Efficiency of adsorption of nucleic acid nitrogenous bases (NBs) on carboxylated detonation nanodiamond (DND−COOH) particles in aqueous media at pH = 7.4−7.6 and pH = 13.4 was investigated using Raman spectroscopy and infrared (IR) absorption spectroscopy. A significant difference in the adsorption activity of NDs toward four different individual NBs, guanine, adenine, cytosine, and thymine, had been observed. The highest adsorption activity on DND−COOH was observed for cytosine and, in descending order, for adenine and thymine. At the same time, adsorption activities of the adenine−thymine and guanine−cytosine complementary pairs on nanodiamonds (NDs) were similar. Analysis of the hydrogen bond parameters in the adsorption of complementary pair adenine−thymine on the ND surface had been done using the density functional theory-based molecular modeling. The theoretical calculations are consistent with the experimental results.

The possibility of drug delivery and retention in cells due to hydrogen bond formation between enriched nanodiamonds and highly toxic drugs (for example doxorubicin), is investigated by numerical simulation. Using molecular modeling by the density functional theory method with the B3LYP functional and the 6-31G(d) basic set, we analyze hydrogen bond formation and their influence on IR-spectra and structure of molecular complex which is formed due to interaction between doxorubicin and nanodiamonds enriched by carboxylic groups. Numerical modeling of carboxylated nanodiamonds and doxorubicin interaction is based on nanodiamond representation by a diamond-like nanoparticle with simpler structure. Enriched adamantane (1,3,5,7-adamantanetetracarboxylic acid) is used as an example of carboxylated diamond-like nanoparticle. Combined IR spectrum as imposing of IR spectra for doxorubicin and 1,3,5,7-adamantanetetracarboxylic acid various interaction positions is obtained. The combined IR spectrum demonstrates good agreement with experimental data. The obtained results demonstrate that there can be strong hydrogen bonds between doxorubicin and nanodiamond as one of basic mechanism for drug delivery and retention in cells.

As a result of an experimental study of the Raman scattering valence bands of water in aqueous suspensions of detonation nanodiamonds with different functional surface groups, the energies of hydrogen bonds in suspensions of nanoparticles were calculated for the first time. It is shown that the degree of influence of different functional surface groups of nanodiamonds on hydrogen bonds in aqueous suspension decreases in the series H > polyfunctional surface > OH > COOH. The obtained data are confirmed by modeling of optimized nanodiamond structures in water clusters and theoretical calculations of the bond parameters in these structures by the density functional theory.KEYWORDS hydrogen bonds, nanodiamonds aqueous suspension, Raman valence band

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доктор физико-математических наук, профессор кафедры информационной безопасности автоматизированных систем, Саратовский государственный технический университет имени Гагарина Ю. А.