A ‘‘Turn-on’’ Al(III)-Mediated Fluorescent Micro-Probe for Quercetin Sensing

• Published in: Sensors and actuators. B, Chemical Chemical, 2024-12, Vol.420, p.136497, Article 136497
• Main Authors: Su, Xiqi, Sun, Wenwen, Wang, Le, Zhang, Xiao, Liu, Mengxia, Qu, Yi, Ming, Li-June
• Format: Article
• Language: English
• Subjects: Al3; Fluorescence Micro-Probe; Quercetin; Smartphone sensing; Turn-on
• ISSN: 0925-4005
• DOI: 10.1016/j.snb.2024.136497

Quercetin (Qr) is a common flavonoid widely found in plants with promising pharmacological activities. It is thus worthwhile to design a convenient method for its detection. In this work, a specific Al3+-regulated poly(cyclotriphosphazene-co-curcumin) (PC-Al) micro-probe was designed for real-time detection of Qr, therein significant “turn-on” fluorescence was observed after addition of Qr to PC-Al. Under optimal conditions, the probe has a detection limit of 23.2 nM for Qr sensing with good linearity in the range of 0–5 × 10−5 M. Moreover, real-time applications of the PC-Al probe in red wine, orange juice, and honey samples were validated. Furthermore, assisted by a consumer smartphone sensing platform, the sensor shows an excellent linear response between the red/blue ratio (R/B) of the two color channels in the picture and the concentration of Qr in the range of 1–120 μM, achieving quantitative detection of Qr. The introduction of smartphone system to realize convenient detection of Qr demonstrates good application prospects of this Al3+-mediated fluorescence probe. •In this paper, we report a Al3+-modified cyclotriphosphazene-co-curcumin microspheres (PC-Al) for the specific detection of quercetin with good selectivity.•The probe can “turn on” detect quercetin with the LOD of 23.2 nM and no response to relevant analytes and other flavonoids.•The NMR titration experiments and mass spectrometry showed that curcumin, Al3+ and quercetin interacted with each other to form the Cur-Al-Qr ternary complex system, causing the fluorescence changes.•The probe was successfully applied to monitor the Qr in different samples including wine, orange juice and honey.•The test stripswere successfully prepared as a sensing device for real-time detection of Qr. The quantitative analysis of Qr concentration can also be achieved by a colour scanning app on smartphones.