This small, voice-activated device extracts and pretreats bacterial DNA and could make the laboratory safer for scientists and technicians. Credit: Adapted from ACS Sensors 2023, DOI: 10.1021/acssensors.2c01849
Yelling commands to Siri and Alexa is a normal part of daily life for many today. But, “Alexa, play my favorite music,” is a little different than, “Alexa, pretreat my pathogenic bacterial sample.”
Even so, researchers at Kyung Hee University in South Korea are working to ensure the latter of those commands is more commonplace in the near future.
In a new study published in ACS Sensors, the researchers describe the development of a portable sample pretreatment microsystem for bacterial samples that can be automatically operated through speech recognition via a smartphone app.
The research team first made a microfluidic chip with multiple chambers linked together by six 3-way solenoid valves, which are operated by a micro-controller connected to a Bluetooth module. Then, using existing speech recognition software, the team customized a smartphone app to listen for specific voice commands.
Once a user says one of the operation commands, the app wirelessly sends an initiation signal to the micro-controller. After receiving the signal, the micro-controller automatically starts a series of steps. In tests, the microsystem successfully carried out sample loading, washing and releasing of purified DNA into a collection chamber.
According to the study, the voice-controlled device successfully extracted DNA from Salmonella Typhimurium, purifying a 10-µL sample with an efficiency of 70% in less than 1 minute.
When the team evaluated the performance of the system against commercial QIAGEN kits, they found the microsystem did not perform as well. However, it had the distinct advantage of voice control, portability and quick automation. Additionally, the palm-sized device only weighs 11 ounces and can be powered by a portable battery or a smartphone charger—making it especially suited for use in both low-resource countries and necessary on-site testing locations.
For example, in the midst of the COVID-19 pandemic, many patient samples were taken and collected in diagnostic centers. The samples had to be tested by laboratory-trained technicians, but in the beginning of the pandemic there were many unanswered questions and roadblocks, including how contagious SARS-CoV-2 was and a lack of personal protective equipment (PPE).
Even when gloves became more readily available, technicians still had to handle the viral samples and then touch the equipment, such as a centrifuge for RNA extraction and a thermal cycler for gene amplification. Those actions alone come with the possibility of contamination from machine-to-person or person-to-person.
A pretreatment microfluidic system that runs on speech recognition almost completely eliminates that contamination risk—which is even higher with more dangerous diseases like Ebola and cholera.
In April 2022, the Democratic Republic of Congo had its sixth recorded outbreak of Ebola in just four years. It then hit neighboring Uganda, causing more than 55 deaths. Additionally, cholera hit Haiti hard last year, although it was far from the only country affected. According to the World Health Organisation, cholera was detected in about 30 countries in 2022—whereas in the previous five years, fewer than 20 countries reported infections.
The miniaturized device needing only a portable battery or smartphone charger would make a difference in low-resource areas like Uganda and Haiti.
The researchers say the voice recognition system could also help scientists with disabilities conduct tests more easily.