3-Hydroxybenzeneboronic Acid Enables Stable and Sensitive Dopamine Detection by Inhibiting Target Self-Polymerization

Resorcinol (Res) and Res-motif-containing molecules have been explored for the design and construction of fluorometric probes toward dopamine (DA) detection. However, the self-polymerization of DA under alkaline conditions competes with the probe-DA reaction, reducing the stability and sensitivity of detection. In this study, a target-triggered cascade reaction strategy has been explored for the development of DA detection probe based on the formation of borate ester intermediates. As a case study, 3-hydroxybenzeneboronic acid (HBBA) was exploited for stable and sensitive DA detection by inhibiting DA self-polymerization. The mechanism study disclosed that DA first reacts with HBBA and forms borate ester, which is then oxidized and hydroxylated to produce Res and DA, further forming fluorescent azamonardine compounds. Using HBBA as the probe, DA detection was achieved with a detection limit of 0.4 nM. In addition, the practical application of the HBBA probe was verified by accurate DA analysis in urine and cerebrospinal fluid samples.