Multichannel ratiometric fluorescence sensor arrays for rapid visual monitoring of epinephrine, norepinephrine, and levodopa

Catecholamines (CAs), as the important signal mediators in normal physiological processes, regulate many basic physiological functions in the body. However, it is hardly to rapidly distinguish different CAs molecules, such as dopamine, epinephrine (Ep), and norepinephrine (NE), because of their extremely similar molecular structures. Here, we, for the first time, propose a simple and fast fluorescence turn-on strategy to distinguish different CAs and their precursor levodopa (L-DOPA). Specifically, novel ratiometric fluorescent probes with high sensitivity and selectivity were constructed for the quantitative detection of Ep, NE, and L-DOPA, with the detection limits of 18.9, 85.5, and 9.7 nM, respectively. In addition, the suitability of these ratiometric fluorescent probes was validated by detection application of Ep, NE, and L-DOPA in real human serum and urine samples. Furthermore, a portable ratiometric fluorescent hydrogel sensing platform was prepared, with agarose chosen as the carrier for semi-quantitative on-site detection of Ep, NE and L-DOPA based on visual inspection with the naked eye. These results indicate that the developed detection strategy opens up a novel and exciting avenue for the rapid identification and clinical diagnosis of CAs.