Lab in an aerogel kit: Fe-G@SA-based aerogel sensor with high-performance peroxidase activity for chlorpyrifos...

The extensive application of organophosphorus pesticides, coupled with their potential hazards to both food safety and human health, underscores the urgent need for reliable and sensitive point-of-care (POC) platforms for pesticide monitoring. Herein, we employ a DNA-guided strategy to synthesize Fe-based nanozymes (Fe-DNA). DNA sequence design enabled programmable regulation of Fe-DNA nanozymes, where variations in base composition and strand length precisely directed their structural evolution and catalytic performance. Among the resulting architectures, the G-rich Fe-G nanozyme exhibited favorable substrate affinity and peroxidase-like activity, providing an optimized catalytic module for biosensing. To improve the operational stability and application feasibility of the sensing platform, Fe-G was further encapsulated into a sodium alginate-based aerogel via a diffusion-hybridization method, forming a robust and portable catalytic matrix. Integrated with high-affinity acetylcholinesterase as the biorecognition element and a smartphone-assisted image-processing algorithm, the "lab in an aerogel kit" platform enabled highly sensitive and selective colorimetric detection of chlorpyrifos. The portable sensor exhibited a broad linear detection range from 3.33 to 1333.33 ng mL^-1, with a detection limit as low as 3.33 ng mL^-1. This work highlights the potential of DNA-mediated nanozyme engineering and aerogel-based solid-phase sensing architectures for the development of high-performance POC platforms.