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Biological thiols including cysteine (Cys), homocysteine (Hcy), and glutathione (GSH) possess the similar structures, but they play different important biological roles. So the detection and discrimination of these biological thiols are of great importance. To date, a number of fluorescent probes have been developed for detection of biothiols. Unfortunately, it is difficult for the probes in discrimination of Cys from Hcy. In this paper, the borondipyrrolemethene -based fluorescent probe named 1 is successfully synthesized. The probe itself exhibits weak fluorescence because the fluorophore is quenched by the acrylate group through a photoinduced electron-transfer (PET) process. Upon reaction of the probe with cysteine, large fluorescence enhancement is produced. The probe could be applied to the quantification of Cys with a linear range covering from 0.2 to 30 μM and the detection limit is 0.05 μM. Furthermore, the fluorescence enhancement shows high sensitivity towards Cys owing that there is more fast reaction rate between the probe and Cys than that of Hcy. Moreover, the response behavior of 1 towards Cys is pH independent in the neutral range from 6.0 to 8.0 and the response of 1 toward Cys was fast. Finally, the probe has low cytotoxicity and is applied for detection of Cys in living cells with encouraging results. [ABSTRACT FROM AUTHOR]

Adenosine triphosphate (ATP) is mainly produced in the mitochondrion and used as a universal energy source for various cellular events. Various fluorescent probes for ATP have been established successfully, but most of them are not appropriate for monitoring the fluctuation of the mitochondrial ATP level. Herein, a fluorescent probe named Mito-Rh is first synthesized and used to recognize ATP in mitochondrion. In the probe, rhodamine, diethylenetriamine, and triphenylphosphonium are selected as fluorophore, reaction site, and mitochondrion-targeting group, respectively. Probe Mito-Rh shows high sensitivity to ATP with 81-fold fluorescence enhancement, and the detection range (0.1-10 mM) can match the concentration level of ATP in the mitochondrion. Moreover, Mito-Rh provides excellent selectivity toward ATP over other biological anions (ADP, AMP, GTP, CTP, UTP) owing to a concurrent effect of dual recognition sites (hydrogen bond and π-π stacking). In particular, the probe can localize in mitochondrion specifically and demonstrates utility in the real-time detection of mitochondrial ATP concentration changes. [ABSTRACT FROM AUTHOR]