A dexterous fluorescence sensor for diversified-biomarker detection using cyclic EDC-CHA (EDCHA) system.

Monitoring the levels of various biomarkers, such as nucleic acids and proteins, is crucial for early disease diagnosis, evaluating treatment efficacy, and predicting patient prognosis, thereby aiding clinical decision-making. Herein_, a robust double-circuit fluorescence assay combining the advantages of EDC and CHA called EDCHA is proposed. The EDCHA includes two cycles, EDC system identifies the target miRNA, realizes first signal amplification and releases an initiator chain to trigger the CHA system. CHA system realizes second signal amplification by opened hairpin structures and different fluorophore groups. In addition, by replacing the waste chain in the EDC system with fluorescent-labeled aptamer, the EDCHA can simultaneously detect both miRNA and protein. The EDCHA was verified with the specific detection of miRNA-21 with a low detection limit (LOD) of 77.18 pM. Furthermore, our method enables the simultaneous detection of two types of biomarkers-nucleic acids and proteins-with a low detection limit (LOD) of 0.94 nM for the AD-related protein AβO. These results demonstrate the enormous potential of EDCHA in diverse biomarkers analysis and cancer diagnosis.