Nanozymatic magnetic nanomotors as active nanoprobes for rapid and multiple detection of cTnI by lateral flow immunoassay

Conventional lateral flow immunoassays (LFIAs) are unable to achieve the rapid diagnosis of Acute Myocardial Infarction (AMI) via cardiac troponin I (cTnI) detection due to their limited sensitivity and speed. To overcome this, a nanozymatic magnetic nanomotor (Fe₃O₄@PDA@AuNS, MPAuNS) is proposed as an active nanoprobe. The nanoprobe, composed of a Fe3O4 core and a PDA shell where gold nanostars grow, enables multimode detection, including colorimetric, photothermal, and catalytic LFIAs, significantly boosting signal intensity. Specifically, the magnetic property of Fe₃O₄ and the glucose oxidase-like catalytic activity of AuNS endow the MPAuNS nanoprobes with both magnetotaxis behavior and enhanced diffusion, which respectively enhance the flow rate and reduce probe residue in the test strip, thus improving detection speed and sensitivity within a given assay time. Such a platform offers diverse detection options for the rapid and highly sensitive diagnosis of cTnI, holding great potential for medical guidance on the early diagnosis of AMI.