Fluorescent sensing of pyrophosphate anion in synovial fluid based on DNA-attached magnetic nanoparticles.

In this work, a new fluorescent method for sensitive detection of pyrophosphate anion (P 2 O 7 4− , PPi) in the synovial fluid was developed using fluorophore labeled single-stranded DNA-attached Fe 3 O 4 NPs. The sensing approach is based on the strong affinity of PPi to Fe 3 O 4 NPs and highly efficient fluorescent quenching ability of Fe 3 O 4 NPs for fluorophore labeled single-stranded DNA. In the presence of PPi, the fluorescence would enhance dramatically due to desorption of fluorophore labeled single-stranded DNA from the surface of Fe 3 O 4 NPs, which allowed the analysis of PPi in a very simple manner. The proposed sensing system allows for the sensitive determination of PPi in the range of 2.0×10 −7 –4×10 −6 M with a detection limit of 76 nM. Importantly, the protocol exhibits excellent selectivity for the determination of PPi over other phosphate-containing compounds. The method was successfully applied to the determination of PPi in the synovial fluid, which suggests our proposed method has great potential for diagnostic purposes. [ABSTRACT FROM AUTHOR]