A Strategy for the Determination of Alkaline Phosphatase Based on the Self-Triggered Degradation of Metal–Organic Frameworks by Phosphate

Abstract

Alkaline phosphatase (ALP) is widely present in the human body and is an important biomarker. Numerous ALP detection studies have been carried out, and ascorbic acid (AA) is often used as the reducing component in the sensors to monitor ALP levels since it can be produced from ascorbic acid 2-phosphate (AA2P) hydrolysis in the presence of ALP. However, it is well-known that AA is a strong reducing agent and can be easily oxidized. The disproportion between oxidized AA and reduced AA reactions results in the generation of AA free radicals with single electrons that may lead to inaccurate results in assays. To solve this problem, we synthesized a core−shell metal−organic framework sensor (PATP-Au@ZIF-8 NP) and used it as a sensitive and accurate ALP detection sensor with self-triggered control of phosphate ions (Pi) to avoid the potential inaccuracy of the method that uses AA as the reducing component. By establishing a physical shell on the surface of the gold nanoparticles (Au NPs), the sensor not only can eliminate the random assembly of metal nanoparticles caused by plasma exposure but also can generate self-triggering of Pi caused by ALP. Pi can decompose ZIF-8 through coordination with Zn 2+ and thus can destroy the ZIF-8 shell structure of the prepared PAZ NPs. Au NPs are released and then become aggregated, in turn causing the SERS "hot spot" area to increase. The enhancement of the SERS signals was found to be directly associated with the level of Pi released from ALP-triggered hydrolysis. The response of the strategy was linear at ALP concentrations ranging from 0.1 to 150 mU/mL (r = 0.996) with a detection limit of 0.03 mU/mL. Lastly, the developed strategy was employed in the evaluation of ALP inhibitors, and the possibility to implement the developed SERS strategy for rapid and selective analysis of ALP in human serum was demonstrated.

Recognition-Activated Primer-Mediated Exponential Rolling Circle Amplification for Signal Probe Production and Ultrasensitive Visual Detection of Ochratoxin A with Nucleic Acid Lateral Flow Strips

“…It can be easily observed that with the designed primer 24, the highest F/F 0 value was obtained, indicating the best recognition response of OTA and releasing of the primer probe to activate the RCA for signal amplification. Meanwhile, according to the previous report, 40 molecular crowding could boost the aptamer's binding affinity by adding the surfactant to increase the viscosity. Different categories of binding buffers including 0.02% w/v PEG 200, PEG 600, PEG 1000, PEG 6000, PEG 10000, PEG 20000, Tween-20, and Tween-80 were verified as shown in Figure 2D.…”

Alkaline Phosphatase-Decorated Au Nanoparticles Immobilized on Bi2S3 Particles Combined with Ag2S Quantum Dots as a Photoelectrochemical Sensing Platform for Alkaline Phosphatase Activity and Fluoride Ions

“…Abnormal enzyme activity is associated with numerous diseases, making enzymes valuable biomarkers for effective clinical diagnosis . For example, alkaline phosphatase (ALP) catalyzes hydrolysis and phosphor-transfer reactions of proteins, nucleic acids, and small-molecules orbiomolecules both inside and outside the organism. , Deviations in ALP levels are linked to various disorders, including bone disease, hepatitis, diabetes, prostate cancer, and hepatocellular carcinoma. Therefore, ALP is widely recognized as a critical diagnostic and treatment predictor .…”

Construction of Aggregation-Induced Emission Molecule–MnO2 Composite Nanoprobe and Its Application in Alkaline Phosphatase Detection

“…In contrast, fluorescence-sensing systems have drawn extensive attention from researchers due to their advantages such as simple operation, less sample consumption and real-time detection. At present, inorganic quantum dots, metal–organic frameworks, coordination polymers and traditional organic dyes have been successfully used in the development of ALP fluorescent sensors [ 16 , 17 , 18 , 19 , 20 , 21 ]. However, the current design of sensing systems still has many defects, such as the complex synthesis and modification process of fluorophores, the high toxicity of inorganic quantum dots and the poor solubility of traditional organic dyes in aqueous solution.…”