC-25923), Escherichia coli (ATCC-25922) and Pseudomonas aeruginosa (ATCC-27853), Candida albicans (M 885 ATCC 10231) and its clinical isolate test-cultures. It has been found that both DMIM-BF 4 and DMIM-BF 4 /β-CD complex possess high antimicrobial activity as revealed by similar zone inhibition values against all tested microorganisms. The acute toxicity studies on Danio rerio (zebrafish) model organism showed that the pure ionic liquid DMIM-BF 4 is slightly toxic compound having LD 50 value of 7 mg/L, whereas DMIM-BF 4 /β-CD complex has considerably reduced toxicity (LD 50 = 100 mg/L) and therefore have potentially wider application areas.

The imidazolium-based ionic liquids (ILs) (1-n-alkyl-3-methylimidazolium tetrafluoroborate, where n = 4, 6–8, 12) were synthesized and characterized in terms of their spectral characteristics, thermal stability, and water, ethanol and cyclohexane vapour sorption behaviour. It was found that the highest hydrophilic character had IL with the shortest alkyl chain on the cation. At the same time, the IL thermal stability was decreased with the increase of the cation alkyl chain length. D'Arcy and Watt and NRTL sorption models allowed to well describe the vapour sorption experimental data. The supported ionic liquid membranes (SILMs) were prepared by impregnation of the porous poly(vinylidene fluoride) (PVDF) membrane with the synthesized ILs. The sorption capacity of PVDF was found to increase after its swelling in IL. An experimental evaluation of the SILMs permeability was carried out for water, ethanol and cyclohexane. The effect of operation parameters such as temperature and concentration of the permeant was studied. It was observed that the presence of the IL strongly influenced the permeability performance of the membrane by reducing the pore sizes and changing the hydrophobic/hydrophilic balance. It is found from the permeation kinetics curves that the SILMs have high potential for separation of organic solvent/water mixtures.

Аbstract This paper describes Quantitative Structure-Activity Relationships (QSAR) studies, molecular docking and in vitro antibacterial activity of several potent imidazolium-based ionic liquids (ILs) against S. aureus ATCC 25923 and its clinical isolate. Small set of 131 ILs was collected from the literature and uploaded in the OCHEM database. QSAR methodologies used Associative Neural Networks and Random Forests (WEKA-RF) methods. The predictive ability of the models was tested through cross-validation, giving cross-validated coefficients q2 = 0.82–0.87 for regression models and overall prediction accuracies of 80–82.1% for classification models. The proposed QSAR models are freely available online on OCHEM server at https://ochem.eu/article/107364 and can be used for estimation of antibacterial activity of new imidazolium-based ILs. A series of synthesized 1,3-dialkylimidazolium ILs with predicted activity were evaluated in vitro. The high activity of 7 ILs against S. aureus strain and its clinical isolate was measured and thereafter analyzed by the molecular docking to prokaryotic homologue of a eukaryotic tubulin FtsZ.

Novel nanoporous film materials of thermostable cyanate ester resins (CERs) were generated by polycyclotrimerization of dicyanate ester of bisphenol E in the presence of varying amounts (from 20 to 40 wt%) of an ionic liquid (IL), i.e., 1-heptylpyridinium tetrafluoroborate, followed by its quantitative extraction after complete CER network formation. The completion of CER formation and IL extraction was assessed using gel fraction content determination, FTIR, 1H NMR, and energy-dispersive X-ray spectroscopy (EDX). SEM and DSC-based thermoporometry analyses demonstrated the formation of nanoporous structures after IL removal from CER networks, thus showing the effective role of IL as a porogen. Pore sizes varied from ~20 to ~180 nm with an average pore diameter of around 45–60 nm depending on the initial IL content. The thermal stability of nanoporous CER-based films was investigated by thermogravimetric analysis.

