Ratiometric\nDual Signal-Enhancing-Based Electrochemical Biosensor for Ultrasensitive\nKanamycin Detection

Abstract

Based\non the signal amplification elements of planar VS₂/AuNPs\nnanocomposites and CoFe₂O₄ nanozyme, we herein\ndeveloped an electrochemical biosensor for sensitive kanamycin (Kana)\nquantification. A ratiometric sensing platform was presented by incorporating\nVS₂/AuNPs nanocomposites as a support material with excellent\nconductivity and high specific surface area, as well as hairpin DNA\n(hDNA) with complementary hybridization of biotinylated Kana-aptamer.\nIn addition, streptavidin-functionalized CoFe₂O₄ nanozyme with superior peroxidase-like catalytic activity were immobilized\nonto the aptasensor, hence the peroxidase-like catalytic reaction\ncould yield amplified electrochemical signals. With the presence of\nKana, the aptamer-biorecognition resulted in a quantitative decrease\nof nanozyme accumulation and an increase of methylene blue response.\nUnder optimal conditions, the electrochemical signal ratio of the\naptasensor revealed a linear relation along with the logarithmic concentration\nof Kana from 1 pM to 1 μM, with the limit of detection reaching\nto 0.5 pM. Moreover, this aptasensor exhibited excellent precision,\nas well as high repeatability, hence possessing potentials in real\nsamples and for diverse targets detection by easy replacement of the\nmatched aptamer.