LRET-based functional persistent luminescence nanoprobe for imaging and detection of cyanide ion

Cyanide anion is an inhibitor of the enzyme cytochrome c oxidase in the fourth complex of the electron transport chain, and usually found in the membrane of the mitochondria of eukaryotic cells, thus exploration of novel analytical methodology for sensitive and accurate detection of cyanide ion in cells is vital and urgent. Herein, we successfully prepared and surface-modified ZnGa2O4: Mn2+ PLNPs with excellent afterglow properties, small size and preferable dispersibility. Furthermore, we report a rational design and fabrication of a functional PL nanoprobe based on luminescence resonance energy transfer (LRET), which for the first time demonstrates detection of cyanide ion without external illumination. The nanoprobe is composed of two main moieties: PLNPs with excellent afterglow properties as energy donor; and DEHSPI, a chromophore with tunable light absorption, as both energy acceptor and CN- recognition element. PL can be effectively quenched by the chromophores assembled on the surface of PLNPs through a LRET process and subsequently recovered upon the addition of CN-. Importantly, the persistent afterglow nature highlights the merits of employing PLNPs as energy donor to eliminate the background noise under in situ excitation. Moreover, the nanoprobe exhibits excellent analytical properties and low cytotoxicity for bio-imaging of CN- in living cells.