In Situ Construction of Oriented Pt-PANI Needle-Like Nanoarrays-Based Label-Free Aptasensor for Ultrafast and Ultrasensitive Recognition of Cardiac Troponin I

Due to the short course and high mortality of acute myocardial infarction (AMI) which will cause irreversible myocardial necrosis to induce cardiac arrest, its early diagnosis within minutes is always a challenge in clinical emergency. In this work, an ultrafast and ultrasensitive aptasensor is designed to achieve quantitatively detection of cardiac troponin I (cTnI) which is proved as a highly specific and sensitive biomarker to AMI, and within only 4 min, the cTnI concentration can be accurately reported. This aptasensor is constructed via an in situ growth of the oriented Pt-polyaniline (PANI) needle-like nanoarrays providing both high electrocatalysis and abundant active sites as the signal magnifier and DNA carrier. A target-induced strand release strategy is proposed to remarkably accelerate the recognition process of cTnI through the specific design of DNA stand for binding. The as-prepared aptasensor can exhibit an ultrawide linear detection range of cTnI from 1 pg mL⁻¹ to 100 ng mL⁻¹ satisfying the clinical demand for AMI diagnosis, together with excellent selectivity among various biomarkers. Based on its fast recognition ability, this aptasensor presents a high accuracy in the practical detection of human serum to prove its promising ability in the early and on-site diagnosis of AMI.