A sensing platform for hypoxanthine detection based on amino-functionalized metal organic framework nanosheet with peroxidase mimic and fluorescence properties

The amino-functionalized metal organic framework (NH2-Cu-MOF) was fabricated via bottom-up synthesis strategy. Detailed characterization using electron microscopy, X-ray photoelectron spectroscopy and atomic force microscopy demonstrated that the as-synthesized NH2-Cu-MOF was two-dimensional nanosheet (a thin thickness ∼4.2 nm). Results showed that the as-synthesized NH2-Cu-MOF nanosheet possessed fluorescence property (λem = 425 nm) as well as peroxidase mimic activity. On the basis of these two properties, we proposed a biosensor for hypoxanthine detection. The fluorescence intensity had a linear relationship with the hypoxanthine concentration in the range of 10-2000 μM. The limit of detection was 3.93 μM (S/N = 3). This work contributes to the synthesis of a new two-dimensional MOF nanosheet and extends the application of two-dimensional MOF nanosheet on biological luminescent sensors.