Multifunctional lanthanide metal-organic framework based ratiometric fluorescence visual detection platform for...

Area of Science:

• Biochemistry
• Materials Science
• Analytical Chemistry

Background:

• Alkaline phosphatase (ALP) is a crucial biomarker for various physiological and pathological processes.
• Accurate and sensitive detection of ALP activity is essential for clinical diagnostics.
• Existing methods for ALP detection often face limitations in sensitivity, selectivity, or ease of use.

Purpose of the Study:

• To develop a novel turn-on/off ratiometric fluorescence detection platform for ALP activity assay.
• To utilize a multifunctional lanthanide metal-organic framework (Ln-MOF) as both a nanozyme and a fluorescence standard.
• To create a portable assay for visual and point-of-care testing of ALP activity.

Main Methods:

• An enzymatic cascade reaction was employed to convert L-phosphotyrosine to L-dopa.
• A multifunctional Ln-MOF (Cu@Eu-BTC) catalyzed the reaction between L-dopa and naphthoresorcinol, producing a fluorescent product at 490 nm.
• The Ln-MOF's intrinsic emission at 620 nm was quenched by phosphate anions, enabling dual-response ratiometric fluorescence detection (F490/F620).

Main Results:

• A good linear relationship was observed between the change in ratiometric fluorescence (Δ(F490/F620)) and ALP activity (0.3-24 U L⁻¹), with a detection limit of 0.02 U L⁻¹.
• A portable assay tube was designed for visual detection of ALP activity via color variation.
• The platform demonstrated successful application in human serum samples with high recovery rates (95.5%-109.0%) and low relative standard deviations (<8.1%).

Conclusions:

• This study presents the first report of an ALP activity assay assisted by a multifunctional Ln-MOF.
• The developed platform offers a sensitive, selective, and convenient method for ALP detection.
• The findings pave the way for advanced point-of-care diagnostics utilizing Ln-MOFs.