Manganese-Induced Highly Fluorescent Oligodopamine for Sensitive Detection of Dopamine Neurotransmitter by Catalytic Action of H2O2/MnO2 Nanosheets

Abstract

Dopamine (DA) is a catecholamine, which plays an important role as neurotransmitter in the central nervous system. Optical sensing technology is commonly used for the rapid detection of DA through the formation of fluorescent polydopamine (PDA). However, it is difficult to quantify low levels of DA (<= 10(-8) m) because the resulting PDA has a low fluorescence (FL) efficiency. In this study, DA analyte is polymerized into highly fluorescent oligodopamine (F-ODA) by the catalytic action of H2O2/MnO2 nanosheets, so-called Mn2+@F-ODA (i.e., manganese (2+) coordinated oligodopamine derivatives). Compared to the F-ODA prepared by NaOH oxidation, Mn2+@F-ODA exhibits a stronger FL intensity with a maximal peak at 465 nm. Mn2+@F-ODA produces a distinct FL emission that allows for the detection of trace DA (10(-8)-10(-12) m) with a detection limit of 10(-13) m. The FL intensity of Mn2+@F-ODA shows a suitable logarithmic linearity over four orders of the magnitude from 10(-8)-10(-11) m. The developed chemical strategy suggests potential applications of Mn2+@F-ODA for the sensitive detection of DA neurotransmitters.