New Delhi

Researchers at the Indian Institute of Technology (IIT), Madras, have developed an innovative and affordable microfluidic device that can rapidly determine whether bacteria are resistant or susceptible to antibiotics, officials said.

Unlike many modern techniques that rely on costly metals, complex fabrication processes, or require highly-skilled technicians, this lab-on-chip device is based on screen-printed carbon electrodes embedded in a simple microfluidic chip.

This approach makes the device not only economical but also suitable for deployment in smaller clinics and rural healthcare centres.

According to S Pushpavanam, Y B G Varma Institute Chair Professor, Department of Chemical Engineering, IIT Madras, the device designed for speed, sensitivity and ease of use holds strong potential for early diagnosis and better treatment of bacterial infections, particularly in regions with limited access to advanced laboratory infrastructure.

The device can deliver results within three hours and is based on 'Electrochemical Impedance Spectroscopy'.

Antimicrobial resistance (AMR) is one of the most pressing challenges facing global healthcare systems today.

The World Health Organization (WHO) has identified AMR as one of the top 10 threats to global health, and estimates suggest that nearly 4.95 million deaths worldwide in 2019 were associated with bacterial AMR.

"The burden is especially high in low and middle-income countries, where diagnostic facilities are limited and infections often go untreated or are improperly managed.

Antimicrobial Susceptibility Testing (AST) is an important method used to identify which antibiotics will work against a specific infection. It helps doctors choose the right treatment and avoid the misuse of antibiotics, which is a major cause of AMR.

"However, traditional AST methods, which involve growing bacterial cultures and observing their response to antibiotics, are labour-intensive and typically take 48 to 72 hours. This delay can lead to the use of broad-spectrum antibiotics as a stopgap, which in turn exacerbates the resistance problem," Pushpavanam said.

To address these limitations, the IIT Madras team developed ε-µD -- a cost-effective phenotypic testing device that uses electrochemical signals to assess bacterial growth and antibiotic susceptibility.

"This device meets several key criteria outlined by the WHO, including affordability, speed, ease of use and reliability. By addressing these priorities, ε-µD takes a significant step toward making antimicrobial susceptibility testing more accessible, especially in low-resource settings," Pushpavanam said.

The research has been published in the prestigious Nature Scientific Reports, a peer-reviewed, open-access scientific mega journal published by Nature Portfolio (part of Springer Nature), covering all areas of natural sciences.

"An important aspect of our device is the use of a specially prepared nutrient solution that serves a dual purpose. It not only supports bacterial growth, which is essential for testing, but also enhances the sensitivity of the electrical signals we use for detection. As the bacteria grow, they cause measurable changes in the electrical properties of the solution, which our system can accurately track," Pushpavanam said.

"This approach will make a real impact on patients in intensive care units, who may be suffering from complications due to bacterial infections. This will help the doctors prescribe the right treatment and can be life-saving.

"Currently, we are doing clinical validation in collaboration with the IITM Institute Hospital. After rigorous clinical validation, we are planning to commercialise this through our startup, Kaappon Analytics India Private Limited," he added.

The researchers tested the device on two types of bacteria -- gram-negative E coli and gram-positive B subtilis.

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They used two antibiotics with different modes of action -- ampicillin, which kills bacteria, and tetracycline, which prevents them from growing -- to confirm the device’s ability to detect both kinds of responses.