A highly specific and ultrasensitive fluorescent probe for basal lysosomal HOCl detection based on the chlorination induced by chlorinium ion (Cl+)
The development of techniques for detecting HOCl at the subcellular level is very important to elucidate its cellular functions. Due to relatively low concentration, it is still a great challenge to specifically track the basal HOCl in normal cells. In this paper, based on the unique chlorination of HOCl by the initiation of chlorinium ion (Cl+) in the acidic medium, we have developed a simple pH-mediated lysosome-targetable fluorescent probe Lyso-HOCl for the specific detection of HOCl over other bioactive molecules at higher concentration (500 μM). Our results show that Lyso-HOCl possesses a detection limit of 8.0 pM, and can quantitatively detect HOCl at the picomolar level. The ultrasensitive and ultrafast response property offers probe Lyso-HOCl a pleasant opportunity to monitor the basal HOCl and the fluctuation of endogenous HOCl levels in the lysosomes of macrophages (Raw264.7 cells), and we thus anticipate that this probe would provide a promising tool for further unraveling the biological functions of HOCl in the subcellular lysosomes.