Photoluminescence light-up detection of zinc ion and imaging in living cells based on the aggregation induced emission enhancement of glutathione-capped copper nanoclusters

In this work, we prepared glutathione (GSH)-capped copper nanoclusters (Cu NCs) with red emission by simply adjusting the pH of GSH/Cu2+ mixture at room temperature. A photoluminescence light-up method for detecting Zn2+ was then developed based on the aggregation induced emission enhancement of GSH-capped Cu NCs. Zn2+ could trigger the aggregation of Cu NCs, inducing the enhancement of luminescence and the increase of absolute quantum yield from 1.3% to 6.2%. GSH-capped Cu NCs and the formed aggregates were characterized, and the possible mechanism was also discussed. The prepared GSH-capped Cu NCs exhibited a fast response towards Zn2+ and a wider detection range from 4.68 to 2240 μM. The detection limit (1.17 μM) is much lower than that of the World Health Organization permitted in drinking water. Furthermore, taking advantages of the low cytotoxicity, large Stokes shift, red emission and light-up detection mode, we explored the use of the prepared GSH-capped Cu NCs in the imaging of Zn2+ in living cells. The developed luminescence light-up nanoprobe may hold the potentials for Zn2+-related drinking water safety and biological applications.