A highly sensitive and selective photoelectrochemical aptasensor for atrazine based on Au NPs/3DOM TiO2 photonic crystal electrode

A photoelectrochemical (PEC) sensing platform with high sensitivity and selectivity has been fabricated based on Au nanoparticles (Au NPs) modified three dimensionally ordered macroporous (3DOM) TiO2 nanostructure frame for trace detection of an endocrine disrupting pesticide, atrazine (ATZ). The resultant photoanode (Au NPs/3DOM TiO2) shows enhanced PEC performance under visible light due to multi signal amplification of the unique structure of 3DOM TiO2 and surface plasmon resonance (SPR) of Au NPs. ATZ aptamers are used as recognition elements and immobilized on Au NPs/3DOM TiO2 by Au-S bond in large packing density and dominant spatial orientation. The specific recognition and high binding affinity between aptamer and ATZ provides the PEC aptasensor with excellent sensitivity. The detection limit is 0.167 ng/L. Besides, this PEC aptasensor exhibits outstanding anti-interference ability in 100-fold concentration of other endocrine disrupting compounds and has been applied successfully to analyze ATZ in real water samples. A simple but efficient PEC aptasensing platform has therefore been successfully developed with high sensitivity, selectivity and repeatability for pollutant monitoring and potential risk evaluation in the environment with great application prospect.