High-Performance SERS Detection of Monoamine Neurotransmitters Using a Nanogap-Engineered Plasmonic Platform with Application to Human Plasma

M and confirming its feasibility for application in real biological matrices. This work pioneers a SERS-based quantitative platform for detecting 5-HT in human plasma, demonstrating its promise for the early diagnosis and monitoring of neuropsychiatric diseases associated with dysregulated 5-HT levels.