Catechol-modified green fluorescent protein as a specific biosensor for Al ions

Abstract A protein-based fluorescent sensor for the efficient detection of Al 3+ is reported. The sensor is genetically engineered through the residue-specific incorporation of 3, 4-dihydroxy- l -phenylalanine (Dopa) into a green fluorescent protein (GFP) (termed as GFP-Dopa) and can selectively detect Al 3+ in aqueous media. Al 3+ could be readily detected through the distinctive fluorescence enhancement as a result of strong chelation of Al 3+ with GFP-Dopa. Among 15 different tested metal ions, only Al 3+ induces a significant fluorescence enhancement of GFP-Dopa, suggesting a high selectivity and exclusive specificity of GFP-Dopa towards Al 3+ . Together with its high biocompatibility, this protein-based sensor could be used in various applications requiring the rapid and sensitive detection of Al 3+ .