Pukyong National University

Vibrio Testing That Once Took a Full Day Can Now Be Completed in Just One Hour

- Pukyong National University Researchers Develop On-Site Diagnostic Technology for Vibrio Bacteria

- Paper-Based Diagnostic Device Automates Complex Genetic Testing

Researchers at Pukyong National University have developed a paper-based diagnostic device capable of detecting Vibrio vulnificus, a potentially fatal foodborne bacterium found in seafood such as oysters, on site in approximately one hour.

Unlike conventional commercial test kits, which rely on laboratory-based testing that requires specialized equipment and trained personnel, the newly developed portable device mechanically automates the processes of genetic amplification and detection. This allows the device to be used relatively easily in the field or at small-scale facilities.

Vibrio vulnificus is a bacterium found in seawater and seafood. Infection can occur through the consumption of contaminated raw oysters and other seafood or through open wounds, potentially causing sepsis and tissue necrosis. Rapid detection and management are particularly important because the bacterium can be fatal for people with liver disease or weakened immune systems.

Commercial real-time PCR kits currently widely used for food safety testing can identify multiple Vibrio species with high accuracy. However, the testing process is complex, requiring samples to be cultured for a certain period and then analyzed using PCR equipment in a specialized laboratory. Results typically take about a day, while the need for expensive equipment and trained personnel limits the use of these methods in field settings.

The device, developed by a research team including doctoral student Won Han of the Department of Industry 4.0 Convergence Bionics Engineering at Pukyong National University as the first author and Professor Joong-Ho Shin of the Major of Biomedical Engineering as the corresponding author, addresses the limitations of conventional testing methods. After a sample is collected from an oyster’s gills using a swab and its DNA is extracted, the sample and buffer solution are placed on a paper pad inside the device. Once the spring mechanism is wounded, the device operates automatically, sequentially carrying out genetic amplification and detection reactions.

The device minimizes complex fluid handling and multi-step manual procedures. After approximately one hour, the test result can be determined simply by visually checking the test line that appears on the paper strip. No complex equipment is required, other than maintaining a temperature of approximately 37°C.

In pure cultures, the device was able to detect as little as a single bacterial cell per reaction. It also reliably identified contamination in oysters raised in seawater artificially contaminated with Vibrio bacteria. In addition, the device was able to distinguish the target bacterium from other closely related Vibrio species. The paper-based reaction pads maintained their performance with little degradation even after being stored at room temperature for several weeks.

The researchers said, “While existing commercial PCR kits are designed primarily for laboratory-based testing, this device focuses on automating the testing process so that it can be used relatively easily in the field or at small-scale facilities.” They added, “By changing the reagents to target specific pathogens, we expect the device could also be applied to the detection of a wide range of pathogens.”

The study, titled “Field-Deployable Paper-Based Detection of Vibrio vulnificus via Mechanically Automated Sequential RPA/CRISPR-Cas12a,” was published in the August issue of ACS Sensors (IF 10.9), an international journal in the field of sensor research.

The study was supported by the Core Research Program of the National Research Foundation of Korea, the Academic Research Support Program for Science and Engineering Fields of the Ministry of Education (including the Doctoral Student Research Incentive Program and the University-Focused Research Institute Support Program - Marine Bionics Convergence Technology Center), and the Ministry of Education’s BK21 Program (Smart Healthcare Program for New Seniors).