A novel and universal dual-channel signal amplification aptasensing platform for ultrasensitive and rapid detection of cardiac biomarkers based on the mutual regulation of bimetallic organic framework and silver nanoclusters

Abstract

Cardiac troponin I (cTnI) is a key biomarker for diagnosing myocardial infarction caused by myocardial injury. The accurate and rapid monitoring of ultralow levels of cTnI is crucial for early diagnosis and risk warning of myocardial injury. Herein, a novel dual-channel signal amplification aptasensor for cTnI detection was developed utilizing the mutual regulation of bimetallic organic framework (MOFs) and silver nanoclusters (AgNCs) with the assistance of catalytic hairpin assembly (CHA). Rationally designed triple-helix molecular switch (THMS) and two hairpin probes (HP1 and HP2) containing AgNCs and a guanine-rich DNA sequence could be adsorbed onto the surface of bimetallic Cu, Mo-MOFs, enhancing the catalytic activity and reducing the fluorescence signal. The target cTnI specifically binds to the aptamer in the THMS, releasing the signal transduction probe which triggers CHA to desorb HP1–AgNCs and HP2, thereby restoring the fluorescence and decreasing the catalytic activity as well as initiating cycling. This enables dual-channel fluorescence and colorimetric detection of cTnI. The linear fluorescence and colorimetric response ranges were 0.001–20 ng/mL with LOD of 0.48 pg/mL and 0.001–10 ng/mL with LOD of 0.69 pg/mL, respectively. The aptasensor significantly increases the detection sensitivity and reduces the time required for cTnI detection in human serum, with excellent anti-interference capability. Moreover, the aptasensor shows promise for the construction of universal dual-channel aptasensors for multiple targets by altering the aptamer in THMS.