Induced circularly polarized luminescence for revealing DNA binding with fluorescent dyes

Abstract

To the best of our knowledge this is the first report on the application of induced circularly polarized luminescence (CPL) for sensing the binding of fluorescent dyes to double stranded DNA. Using Thiazole Orange (TO) and 4',6-diamidino-2-phenylindole (DAPI) as models, we show utility and limitations of CPL in DNA binding studies. The results obtained indicate that CPL can be used as a new chiroptical tool for this purpose, however, special attention while recording CPL data must be used, in order to exclude measurement artefacts caused by linear polarization components.

Polarization spectroscopy methods in the determination of interactions of small molecules with nucleic acids – tutorial

“…Furthermore, fluorescence detected circular dichroism (FDCD) combines the advantages of both CD and fluorescence emission technique, which is ideal for the selective study of DNA ligands that strongly change fluorescence upon binding [ 3 ]. In a sense complementary to FDCD, also circularly polarized luminescence (CPL) is a chiroptical emission technique which has been employed in the same context for the first time recently [ 12 ].…”

“…On the contrary, CPL is still in its infancy regarding the same context. The first paper describing the interaction of ct -DNA with two fluorescent ligands has recently appeared [ 12 ]. CPL may complement ECD by providing specific information on the emission behavior of a fluorescent achiral ligand bound to DNA.…”

“…CPL is also subjected to various kinds of artifacts, which need to be properly considered [ 12 ]. It must be stressed that the first commercial CPL instrument has only recently appeared on the market, sold by Jasco, Inc., but several home-made instruments are active.…”

A chiral lactate reporter based on total and circularly polarized Tb(iii) luminescence

“…Firstly, the interaction between the target anion (lactate) and the positively charged lanthanide cation can be signaled by a unique change of the TL features. In addition, CPL spectroscopy has proven to be particularly suitable to track interaction between luminescent molecular probes (even non-chiral or racemic ones) with chiral species, such as proteins, 7,8 DNA, 9 aminoacids, [10][11][12][13] or chiral ions (lactate is a chiral anion) or molecules (sialic acid). 14 CPL efficiency is measured in terms of the dissymmetry factor (or glum), defined as: glum = 2(IL -IR)/(IL + IR) (with IL and IR the left-and right-polarized intensity, respectively).…”

Chiroptical detection of a model ruthenium dye in water by circularly polarized-electrochemiluminescence

“…12 Indeed, circularly polarized photoluminescence (CP-PL or CPL) has been measured also in case of racemic or non-chiral emitters following and demonstrating their interaction with biomolecular non-racemic analytes. [13][14][15] Thus, resolving the circular polarization provides valuable information on optically active chiral molecules. CP-PL or CPL is the differential photoexcited emission of left-or right-circularly polarized emission from an excited electronic state in the presence of a chiral field.…”