DNA origami signal amplification in lateral flow immunoassays

Lateral flow immunoassays (LFIAs) enable a rapid detection of analytes in
a simple, paper-based test format. Despite their multiple advantages, such
as low cost and ease of use, their low sensitivity compared to
laboratory-based testing limits their use in e.g. many critical
point-of-care applications. Here, we present a DNA origami-based signal
amplification technology for LFIAs. DNA origami is used as a structurally
precise adapter to connect detection antibodies to tailored numbers of
signal-generating labels. As a proof of concept, we apply the DNA origami
signal amplification in a sandwich-based LFIA for the detection of cardiac
troponin I (cTnI) in human serum. We show a 55-fold improvement of the
assay sensitivity with 40 nm gold nanoparticle labels and an adjustable
signal amplification of up to 125-fold with fluorescent dyes. The
technology is compatible with a wide range of existing analytes, labels,
and sample matrices, and presents a modular approach for improving the
sensitivity and reliability of lateral flow testing.