Detection of blood glucose based on the aggregation induced luminescence effect in 4-formyl-3-hydroxybenzoic acid@ZIF-8 and a ratiometric fluorescence method based on Förster resonance energy transfer between aggregation-induced emission molecules and diallyl phthalate

A novel and simple ratiometric fluorescence detection method for H₂O₂ and glucose was proposed on the basis of the aggregation-induced luminescence effect of the aggregation-induced emission (AIE) molecule 4-formyl-3-hydroxybenzoic acid (FHBA) in ZIF-8 and the mechanism of fluorescence resonance energy transfer (FRET) between the complex FHBA@ZIF-8 and diallyl phthalate (DAP). First, glucose was oxidized to H₂O₂ under the catalysis of glucose oxidase. In the presence of horseradish peroxidase, the latter further oxidized o-phenylenediamine to produce yellow fluorescent DAP with an emission wavelength of 560 nm. The fluorescence of FHBA@ZIF-8 at 445 nm can be effectively quenched because the ultraviolet absorption spectrum of DAP overlaps well with the emission spectrum of FHBA@ZIF-8. Therefore, a highly sensitive ratiometric fluorescence detection method for detecting H₂O₂ and glucose was constructed using the change in the ratio of fluorescence intensity at two wavelengths (F₅₆₀/F₄₄₅). The linear range of H₂O₂ detection by this method is 1-150 μM, and the detection limit is 0.21 μM. The linear range of glucose detection is 1-100 μM, and the detection limit is 0.17 μM. The method was successfully applied for the detection of glucose in human serum samples, and it has broad potential in clinical diagnosis and research.