Protein-assisted formation of gold clusters-MnO2 nanocomposite for fluorescence imaging of intracellular glutathione

Herein, a bovine serum albumin-stabilized gold clusters-MnO2 nanocomposite (BSA@AuNCs-MnO2) was constructed. Manganese dioxide (MnO2) was generated in situ on the gold clusters (BSA@AuNCs) based on the redox reaction between bovine serum albumin (BSA) and potassium permanganate (KMnO4). The fluorescence of BSA@AuNCs can be quenched by the in-situ grown MnO2, which has strong light absorption ability. It is worth noting that the quenched fluorescence of the BSA@AuNCs can be restored in the presence of glutathione (GSH), and MnO2 was reduced to Mn2+ in return. Encouragingly, 1 mu M GSH can cause a detectable fluorescence change. This sensitivity is comparable to other nanomaterials based fluorescent probes. Furthermore, this nanocomposite has obvious superiorities, such as good uniformity, simple preparation and mild reaction. The nanocomposite also has good stability and specificity, which can be further used for visualizing of intracellular GSH.