A multimode detection of silver ions based on peroxidase-like activity and photothermal effect of Prussian blue nanoparticles

Silver ion (Ag+), as a heavy metal ion easily absorbed by organisms, can be enriched through the food chain. This study present a novel multimodal detection system for Ag+ using Prussian blue nanoparticles (PB NPs) with excellent photothermal effect and peroxidase-like activity. The PB NPs undergo a dissolution-precipitation equilibrium, converting blue PB NPs into colourless silver ferrocyanide ions in the presence of Ag+. The color, photothermal effect, and peroxidase-like activity of the PB NPs change with the concentration of Ag+, making them an effective probe for detecting Ag+. The key parameters that affect the performance of multimode detection assay were optimized. Under optimal conditions, the detection limit of visual detection was estimated to be 2.94 & mu;M. Based on catalytic color development and the photothermal effect of PB NPs, the detection limit of color development detection and photothermal analysis were reduced to 0.57 & mu;M and 0.23 & mu;M, respectively. And the detection range was also broadened than visual direct detection. Besides, the multimode detection of Ag+ improves the accuracy of detection by mutual verification. The promising multimode system exhibited good repeatability and specificity of Ag+ in different sample implementations, which has great potential for applications in food safety regulation and environmental monitoring.