Organic ligand-dependent performance of Zr-MOF functionalized magnetic polydopamine nanocomposites for camel meat DNA purification

Traditional DNA purification methods face limitations in efficiency and complexity, particularly for food authenticity verification. To address this, we developed novel magnetic nanocomposites by integrating polydopamine-coated Fe 3 O 4 nanoparticles (Fe 3 O 4 @PDA) with zirconium-based metal-organic frameworks (Zr-MOFs) functionalized via varying organic ligands (terephthalic acid, 2-aminoterephthalic acid, and 1,2,4-benzenetricarboxylic acid). The resulting materials—MUIO-66, MUIO-66-NH₂, and MUIO-66-COOH—were characterized for structure, magnetism, and DNA adsorption performance. MUIO-66-COOH exhibited superior efficiency, achieving >80 % DNA recovery from camel meat under optimized conditions (25 °C, 10 min), outperforming commercial kits. Adsorption kinetics and isotherms revealed a multilayer process (Freundlich model) governed by pseudo-second-order kinetics, driven by "salt-bridge" interactions between DNA phosphate groups and surface carboxyl moieties. The method demonstrated high precision (RSD = 2.75 %), reproducibility, and reusability (>81 % efficiency after 5 cycles). This work establishes a rapid, ligand-tunable magnetic solid-phase extraction (MSPE) platform for high-quality DNA extraction, advancing biosensing applications in food authenticity.