Manganese-doped CeO2 nanoparticles with phosphatase-like activity for dual-mode detection of aluminum ions

Chronic overexposure to aluminum ions can cause damage to human brain and nervous system. In this work, a new strategy for colorimetric and fluorescent dual-mode detection of aluminum ions (Al 3+ ) was developed, which based on the excellent phosphatase-like activity of histidine-functionalized manganese-doped cerium dioxide nanoparticles (Mn-CeO 2 NPs). Water-soluble, uniform and highly dispersible Mn-CeO 2 NPs were prepared by a green and simple one-pot synthesis method. And the NPs with phosphatase-like activity can catalyze the dephosphorylation of phosphate substrates p-nitrophenyl picolinate (p-NPP) and 4-methylumbelliferyl phosphate (4-MUP) to obtain products with UV–vis and fluorescence signals. Interestingly, Al 3+ can chelate with O atoms on the surface of nanozymes, causing them to aggregate, and thereby reducing their catalytic activity. Based on this principle, a simple, sensitive colorimetric and fluorescent dual-mode sensor for detecting Al 3+ was constructed, and the response time could be as short as 1 min. The linear ranges of colorimetric and fluorescent analysis of Al 3+ were 1–30 μM and 1–15 μM, and the limits of detection (LOD) were 0.86 μM and 0.29 μM, respectively. This study not only synthesized an efficient phosphatase-like nanozyme by defect engineering, but also opened up a new channel for sensitive and rapid detection of Al 3+ .