Construction of a mito-targeting fluorescent probe for specific identification of Al3+ in environmental and biological systems

Abstract

A novel benzothiazole-based fluorescent probe HMH-Al was designed and synthesized for the selective sensing of Al³⁺. It showed a remarkable turn-on fluorescence response toward Al³⁺ with bright cyan-blue emission in EtOH/H₂O (v/v = 3 : 2). A 1 : 1 binding stoichiometry was confirmed by Job's plot, giving a binding constant of 2.06 × 10⁴ M⁻¹ and a detection limit of 2.83 × 10⁻⁷ M. Notably, HMH-Al was successfully applied for Al³⁺ determination in real water samples, portable paper-based test strips, and fluorescence imaging in living A549 and HeLa cells. These results demonstrate that HMH-Al is a promising candidate for monitoring Al³⁺ in mitochondria-targeted biological systems and environmental matrices.