Induced circularly polarized luminescence for revealing DNA binding with fluorescent dyes

- CPL application to DNA/organic dyes binding is described for the first time.
- Strengths and possible artefacts of the CPL approach are discussed.
- CPL reveals the most relevant information in the case of thiazole orange/DNA intercalation or external binding.
- For the DAPI/DNA system, dye aggregates produce CPL artefacts connected to photoselection.
- CPL can be a useful complement to other measurements for advanced analysis of DNA binding

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.

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