A novel flexible ion-selective sensor for potassium and sodium detection was proposed. Flexible ion-selective electrodes with pseudo-liquid internal solution on contrary to the system with a solid contact provided a more stable analytical signal. Such advantages were achieved because of polyelectrolyte (PEI/PSS) layers adsorption on the conduct substrate with a layer-by-layer technique. Such an approach demonstrated that ion-selective electrodes save sensitivity with Nernstian dependence: 56.2 ± 1.4 mV/dec aNa+ and 56.3 ± 1.9 mV/dec aK+, as well as a fast time of response for potassium (5 s) and sodium (8 s) was shown. The sensing platform proposed demonstrates a better time of response and is close to the Nernstian value of sensitivity with a sensor low cost. The results proposed confirm a pseudo-liquid junction for the ion-selective electrode. Biocompatibility of an ion-selective sensing platform was demonstrated at potassium potentiometric measurements in Escherichia coli biofilms. Potassium levels in a biofilm were measured with potentiometry and showed agreement with the previous results.

Biofilms are the reason for a vast majority of chronic inflammation cases and most acute inflammation. The treatment of biofilms still is a complicated task due to the low efficiency of drug delivery and high resistivity of the involved bacteria to harmful factors. Here we describe a magnetically controlled nanocomposite with a stimuli-responsive release profile based on calcium carbonate and magnetite with an encapsulated antibiotic (ciprofloxacin) that can be used to solve this problem. The material magnetic properties allowed targeted delivery, accumulation, and penetration of the composite in the biofilm, as well as the rapid triggered release of the entrapped antibiotic. Under the influence of an RF magnetic field with a frequency of 210 kHz, the composite underwent a phase transition from vaterite into calcite and promoted the release of ciprofloxacin. The effectiveness of the composite was tested against formed biofilms of E. coli and S. aureus and showed a 71% reduction in E. coli biofilm biomass and an 85% reduction in S. aureus biofilms. The efficiency of the composite with entrapped ciprofloxacin was higher than for the free antibiotic in the same concentration, up to 72%. The developed composite is a promising material for the treatment of biofilm-associated inflammations.

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Giant hogweed is one of the most widespread invasive alien species of the Baltic region. The pycnidial fungus, Calophoma complanata is being evaluated as a potential bioherbicide for control of Heracleum sosnowskyi. The aim of this work is to evaluate an ability of the potential mycoherbicide C. complanata MF-32.121 to overwinter in the conditions of Saint Petersburg area. Plants inoculated by C. complanata MF-32.121 successfully survives wintering in the conditions of Saint Petersburg area. Pearl barley covered by C. complanata MF-32.121 mycelium successfully survives wintering in the same conditions as well. When favorable conditions have arisen, the C. complanata MF-32.121 mycelium is capable to infecting young giant hogweed. Moreover, it was revealed that a change in the biochemical composition, namely, an increase in the level of trehalose, contributes to the manifestation of a greater tolerance of C. complanata MF-32.121 mycelium to temperature-humidity conditions.

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