Fluorescence recovery based on synergetic effect for ALP detection

Alkaline phosphatase (ALP) is an important biomarker associated with diabetes, liver dysfunction, bone diseases, and breast cancer. Here we developed a method based on synergetic fluorescence recovery for the sensitive detection of ALP. Cadmium-zinc-selenium (CdZnSe) quantum dots (QDs) were prepared by one-pot water bath method without any complicated and rigorous conditions. CdZnSe QDs displayed high luminous efficiency, good stability, and good biocompatibility. KMnO4 and ascorbic acid phosphate (AAP) can dynamically quench the fluorescence of CdZnSe QDs. Ascorbic acid, produced by ALP-catalyzed hydrolysis of AAP, reacted with KMnO4, causing the synergetic fluorescence recovery of CdZnSe QDs. The synergetic recovery efficiency correlates well with the logarithmic ALP concentration in the range of 2.5-250 U/L with a detection limit of 0.21 U/L. In addition, good recoveries were obtained in the detection of ALP in human serum. This method provided a new research idea to improve the detection sensitivity and selectivity of ALP detection.