Facile Post-deposition Annealing of Graphene Ink Enables Ultrasensitive Electrochemical Detection of Dopamine

Derrick Butler, David Moore, Nicholas R. Glavin, Joshua A. Robinson, Aida Ebrahimi

Research output: Contribution to journalArticlepeer-review

22 Scopus citations


A growing body of research focuses on engineering materials for electrochemical detection of dopamine (DA), a critical neurotransmitter involved in motor function, reward processes, and blood pressure regulation. Among various sensing materials, graphene is highly attractive due to its excellent electrical conductivity and, in particular, the π-πinteraction between the aromatic rings of DA and graphene. However, the lowest detection limits reported solely using graphene are nominally 1 nM. To improve the sensor sensitivity, various strategies are being explored, including chemical functionalization, heterostructure/composite formation, elemental doping, and modification with biomolecules (aptamers, enzymes, etc.). In this work, we demonstrate that commercially available graphene ink can exhibit selective and highly sensitive detection of DA by tuning the surface chemistry utilizing a simple, one-step annealing process. The annealing condition directly impacts the sensor response to DA, with the optimal conditions (30 min at 300 °C under 3% H2 + Ar) yielding a distinguishable and selective response to DA down to 5 pM. X-ray photoelectron spectroscopy (XPS) confirms that the improved selectivity is due to the increased fraction of oxygen functionalities (in particular, C-OH), while Raman spectroscopy shows a higher degree of defectiveness for this condition compared to others. Evaluation of the interaction of three molecular components of DA (i.e., aromatic ring, hydroxyl groups, and amine group) with graphene confirms that the π-πinteraction and -OH groups play a prominent role in the improved adsorption of DA on the graphene surface. Furthermore, we demonstrate a proof-of-concept, all-solution processable sensor on polyimide substrates using graphene ink. Tuning the sensor response by varying the annealing condition offers a simple avenue for developing sensitive, selective, and low-cost point-of-care biosensors, while low-temperature annealing ensures compatibility with flexible substrates, such as polyimide.

Original languageEnglish (US)
Pages (from-to)11185-11194
Number of pages10
JournalACS Applied Materials and Interfaces
Issue number9
StatePublished - Mar 10 2021

All Science Journal Classification (ASJC) codes

  • Materials Science(all)


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