Introduction: Cardiac troponin I (cTnI) has been regarded as a gold standard for early diagnosis and prognosis monitoring of acute myocardial infarction (AMI) in clinical practice. Owing to its low concentration in blood, accurate determination of cTnI often requires high sensitivity. However, current established point-of-care (POC) assays are insufficient to meet clinically analytical requirements due to their low sensitivity.
Methods: To this end, we established a highly sensitive and reliable POC lateral flow strip based on lanthanide-doped nanoparticles (NPs) for cTnI determination in human blood samples. The capture of cTnI on the lateral flow strip was performed in a sandwich assay, where Eu³⁺-doped vanadate nanoparticles (GdVO₄:30% Eu NPs) were used as luminescent probes to allow quantification.
Results: Our platform realized the analytical sensitivity enhancement with limit-of-detection (LOD) as low as 17 pg mL^{− 1} for cTnI detection, which was lower than the commercial counterpart; meanwhile, it displayed high specificity, excellent reproducibility and outstanding accuracy for analyzing clinical serum samples.
Conclusion: Overall, this strategy provided an ultrasensitive, cost-effective and user-friendly platform for on-site cTnI detection, demonstrating the prospect of lanthanide-doped NPs-based POC diagnosis of disease-related biomarkers.
Keywords: cardiac troponin I, GdVO₄:30% Eu NPs, lateral flow test strip, point-of-care test