Handheld, Sound-Based Diagnostic System Delivers Bedside Blood Test Results in An Hour

Patients who go to a doctor for a blood test often have to contend with a needle and syringe, followed by a long wait—sometimes hours or even days—for lab results. Scientists have been working hard to make diagnostic testing more accessible, especially for individuals in rural areas or developing countries, and for those who fear needles when it comes to blood tests. Existing rapid tests, known as lateral-flow assays, such as COVID tests or pregnancy tests, can quickly indicate a "yes" or "no" regarding the presence of a specific biomarker or biomolecule in blood or urine. However, these tests usually cannot quantify how much of the substance is present and often lack the sensitivity to detect very low amounts. On the other hand, the gold standard for clinical blood tests, the enzyme-linked immunosorbent assay (ELISA), is highly sensitive and specialized enough to identify rare or scarce biomarkers. However, it requires costly equipment and complex procedures, leading to delays of hours or days before patients receive their results. But all that could now change with the introduction of a new handheld, sound-based diagnostic system that can provide accurate results in just an hour using only a small finger prick of blood.

Based on systematic experiments and peer-reviewed research, researchers at the University of Colorado Boulder (Boulder, CO, USA) are developing a diagnostic tool that is sensitive, portable, and user-friendly. Their innovative components include tiny particles referred to as “functional negative acoustic contrast” particles (fNACPs) and a custom-built handheld device known as an “acoustic pipette,” which emits sound waves to the blood samples. The fNACPs, which resemble cell-sized rubber balls, are engineered with functional coatings that enable them to recognize and capture a specific biomarker of interest, such as an infectious virus or a protein associated with a potential health issue. These particles respond to sound wave pressure differently than blood cells, and the acoustic pipette is designed to take advantage of this unique response.

When a small blood sample is combined with the custom particles and placed into the acoustic pipette, sound waves push the particles to the side of a chamber where they are trapped, allowing the rest of the blood to be flushed away. The remaining biomarkers attached to the particles are then tagged with fluorescent markers and illuminated with lasers to quantify their presence. This entire process takes less than 70 minutes and is within a device small enough to fit in the palm of a hand. The pipette and particle system, detailed in a new paper published in the journal Science Advances, shows that it can provide the same level of sensitivity and specificity as a gold-standard clinical test while simplifying the workflow significantly. Future enhancements could further decrease testing time, enabling blood diagnostics to be conducted right at the patient’s bedside. This could be particularly beneficial for determining whether a patient has an infectious disease, assessing their viral load, and monitoring how quickly it increases. Additionally, the device could potentially be used to measure antibodies to establish the need for booster shots, test for allergies, or detect proteins linked to certain cancers.

“We’ve developed a technology that is very user-friendly, can be deployed in various settings, and provides valuable diagnostic information in a short time frame,” said senior author Wyatt Shields, assistant professor in the Department of Chemical and Biological Engineering at CU Boulder. “We think this has a lot of potential to address some of the longstanding challenges that have come from having to take a blood sample from a patient, haul it off to a lab and wait to get results back.”