A novel smartphone-based colorimetric biosensor for reliable quantification of hydrogen peroxide by enzyme-inorganic hybrid nanoflowers

A novel smartphone-based colorimetric biosensor based on enzyme-inorganic hybrid nanoflowers was applied for ultrasensitive determination of of hydrogen peroxide (H 2 O 2 ). Horseradish peroxidase-inorganic hybrid nanoflowers (HRP-Cu 3 (PO 4 ) 2 ⋅3H 2 O HNFs) were facilely synthesized by a one-pot incubation using HRP and Cu 3 (PO 4 ) 2 ⋅3H 2 O as organic and inorganic components, respectively. Characterization results revealed HRP molecules were well immobilized in HRP-Cu 3 (PO 4 ) 2 ⋅3H 2 O HNFs via self-assembly. The results of smartphone-based colorimetric assay successfully demonstrated the good sensing performance of HRP-Cu 3 (PO 4 ) 2 ⋅3H 2 O HNFs. The linear detection range of H 2 O 2 was from 5 to 500 μM, and the detection limit was 0.5 μM. Further, the proposed assay showed good anti-interference ability and high sensitivity for H 2 O 2 detection owing to the high specificity of HRP and excellent accuracy of color parameters obtained by Color Detector software, respectively. In addition, HRP-Cu 3 (PO 4 ) 2 ⋅3H 2 O HNFs had desirable storage stability and reusability, and this colorimetric system can realize the H 2 O 2 detection in tap water, which indicated the good applicability of HRP-Cu 3 (PO 4 ) 2 ⋅3H 2 O HNFs in real sample.