Indian Institute of Science

Tuberculosis

TB

Bangalore

Bengaluru

An untrained user can perform a TB DNA detection test by simply adding liquid samples to the paper reaction zones and placing the device in an incubator for 60-80 minutes –Bhushan Toley, Assistant Professor

Thanks to IISc, which has developed a low-cost deviceResearchers of the Chemical Engineering Department at the(IISc) have developed a low-cost, easy-to-access device to conduct DNA-based) diagnostic tests.The research conducted by Navjot Kaur, a PhD student, and led by Assistant Prof. Bhushan Toley, focuses on increasing access to DNA-based TB diagnostic tests.“TB is the deadliest infectious disease today and India has the largest number of TB-related deaths among all countries in the world. In 2016, 4.23 lakh people died from TB in India. The standard and most accurate TB diagnostic test (culture test) requires several weeks to perform and it is often difficult to track patients after such a long duration,” Kaur toldMirror.Kaur added that state-of-the-art technology for rapid detection of TB is using ‘molecular diagnostics’, probing for the DNA of Mycobacterium tuberculosis (MTB), the TB-causing bacteria.“Unfortunately, the World Health Organisation-endorsed DNA-based TB test (GeneXpert) currently costs Rs 1,800 per test and is unaffordable to a majority of India’s poor population. Further, the GeneXpert instrument costs around Rs 18 lakh. As a result, there are only an estimated 3000 GeneXpert machines across India, too few to cover the needs of the large Indian population,” Kaur added.To overcome the limitation of expensive DNA-based diagnosis, the researchers have invented a low-cost paper-and-plastic device that can detect the presence of TB DNA in liquid samples.“Using this all reagents (substance used to create a chemical reaction) required to detect TB DNA are pre-applied to paper reaction zones within the device. An untrained user can perform a TB DNA detection test by simply adding liquid samples to the paper reaction zones and placing the device in an incubator for 60-80 minutes. The results of the test are read using a cell phone camera installed within a small plastic box. The material cost of fabricating the device is only Rs. 61 and the cost of reagents per reaction is Rs 41. The device eliminates all expensive instruments traditionally required for DNA detection,” said Toley.The researchers have already developed an early working prototype of this device and plan to deploy some devices to a nearby hospital to conduct early clinical validation. The hospitals include one inand another in Tamil Nadu.Recently Kaur won the second prize at the national Falling Walls Lab contest for this research project.