Abstract: A simple, sensitive and accurate method for the detection of Cd2+ was established based on fluorescence resonance energy transfer to quench fluorescently labeled Cd2+ aptamers. Among three metal-organic framework materials (UiO-66-NH2, MIL-101(Cr), and ZIF-8), UiO-66-NH2, with larger positive charges, suitable particle size and stable dispersion in water, was selected as a fluorescence quencher. Fluorescence resonance energy transfer was generated by the interaction between positively charged UiO-66-NH2 and negatively charged aptamers to achieve fluorescence quenching. A fluorescent sensor for the detection of Cd2+ was constructed by using the specific interaction between Cd2+ and the aptamer to release the fluorescently labeled aptamer and restore the fluorescence. The fluorescence intensity of the sensor showed a good linear relationship with Cd2+ concentration in the range of 0.01–10 µmol/L. The biosensor had good selectivity and specificity for Cd2+, and could detect Cd2+ in actual samples. Most importantly, by adjusting the aptamer sequence, it is convenient to explore and construct fluorescent sensors for the detection of other heavy metal ions, so the sensor has wide applicability.

Key words: UiO-66-NH2; Cd2+; aptamer; detection; fluorescence sensor