The layer-by-layer assembled ERGO+/ERGO− multilayer modified electrode for sensitive detection of dopamine

Graphene materials represented by graphene oxide (GO) have been widely regarded as functional coatings or films to modify surface of the electrode for detecting dopamine molecules. However, interfacial material properties for detection sensitivity, film stability, and applicability to electrodes are still highly desired. Herein, we first present a screen-printing carbon electrode (SPCE) coated with an electrochemically reduced layer-by-layer (LbL) assembled multilayer driven by an electrostatic interaction between positively charged polyethyleneimine-modified GO with amine groups (ERGO+) and negatively charged carboxyl-functionalized GO (ERGO−), which is briefly described as (ERGO+/ERGO−) n /SPCE. Firstly, without using conventional glassy carbon and gold electrodes, SPCE was tried to make coatings adapt to more flexible and unstable electrodes, simultaneously guaranteeing higher detection performance. Secondly, although a variety of electrochemical sensors such as GO−/SPCE and ERGO−/SPCE were obtained through the drop-casting technique, as-prepared (ERGO+/ERGO−) n /SPCE showed much higher electrocatalytic activities with enhanced peak current signals and reduced charge transfer resistance. Finally, excellent electrochemical properties and sensing performances of the (ERGO+/ERGO−) n /SPCE sensor for detection of dopamine were demonstrated, especially having a linear range of 1 μ M to 1000 μ M. Meanwhile, the detection limit is as low as 0.39 μ M and S/N is equal to 3. The present work offers a potential direction to develop GO modified electrodes for sensitive biomolecular detection.