Logic gate-based fluorescent probes are powerful tools for the discriminative sensing of multiple signaling molecules that are expressed in concert during the progression of many diseases such as inflammation, cancer, aging, and other disorders. To achieve logical sensing, multiple functional groups are introduced to the different substitution sites of a single fluorescent dye, which increases the complexity of chemical synthesis. Herein, we report a simple strategy that incorporates just one responsive unit into a hemicyanine dye achieving the logic gate-based sensing of two independent analytes. We introduce boronic acid to hemicyanine to quench the fluorescence, and in the presence of hydrogen peroxide (H 2 O 2 ), the fluorescence is recovered due to removal of the boronate. Interestingly, the subsequent decrease in pH turned the red fluorescence of hemicyanine to green emissive because of protonation of the phenolic alcohol. This unique feature of the probe enables us to construct "INHIBIT" and "AND" logical gates for the accurate measuring of intracellular H 2 O 2 and acidic pH in tandem. This study offers insight into the simple construction of logic-gate based fluorescent probes for the tandem sensing of multiple analytes that are correlatively produced during disease progression.
Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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