Alizarin-based molecular probes for the detection of hydrogen peroxide and peroxynitrite

Phenol fluorophores are a large family of fluorophores, which have attracted more and more attention in the design of probes. Using the self-assembly of aromatic boronic acid with Alizarin Red S (ARS) and Gallein (GAL), the novel chemosensors ARS-CBA and GAL-CBA were provided for hydrogen peroxide (H₂O₂), which demonstrated their ability to detect H₂O₂ with indicator displacement assay (IDA) by colorimetric and electrochemical measurements. After ARS-CBA and GAL-CBA reacted with H₂O₂, the systems displayed a red-shifted visible color change in aqueous media and off-on electrochemical signals showing generation of phenol. The chemosensor ARS-CBA also had good performance in fluorometric measurements and turn-off fluorescent response indicated removal of aromatic boronic acid. In addition, a designed near-infrared (NIR) dual-modal fluorescent probe alizarin blue S (ABS) was used for peroxynitrite (ONOO^-) with a visible colorimetric change in dimethyl sulfoxide (DMSO) and "on-off" fluorescent response indicating the oxidation of hydroxyl. The flexible Phenol fluorophores are allowed to prepare multiple fluorescent probes towards H₂O₂ or ONOO^- for environmental and physiological applications.