Luminescent lanthanide coordination polymer as a platform for DNA colorimetric detection

Lanthanide coordination polymers (LnCPs) have aroused tremendous interest in recent years because of their unique structural and optical properties, but the construction of LnCPs-based fluorescent probe for sensing of biomacromolecules still remains a great challenge. In this work, a sensitive DNA fluorescent sensor was developed by integrating europium-containing coordination polymers (Eu/BTC CPs) with single-stranded DNA (ssDNA) probe labelled with dye. The Eu/BTC CPs is able to selectively absorb ssDNA probe due to π–π stacking interaction, and release it upon the introduction of complementary target DNA, leading to a fluorescence change of ssDNA probe labelled dye. However, the fluorescence of Eu/BTC CPs itself remains constantly along with the absorption and detachment of ssDNA probe on the surface of Eu/BTC CPs, which enables target DNA to be detected by naked-eyes. The presented DNA sensor not only showed high detection sensitivity, but also is capable of distinguishing complementary and single-base mismatched target DNA sequence with excellent selectivity. As a DNA sensing material, Eu/BTC CPs also possesses the features of simple preparation procedures and outstanding stability. Moreover, the presented sensor was successfully applied to determine the DNA levels in fetal bovine serum sample and showed a satisfactory result. We believe that the integration of LnCPs with ssDNA probe could find great potential applications for ultrasensitive fluorometric assays and biomedical imaging in the future.