Sensitive luminescent determination of DNA using the terbium(III)-difloxacin complex.
The interaction of the terbium-difloxacin complex (Tb-DFX) with DNA has been examined by using UV-vis absorption and luminescence spectroscopy. The Tb-DFX complex shows an up to 85-fold enhancement of luminescence intensity upon titration with DNA. The long decay times allow additional detection schemes like time-resolved measurements in microplate readers to enhance sensitivity by off-gating short-lived background luminescence. Optimal conditions are found at equimolar concentrations of Tb(3+) and DFX (0.1 or 1 microM) at pH 7.4. Under these conditions, the luminescence intensity is linearly dependent on the concentration of ds-DNAs and ss-DNA between 1-1500 ng mL(-1) and 4.5-270 ng mL(-1), respectively. The detection limit is 0.5 ng mL(-1) for ds-DNAs and 2 ng mL(-1) for ss-DNA. The mechanism for the luminescence enhancement was also studied.
Yegorova
Alla V
AV
Institute of Analytical Chemistry, Chemo- and Biosensors, University of Regensburg, D-93040 Regensburg, Germany. yegorova@interchem.com.ua <yegorova@interchem.com.ua>
Scripinets
Yulia V
YV
Duerkop
Axel
A
Karasyov
Alexander A
AA
Antonovich
Valery P
VP
Wolfbeis
Otto S
OS
D002939:Ciprofloxacin / Q000031:analogs & derivatives* / Q000737:chemistry; D004247:DNA / Q000032:analysis* / Q000737:chemistry; D005456:Fluorescent Dyes / Q000737:chemistry*; D024841:Fluoroquinolones / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D008163:Luminescent Measurements; D009994:Osmolar Concentration; D013725:Terbium / Q000737:chemistry*
D005456:Fluorescent Dyes; D024841:Fluoroquinolones; D013725:Terbium; D002939:Ciprofloxacin; C047225:difloxacin; D004247:DNA