Nucleic acid-binding bis-acridine orange dyes with improved properties for bioimaging and PCR applications.

Understanding the intricate interactions of molecular dyes with nucleic acids is pivotal for advancing medical and biochemical applications. In this work, we present a comprehensive study of the interplay between a novel series of bis-acridine orange (BAO) dyes and double-stranded DNA (dsDNA). These BAO dyes were intentionally designed as two acridine orange units connected by neutral linkers featuring a 2,5-disubstituted thiophene moiety.

Effect of hydrophilicity-imparting substituents on exciton delocalization in squaraine dye aggregates covalently templated to DNA Holliday junctions.

Molecular aggregates exhibit emergent properties, including the collective sharing of electronic excitation energy known as exciton delocalization, that can be leveraged in applications such as quantum computing, optical information processing, and light harvesting. In a previous study, we found unexpectedly large excitonic interactions (quantified by the excitonic hopping parameter ) in DNA-templated aggregates of squaraine (SQ) dyes with hydrophilic-imparting sulfo and butylsulfo substituents. Here, we characterize DNA Holliday junction (DNA-HJ) templated aggregates of an expanded set of SQs and evaluate their optical properties in the context of structural heterogeneity.

Intramolecular Charge Transfer and Ultrafast Nonradiative Decay in DNA-Tethered Asymmetric Nitro- and Dimethylamino-Substituted Squaraines.

Molecular (dye) aggregates are a materials platform of interest in light harvesting, organic optoelectronics, and nanoscale computing, including quantum information science (QIS). Strong excitonic interactions between dyes are key to their use in QIS; critically, properties of the individual dyes govern the extent of these interactions. In this work, the electronic structure and excited-state dynamics of a series of indolenine-based squaraine dyes incorporating dimethylamino (electron donating) and/or nitro (electron withdrawing) substituents, so-called asymmetric dyes, were characterized.

Exciton Chirality Inversion in Dye Dimers Templated by DNA Holliday Junction.

While only one enantiomer of chiral biomolecules performs a biological function, access to both enantiomers (or enantiomorphs) proved to be advantageous for technology. Using dye covalent attachment to a DNA Holliday junction (HJ), we created two pairs of dimers of bis(chloroindolenine)squaraine dye that enabled strongly coupled molecular excitons of opposite chirality in solution. The exciton chirality inversion was achieved by interchanging single covalent linkers of unequal length tethering the dyes of each dimer to the HJ core.

Tandem crystallization strategies for resolution of 3,3,3-trifluorolactic acid [CF CH(OH)COOH] by chiral benzylamines.

Resolution of rac-3,3,3-trifluorolactic acid by diastereomeric salt formation was reinvestigated. The use of (S)-1-phenylethylamine gives coprecipitation of two diastereomeric phases, 1 (S)-[NH CH(CH )Ph](S)-[CF CH(OH)COO] and 2 (S)-[NH CH(CH )Ph](R)-[CF CH(OH)COO]·H O. Pure phase 1 may be obtained using molecular sieves as desiccants.

Negative Cooperativity in the Interaction of Prostaglandin H Synthase-1 with the Competitive Inhibitor Naproxen Can Be Described as the Interaction of a Non-competitive Inhibitor with Heterogeneous Enzyme Preparation.

The kinetic mechanism of the interaction of nonsteroidal anti-inflammatory drugs (NSAIDs) with their main pharmacological target, prostaglandin H synthase (PGHS), has not yet been established. We showed that inhibition of PGHS-1 from sheep vesicular glands by naproxen (a representative of NSAIDs) demonstrates a non-competitive character with respect to arachidonic acid and cannot be described within a framework of the commonly used kinetic schemes. However, it can be described by taking into account the negative cooperativity of naproxen binding to the cyclooxygenase active sites of the PGHS-1 homodimer (the first naproxen molecule forms a more stable complex (K = 0.

Prostaglandin H synthase kinetics in the two-phase aqueous-micellar system.

Reaction mixture for PGHS (prostaglandin-H-synthase) is a two-phase system including micellar hydrophobic phase and hydrophilic aqueous phase. Reagents added to the mixture are distributed between phases, thus concentrations of reagents dissolved in phases can differ significantly from their overall contents. Using dynamic light scattering we found that the hydrophobic phase produced by tween-20 consists of micelles, which radius (4-5nm) does not depend on either tween-20 overall content (0.

Enhanced orientational Kerr effect in vertically aligned deformed helix ferroelectric liquid crystals.

We disclose the vertically aligned deformed helix ferroelectric liquid crystal whose Kerr constant (Kkerr≈130  nm/V2 at λ=543  nm) is around one order of magnitude higher than any other value previously reported for liquid crystalline structures. Under certain conditions, the phase modulation with ellipticity less than 0.05 over the range of continuous and hysteresis-free electric adjustment of the phase shift from zero to 2π has been obtained at subkilohertz frequency.

Thermodynamically stable dispersions of quantum dots in a nematic liquid crystal.

Using transmittance electron microscopy, fluorescence and polarizing optical microscopy, optical spectroscopy, and fluorescent correlation spectroscopy, it was shown that CdSe/ZnS quantum dots coated with a specifically designed surfactant were readily dispersed in nematic liquid crystal (LC) to form stable colloids. The mixture of an alkyl phosphonate and a dendritic surfactant, where the constituent molecules contain promesogenic units, enabled the formation of thermodynamically stable colloids that were stable for at least 1 year. Stable colloids are formed due to minimization of the distortion of the LC ordering around the quantum dots.

Piezoelectric and flexoelectric effects in ferroelectric liquid crystals.

Flexoelectric and piezoelectric effects in ferroelectric liquid crystals (FLCs) have been studied. It is shown that nonlinear electromechanical coupling is determined by a local flexoelectric effect. Dependence of the parameters of nonlinearity of the flexoelectric effect on the parameter of phase transition from a paraelectric phase to a polar phase has been studied.