Researchers have designed a DNA-based biosensor that can aid the diagnosis of meningitis, a fatal infection of fluid in spinal cord and fluid surrounding the human brain1. The biosensor could rapidly detect meningitis initiated by bacterium (Neisseria meningitidis) at an early stage of infection.
Available methods to detect meningitis are time-consuming and expensive. This led the researchers to invent the faster, simpler and economic diagnostic tools. For the study, the researchers selected ctrA (capsular transport protein A) gene from the meningitis-causing bacteria.
The researchers used the ctrA gene (basically DNA single strand) as probe and placed it on gold electrode. Then they made complimentary DNA sequence from the ctrA gene. A change in current was observed when DNA probe on electrode merged (hybridized) with the complimentary DNA sequence.
Exposure of DNA probe on the electrode to non-complimentary DNA caused almost no current change, indicating no hybridisation. The hybridisation time of the probe with complimentary DNA is 5 minutes and the electrode response time is 60 seconds.
"Our research will lead to cost-effective, rapid and sensitive biosensor for detection of meningitis directly from the patients' fluid in spinal cord or blood samples," says lead researcher Ashok Kumar. Work is underway to devise electrochemical DNA biosensors for other infectious diseases like typhoid and rheumatic heart disease, he adds.
The authors of this work are from: Institute of Genomics and Integrative Biology, New Delhi; National Physical Laboratory, New Delhi and National Institute of Communicable Diseases, New Delhi, India.