Non-invasive and Sensitive Fluorescence Detection of Phenylpyruvic Acid via a Guanidinomethyl-modified Calixarene

Abstract

Detection of phenylpyruvic acid (PPA) is important for the diagnosis of phenylketonuria (PKU). In this study, we designed a guanidinomethyl-modified calix[5]arene that can strongly and selectively bind with PPA. Via indicator displacement assay, we set up a calibration line for accurately determining PPA concentration down to the μM range in artificial urine based on the linear relationship between the fluorescence intensity and PPA concentration. This work provides a low-cost, easy-to-operate, rapid, and sensitive method for PPA detection, and may offer an alternative for PKU diagnosis in clinical study.