MOF/DNA luminescent sensing platform for detection of potential COVID-19 biomarker and drug

COVID-19 has afflicted people's life worldwide. Interleukin-6 (IL-6) is an important COVID-19 biomarker in human body fluid that can be used as reference to monitor COVID-19 in real-time and therefore to reduce the risk of virus transmission. On the other hand, Oseltamivir is a potential COVID-19 curing drug, but its overuse easily leads to hazardous side effects, calling for its real time monitoring in body fluids. For these purposes, a new Yttrium Metal-Organic Framework (Y-MOF) has been synthesized, in which the 5-(4-(imidazol-1-yl)phenyl)isophthalic linker contains a large aromatic backbone capable of strongly interacting with DNA sequences through π-π stacking interactions, which is appealing to build a unique sensor based on DNA functionalized MOFs. The MOF/DNA sequence hybrid luminescent sensing platform presents excellent optical properties associated with a high Förster Resonance Energy Transfer (FRET) efficiency. Furthermore, to construct a dual emission sensing platform, a 5'-carboxylfluorescein (FAM) labeled DNA sequence (S2) with stem-loop structure that can specifically interact with IL-6 has been associated to the Y-MOF. The resulting Y-MOF@S2 exhibits an efficient ratiometric detection of IL-6 in human body fluid with extremely high Ksv value 4.3×10 8 M-1 and a low detection limit (LOD) of 70 pM.