Split aptamer based sensing platform for adenosine deaminase detection by fluorescence resonance energy transfer

In this paper, a split aptamer based fluorescence resonance energy transfer (FRET) platform was constructed for the determination of adenosine deaminase (ADA) activity by using gold nanoclusters (AuNCs) and gold nanoparticles (AuNPs). A single adenosine triphosphate (ATP) aptamer was split into two fragments (referred to as P1 and P2). P1 was covalently attached to the AuNCs at the 5′ end (P1-AuNCs), and P2 was labeled with AuNPs at the 3′ end (P2-AuNPs). In the presence of ATP, ATP bound with the two fragments with high affinity to link P1-AuNCs and P2-AuNPs together, thus the fluorescence of P1-AuNCs was quenched via FRET from P1-AuNCs to P2-AuNPs. With the addition of ADA, ATP was transformed into inosine triphosphate (ITP), and then P1 and P2 were released to cause the fluorescence recovery of the system. So a split aptamer based FRET platform for ADA detection can be established via the fluorescence intensity change of the system. This platform showed a good linear relationship between the fluorescence intensity and ADA concentration in the range of 2–120 U L −1 , and the limit of detection (LOD) was 0.72 U L −1 . Moreover, the detection of ATP in human serum sample demonstrated the accuracy and applicability of the method for ADA detection in real sample.