Computer-Aided Rational Hapten Design for Broad-Spectrum Monoclonal Antibody Development against Anthraquinones and Its Application in Lateral Flow Immunoassay

Plant-derived foods are a vital component of the human diet, but they pose health risks due to the potential presence of anthraquinones (AQs) and their derivatives, and long-term intake of these substances can lead to health issues. Therefore, there is an urgent need for a method to rapidly and simultaneously detect seven AQs, including AQ, emodin, rhein, chrysophanol, aloe emodin, alizarin, and purpurin. In this study, four haptens were designed based on the common parent nucleus structure of the seven AQs combined with computer-aided simulation analysis. MD was used to analyze the recognition mechanism between AQ mAb-4D7 and the seven AQs, revealing that key amino acid residues (TRP90, ASP99, and TYR31) in the complementarity-determining region of the antibody maintain broad-spectrum recognition of AQs through the combined effects of Pi-Pi stacking, hydrogen bonding, and hydrophobic interactions. Based on AQ mAb-4D7, gold nanoparticles based on lateral flow immunoassay (GNP-LFIA) was developed for detecting the seven AQs in tea, aloe vera, and herbal drinks, with calculated limits of detection of 7.282-34.112 μg/kg, 5.536-27.338 μg/kg, and 5.025-26.319 μg/kg, respectively. In real sample detection, the method exhibited high consistency with the results of liquid chromatography-tandem mass spectrometry confirming the accuracy and stability of GNP-LFIA and providing a reliable technical tool for the on-site rapid screening of multiple AQs in plant-derived foods.