Probing catecholamine neurotransmitters based on iron-coordination surface-enhanced resonance Raman spectroscopy label

[Display omitted] •The Fe-NTA modified PVP stabilized Au NPs as a Raman label exhibits high selectivity and sensitivity for CA molecules.•This SERRS strategy was successfully applied to distinguish the three CA molecules in complex serum specimen.•Propose a reliable method for quantitative SERS detection of CA molecules. Catecholamine (CA) is neurotransmitters of the biological amines class which play an important role in organism. However, it is quite difficult to realize sensitive and selective detection of CA in complex system. Here, we employ surface-enhanced resonance Raman spectroscopy (SERRS) strategy, iron-nitrilotriacetic acid functionalized PVP-Au NPs (Au-Fe(NTA)) as Raman label for rapid and sensitive detection of CA containing dopamine (DA), norepinephrine (NE) or epinephrine (EP) in complex serum. The Au NPs is sufficient to provide Raman enhancement and Fe-NTA label can rapidly trap CA molecules adjoining gold core to form NTA-Fe-CA resonant structure, which can amplify the signals of CA. More important, we successfully distinguish these three CA molecules in serum since surface-enhanced Raman spectroscopy (SERS) technique can provide fingerprint identification. Furthermore, the SERS signals of Au-O band from PVP stabilized Au NPs can be utilized as a stable internal calibration standard for quantitative detection of target. Additionally, we continue to investigate the binding constants between different CA molecules and functionalized substrate to evaluate the corresponding adsorption property. This SERRS strategy is not only capable to offer exciting opportunities to selectively trap the analyte, but also strongly amplify the Raman signals of CA as well as achieve quantitative measurement.