A dynamic nucleic acid extraction platform based on compressible chitosan cryogel for foodborne pathogen detection

Extraction and purification of nucleic acids are essential for the detection of foodborne pathogens, yet conventional methods are often limited by operational complexity and reliance on specialized instrumentation, restricting their use in low-resource settings. Herein, we report a simple and efficient nucleic acid extraction platform based on a chitosan-derived sponge-like cryogel (CSC), enabling dynamic adsorption-elution-driven separation under mild conditions. The CSC exhibits high nucleic acid binding capacity (88 μg for DNA and 305 μg for RNA per 10 mg material) and rapid adsorption kinetics following a pseudo-second-order model. Isotherm analyses indicate that RNA and DNA binding follow the Langmuir and Freundlich models, respectively, suggesting a combined mechanism of electrostatic interaction and physical entanglement. Notably, the compressible and shape-recoverable structure enables dynamic extraction through simple aspiration-compression operations, eliminating the need for external equipment. For practical application, the CSC was integrated into a Pasteur pipette to construct a portable extraction device. This system allows rapid nucleic acid purification from Vibrio parahaemolyticus and Salmonella in bacterial cultures and milk samples, with direct compatibility for quantitative polymerase chain reaction (qPCR) and recombinase polymerase amplification (RPA)-clustered regularly interspaced short palindromic repeats (CRISPR)/Cas12a assay. The method achieved sensitive detection down to 10³ CFU ·mL^-1, outperforming a commercial kit. Importantly, the entire extraction process avoids chaotropic salts, organic solvents, and complex instrumentation, offering a simplified and environmentally friendly alternative. This work provides a practical and scalable strategy for nucleic acid purification with potential applications in point-of-care testing for food safety.