Single aptamer hairpin DNA-based response system combined with COF-based signal amplification strategy for ultrasensitive detection of cancer-associated thrombin

Thrombin (Thr) plays various roles in cancer development and metastasis, motivating the search for ultrasensitive methods for Thr detection. Herein, we combined a single aptamer hairpin DNA-based response system (SAHRS) with a covalent organic framework (COF)-based signal amplification strategy, resulting in a COF-SAHRS electrochemical biosensor for ultrasensitive Thr detection. The SAHRS consisted single hairpin DNA containing a Thr-specific aptamer sequence. In the presence of Thr, the hairpin DNA conformation in COF-SAHRS is altered to trigger the efficient electrochemical sensing of Thr. COF-SAHRS delivered a wide linear detection range (from 10 pM to 20 nM) for Thrombin, with a very low limit of detection (0.17 pM). COF-SAHRS was successfully applied to detection of Thr in spiked in human blood plasma, with recoveries of 95.31–102.50 % achieved. In addition, COF-SAHRS was clinically validated using blood plasma sample from 50 cancer patients, with thrombin levels increasing with cancer progression. Results suggest that Thr could be used a potential biomarker to profile cancer progression associated with thrombosis. COF-SAHRS emerges a very promising tool for the detection of cancer-related Thr and other biomarkers.