A Sensitive and Selective Fluorescent Sensor for Berberine Chloride Based on the Supramolecular Self-Assembly of Perylene Diimide in Aqueous Solution

Developing a rapid and simple method for the detection of berberine chloride (BBC), one kind of natural antibiotic, is significant to ensure reasonable control and administration of antibiotic residues in food and other feed. In this report, a sensitive and selective fluorescent probe based on a water-soluble perylene diimide derivative (PDI-Asp) has been screened for the detection of berberine chloride (BBC). The sensing performance and mechanism of this probe were systematically investigated by using UV-vis and fluorescence spectroscopic techniques. Meanwhile, the influencing factors of probe structures on the sensing performance were also addressed. It was identified that the formation of supramolecular complex between BBC and PDI-Asp through synergy of electrostatic and pi-pi interactions promoted a rapid and fluorometric assay for BBC in 100% aqueous systems. The detection limit for BBC was found to be as low as 28 nmol/L. Finally, PDI-Asp was a highly promising fluorometric probe for the direct determination of BBC in practical samples. To the best of our knowledge, this is the first report of PDI-based probe for detecting small biomolecules in pure aqueous solution. We believe that this approach will not only extend the sensing scope of PDIs but also contribute to understanding the mechanism of the interaction between BBC and PDIs, and it will provide some useful information for the design of PDI-based probes for other small biomolecules.