Researchers form CSIR-Institute of Genomics and Integrative Biology (CSIR-IGIB) and National Centre for Disease Control (NCDC) have developed an ultrasensitive DNA chip based sensor for quick pathogen detection.
The senor can detect S. pyogenes, a bacterium which causes a wide range of diseases in about 30 minutes. The conventional method takes 18-24 hours identification of the S. pyogenes.
The DNA chip based sensor consists of a carbon electrode embedded with gold nanoparticles. By means of a bioinformatics study, researchers were able to design probes which are specific for S. pyogenes. The working electrode surface of the sensor is attached with several small-sized, single-stranded DNA probe specific to the pathogen.
When patients’ DNA, isolated from throat swabs are placed on the surface of the sensor, they bind to the complementary single-stranded DNA on the device leading to electrochemical change. This is measured using a differential pulse voltammetry.
Significance: The sensor is highly sensitive and could detect even 60-65 bacteria in a 6 microlitre sample. It could identify the pathogen even at very low concentrations of DNA.The sensor was found to be stable for 12 months with only 10% loss in initial current peak on storage at 4 degree C.
S. pyogenes infections
S. pyogenes cause diseases ranging from mild skin and throat infections to life-threatening toxic shock syndrome. If not treated during early stages of the infection, it can even lead to rheumatic heart disease (heart valves damage). It affects 700 million people every year.