Toward Non-Invasive Neurological Biomarker Monitoring: Dopamine Sensing in Tears with Laser-Induced Graphene Electrochemical Sensors.
Toward Non-Invasive Neurological Biomarker Monitoring: Dopamine Sensing in Tears with Laser-Induced Graphene Electrochemical Sensors.
Where did the research take place?
The study site has not been established. Author addresses may differ from where the research occurred.
Pelotas, BR · Author affiliation
Graduate Program in Materials Science and Engineering, Technology Development Center, Federal University of Pelotas, 96010-000 Pelotas, Rio Grande do Sul, Brazil.Location evidence
Rio Grande, BR · Author affiliation
Graduate Program in Materials Science and Engineering, Technology Development Center, Federal University of Pelotas, 96010-000 Pelotas, Rio Grande do Sul, Brazil.Location evidence
São Leopoldo, BR · Author affiliation
Center for Embedded Devices and Research in Digital Agriculture (CEDRA), São Leopoldo, RS 93025-753, Brazil.Location evidence
Rivera, UY · Author affiliation
Northern Regional Technological Institute (ITR Norte), Technological University of Uruguay (UTEC), 40000 Rivera/Rivera, Uruguay.Location evidence
Porto Alegre, BR · Author affiliation
Institute of Physics, Universidade Federal do Rio Grande do Sul, Porto Alegre RS 91501-970, Brazil.Location evidence
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Original abstract
Dopamine plays a crucial role in motor control, cognition, and emotional regulation, and its abnormal levels are associated with disorders such as Parkinson's disease and schizophrenia, highlighting the need for sensitive, selective, and noninvasive detection methods. This study reports the development of a high-performance, nonenzymatic electrochemical sensor based on laser-induced graphene, functionalized with nickel nitrate and urea, for the detection of dopamine. Cyclic voltammetry and differential pulse voltammetry were employed to assess the sensor's selectivity and overall performance. In-depth characterization by scanning electron microscopy and Raman spectroscopy confirmed the successful formation of a porous and electroactive graphene structure, uniformly functionalized with nickel ions and nitrogen-containing groups. These modifications enhanced electron transfer rates and increased the number of active sites for dopamine oxidation. Electrochemical measurements demonstrated excellent performance, with a linear detection range of 0.25-16.44 μmol·L-1, a limit of detection of 17.86 nmol·L-1, and a limit of quantification of 54.14 nmol·L-1, with R 2 = 0.98 in phosphate-buffered solution. In synthetic tear fluid, the sensor maintained a reliable response across four different concentrations ranging from 3.23 to 9.32 μmol·L-1. Furthermore, the sensor exhibited excellent analytical performance in real matrices, achieving recovery rates close to 100% in real sample analyses.