A bifunctional reagent regulated ratiometric electrochemiluminescence biosensor constructed on surfactant-assisted synthesis of TiO2 mesocrystals for the sensing of deoxynivalenol.

Herein, a delicate bifunctional reagent regulated ratiometric electrochemiluminescence (ECL) biosensor was developed for the detection of deoxynivalenol (DON) by virtue of the ratio of two ECL signals from Luminol and tris(4,4'-dicarboxylicacid-2,2'-bipyridyl) ruthenium(II) dichloride (Ru(dcbpy)32+). Initially, surfactant-assisted synthesis of TiO2 mesocrystals dispersing in Nafion and ionic liquid (IL) complex film held great promises in loading Ru(dcbpy)32+ and amplifying the ECL signal. Additionally, helical carbon nanotube (HCNTs) with superior specific area and good conductivity emerging as a scaffold not only realized the high fixing of Luminol, ferrocenecarboxylic acid (FCA) and secondary antibody (Ab2), but accelerated the electron transfer. It's noteworthy that FCA was first utilized as a bifunctional reagent to regulate the ratiometric ECL sensing mode on account of the influences in enhancing the ECL response of Luminol and quenching the ECL emission of Ru(dcbpy)32+. On the basis of the sandwich-type immunoreactions between Ab1, DON and Ab2, an accurate and sensitive ratiometric ECL immunosensor was established for the detection of DON in a wide range from 0.05 pg/mL to 5 ng/mL with the detection limit of 1.67 × 10-2 pg/mL.