To elaborate a new antimicrobial bacterial cellulose (BC) based material, the porous structure of BC has been combined with polymeric biocide polyhexamethylene guanidine hydrochloride (PHMG-Cl). A sufficient saturation of the BC matrix with PHMG-Cl and the formation of hydrogen bonds between chloride ions of the polymeric biocide and the hydroxyl groups of BC was confirmed by FT-IR analysis. The formation of an interconnected network of fiber bundles within the cellulose-based composite after the introduction of PHMG-Cl was revealed by Atomic Force Microscopy (AFM). The modified PHMG-Cl biocide bacterial cellulose film specimens showed excellent efficacy against multidrug resistant strains Staphylococcus aureus and Klebsiella pneumonia IMBG233, the phytopatogenic Xanthomonas campestris pv. campestris IMBG299 and Pseudomonas syringae pv. tomato DC3000, as well as yeast. Moreover, the introduction of PHMG-Cl also prevented a biofilm formation by a model association of pro- and eukaryotic microorganisms and stopped de novo cellulose synthesis in the existed biofilm. The biocide release rate from BC matrix was shown to depend on the moisture content of the composite films. PHMG-Cl-embedded cellulose is therefore a new formulation of biocide which could be further used for wounds healing.

Supported ionic liquid membranes (SILMs) were prepared by impregnating a porous Matrimid ® membrane with protic room-temperature ionic liquids (RTILs): 1-n-methylimidazolium dibutylphosphate ([C 1 im][DBP]), 1-n-butylimidazolium dibutylphosphate ([C 4 im][DBP]) and 1-n-butylimidazolium bis(2-ethylhexyl)phosphate ([C 4 im][BEHP]). After immersion of the porous Matrimid ® membrane in each RTIL, the prepared SILMs were composed of 53 ± 3% of RTIL phase. The control of the full impregnation of the porous Matrimid ® membrane by the RTILs was verified by FTIR spectroscopy. From the bubble point test, the SILMs displayed a good retention of their RTIL phase and, thus, showed a good stability against the increased pressure on one of the faces. The ionic conductivity of SILMs, used as electrolyte membranes for proton exchange membrane fuel cell (PEMFC) was measured by impedance spectroscopy. Unlike the Nafion ® , the conductivity of the SILMs still increases at high temperatures (> 80 °C). The [C 4 im][DBP]-impregnated SILM showed the best result in terms of conductivity (2.0 10 −2 S/cm at 115 °C). Moreover, all SILMs showed satisfactory stability since they retained a large amount of the RTIL phase in the membrane pores.

Supported ionic liquid membranes (SILMs) were prepared by immobilizing the room temperature ionic liquids (RTILs) ([C4C1im][BF4] and [CnC1im][PF6] (n=4 and 6)) in a porous Matrimid membrane. The Matrimid membrane was prepared by water vapor-induced phase inversion, and its porous structure was characterized by SEM. After immersion of the porous Matrimid membrane in RTILs, the prepared SILMs were composed of 60% of RTIL phase. From the bubble point test, the SILMs displayed an excellent retention of their RTIL phase, and thus showed a good stability in the face of increased pressure on one of their faces. The feasibility of the prepared SILMs for the separation of water and volatile organic compounds (VOCs) such as ethanol and cyclohexane by vapor permeation was investigated. For this purpose, a preliminary study of water and VOC vapor sorption in RTILs was necessary to determine the affinity between each solute and RTILs. Only [C4C1im][BF4] showed both the best sorption capacities and the good sorption selectivities. The vapor permeation measurements were therefore carried out only through the SILMs impregnated with [C4C1im][BF4]. The SILM permeability was found to increase in the same sorption affinity order as for [C4C1im][BF4], i.e. cyclohexane

We have tested silicones containing 2% or 5% of the cationic biocides polyhexamethylene guanidine dodecylbenzenesulfonate (PHMG-DBS), 1-octyl-3-methylimidazolium tetrafluoroborate (OMIM-BF4) or 1-dodecyl-3-methylimidazolium tetrafluoroborate (DMIM-BF4) against the major relevant bacterial and yeast species in health care-associated infections (HCAI). Study conducted according to the international standard ISO 22196 revealed that silicones containing 2% or 5% DMIM-BF4 or 5% PHMG-DBS presented the highest antimicrobial activity, leading to a logarithmic growth reduction of 3.03 to 6.46 and 3.65 to 4.85 depending on the bacterial or fungal species. Heat-pretreated silicones containing 2% DMIM-BF4 kept a high activity, with at least a 3-log reduction in bacterial growth, except against P. aeruginosa where there was only a 1.1-log reduction. After 33days, the release ratio of cationic biocide from silicone films containing 5% of DMIM-BF4 was found to be 5.6% in pure water and 1.9% in physiological saline solution, respectively. No leaching of PHMG-DBS polymeric biocide was detected under the same conditions. These results demonstrate unambiguously that silicones containing 2% DMIM-BF4 or 5% PHMG-DBS present high antimicrobial activity, as well as high leaching resistance and therefore may be good candidates for the development of safer medical devices.

