Multifunctional
Electrochemical Platforms Based on the Michael Addition/Schiff Base
Reaction of Polydopamine Modified Reduced Graphene Oxide: Construction
and Application
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Abstract
In
this paper, a new strategy for the construction of multifunctional
electrochemical detection platforms based on the Michael addition/Schiff
base reaction of polydopamine modified reduced graphene oxide was
first proposed. Inspired by the mussel adhesion proteins, 3,4-dihydroxyphenylalanine
(DA) was selected as a reducing agent to simultaneously reduce graphene
oxide and self-polymerize to obtain the polydopamine-reduced graphene
oxide (PDA-rGO). The PDA-rGO was then functionalized with thiols and
amines by the reaction of thiol/amino groups with quinine groups of
PDA-rGO via the Michael addition/Schiff base reaction. Several typical
compounds containing thiol and/or amino groups such as 1-[(4-amino)phenylethynyl]
ferrocene (Fc-NH<sub>2</sub>), cysteine (cys), and glucose oxidase
(GOx) were selected as the model molecules to anchor on the surface
of PDA-rGO using the strategy for construction of multifunctional
electrochemical platforms. The experiments revealed that the composite
grafted with ferrocene derivative shows excellent catalysis activity
toward many electroactive molecules and could be used for individual
or simultaneous detection of dopamine hydrochloride (DA) and uric
acid (UA), or hydroquinone (HQ) and catechol (CC), while, after grafting
of cysteine on PDA-rGO, simultaneous discrimination detection of Pb<sup>2+</sup> and Cd<sup>2+</sup> was realized on the composite modified
electrode. In addition, direct electron transfer of GOx can be observed
when GOx-PDA-rGO was immobilized on glassy carbon electrode (GCE).
When glucose was added into the system, the modified electrode showed
excellent electric current response toward glucose. These results
inferred that the proposed multifunctional electrochemical platforms
could be simply, conveniently, and effectively regulated through changing
the anchored recognition or reaction groups. This study would provide
a versatile method to design more detection or biosensing platforms
through a chemical reaction strategy in the future