Surface-enhanced Raman spectroscopy combined with multivariate analysis for the detection and differentiation of dopamine and DOPAC in cerebrospinal fluid

Dopamine (DA) is a vital neurotransmitter for brain functions, including pleasure, memory, motivation, and movement control. Dopaminergic neuron degradation is correlated to neurological disorders such as Parkinson's disease, and changes in DA concentration are related to mental health disorders. Currently, the gold standard for monitoring DA concentrations in the brain is electrochemistry. However, although electrochemistry has high sensitivity, it has low specificity for molecules with similar molecular structures, such as DA and its metabolites. Here, we demonstrate that surface-enhanced Raman spectroscopy (SERS), a vibrational spectroscopy that provides molecule-specific information with excellent sensitivity, requires small sample sizes/volumes, and is non-destructive, is optimal for the detection and differentiation of DA and its metabolites. We show that SERS combined with multivariate analysis allows for the detection and differentiation of DA and its metabolites, including 3-O-methyldopamine (3-OMD), homovanillic acid (HVA), 3,4-dihydroxyphenylacetic acid (DOPAC), and 3-methoxytyramine (3-MT) at physiologically relevant concentrations in artificial cerebrospinal fluid (aCSF).

Automated summary

Dopamine is a crucial neurotransmitter in the brain responsible for pleasure, memory, motivation, and movement control. Electrochemistry is currently used to monitor dopamine concentrations, but lacks specificity for differentiating similar molecules. Surface-enhanced Raman spectroscopy (SERS) with multivariate analysis is shown to be optimal for detecting and distinguishing dopamine and its metabolites at physiologically relevant concentrations, offering molecule-specific information with high sensitivity and non-destructive sampling.