Ternary MIL-101(Fe)@P2W18@SWNT Nanocomposites as Colorimetric Biosensors with Highly Peroxidase-Like Activity

To explore novel nanozymes as colorimetric biosensors with highly activities, the ternary MIL-101(Fe)@P 2 W 18 @SWNT nanocomposite was successfully fabricated based on the optimal matching principle, namely, Wells–Dawson-type polyoxometalates (POMs, H 6 P 2 W 18 O 62 abbreviated as P 2 W 18 ) were encapsulated in a custom MIL-101(Fe) cavity, and single-walled carbon nanotubes (SWNT) was then fixed. The peroxidase-like activities of MIL-101(Fe)@P 2 W 18 @SWNT nanocomposite were evaluated by detecting hydrogen peroxide (H 2 O 2 ) and glucose (GLC). Compared with the MIL-101(Fe), P 2 W 18 and SWNT, the MIL-101(Fe)@P 2 W 18 @SWNT exhibits better peroxidase-like properties and stability due to the nature of all components and their optimal synergy. Based on the excellent catalytic activity of MIL-101(Fe)@P 2 W 18 @SWNT , two colorimetric biosensors for detecting H 2 O 2 and GLC with linear ranges of 0–80 μM (H 2 O 2 ) and 0–150 μM (GLC) were constructed, and the low detection limit of 0.3 μM for H 2 O 2 and 0.2 μM for GLC are superior to the most reported nanozymes. The work opens a promising route in constructing heterogeneous MOFs and POMs-based nanozymes for biosensing application.