Diagnosis of Pathogens Using 'Coffee Ring'... Research on COVID-19 Also Underway

Development of Infectious Pathogen Detection Method Using Coffee Ring Effect
Visual Diagnosis Possible Through Specific Patterns
Research Underway for Application in COVID-19 Diagnosis

Schematic diagram of coffee ring isothermal gene detection method and analysis results of antibiotic-resistant hospital pathogens.

[Asia Economy Reporter Junho Hwang] A technology has been developed that can accurately detect infectious pathogens by utilizing the characteristic ring shape left behind as coffee droplets evaporate. This method allows for fast and easy on-site detection of pathogens and is expected to be applicable for detecting the novel coronavirus infection (COVID-19) in the future.

The research team led by Professor Hyunjeong Jung of the Department of Life Sciences at the Korea Advanced Institute of Science and Technology (KAIST) announced on the 16th that they developed a coffee ring isothermal gene detection method, with the related paper published in 'Biosensors and Bioelectronics.'

Inducing Coffee Ring Patterns to Visually Identify Pathogens

Professor Jeong-Hyun Jung (right) and the research team

The research team developed a technology that induces coffee ring patterns by dropping samples onto pathogens, enabling visual identification of the pathogen types. They utilized the phenomenon where, as a colloidal solution evaporates on a substrate surface, surface tension and capillary flow cause microparticles to move around the droplet, forming characteristic ring patterns.

If target genetic material is present, selective recognition between microparticles and genetic material induces co-condensation between particles and nucleic acids, suppressing the ring pattern and thereby allowing differentiation of pathogens.

The team enhanced accuracy by integrating the coffee ring phenomenon with rotation-assisted isothermal amplification technology. During this fusion process, the long single-stranded target DNA material generated was maximally condensed to microparticle sizes (approximately 0.1 to 10 micrometers in diameter). Additionally, the team developed technology capable of visually detecting pathogen target materials even at sub-zeptomolar concentrations and enabling both recording and reading via mobile devices such as smartphones.

Capable of Diagnosing COVID-19 as Well

The research team stated that the coffee ring isothermal gene detection method possesses high selectivity and sensitivity, allowing it to distinguish differences of two bases in genetic sequences. They also explained that antibiotic resistance genes can be detected within 30 minutes without separate analytical equipment, and that complex samples such as serum can also be detected.

Professor Hyunjeong Jung said, "The coffee ring isothermal gene detection method developed by our team is expected to be usefully applied for bedside analysis in clinics and medical offices," adding, "We are currently conducting research to apply this method for diagnosing coronavirus infection (COVID-19)."