Recent achievements and problems associated with the use of metallopolymers as self-healing and shape memory materials are presented and evaluated.

Current paper presents biological effects of magnetite nanoparticles (MNPs). “Relations of MNP’ characteristics (zeta-potential and hydrodynamic diameters) with effects on bacteria and their enzymatic reactions were the main focus.”. Photobacterium phosphoreum and bacterial enzymatic reactions were chosen as bioassays. Three types of MNPs were under study: bare Fe3O4, Fe3O4 modified with 3-aminopropyltriethoxysilane (Fe3O4/APTES), and humic acids (Fe3O4/HA). Effects of the MNPs were studied at a low concentration range (< 2 mg/L) and attributed to availability and oxidative activity of Fe3+, high negative surface charge, and low hydrodynamic diameter of Fe3O4/HA, as well as higher Fe3+ content in suspensions of Fe3O4/HA. Low-concentration suspensions of bare Fe3O4 provided inhibitory effects in both bacterial and enzymatic bioassays, whereas the MNPs with modified surface (Fe3O4/APTES and Fe3O4/HA) did not affect the enzymatic activity. Under oxidative stress (i.e., in the solutions of model oxidizer, 1,4-benzoquinone), MNPs did not reveal antioxidant activity, moreover, Fe3O4/HA demonstrated additional inhibitory activity. The study contributes to the deeper understanding of a role of humic substances and silica in biogeochemical cycling of iron. Bioluminescence assays, cellular and enzymatic, can serve as convenient tools to evaluate bioavailability of Fe3+ in natural dispersions of iron-containing nanoparticles, e.g., magnetite, ferrihydrite, etc.

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The interest in the metal-containing polymeric nanocomposites is caused by a unique combination of properties of metals nanoparticles, their oxides and chalcogenides, and by mechanical, film-forming and other characteristics of polymers with opportunities for their use as magnetic materials for record and storage of information, as catalysts and sensors, in medicine and biology [1]. Homo-and copolymers of acrylic and methacrylic acids and their salts are widely used for the stabilization of metal-containing dispersions. 4 , atomic ratio Zn=Cd D 3:3 W 1) [7]. Such examples are very numerous. On the one hand, carboxylated compounds of a monomeric and polymeric structure can be molecular precursors of nanocomposite materials. On the other hand, carboxyl groups of macroligands are efficient stabilizers of nanoparticles; these functions are frequently developed together in one system. Amphiphilic character of carboxylated polymers and copolymers allows not only to encapsulate nanoparticles of metals or to combine them with polymeric and inorganic matrixes or biological objects, but also allows to give such properties as solubility in various mediums, ability to self-organization, etc., to nanoparticles. Formation and Stabilization of Nanoparticles at Presence of Macroligands with Carboxyl Functional GroupsAggregative stability of particles in a polymeric matrix is defined by the processes of steric stabilization, flocculation, phase division, electrostatic interactions, etc. It was shown by AFM researches [8], that Van der Waals attraction forces act between two uncovered polymer surfaces of the yttrium-stabilized zirconyl (YSZ) nanoparticles at distance up to 200 nm, causing their aggregation. At the same time, the presence of an adsorbed layer of ammonium polyacrylate or polymethacrylate on the surface A.D. Pomogailo et al