A naphthalene-based Al3+ selective fluorescent sensor for living cell imaging

Abstract

An efficient fluorescent Al³⁺ receptor, N-(2-hydroxy-1-naphthalene)-N′-(2-(2-hydroxy-1-naphthalene)amino-ethyl)-ethane-1,2-diamine (L) has been synthesized by the condensation reaction between 2-hydroxy naphthaldehyde and diethylenetriamine. High selectivity and affinity of L towards Al³⁺ in ethanol (EtOH) as well as in HEPES buffer at pH 7.4, makes it suitable to detect intracellular Al³⁺ with fluorescence microscopy. Metal ions, viz.Li⁺, Na⁺, K⁺, Mg²⁺, Ca²⁺, Mn²⁺, Co²⁺, Ni²⁺, Cu²⁺, Zn²⁺, Ag⁺, Cd²⁺, Hg²⁺ and Pb²⁺ do not interfere. The lowest detection limit for Al³⁺ is 3.0 × 10⁻⁷ M and 1.0 × 10⁻⁷ M in EtOH and HEPES buffer respectively.