NOVEL FLUORESCENT NEAR-INFRARED AGENT FOR BIOMEDICAL APPLICATIONS

Squaraines represent a class of organic dyes operating in red and near-infrared regions. Due to their unique optical characteristics, such as high extinction coefficients, reduced background fluorescence and light scattering, photostability, these fluorophores attract ever-growing attention as prospective bioimaging agents. The present contribution overviews the spectral properties and some biological applications of the novel squaraine dye SQ-1. This probe was found to possess very high lipid-associating ability manifesting itself in a sharp increase of its emission. Binding of SQ-1 to the lipid bilayers containing zwitterionic and anionic lipids was found to be controlled mainly by hydrophobic interactions. Analysis of SQ-1 spectral behavior in the model membrane systems containing heme proteins revealed the dye sensitivity to the reactive oxygen species. This effect was supposed to originate from the reaction between lipid radicals and SQ-1 occuring at the squaric moiety or in its vicinity. Resonance energy transfer studies highlight the applicability of SQ-1 to structural characterization of amyloid fibrils

NOVEL CYANINE DYES AS POTENTIAL AMYLOID PROBES: A FLUORESCENCE STUDY

The applicability of the novel heptamethine cyanine dyes AK7-5 and AK7-6 to the detection and characterization of one-dimensional protein aggregates (amyloid fibrils) associated with numerous pathologies has been evaluated using the method of fluorescence spectroscopy. It was found that both the monomeric and aggregated forms of these dyes can bind to amyloidogenic protein lysozyme, but the concomitant changes in the electronic structure of H-aggregates render them capable of fluorescing. The growth of the hypsochromic bands with negligible changes of the monomeric peaks induced by the native protein and the opposite effects induced by the lysozyme fibrils suggest that the native lysozyme has more binding sites for the dye aggregates than fibrillar protein, while the fibril grooves represent specific binding site for the dyes monomers. The observed spectral behavior of the cyanine dyes, viz. significant distinctions in the fluorescence responses produced by the monomeric and fibrillar forms of lysozyme, suggest the possibility of recruiting these compounds as fluorescent amyloid markers along with the classical amyloid marker Thioflavin T

A novel phosphonium dye for amyloid fibril detection

Молекулярная биофизик

A novel phosphonium dye for amyloid fibril detection

Молекулярная биофизик