Single-Atom-Enhanced Fully Inkjet-Printed Electrochemical Sensor for Dopamine Detection

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Single-atom (SA) engineering provides precise control over interfacial reactivity.
• The development of printable SA-based inks is crucial for translating this technology into practical electrochemical sensing applications.
• Existing methods lack scalable and cost-effective solutions for fabricating SA-based sensors.

Purpose of the Study:

• To introduce a novel, fully water-based inkjet-printable ink based on nitrogen-doped graphene acid (NGA) hosting atomically dispersed copper (Cu) centers (NGA-Cu-ink).
• To demonstrate the fabrication of low-cost, sustainable electrochemical sensors using digitally controlled, spatially defined deposition of the NGA-Cu-ink on paper.
• To investigate the influence of different single-atom dopants on the electrochemical sensing performance.

Main Methods:

• Development of a water-based inkjet-printable ink using nitrogen-doped graphene acid (NGA) with atomically dispersed copper centers.
• Fabrication of electrochemical sensors on paper substrates via inkjet printing.
• Comparative analysis of NGA functionalized with different single-atom dopants (Cu, Mn, Fe, Ce) to assess their impact on electrochemical response.
• Electrochemical detection of dopamine using the fabricated sensors.

Main Results:

• The NGA-Cu-ink enabled the fabrication of fully inkjet-printed, sustainable electrodes on paper at a low cost ($0.04 per sensor).
• A strong dopant-dependent electrochemical response was observed, with Cu uniquely enhancing the analyte signal, while other dopants suppressed it.
• The NGA-Cu-ink demonstrated enhanced dopamine oxidation, enabling quantitative detection with a limit of detection of 9.7 µM on fully printed devices and 10.6 µM on printed-on-electrode platforms.
• The sensors exhibited excellent stability, with less than 10% signal variation over 11 weeks.

Conclusions:

• Single-atom identity is a critical design parameter for tuning sensitivity and selectivity in printed sensing interfaces.
• The NGA support effectively stabilizes atomically dispersed metal centers and creates active microenvironments for adsorption and electron transfer.
• The developed NGA-based inks offer a general and scalable route for the reproducible, low-material-consumption manufacturing of advanced electrochemical sensors.