Thrombosis-related diseases are undoubtedly the deadliest disorders. Numerous attempts were made during the last decades to reduce the overall death rate and severe complications caused by treatment delays. Significant progress...

For decades, scientists have been looking for a way to control catalytic and biocatalytic processes through external physical stimuli. In this Letter, for the first time, we demonstrate the 150 ± 8% increase of the conversion of glucose to ethanol by Saccharomyces cerevisiae due to the application of a low-frequency magnetic field (100 Hz). This effect was achieved by the specially developed magnetic urchin-like particles, consisting of micrometer-sized core coated nanoneedles with high density, which could provide a biosafe permeabilization of cell membranes in a selected frequency and concentration range. We propose an acceleration mechanism based on magnetic field-induced cell membrane permeabilization. The ability to control cell metabolism without affecting their viability is a promising way for industrial biosynthesis to obtain a beneficial product with genetically engineered cells and subsequent improvement of biotechnological processes.

Rapid detection of bacterial contamination is an essential task in numerous medical and technical processes and one of the most rapidly developing areas of nano-based analytics. Here, we present a simple-to-use and special-equipment-free test-system for bacteria detection based on magnetite nanoparticle arrays. The system is based on peroxide oxidation of chromogenic substrate catalyzed by magnetite nanoparticles, and the process undergoes computer-aided visual analysis. The nanoparticles used had a pristine surface free of adsorbed molecules and demonstrated high catalytic activities up to 6585 U/mg. The catalytic process showed the Michaelis–Menten kinetic with Km valued 1.22 mmol/L and Vmax of 4.39 µmol/s. The nanoparticles synthesized were used for the creation of inkjet printing inks and the design of sensor arrays by soft lithography. The printed sensors require no special equipment for data reading and showed a linear response for the detection of model bacteria in the range of 104–108 colony-forming units (CFU) per milliliter with the detection limit of 3.2 × 103 CFU/mL.

This paper presents the results of a study of the temperature dependences of the magnetic susceptibility of water-based magnetic fluids (magnetic colloids) with magnetite particles stabilized by their electrostatic interaction. The average size of dispersed particles was 8 nm, and the volume concentration of particles in the selected samples under study was 1.4% and 1.6%. The investigations were carried out over a wide temperature range. The temperature dependence of the susceptibility, for the first time, was obtained in the region of the colloidal phase transition under supercooling of the dispersion medium (water). Significant differences were found between the temperature dependences of the magnetic susceptibility of such magnetic fluids, where as similar dependences have been found for the susceptibility of magnetic hydrocarbon-based fluids. The observed behavior of such dependences near the water phase transition temperature is determined by the changes in the water phase state, heat release and structuring of the colloid as a result of water crystallization. Moreover, it is suggested that a certain impact on the dependence behavior in the region of the colloidal solidification temperature can also come from the process of blocking the Brownian degrees of freedom of a small fraction of large dispersed particles. It is concluded that the observed maxima in the investigated susceptibility temperature dependences in the lower temperature region are due to magnetic transformations in the colloidal zones formed at the solidification front of the disperse medium with a dense packing of single-domain colloidal particles.