Facile colorimetric smartphone-based biosensor for rapid detection of organophosphorus pesticides residues in environment using the aptamer-enhanced oxidase activity of octahedral Ag2O particles

The long-term and excessive use of organophosphorus pesticides (OPs) leads to hazardous residues in the environment, which threatens human health to a considerable extent. Colorimetric methods can quickly and readily identify pesticide residue , but they still have various challenges in accuracy and stability. Herein, a smartphone-assisted and non-enzymatic colorimetric biosensor was constructed for rapid monitoring of multiple OPs based on the enhanced effect of aptamer on the catalytic ability of octahedral Ag 2 O. It was demonstrated that the aptamer sequence could enhance the affinity of colloidal Ag 2 O to chromogenic substrates, and accelerate the generation of oxygen radicals such as superoxide radical (·O 2 − ) and singlet oxygen ( 1 O 2 ) from dissolved oxygen, thereby significantly increasing the oxidase activity of octahedral Ag 2 O. The color change of the solution can be easily converted to the corresponding RGB values by a smartphone for quantitative and rapid detection of multiple OPs. Hence, the smartphone-based and visual biosensor of multiple OPs was acquired with limit of detection of 10 μg L −1 , 28 μg L −1 and 40 μg L −1 for isocarbophos , profenofos and omethoate , respectively. The colorimetric biosensor also exhibited good recoveries in several environmental and biological samples, showing that it may have broad application prospects for detecting OPs residues.