This review examines the state of art in research aimed at the development of electronic paper (electronic ink, e-ink), namely, the general principles to design a colloidal system with desired properties, having sedimentation and aggregate stability, consisting of a dispersed phase (reverse-micellar nanoreactors based on pigments) and a dispersion phase (nonpolar solvent/surfactant). More specifically, the subject matters of the review are: general methods and approaches used in the synthesis and modification of colloidal pigment particles; the electrophoretic properties of various dispersion systems comprising these particles (one-, two-, and three-color e-inks), which depend on the size of modified pigments, their zeta potentials, electrophoretic mobility, the presence of surfactants, dispersants, and emulsifiers; the chemical, physicochemical, and physicomechanical methods for microencapsulation of ink dispersions; and methods for manufacturing electrophoretic cells, including those used in micron-level cell design.

Magnetic iron oxides have been widely used in bio- and agrotechnology, however, procedures of their synthesis can be improved. Magnetic nanopowders whose composition corresponds to magnetite–maghemite solid solutions have been obtained by chemical precipitation from aqueous solutions of iron(II, III) chlorides. Synthesis conditions (exposure to ultrasound, inert gas bubbling, heating to 70°C, keeping in mother liquor) have been shown by scanning and transmission electron microscopy and by computing unit cell parameters for magnetite and maghemite lattice to affect the size, shape, and aggregation extent of nanoparticles. No monophase magnetite and maghemite formed during the synthesis, a solid solution of mixed composition has precipitated.

The effect of bacteria that present in the human urine (Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, and Staphylococcus aureus) was studied under the conditions of biomimetic synthesis. It was shown that the addition of bacteria significantly affects both the phase composition of the synthesized material and the position of crystallization boundaries of the resulting phosphate phases, which can shift toward more acidic (struvite, apatite) or toward more alkaline (brushite) conditions. Under conditions of oxalate mineralization, bacteria accelerate the nucleation of calcium oxalates by almost two times and also increase the amount of oxalate precipitates along with phosphates and stabilize the calcium oxalate dihydrate (weddellite). The multidirectional changes in the pH values of the solutions, which are the result of the interaction of all system components and the crystallization process, were analyzed. The obtained results are the scientific basis for understanding the mechanisms of bacterial involvement in stone formation within the human body and the creation of biotechnological methods that inhibit this process.