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Current research interests: theoretical and applied principles of synthesis and chemical purification of detonation nanodiamonds, development of new methods for producing modified and doped nanodiamonds, surface chemistry of nanomaterials, development of techniques for using nanodiamonds in various fields of technology. A.N.Ozerin. Doctor of Chemical Sciences, Scientific Supervisor of ISPM RAS.

Nanodiamond (ND) particles are popular platforms for the immobilization of molecular species. In the present research, enzyme Escherichia coli inorganic pyrophosphatase (PPase) was immobilized on detonation ND through covalent or noncovalent bonding and its enzymatic activity was characterized. Factors affecting adsorption of PPase such as ND size and surface chemistry were studied. The obtained material is a submicron size association of ND particles and protein molecules in approximately equal amounts. Both covalently and noncovalently immobilized PPase retains a significant enzymatic activity (up to 95% of its soluble form) as well as thermostability. The obtained hybrid material has a very high enzyme loading capacity (∼1 mg mg(-1)) and may be considered as a promising delivery system of biologically active proteinaceous substances, particularly in the treatment of diseases such as calcium pyrophosphate crystal deposition disease and related pathologies. They can also be used as recoverable heterogeneous catalysts in the traditional uses of PPase.

Detonation ND (nanodiamond) holds much promise for biological studies and medical applications. Properties like size of particles, inclination for modification of their surface and unambiguous biocompatibility are crucial. Of prime importance is interaction between ND and immune cells, which supervise foreign intrusion into an organism and eliminate it. Neutrophils are more reactive in inflammatory response implementing cytotoxical arsenal including ROS (reactive oxygen species). The aim of the work was to estimate the ability of two ND samples (produced by Diamond Center and PlasmaChem) to keep the vitality of neutrophils from the inflammatory site. The ability of cells to generate ROS in the presence of ND particles is considered as indicating their biocompatibility. IR spectra and size of particles in the samples were characterized. Acid modification of ND was carried out to get the luminescent form. In the biological aspect, ND demonstrated up or down action, depending on the concentration, time and conditions of activation of cells. Weak action of ND in whole blood was obtained possibly owing to the ND adsorbed plasma proteins, which mask active functional groups to interact with the cell membrane. ND did not influence the viability of isolated inflammatory neutrophils in low and moderate concentrations and suppressed it in high concentrations (≥1 g/l). Addition of ND to the cell suspension initiated concentration-dependent reaction to produce ROS similar to respiratory burst. ND up-regulated response to bacterial formylpeptide, but up- and down-modified (low or high concentrations, accordingly) response to such bacterial agents as OZ (opsonized zymosan), which neutrophils swallow up by oxygen-dependent phagocytosis. Localization of the particles on the cell surface as into the cells was identified by monitoring the intrinsic fluorescence of oxidized ND. The various mechanisms that could account for penetration of ND particles into the cell are discussed. Common conclusion concerns compatibility of ND with living neutrophils from inflammatory site and their normal functioning for infection safeguard.

A procedure for the photochemical chlorination of nanodiamond by molecular chlorine in the liquid phase was proposed. This process was studied quantitatively for the first time. Hydrolytic stability of the chlorinated nanodiamond surface in air and in a 0.05 М solution of NaOH was determined. A possibility of disintegration of the initial aggregates (<60 µm) to finer aggregates (<200 nm) was shown. The reactions of a series of C nucleophiles (organolithium reagents, CN -ion) with the chlorinated surface were carried out.Natural and synthetic diamonds possess several unique physicochemical properties that attract significant inter est in these systems as industrially important materials.Diversity of diamond materials should be mentioned. These are single crystals and powders of natural and syn thetic diamonds of different dispersity, ultradispersed dia monds produced by detonation synthesis, and diamond films prepared by carbon deposition from the gaseous phase onto different supports. All these materials are char acterized by the crystalline diamond structure. The prop erties of synthetic diamond materials depend substan tially on the method of preparation and, which is espe cially important for ultradispersed diamonds produced by detonation synthesis, on the type of functional groups on the surface. Therefore, chemical and physicochemical methods for the directed modification of the surface of diamond ma terials become very significant. The purpose of this modi fication is the preparation of the predominantly mono functional layer of a grafted surface compound of organic or inorganic nature on the surface of a diamond material. Thus, chemical modification of diamond powders results in the creation of a new class of promising materials, because they combine the unique properties of diamond and specific properties of the grafted chemical compound. 1Halogenation of pre hydrogenated diamonds is a con venient method for activation of their surface by the cre ation of electrophilic centers capable of further interact ing with a wide set of nucleophilic reagents. This ap proach provides wide possibilities for the further surface modification of both nanodiamond 2,3 and diamonds of other types. 4 Since quantitative data on the chlorination of nanodiamond and other diamond materials are virtu ally lacking, in the present work we aimed at studying the regularities of the liquid phase chlorination of nano diamond by molecular chlorine and the interaction of the chlorinated surface with organolithium reagents and CN -ions. ExperimentalNanodiamond (UDA SF trade mark, Joint Stock Co. "Almaznyi Tsentr," St. Petersburg, Russia) was produced ac cording to technical conditions TU 05121441 275 95. The con tent of diamond and non diamond carbon was 98.75 and 0.8%, respectively, and the ash residue was 0.45% (ignoring volatile admixtures). The nanodiamond is a light gray powder with S sp = 284±1 m 2 g -1 and a size of primary diamond particles of 4-5 nm. Solutions of methyl and n butyllithium (1.7 and 2.5 mol L -1 , respectively) we...

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