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Considering the vast importance of peptide and protein interactions with inorganic surfaces, probing hydrogen bonding during their adsorption on metal oxide surfaces is a relevant task that could shed light on the essential features of their interplay. This work is devoted to studying the dipeptides' adsorption on anatase nanoparticles (ANs) in light and heavy water to reveal differences arising upon the change of the major hydrogen bonding carrier. Thermodynamic study of six native dipeptides' adsorption on ANs in both media shows a strong influence of the solvent on the Gibbs free energy and the effect of side-chain mobile protons on the entropy of the process. The adsorption is endothermic irrespective of the medium and is entropy-driven. Computer simulations of peptide adsorption in both media shows similarity in binding via an amino group and demonstrates structural features of protonated and deuterated peptides in obtained complexes. Calculated peptide- anatase nanoparticle (AN) descriptors indicate surface oxygens as points of peptide-nanoparticle contacts.

The properties of TiO2 can vary greatly, depending on the size and morphology of the particles used. The modeling of TiO2 nanoparticles of various diameters, and the study of their properties and morphology are of great interest for identifying the factors affecting the properties of nanoparticles. In this paper, the theoretical study based on the modeling of nanoparticles of TiO2 and the relationship between morphological parameters and calculated descriptors has been carried out. As a result of simulation, the nanoparticle structures of the composition Ti17O34–Ti568O1136 have been obtained. The surface analysis of nanoparticles has been carried out, and their density is calculated. We explained the increase in N3 dye adsorption and photovoltaic parameters with the decrease in the surface area of nanoparticles. We found that dye adsorption, short circuit photocurrent density, and power conversion efficiency are related to the solvent accessible surface area of the nanoparticle as well as the accessible surface area of oxygens.

Electronic properties of benzothiadiazole (BTD) unit containing dyes adsorbed on TiO2 nano-particles have been estimated using Quantum Theory of Atoms in Molecules (QTAIM). We found that short circuit photocurrent density Jsc and open circuit photovoltage Voc of the studied DSSCs are well related to the electronic properties of dyes, namely charges of BTD atomic basins of nitrogens, summary isodensity surface area and summary volume of hydrogen basins. Analysis of deviations of predicted and observed photovoltaic properties allowed to reveal device fabrication details influencing positively and negatively on device efficiency. Found relationships have been used for design of new promising dyes and recommendation of the better fabrication details of DSSCs with significantly higher photovoltaic properties as compared to the studied and published. For newly designed metal-free BTD-unit containing dyes, Jsc is expected to reach 20.7–25.8 mA/cm2, Voc – 0.858–1.029 V and power conversion efficiency η – 10.6–16.3%.

The affinity of biomolecules, such as peptides and proteins, with inorganic surfaces, is a fundamental topic in biotechnology and bionanotechnology. Amino acids are often used as “model” bits of peptides or proteins for studying their properties in different environments and/or developing functional surfaces. Despite great demand for knowledge about amino acid interactions with metal oxide surfaces, studies on the issue represent a fragmentary picture. In this paper, we describe amino acid adsorption on nanocrystalline anatase systematically at uniform conditions. Analysis of the Gibbs free adsorption energy indicated how the aliphatic, aromatic, polar, and charged side chain groups affect the binding affinity of the amino acids. Thermodynamic features of the L-amino acid adsorption receive thorough interpretation with calculated molecular descriptors. Theoretical modelling shows that amino acids complex with TiO2 nanoparticles as zwitterions via ammonium group., This work was financially supported by the Russian Foundation for Basic Research (grant no. 15-03-07834-a). I.K. acknowledge the financial support from Spanish MINECO (CTQ2014-52956-C3-1-R and MAT2016-78155-C2-1-R).

The affinity of biomolecules, such as peptides and proteins, with inorganic surfaces, is a fundamental topic in biotechnology and bionanotechnology. Amino acids are often used as "model" bits of peptides or proteins for studying their properties in different environments and/or developing functional surfaces. Despite great demand for knowledge about amino acid interactions with metal oxide surfaces, studies on the issue represent a fragmentary picture. In this paper, we describe amino acid adsorption on nanocrystalline anatase systematically at uniform conditions. Analysis of the Gibbs free adsorption energy indicated how the aliphatic, aromatic, polar, and charged side chain groups affect the binding affinity of the amino acids. Thermodynamic features of the l-amino acid adsorption receive thorough interpretation with calculated molecular descriptors. Theoretical modeling shows that amino acids complex with TiO