Controllable formation of polydopamine on carbon dots for ultrasensitive detection of alkaline phosphatase and ratiometric fluorescence immunoassay of benzocaine

Sensing alkaline phosphatase (ALP) activity with high sensitivity and accuracy is critical for both ALP-related health and food safety supervision and the development of ALP-triggered immunoassay platforms. Herein, an ultrasensitive ratiometric fluorescence (RF) sensing system based on the controllable formation of luminescent polydopamine and efficient quenching of carbon dots was proposed for the ALP activity assay, achieving quantitative detection in the range of 0.01-100 mU/L. Furthermore, this RF sensing system was integrated with an ALP-based ELISA platform to construct an RF-ELISA for benzocaine, a potentially abused anesthetic in edible fish, and ultrasensitive assay at the level of fg/mL was realized. This ratiometric strategy-based platform effectively shields various interferences through the self-calibration effect, thus providing more accurate and reliable quantification results. This study not only offers an efficient method for ultratrace detection of ALP and benzocaine but also proposes a universal platform for ultrasensitive detection of diverse targets in food analysis by replacing the recognition unit.

Automated summary

In this study, an ultrasensitive ratiometric fluorescence (RF) sensing system based on the controllable formation of luminescent polydopamine and efficient quenching of carbon dots was proposed for the detection of alkaline phosphatase (ALP) activity. It achieved quantitative detection in the range of 0.01-100 mU/L and was integrated with an ALP-based ELISA platform to construct an RF-ELISA for the ultrasensitive detection of benzocaine in edible fish. This study not only provides an efficient method for ultratrace detection of ALP and benzocaine, but also proposes a universal platform for ultrasensitive detection of diverse targets in food analysis.