Kinetics of the formation and structure of oligoperoxide nanolayers and grafted polymer brushes on glass plate surface

Functional oligoperoxide surfactants and coordinating oligoperoxide metal complexes were studied as modifiers of glass flat plates to provide the localization of radical forming sites and other functional fragments in adsorbed polymeric layers of a nanoscale thickness. Both the kinetics of the coating formation and properties of the nanolayers witness the dependence of the packing density of oligoperoxide molecules in the coatings on the oligoperoxide natures, concentrations and conditions of the sorption modification. The availability of definite amount of peroxide groups in formed nanolayer provides the possibility of controlled radical graft polymerization initiated from modified surface leading to reliable surface protection, functionality and targeted surface hydrophilic-hydrophobic properties.      

Enantiopure vicinally trisubstituted all-cis-bis(hydroxymethyl)-cyclopentenols and their derivatives

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Pulse Plasma Deposition of Terpinen-4-ol: An Insight into Polymerization Mechanism and Enhanced Antibacterial Response of Developed Thin Films

Plasma Chemistry and Plasma Processing - Antifouling/antibacterial coating derived from a sustainable natural resource for biomedical devices have shown promising outcomes, especially in the...     

Synthesis of γ-halogenated and long-chain β-hydroxy-α-amino acids and 2-amino-1,3-diols using threonine aldolases

The l- and d-threonine aldolase catalyzed formation of γ-halogenated and long-chain l- and d-3-alkylserine-derivatives 1-12, respectively, was shown starting from glycine and halogenated C₂- or C₄-C₁₂ aldehydes. lTA from Pseudomonas putida accepted all tested aldehydes with strongly varying diastereoselectivity (de up to 93%). Only aldehydes smaller than decanal were converted by dTA from Alcaligenes xylosoxidans with good selectivities (de up to 73%). Utilizing isobutanal enantio- and diastereopure d-syn-2-amino-3-hydroxy-4-methylpentanoic acid was obtained (ee>99%, de>95%), which was converted to the corresponding 2-amino-1,3-diol.     

Fluorescence Investigation of Interactions Between Novel Benzanthrone Dyes and Lysozyme Amyloid Fibrils

A series of novel fluorescent benzanthrone dyes have been tested for their ability to identify and characterize fibrillar aggregates of lysozyme prepared by protein denaturation in concentrated ethanol solution (F_eth) or acidic buffer (F_ac). Quantitative parameters of the dye association with native and fibrillar protein have been derived from the results of fluorimetric titration. The binding characteristics proved to be different for F_eth- and F_ac-bound benzanthrones, highlighting the dye sensitivity to the distinctions in fibril morphology. By comparing the dye preference to fibrillar protein aggregates, AM2, A8 and A6 were selected as the most prospective amyloid tracers. Based on the analysis of red edge excitation shifts and fluorescence lifetimes of the amyloid-bound dyes it was assumed that surface grooves or dry “steric zipper” interface are potential fibril binding sites for the novel fluorophores.     

Redox-active tetrahydrosalen (salan) complexes of titanium

A diarylamino-substituted N-methyl tetrahydrosalen (salan) ligand, (An2N)LH(2), is prepared in four steps and overall 53% yield from 5-bromosalicylaldehyde, with the key step a palladium-catalysed Hartwig-Buchwald amination of the tert-butyldimethylsilyl-protected 5-bromo-N-methylsalan ligand. Reaction of (An2N)LH(2) or its bromo analogue with Ti(O(i)Pr)(4) or TiF(4) results in metalation of the ligand. The isopropoxide groups are readily exchanged with α- or β-hydroxyacids to form chelated complexes. X-ray crystallography and NMR spectroscopy indicate that the salan ligands are quite flexible, with (An2N)LTiF(2), for example, showing four stereoisomers in its (19)F NMR spectrum. The major stereoisomer of (salan)Ti(X)(Y) depends principally on the trans influence of the X and Y groups. Complexes of (An2N)L show two reversible, closely spaced redox couples at approximately + 0.1 V vs. ferrocene/ferrocenium, and a second set of two closely spaced redox couples at ~ + 0.8 V vs. Fc/Fc(+).     

Hydroxy and Methoxy Substituted Thiacarbocyanines for Fluorescent Detection of Amyloid Formations

In present paper series of trimethine cyanines modified in 5,5′- or 6,6′- position with hydroxy- or methoxy- substituents is studied for their ability to interact selectively with fibrillar formations. Processes of dye aggregation that accompany this interaction were also investigated. Meso-methyl trimethynecyanines with 5,5′- methoxy (7519) and hydroxy (7515) substituents strongly (up to 40 times) increase fluorescence intensity in the presence of fibrillar insulin, and also give noticeable fluorescent response on the presence of various aggregated proteins (lysozyme, β-lactoglobulin, α-synuclein A53T). 7519 and 7515 dyes can be used for fluorometric detection of fibrillar insulin at concentrations of approximately 1.5–120 microg/ml. For meso-ethyl substituted dye 7514 the ability to form H- and J-aggregates upon interaction with insulin fibrils was suggested. The model of the H- and J-aggregate packing in the protein fibrillar structure has been proposed.     

Studies of Benzothiazole and Benzoselenazole Squaraines as Fluorescent Probes for Albumins Detection

Series of squaraine benzothiazole and benzoselenazole dyes were studied as possible fluorescent probes for the detection of proteins, particularly albumins. It was shown that majority of the studied squaraines give significant fluorescent response on the human serum albumin (HSA) and bovine serum albumin presence. For squaraine dyes with N-hexyl pendent groups (P-1, P-2, P-3, P-5) about 100−540-fold fluorescence intensity increase upon albumins addition was observed. At the same time in presence of other proteins, namely insulin, avidin from hen egg white, immunoglobulin G (IgG), carbonic anhydrase fluorescence enhancement values were considerably lower —up to 43 times in IgG presence. It was noted that generally, squaraines with long N-hexyl pendent groups demonstrate higher emission increase values upon proteins addition comparing with their analogues with short N-ethyl tails. It was shown that fluorescence intensity enhancement for benzothiazole squaraine dye P-3, relates linearly to the HSA concentration over the wide range—from 0.2 to 500 μg/ml. Together with noticeable selectivity of this dye to albumins, existence of wide dynamic range gives possibility to propose P-3 dye as probe for HSA quantification.