Abstract
A rapid and sensitive method to detect cardiac troponin I (cTnI) in human blood is critical to the diagnosis and treatment of acute myocardial infarction (AMI). Here, we describe a simple one-step digital immunoassay for single-molecule detection without washing steps. A sample containing cTnI mixed with detection antibody-conjugated gold nanoparticles (AuNPs) is added to a capture antibody-coated sensor surface and the formation of the antibody-cTnI-antibody sandwich is detected by digitally counting the binding of the individual gold nanoparticles to the sensor surface in real time using a bright-field optical imaging setup together with a differential imaging algorithm. The digital immunoassay detects cTnI in undiluted human plasma, which achieves a detection limit of 5.7 ng/L within a detection time of only 10 min, which meets the requirement of current clinical high-sensitivity troponin assay (&tild;70 ng/L cutoff). We anticipate that the one-step and real-time digital immunoassay can be applied to the detection of other disease biomarkers in blood.
Original language | English (US) |
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Pages (from-to) | 1126-1131 |
Number of pages | 6 |
Journal | ACS sensors |
Volume | 5 |
Issue number | 4 |
DOIs | |
State | Published - Apr 24 2020 |
Keywords
- cardiac troponin I
- digital immunoassay
- high-sensitivity troponin assay
- one-step immunoassay
- single nanoparticle counting
ASJC Scopus subject areas
- Bioengineering
- Instrumentation
- Process Chemistry and Technology
- Fluid Flow and Transfer Processes