Selective determination of DNA based on the fluorescence recovery of carbon dots quenched by Ru(bpy)2(dppz)2+

A quick, highly selective and sensitive method for the determination of DNA was constructed based on the recovery of red fluorescence of carbon dots quenched by a ruthenium complex Ru (bpy)(2)(dppz)(2+), bpy = 2,2'-bipyridine; dppz = dipyrido [3.2-a:2',3'-c]phenazine). The carbon dots showed two emission peaks at 450 and 683 nm under excitation wavelength of 420 nm. After addition of Ru (bpy)(2)(dppz)(2+), the fluorescence of carbon dots at 683 nm was markedly quenched. Due to the stronger interaction between DNA and Ru (bpy)(2)(dppz)(2+), the quenched fluorescence of carbon dots was recovered with DNA added. Under the optimum conditions, there was a good linear relationship between the degree of fluorescence recovery of carbon dots and DNA concentration in range of 0.0150-9.60 mu g(-1). The detection limit was 0.00536 mu g(-1). The carbon dots were successfully applied to detect DNA in the simulated sample and the spiked recoveries were between 97.4% and 106%.