Functionalized nitrogen doped graphene quantum dots and bimetallic Au/Ag core-shell decorated imprinted polymer for electrochemical sensing of anticancerous hydroxyurea.

A novel molecularly imprinted polymer-capped acrylated nitrogen doped graphene quantum dots and bimetallic Au/Ag core-shell was synthesized to serve as a sensing nano-hybrid film for the detection of an anticancerous drug, hydroxyurea. This exploited the use of a functionalized nitrogen doped graphene quantum dots iniferter. This initiated the polymerization, following "surface grafting-from" approach, over the surface of a screen-printed carbon electrode to obtain requisite stability and selectivity of the measurement. Herein, nitrogen doped graphene quantum dots were prepared utilizing the degree of dehydration/carbonization of citric acid (carbon skeleton) and urea (nitrogen dopant) as source materials. This provided an efficient sensor platform anchoring bimetallic Au/Ag core-shell on its surface. The nano-assembly of acrylated nitrogen doped graphene quantum dots and bimetallic Au/Ag core-shell@imprinted polymer actually amplified the electrode kinetics by improving the diffusion coefficient (~20-fold) and electron-transfer kinetics (~5-fold), in comparison to the simple bimetallic Au/Ag core-shell decorated imprinted sensor. Under optimized conditions of differential pulse anodic stripping voltammetric transduction, a linear relationship between the current and the concentration was obtained in the range of 0.62-102.33 ng mL-1 for hydroxyurea. The detection limit was observed to be 0.07 ng mL-1 in blood plasma, without having any matrix effect, cross-reactivity, and false-positives. The proposed sensor assures its clinical applicability for the treatment of cancer.