Selective detection of superoxide anion radicals generated from macrophages by using a novel fluorescent probe.

Quantitation of superoxide radical (O (2)(-).) production at the site of radical generation remains challenging. A simple method to detect nanomolar to micromolar levels of superoxide radical in aqueous solution has been developed and optimized. This method is based on the efficient trapping of O(2)(-). using a novel fluorescent probe (2-chloro-1,3-dibenzothiazolinecyclohexene), coupled with a spectra character-signaling increase event. A high-specificity and high-sensitivity fluorescent probe was synthesized in-house and used to image O(2)(-). in living cells. Better selectivity for O(2)(-). over competing cellular reactive oxygen species and some biological compounds illustrates the advantages of our method. Under optimal conditions, the linear calibration range for superoxide anion radicals was 5.03 x 10(-9)-3.33 x 10(-6) M. The detection limit was 1.68 x 10(-9) M. Fluorescence images of probe-stained macrophages stimulated with 4beta-phorbol 12-myristate 13-acetate were obtained successfully using a confocal laser scanning microscope.