Researchers at the University of California, Berkeley have developed a groundbreaking at-home testing technology that leverages the same physics behind the “coffee-ring effect” to significantly enhance the sensitivity of rapid diagnostic tests.

You may have noticed how coffee or wine stains often leave a dark ring around the edges. This phenomenon occurs as the liquid evaporates, pushing particles outward and concentrating them along the rim.

Figure 1. Coffee-Ring Effect.

The UC Berkeley team found a way to harness this natural effect to concentrate disease biomarkers in test samples, making them far easier to detect. Figure 1 shows Coffee-Ring Effect.

The result is a low-cost, user-friendly device that’s up to 100 times more sensitive than today’s at-home COVID-19 tests. It also holds promise for detecting serious illnesses like sepsis and prostate cancer in as little as 12 minutes.

Their innovative system combines the coffee-ring effect with plasmonic nanoparticles and an AI-powered smartphone app to identify minute traces of disease-related proteins from just a single droplet of fluid.

As the droplet dries, it pulls the target proteins to the outer edge, creating a concentrated ring [1]. Specially engineered nanoparticles are then added to bind to these proteins and form light-reflecting clusters that can be seen by eye or detected via smartphone.

“This simple but powerful technique can deliver highly accurate results in just minutes—much faster than traditional diagnostics,” said Kamyar Behrouzi, who recently earned his Ph.D. at UC Berkeley.

“Our approach makes testing more accessible and affordable, especially in low-resource environments.”

A Smart, Portable Diagnostic Platform

The prototype test kit includes a 3D-printed scaffold for guiding sample placement, a syringe, and a small electric heater to speed up evaporation.

To use it, a person places a droplet—such as one collected from a cheek or nasal swab—onto a membrane. As it dries, disease markers concentrate at the outer edge, forming a coffee-ring pattern.

A second droplet, containing plasmonic nanoparticles, is then applied. If target biomarkers are present, the particles bind and create distinct clusters that change how light reflects off the surface. These changes can be visually detected or analyzed with an AI-enhanced phone app.

“One of the key biomarkers we can detect with this method is associated with sepsis—a dangerous inflammatory condition caused by bacterial infections that can develop rapidly, especially in adults over 50,” explained Liwei Lin, the study’s senior author.

This fusion of natural fluid dynamics, nanotechnology, and AI could mark a major leap forward in rapid, affordable disease detection—especially where resources are limited and early diagnosis is critical.

Reference:

1. https://interestingengineering.com/innovation/eco-sheets-from-bacteria-plastic-breakthrough

Cite this article:

Keerthana S (2025), New Diagnostic Technology Harnesses Coffee-Ring Effect to Detect Deadly Diseases in Just 12 Minutes, AnaTechMaz, pp. 343