An electrochemical metallic nanowire aptasensor for rapid and ultrasensitive detection of cardiac troponin I

Cardiac troponin I (cTnI) is regarded as a significant protein marker of cardiovascular diseases. Slight increase of blood cTnI level could reflect cardiomyocyte injury, presenting great clinical value in early diagnosis and prognostic monitoring of heart failure (HF). Here, we report for the first time, a metallic nanowire aptasensor with high sensitivity and short detection time as a promising strategy for POC detection of cTnI. We designed and fabricated a novel single Au nanowire electrode with stable anchor structure, and successfully attained immobilization of cTnI-specific aptamer probes. The metallic nanowire aptasensor exhibited high-rate mass transfer and low background current, as well as high affinity and selectivity of the aptamers that facilitated excellent detection performance such as high sensitivity (limit of detection: 13 fg/mL, S/N = 3), short detection time (≤ 15 min), high specificity and good reproducibility in serum samples. These unique properties enabled the nanowire aptasensor for POC detection of cTnI in early diagnosis and prognostic monitoring of HF. Moreover, this nanowire aptasensor was also featured with high stability and regeneration capability, which was envisioned to be further integrated into portable devices, providing potential applications in continuous monitoring of cardiomyocyte injury.