Poly(noradrenalin) based bi-enzyme biosensor for ultrasensitive multi-analyte determination.

In order to realize the multi-analyte assays for physiological molecules and environmental contaminants, a bi-enzyme biosensor based on horseradish peroxidase (HRP)-catalyzed noradrenalin (NA) polymerization in the presence of HO was fabricated for the first time and utilized in immobilizing HRP and glucose oxidase (GOx) simultaneously. The resultant bi-enzyme modified electrode was demonstrated to be efficient in monitoring multi-analyte (HO, Cr(III), glucose, and Cr(VI)). It was shown that the prepared PNA-HRP-GOx/Pt electrode exhibits a sensitivity (S) high up to 628.4 μA mM cm in the linear range (LR) of 0.50 μM ~ 0.42 mM and a S of 208.9 μA mM cm in the LR of 0.42 mM~3.5 mM in glucose sensing, with a limit of detection (LOD) of 0.08 μM observed; in Cr(VI) sensing a LOD of 0.20 nM and a LR of 0.50 ~ 6.0 nM were obtained. With the addition of polyaniline (PANI), the resultant PNA-HRP-GOx/PANI/Pt electrode potentiostated at - 0.20 V responded linearly to HO concentration in 0.05 ~ 30.2 mM range, with linearly responses to Cr(III) concentration in the LR of 0.01 ~ 3.8 μM. Hence, amperometric biosensors with high S, low LOD and good anti-interference ability for detection of glucose, HO and heavy metal ions (Cr(III) and Cr(VI)) were developed.