Binding of a Tricationic meso-Substituted Porphyrin to poly(A)⋅poly(U): an Experimental Study.

The porphyrins are macrocyclic compounds widely used as photosensitizers in anticancer photodynamic therapy. The binding of a tricationic meso-tris(N-methylpyridinium)-porphyrin, TMPyP, to poly(A)⋅poly(U) polynucleotide has been studied in neutral buffered solution, pH6.9, of low and near-physiological ionic strength in a wide range of molar phosphate-to-dye ratios (P/D).

Interaction of double-stranded polynucleotide poly(A:U) with graphene/graphene oxide.

Hybrids formed by DNA/RNA and graphene family nanomaterials are considered as potentially useful multifunctional agents in biosensing and nanomedicine. In this work, we study the noncovalent interaction between double-stranded (ds) RNA, polyadenylic:polyuridylic acids (poly(A:U)) and graphene oxide/graphene (GO/Gr) using UV absorption spectroscopy and molecular dynamics (MD) simulations. RNA melting showed that relatively long ds-RNA is adsorbed onto GO (at an ionic strength of [Formula: see text]) at that a large fraction of RNA maintains the duplex structure.

Adsorption of Polyadenylic acid on graphene oxide: experiments and computer modeling.

In this work, we study the adsorption of poly(rA) on graphene oxide (GO) using AFM and UV absorption spectroscopies. A transformation of the homopolynucleotide structure on the GO surface is observed. It is found that an energetically favorable conformation of poly(rA) on GO is achieved after a considerable amount of time (days).

Interaction of a tricationic meso-substituted porphyrin with guanine-containing polyribonucleotides of various structures.

The interaction of a tricationic water-soluble meso-(N-methylpyridinium)-substituted porphyrin, TMPyP, derived from classic TMPyP4, with double-stranded poly(G)  ⋅  poly(C) and four-stranded poly(G) polyribonucleotides has been studied in aqueous buffered solutions, pH 6.9, of low and near-physiological ionic strengths in a wide range of molar phosphate-to-dye ratios (P/D). To clarify the binding modes of TMPyP to biopolymers various spectroscopic techniques, including absorption and polarized fluorescence spectroscopy, Raman spectroscopy, and resonance light scattering, were used.

Enhancement of Photoluminescence from Semiconducting Nanotubes in Aqueous Suspensions due to Cysteine and Dithiothreitol Doping: Influence of the Sonication Treatment.

The influence of tip sonication duration on the spectral characteristics of carbon single-walled nanotubes (SWNTs) in aqueous suspension with single-stranded DNA (ssDNA) has been studied by NIR luminescence, NIR absorption, and Raman spectroscopy. It was revealed that prolongation of sonication leads to weakening of the SWNT polymer coverage and appearance of additional defects on the nanotube surface. Prolongation of the tip sonication treatment of SWNT/ssDNA from 30 to 90 min leads to the increase of the number of individual nanotubes in the aqueous suspension, but it significantly decreases the photoluminescence (PL) from semiconducting SWNTs because more defects are formed on the nanotube surface.