Prussian Blue Nanosphere/Fe-Metal Organic Frameworks/Ce Nanocomposite as a Colorimetric Sensing Platform for Direct Detection in Organophosphorus Pesticides in Fetal Bovine Serum

Acute pesticide poisoning has resulted in several symptoms that threaten life safety. Thus, developing a rapid detection method would facilitate the identification of toxicants as soon as possible. This study presented an affordable and straightforward detection platform based on a core-shell structure nanocomposite of Prussian blue/Fe-metal-organic frameworks/Ce nanocomposite material, which exhibited peroxidase-like activity and multiple capture sites [marked as phosphate buffer (PB)/Fe-MOF/Ce NPs]. Fe³⁺ and Fe²⁺ are located at the core of PB nanoparticles (PB NPs), metal-porphyrin as a metal-organic framework (MOF) shell, and Ce NPs grown on the shell. A practical, economical, accurate, and colorimetric strategy was synthesized to detect organophosphorus pesticides directly in fetal bovine serum. The solution-based PB/Fe-MOF/Ce NP colorimetric sensor demonstrated an ultrasensitive detection performance and excellent reproducibility. The absorbance variation of dichlorvos, methamidophos, and dimethoate follows the linear equation of y = 0.093x + 0.024, y = 0.083x + 0.017, and y = 0.114x + 0.117 under a low content, and the limit of detection (LOD) of the colorimetric sensor was determined using 3s/slope, which was as low as 5.6, 4.8, and 6.5 μg/L, respectively, with the recovery rates ranging from 83.4% to 98.6% and an RSD less than 6%. This study provides an excellent method for effectively detecting acute poisoning samples and offers profound insights for further improving the treatment efficiency of pesticide poisoning, and it has excellent prospects in clinical point-of-care testing.