Ocean green tide derived hierarchical porous carbon with bi-enzyme mimic activities and their application for sensitive colorimetric and fluorescent biosensing

Abstract

The hierarchical porous carbon with high specific surface area was facilely synthesized by calcination of Enteromorpha prolifera (EP), a renewable ocean waste biomass. The resultant carbon exhibited bienzyme mimetic properties including oxidase-like and peroxidase-like activities, which can be regulated by varying carbonized temperature. The reaction mechanism of the oxidase-like activity of EP-based hierarchical porous carbon (EPC) contributes to singlet oxygen and superoxide anions generated during the reaction, while the peroxidase-like activity arises from hydroxyl radicals. Finally, a sensitive colorimetric biosensor for acid phosphatase was explored based on the oxidase-like activity, demonstrating a linear range of 0.5–15 U/L and the limit of detection (LOD) of 0.1 U/L (S/N = 3). A fluorescent biosensor for H2O2 was also developed with the linear range of 0.05–80 μM and a LOD of 0.017 μM (S/N = 3), based on OH produced with the peroxidase-like activity, which react with terephthalic acid to form 2-hydroxyterephthalic acid. Further, incorporated with glucose oxidase, fluorometric sensing of glucose was realized with the linear range of 0.05–10 mM and a LOD of 30 μM. The bi-enzyme mimics also exhibited high reproducibility and stability. Thus, this EPC can be promising candidates for broad applications in sensing, nanomedicine, industrial catalysis and environmental engineering.