BODIPY-Substituted Hydrazine as a Fluorescent Probe for Rapid and Sensitive Detection of Formaldehyde in Aqueous Solutions and in Live Cells

Abstract

Formaldehyde (FA) is not only a ubiquitous chemical pollutant in indoor environments but also a reactive carbonyl species (RCS) in biological processes. Therefore, it is important to develop noninvasive detection methods for elucidation of the roles and functions of FA in biological processes. In this work, we have prepared a BODIPY-substituted hydrazine (BHA) as a FA fluorescent probe based on a facile nucleophilic substitution of a meso-chlorinated BODIPY dye by hydrazine. The probe BHA can react with FA efficiently to form a blue fluorescent compound, hydrazone (2), giving a very large turn-on fluorescence response (>900-fold increment). The sensing reaction has been demonstrated as a switch of the intramolecular charge transfer (ICT) process from a twisted ICT for BHA to ICT for 2 by experiments and theoretical calculations. The probe BHA displays fast response to FA (<30 min), a low limit of detection (0.18 μM), high selectivity over other RCS, and very low cytotoxic effect on HeLa cells. Moreover, BHA can achieve detections of exo- and endogenous FA in live cells successfully.