Os-Single-Atom Anchored Artificial Enzymes with POD-Mimetic Activities as Smartphone-Based Biosensor for the Visual and Multimodal Detection of Food Additives.

Real-time and high-efficient detection of food additives is of great significance for global public health. As a popular biosensor, colorimetric detection has been widely applied in various fields, including the food industry. However, owing to the complex structure, weak ROS-catalytic activities and unclear catalytic mechanism, recently reported biocatalysts as biosensors still face major challenges in achieving high-efficient and multimodal aspects. Here, the novel design of high-efficient, robust, multimodal, and Os-based active centers on the oxygen vacancies (O)-containing CuCl(OH) substrates (Os@TBCC-O) to serve as ROS-catalytic biosensors to colorimetric detection of food additives is reported. Benefiting from the highly active and excellent electronic structure of Os-single-atom sites, the synthesized Os@TBCC-O biocatalysts exhibit superior POD-mimetic activities, thus facilitating the exceptional and exclusive detecting activities. Moreover, colorimetric studies found that the POD-mimetic biosensor of Os@TBCC-O can provide high-efficient, wide-range and visual detection abilities of food additives, including HO, L-Cysteine and glucose, which is much higher efficient than that of previously reported biosensors. Meanwhile, the results of practical application further demonstrate the feasibility of Os@TBCC-O-based biosensors in detection of food additives. It is suggested that this design will offer a novel pathway for high-efficient colorimetric detection of POD-mimetic biocatalysts in food industry and other related fields.