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 Ag2O. It was demonstrated that the aptamer sequence could enhance the affinity of colloidal Ag2O to chromogenic substrates, and accelerate the generation of oxygen radicals such as superoxide radical (center dot O-2(-)) and singlet oxygen (O-1(2)) from dissolved oxygen, thereby significantly increasing the oxidase activity of octahedral Ag2O. 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 mu g L (-1), 28 mu g L (-1) and 40 mu g 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.

Automated summary

A smartphone-assisted and non-enzymatic colorimetric biosensor was developed for rapid monitoring of multiple organophosphorus pesticides (OPs). The biosensor utilizes the enhanced effect of aptamer on the catalytic ability of octahedral Ag2O to achieve accurate and stable detection of pesticide residues. The color change of the solution can be easily converted to RGB values by a smartphone, enabling quantitative and rapid detection of multiple OPs.