Electrochemical dopamine sensor using a nanoporous gold microelectrode: a proof-of-concept study for the detection of dopamine release by scanning electrochemical microscopy
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Nanoporous gold (NPG) structures were prepared on the surface of a gold microelectrode (Au-μE) by an anodization-reduction method. Cyclic voltammetry and field emission scanning electron microscopy were used to study the electrochemical properties and the morphology of the nanostructured film. Voltammetry showed an improved sensitivity for dopamine (DA) oxidation at this microelectrode when compared to a bare gold microelectrode, with a peak near 0.2 V (vs. Ag/AgCl) at a scan rate of 0.1 V s−1. This is due to the increased surface area and roughness. Square wave voltammetry shows a response that is linear in the 0.1–10 μmol L−1 DA concentration range, with a 30 nmol L-1 detection limit and a sensitivity of 1.18 mA (μmol L−1)−1 cm−2. The sensor is not interfered by ascorbic acid. The reproducibility, repeatability, long-term stability and real sample analysis (spiked urine) were assessed, and acceptable performance was achieved. The “proof-of-concept” detection of dopamine release was demonstrated by using scanning electrochemical microscopy (SECM) with the aim of future applications for single cell analysis.
KeywordsAnodization-reduction Large surface area Electrocatalytic activity Square wave voltammetry Cyclic voltammetry Single cell analysis
The authors thank Sao Paulo Research Foundation (FAPESP), CNPq and CAPES for regular final supports. SAK and MB gratefully acknowledged FAPESP and CNPq for the research grants #2014/15215-5 & #2015/20776-9 and 150177/2018-6, respectively. JSGS thanks to CNPq for a PhD fellowship grant #141866/2016-0. HSCS acknowledges to Oficina de Porgramas y Servicios Internacionales, OPSI, of the Escuela Politécnica Nacional for the funding granted for his stay at Institute of Chemistry, USP-Brazil.
Compliance with ethical standards
The author(s) declare that they have no competing interests.
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