Development of a fluorescent probe for nitric oxide detection based on difluoroboradiaza-s-indacene fluorophore

Nitric oxide (NO) is an important mediator involved in various physiological phenomena. To obtain direct evidence for NO functions in vivo, a novel fluorescent probe for NO, 1,3,5,7-tetramethyl-8-(3',4'-diaminophenyl)-difluoroboradiaza-s-indacence (TMDABODIPY) was designed and synthesized, which features high photostability and no pH dependency over a wide pH range. The fluorescence of 1,3,5,7-tetramethyl-8-(3',4'-diaminophenyl)-difluoroboradiaza-s-indacence is very strong, however, when the reagent traps NO in the presence of dioxygen, the weakly fluorescent triazole form is obtained, which offers the advantages of specificity and sensitivity for direct detection of NO. Calibration for NO showed the response has good linearity (0.01-0.4 mumol l(-1)) and its detection limit is 2.5 nmol l(-1) (s/n = 3). The proposed method has been used to monitor the release of NO from S-nitrosocysteine, a NO-releasing agent. (C) 2003 Elsevier Science B.V. All rights reserved.