Selectivity of a bromoacridine-containing fluorophore for triplex DNA

Fluorophore 1,8-naphthilamide was linked to 2-bromoacridine through an ethylenediamine spacer using a succinct synthetic route to give a bromoacridine-linked, bifunctional fluorophore conjugate for the detection of triplex DNA. Acridine is well known to intercalate into duplex DNA whereas introduction of a bulky bromine atom at position C2 redirects specificity for triplex over duplex DNA. In this work, photoelectron transfer assay was used to demonstrate that the synthesised 2-bromoacridine-linked fluorophore conjugate had good selectivity for the representative triplex DNA target sequence d(T*A.T)₂₀ compared with double-stranded d(T.A)₂₀, single-stranded dT₂₀ or d(G/A)₁₉ DNA sequences. Graphic abstract: