A dual-mode detection strategy for alkaline phosphatase activity based on dimeric G-quadruplex

Alkaline phosphatase (ALP) is an important hydrolase found in mammalian tissues and plays a crucial role in numerous fundamental physiological processes within organisms by means of dephosphorylation. From a clinical perspective, the level of ALP is regarded as a vital indicator for numerous diseases, including neurological disorders, diabetes, and hepatocellular carcinoma. In this study, a novel dual-mode assay system was developed with the objective of facilitating quantitative ALP detection. This method used a G-quadruplex dimer (Di-G4) to enhance the signal, resulting in the quantification of the ALP concentration in either fluorescence or colorimetric mode. Under optimal conditions, wide linear ranges (fluorescence mode, 1-200 U L^-1; colorimetric mode, 1-300 U L^-1) were achieved with excellent limits of detection (fluorescence mode, 0.79 U L^-1; colorimetric mode, 1 U L^-1). The proposed method was employed for the detection of ALP in human serum samples and yielded satisfactory results. The advantageous characteristics of this method, including high sensitivity, simple operation and low cost, suggest that it has considerable application potential in the diagnosis and treatment of clinical diseases.