RNA aptamer-modified gold-plated carbon fiber microelectrodes for selective dopamine sensing.

Area of Science:

• Electrochemistry
• Biosensing
• Neuroscience

Background:

• Accurate neurotransmitter detection is crucial for understanding brain function and disease.
• Miniaturized electrodes are needed for in-vivo and cellular-level analysis.
• Electrode miniaturization often leads to reduced sensitivity and higher detection limits.

Purpose of the Study:

• To adapt an RNA-aptamer-based macroelectrode assay for dopamine detection to a microelectrode format.
• To enhance sensitivity and selectivity for dopamine analysis using gold-plated carbon fiber microelectrodes (CFE).
• To evaluate the performance of these microelectrodes in various biological matrices.

Main Methods:

• Modification of gold-plated carbon fiber microelectrodes (CFE) with cysteamine and an RNA aptamer via thiol chemistry.
• Electrochemical detection of dopamine at different potentials.
• Testing selectivity against interfering species like epinephrine, norepinephrine, L-DOPA, DOPAC, uric acid, and ascorbic acid.
• Assessing performance in phosphate-buffered saline (PBS) and artificial cerebrospinal fluid (CSF).

Main Results:

• A 90-fold improvement in sensitivity for dopamine detection was achieved with the modified CFEs compared to macroelectrodes.
• The limit of detection (LOD) was determined to be 60 nM in PBS and 100 nM in artificial CSF.
• Excellent selectivity for dopamine was demonstrated over common interfering molecules at an optimized potential (0.05 V).
• Dopamine oxidation was inhibited in serum, suggesting the need for protective membranes for blood analysis.

Conclusions:

• A straightforward strategy for creating specific aptamer-based microelectrodes was established.
• The developed microelectrodes offer a promising tool for sensitive and selective dopamine detection in relevant biological fluids.
• Further development, including protective membranes, is necessary for effective dopamine monitoring in blood samples.