DNA Nanotechnology Boosts Sensitivity of Test Strips

Since the Covid-19 pandemic, most people have become familiar with paper-based rapid test strips, also known as lateral flow immunoassays (LFIAs). These tests are used to quickly detect biomarkers that indicate the presence of specific pathogens or health conditions. Due to their simplicity and cost-effectiveness, rapid tests are widely used for point-of-care diagnostics. However, traditional test strips often struggle to detect essential biomarkers that exist in very small amounts in blood, saliva, or urine. This limitation can result in critical conditions, such as strokes or heart attacks, going undiagnosed in their early stages, even though fast medical intervention is crucial for a favorable recovery. Now, researchers have significantly improved conventional test strips by using DNA origami to create a nanoscale amplifier, enabling the amplification of signals from biomarkers, which can now be enhanced up to 125 times.

A research team from Ludwig Maximilian University of Munich (Munich, Germany) has enhanced these tests by employing DNA origami, an advanced nanotechnology. In DNA origami, DNA is folded—much like the Japanese art of paper folding—into nanoscale structures that can take nearly any shape. The researchers used this technology to build a nanoscale amplifier, which dramatically boosts the sensitivity of LFIAs. Their findings, published in Nature Communications, detail how this approach improves the detection of various biomarkers, such as the heart attack marker cardiac troponin I (cTnI) and the stroke marker neurofilament light chain (NfL).

The new signal amplification system, based on DNA nanotechnology, acts as a molecular amplifier by linking detection antibodies to a precise number of signal-generating labels. This method enhances sensitivity by up to 125 times. It is adaptable to various biomarkers and sample types, including drugs of abuse, making it a flexible solution for improving existing rapid tests. According to the research team, this innovation will pave the way for more sensitive, rapid, and accessible diagnostic tools for both clinical and home-based testing. Additionally, the cost of the molecular amplifier is estimated to be about one cent per test.

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