Rapid, reagent-free, and ultrasensitive analysis of cardiac troponin I (cTnI) is of significance for early diagnosis of acute myocardial infarction (AMI). The electrochemical aptamer-based (EAB) sensors are promising candidates to fill this role as they are reagentless and can be directly interrogated in complex matrices (e.g., blood). To achieve high sensitivity, EAB sensors typically require nanomaterials or other amplification strategies, which often involves a cumbersome fabrication process. To circumvent this, here we develop a simple yet effective electrocatalytic electrochemical aptamer-based (Ec-EAB) sensor that utilizes target-induced regulation of the catalytic mechanism to achieve ultrasensitive measurement of cTnI. In this assay, we employed a probe-attached redox reporter (i.e., methylene blue, MB) and a solution-diffusive redox reporter (i.e., Fe(CN) 6 3- ) to generate two signals, of which the latter is used to catalyze MB to amplify aptamer-mediated charge transfer. The recognition of target altered the diffusion of catalysts (2.2 × 10 -9 mol/cm 2 in the target-free state versus 1.2 × 10 -9 mol/cm 2 in the target-bound state) and thus electrocatalytical efficiency, enabling ultrasensitive measurement of cTnI with a 1000-fold improvement in their sensitivity (a limit of detection value: 10 pg/mL).
Keyphrases
- label free
- gold nanoparticles
- acute myocardial infarction
- reduced graphene oxide
- metal organic framework
- molecularly imprinted
- low cost
- high throughput
- left ventricular
- sensitive detection
- squamous cell carcinoma
- heart failure
- diabetic rats
- percutaneous coronary intervention
- mass spectrometry
- living cells
- highly efficient
- single cell
- nucleic acid
- solid phase extraction
- real time pcr
- transition metal