Fabrication of a Reusable Carbon Dot/Gold Nanoparticle/Metal-Organic Framework Film for Fluorescence Detection of Lead Ions in Water.

Solid-state sensing platforms are desirable for the development of reusable sensors to promote public health measures such as testing for drinking water contamination. A bioinspired metal-organic framework (MOF)-based material has been developed by imitating metal-protein interactions in biological systems to attain high sensitivity and selectivity to Pb 2+ through fluorescence sensing. A zirconium terephthalate-type framework (also known as NH 2 -UiO-66) was modified with both gold nanoparticles and thiol-functionalized carbon dots to give HS-C/Au( x )/UiO-66 composites with different Au content ( x ) and were subsequently adapted into films that show extraordinary sensitivity to Pb 2+ . The HS-C/Au(1.4)/UiO-66 film that consists of 1.4 wt % Au shows a quenching response with the limit of detection of 80 parts per trillion and sustained performance for five cycles. Moreover, the fluorescence response of the HS-C/Au( x )/UiO-66 film to Pb 2+ can be reversed from emission quenching to enrichment of fluorescence by increasing the Au content. The performance of the HS-C/Au( x )/UiO-66 film as a solid-state sensor demonstrates its potential for application in reusable sensing devices to ensure public safety from Pb 2+ contamination in drinking water.