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Improving rapid tests: DNA nanotechnology boosts sensitivity of test strips

Since the COVID-19 pandemic, pretty much everybody is familiar with this technology: paper-based rapid test strips, also called lateral flow immunoassays (LFIAs). They enable easy detection of biomarkers that indicate the presence of specific pathogens or states of health.

Now a research group led by Heini Ijäs, Maximilian J. Urban, and Tim Liedl from LMU Munich has managed to significantly improve such tests using a cutting-edge nanotechnology called DNA origami.

In DNA origami, DNA is folded—akin to the Japanese art of paper folding—to create nanoscale structures of virtually any shape. In this case, the researchers engineered a nanoscale amplifier substantially boosting the sensitivity of LFIAs.

The researchers from the Faculty of Â鶹ÒùÔºics and the Center for NanoScience (CeNS) have presented their in the journal Nature Communications, laying out how the technique improves testing for a variety of biomarkers, including the heart attack marker, cardiac troponin I (cTnI), and the stroke marker, neurofilament light chain (Nfl).

Nanotechnology for early detection of strokes and heart attacks

Rapid tests are widely used for point-of-care diagnostics due to their simplicity and cost-effectiveness. However, conventional test strips often fail to detect essential biomarkers that exist only in trace amounts in blood, saliva, or urine. As a result, life-threatening conditions such as strokes or heart attacks may remain unnoticed at early stages, whereas fast medical intervention is key for a good recovery prognosis in exactly such cases.

The newly developed signal amplification system is based on DNA nanotechnology and acts as a molecular amplifier, connecting detection antibodies to a precisely tunable number of signal-generating labels. The research demonstrates an increase in sensitivity of up to 125-fold.

"Our technology allows for unparalleled control over the amplification factor, making LFIA tests more reliable and effective for clinical applications," says lead author Dr. Ijäs. "This innovation has the potential to transform diagnostic testing across a broad range of diseases."

The method is adaptable to various biomarkers and samples, including drugs of abuse, making it a versatile solution for improving existing rapid tests. According to the research team, this breakthrough will lead to more sensitive, rapid, and accessible diagnostic tools for both clinical and home-based testing.

The cost of the molecular amplifier is around 1 cent per test. "We want to make the technology available to doctors in everyday practice and improve patient care. With the help of a grant from the federal government's EXIST Transfer of Research program, we're now commercializing the technology.

"We're seeing high demand for our tests in smaller clinics and practices without quick access to laboratories and in emergency departments, where every minute counts," says Dr. Maximilian Urban.