Reusable pectin-coated magnetic nanosorbent functionalized with an aptamer for highly selective Hg2+ detection

A pectin-coated magnetite nanoparticle functionalized with Hg2+-specific aptamer was developed to obtain a magnetic nanosorbent having high selectivity toward Hg2+ and facile reusability. The aptamer labeled with biotin was immobilized on pectin-coated MNP conjugated with streptavidin through the specific biotin-streptavidin interaction to obtain an aptamer-functionalized nanosorbent. Pectin coated on the particle improved its stability and dispersibility in water, while thymine in the aptamer played an important role as a recognition element, which can bind to the Hg2+ target via T-Hg2+-T complexes. The nanosorbent showed a linear concentration, ranging from 2.8 to 700 mu g/L, with the limit of detection of 0.8 +/- 0.2 mu g/L and limit of quantitation of 2.8 +/- 0.2 mu g/L for the detection of Hg2+. It showed high selectivity with good tolerance toward Hg2+ in the presence of other metal ions. The system can be repeatedly used for up to 10 cycles of Hg2+ adsorption with only slight changes in its performance. In addition, satisfactory recoveries were also obtained for the detection of Hg2+ in real water samples. This nanosorbent might be a promising tool for extended applications in biological and analytical fields.

Automated summary

The pectin-coated magnetite nanoparticle functionalized with Hg2+-specific aptamer showed high selectivity and facile reusability for Hg2+ detection. The system displayed a wide linear concentration range and good tolerance towards Hg2+, while maintaining stability and dispersibility in water. It exhibited promising recoveries for detecting Hg2+ in real water samples, suggesting potential applications in biological and analytical fields.