Simple and Reliable Method for the Determination of Exocellular DNA in a Bacterial Culture by Ru(phen)2(dppz)2

A novel fluorimetric method was developed for the selective determination of DNA under physiological conditions with the molecular "light-switch" complex Ru(phen)(2)(dppz)(2+). Under optimal conditions, the fluorescence intensity was linear to the concentration of DNA. The linear range for calf thymus DNA (CT-DNA) was 0-2.0 mu g/mL, and the limit of detection was 0.001 mu g/mL. The proposed method was successfully applied to the determination of exocellular DNA in a bacterial culture.