The synthesis of tunable fluorescence iron nanoclusters and the detection of pH value and hydroxyl radical.

[Display omitted] • A novel route for the synthesis of fluorescent iron nanoclusters in aqueous solution was synthesized. • The fluorescence emission peak of iron nanoclusters were adjustable from red to blue fluorescence. • The fluorescence of iron nanoclusters can be used for monitoring the changes of pH value. • The fluorescence of iron nanoclusters can be inhibited significantly by hydroxyl radical. In this work, we developed a novel route for the synthesis of fluorescent iron nanoclusters (Hb-Fe NCs) in aqueous solution with natural protein and amino acid as the original materials. Moreover, the fluorescence emission of Hb-Fe NCs were adjustable from red to blue fluorescence by regulating the dosage of sodium hydroxide in the synthesis process. We have examined the fluorescence response of Hb-Fe NCs in various temperature, metal ions or biomolecules environment, and exhibited excellent stability in the complex environment. Furthermore, the fluorescence of Hb-Fe NCs gradually enhanced as the pH value of environment increased from 5.0 to 9.0. More importantly, the fluorescence of Hb-Fe NCs can be inhibited significantly by hydroxyl radical (OH·). [ABSTRACT FROM AUTHOR]