Investigation of solid surface-enhanced Raman scattering (SERS) substrates for the quantification of dopamine in cell culture media

Since its discovery, surface-enhanced Raman spectroscopy (SERS) has constantly gained ground among the analytical techniques. One field of SERS that is rapidly expanding concerns the development of solid SERS substrates. These are made up of metallic nanomaterials set in a fixed configuration: either by complex and expensive techniques (lithography, printing) or by the immobilisation of suspensions of nanoparticles (NPs) previously synthesised. In bioanalysis, solid SERS substrates allow the performance of real-time monitoring of biological or cellular processes such as the release of neurotransmitters by stimulated cells or intercellular communications between cancer cells and the immune system. Dopamine (DA) is an important neurotransmitter of the central and peripheral nervous systems, as evidenced by the diseases arising when DA levels are dysregulated. Consequently, analytical techniques being able to determine DA in sensitive and specific ways are requested. In this context, this work was dedicated to the development of solid SERS substrates enabling the quantification of DA in the culture medium of rat phaeochromocytoma PC-12 cells. These cells are a cellular model for the neurosecretion of DA. The solid SERS substrates developed could furthermore be employed to investigate the cellular release of DA under various stimulation conditions directly in the culture medium.