A new polymeric biocide polyhexamethylene guanidine (PHMG) molybdate has been synthesized. The obtained cationic polymer has limited water solubility of 0.015 g/100 mL and is insoluble in paint solvents. The results of acute toxicity studies indicate moderate toxicity of PHMG molybdate, which has a median lethal dose at 48 h of 0.7 mg/L for Daphnia magna and at 96 h of 17 mg/L for Danio rerio (zebrafish) freshwater model organisms. Commercial ship paint was then modified by the addition of a low concentration of polymeric biocide 5% (w/w). The painted steel panels were kept in Dnipro River water for the evaluation of the dynamics of fouling biomass. After 129-d exposure, Bryozoa dominated in biofouling of tested substrates, forming 86% (649 g/m

Antimicrobial polyamide 11 (PA-11) films containing low-cost, thermally stable and water resistant polymeric biocide polyhexamethylene guanidine dodecylbenzenesulfonate (PHMG-DBS) have been obtained by compression moulding. The structure of the modified PA-11 films containing from 3 to 10 wt% of PHMG-DBS was characterized using Raman and FTIR spectroscopy and atomic force microscopy (AFM). The surface properties were evaluated both by contact angle and contactless inductive method. The introduction of PHMG-DBS into PA-11 films was found to increase positive surface charge density to 5.5·10−11 C/cm2 for 10 wt% of PHMG-DBS. Antibacterial activity of PA-11/PHMG-DBS films against both Gram-positive (Escherichia coli) and Gram-negative (Bacillus subtilis) bacteria was demonstrated for films containing from 5 to 7 wt% of polymeric biocide. According to thermal investigations data, PA-11/PHMG-DBS composite has excellent thermal stability to at least 390 °C both in air and in argon atmosphere which indicates on its availability for the melt processing by common methods. It has also been found that polymeric biocide is highly resistant to leaching from PA-11 film.

Composite polyamide‐12/polyaniline (PA‐12/PANI) films were prepared by a treatment of PA‐12 films swelled in aniline with a water solution of ammonium persulfate (APS) and HCl. The existence of a very thin (2 µm) subsurface PANI containing layer in the composite film was shown by confocal micro‐Raman resonance spectrometry. A combination of the micro‐Raman and UV–Vis measurements allowed determining the PANI concentration in this conductive layer. This approach allowed studying the kinetics of the matrix polymerization process. It is shown that this solid phase process has the strong kinetic specificity as compared with known solution based systems. It is suggested that this is due to not only the physical‐chemical interactions of aniline and formed PANI with amide groups of the matrix but also to a physical state of aniline localized in voids of the free volume of the matrix and to formation of the additional oxidant HOCl in the oxidizing solution.

Predictive QSAR models for the inhibitors of B. subtilis and Ps. aeruginosa among imidazolium-based ionic liquids were developed using literary data. The regression QSAR models were created through Artificial Neural Network and k-nearest neighbor procedures. The classification QSAR models were constructed using WEKA-RF (random forest) method. The predictive ability of the models was tested by fivefold cross-validation; giving q(2) = 0.77-0.92 for regression models and accuracy 83-88% for classification models. Twenty synthesized samples of 1,3-dialkylimidazolium ionic liquids with predictive value of activity level of antimicrobial potential were evaluated. For all asymmetric 1,3-dialkylimidazolium ionic liquids, only compounds containing at least one radical with alkyl chain length of 12 carbon atoms showed high antibacterial activity. However, the activity of symmetric 1,3-dialkylimidazolium salts was found to have opposite relationship with the length of aliphatic radical being maximum for compounds based on 1,3-dioctylimidazolium cation. The obtained experimental results suggested that the application of classification QSAR models is more accurate for the prediction of activity of new imidazolium-based ILs as potential antibacterials.