Abstract
Ethidium Bromide (EB) is a commonly used dye in a deoxyribonucleic acid (DNA) study. Upon an intercalation, this dye significantly increases its brightness and lifetime. In this report we studied time-resolved fluorescence properties of EB fluorophore existing simultaneously in free and bound forms in the solution. Fluorescence intensity decays were fitted globally to a double exponential model with lifetimes corresponding to free (1.6ns) and bound (22ns) forms, and molar fractions were determined for all used solutions. Anisotropy decays displayed characteristic time dependence with an initial rapid decline followed by an increase and a slow decay. This is because two existing fractions contributing to a total anisotropy change in time. The short-lived fraction associated with free molecules decreases faster than long-lived fraction associated with bound EB. In a consequence, the contribution of fast rotation (free EB) to total anisotropy decreases in time. The effect of associated anisotropy decays in systems EB-DNA is clearly visible in a wide range of concentrations and should be taken into account in polarization assays.
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call