Fluorescent Hydroxylamine Derived from the Fragmentation of PAMAM Dendrimers for Intracellular Hypochlorite Recognition

Abstract

Herein, a promising sensing approach based on the structure fragmentation of poly(amidoamine) (PAMAM) dendrimers for the selective detection of intracellular hypochlorite (OCl⁻) is reported. PAMAM dendrimers were easily disrupted by a cascade of oxidations in the tertiary amines of the dendritic core to produce an unsaturated hydroxylamine with blue fluorescence. Specially, the novel fluorophore was only sensitive to OCl⁻, one of reactive oxygen species (ROS), resulting in an irreversible fluorescence turn-off. The fluorescent hydroxylamine was selectively oxidised by OCl⁻ to form a labile oxoammonium cation that underwent further degradation. Without using any troublesomely synthetic steps, the novel sensing platform based on the fragmentation of PAMAM dendrimers, can be applied to detect OCl⁻ in macrophage cells. The results suggest that the sensing approach may be useful for the detection of intracellular OCl⁻ with minimal interference from biological matrixes.