Jin-Ha Choi^†,‡, Tae-Hyung Kim^†,§, Waleed Ahmed El-said^‡,⊥, Jin-Ho Lee^†,‡, Letao Yang^†, Brian Conley^†, Jeong-Woo Choi^*,‡ and Ki-Bum Lee^*,†

^†Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey,123 Bevier Road, Piscataway, NJ 08854, USA
^‡Department of Chemical & Biomolecular Engineering, Sogang University, 35 Baekbeom-ro, Mapo-gu, Seoul 04107, Republic of Korea
^§Present Address: School of Integrative Engineering, Chung-Ang University, 84 Heukseok-ro, Dongjak-gu, Seoul 06974, Republic of Korea
^⊥Department of Chemistry, Faculty of Science, Assiut University, Assiut 71516, Egypt

^*Corresponding authors:

In situ quantitative measurements of neurotransmitter activities can provide useful insights into the underlying mechanisms of stem cell differentiation, the formation of neuronal networks, and neurodegenerative diseases. Currently, neurotransmitter detection methods suffer from poor spatial resolution, nonspecific detection, and a lack of in situ analysis. To address this challenge, herein, we first developed a graphene oxide (GO)-hybrid nanosurface-enhanced Raman scattering (SERS) array to detect dopamine (DA) in a selective and sensitive manner. Using the GO-hybrid nano-SERS array, we successfully measured a wide range of DA concentrations (10^–4 to 10^–9 M) rapidly and reliably. Moreover, the measurement of DA from differentiating neural stem cells applies to the characterization of neuronal differentiation. Given the challenges of in situ detection of neurotransmitters at the single-cell level, our developed SERS-based detection method can represent a unique tool for investigating single-cell signaling pathways associated with DA, or other neurotransmitters, and their roles in neurological processes.