A Eu(III) doped metal-organic framework conjugated with fluorescein-labeled single-stranded DNA for detection of Cu(II) and sulfide

- Eu3+ modified Bio-MOF-1 hybrid system with via cation exchange shows Eu3+ luminescence.
- FAM-labeled ssDNA fabricated with Eu3+@Bio-MOF-1 exhibits the fluorescence of Eu3+ and FAM by adjusting the ratio of them.
- The hybrid material is used for the detection of Cu2+, with limit of detection of 0.14 μM.
- Cu2+ involved hybrid system then be further employed for the detection of S2−.

In this paper, Bio-MOF-1 is prepared as reported and then Eu3+ is introduced into it via cation exchange method. A FAM-labeled ssDNA is chosen to fabricate with the obtained Eu3+@Bio-MOF-1. A luminescent hybrid material is assembled, which can exhibit the fluorescence of Eu3+ and FAM simultaneously by adjusting the ratio of FAM-ssDNA and Eu3+@Bio-MOF-1. The sample is then used for the detecting of metal ions, results shows which has good selectively for Cu2+ (LOD = 0.14 μM, 0-250 μM). The introduction of Cu2+ can quench the fluorescence of FAM while the luminescent intensity of Eu3+ enhancing. After the detection of Cu2+, the Cu2+ involved hybrid system can then be further employed for the detection of S2− (LOD = 1.3 μM, 0-50 μM). Low concentration of S2− can make the luminescent intensity of Eu3+ decrease gradually while high concentration of S2− can further recover the luminescent of FAM, which is quenched by Cu2+.

FAM labeled ssDNA is fabricated with Eu3+@MOF-1 and then be used for Cu2+ detection, afterwards, Cu2+ involved materials is be employed for the sensing of S2−.142