The device, a DNA chip-based sensor, consists of a carbon electrode embedded with gold nanoparticles to improve electronic properties. Many small-sized DNA probes are located on the modified chip. They attach themselves to the target DNA samples of bacteria taken from throat swabs of the patient.
The new sensor has been found to be better than earlier reported sensors due to its ability to pick up bacterial DNA even if present in small numbers, within 30 minutes. It correctly distinguishes S. pyogenes from other bacteria, according to the study published in International Journal of Biological Macromolecules.
“The aim was to develop a rapid, accurate, sensitive, specific and cost-effective method for detection of S. pyogenes. The current methods of detection S. pyogenes infection are culture test, biochemical assays, polymerase chain reaction, genetic markers. And these methods are time-consuming, expensive, are unable to pick up the bacteria if present in small numbers and may even wrongly identify other bacteria as S. pyogenes,” Professor Ashok Kumar from the Institute of Genomics and Integrative Biology, who led the research, told India Science Wire.
Based on this technique, he said, several other infection-causing microbes can be identified to prevent the disease by taking medical treatment at early stage of infection.
The most common cause of throat infections in humans is S. pyogenes bacteria. If left untreated it may damage human heart valves resulting in a severe form of rheumatic heart disease. Early diagnosis can prevent damage of human heart valves by taking timely and correct medical care.
The team of researchers included Swati Singh and Ankur Kaushal from the CSIR-Institute of Genomics and Integrative Biology, Delhi, and Dr. Shashi Khare from the National Centre for Disease Control, Delhi.
ABSTRACT:
Several infectious pathogens are found in human whose detection is essential for rapid cure of diseases. The most commonly found pathogen in human is Streptococcus pyogenes which leads to a wide range of infections from mild pharyngitis to rheumatic heart disease. An ultrasensitive DNA chip based sensor was developed for quick identification of pathogen S. pyogenes from patient throat swab samples. The amperometric response was measured after hybridization of specific probe with single stranded genomic DNA (ssG-DNA) from the patient samples. The DNA chip was characterized by FTIR, SEM and validated with suspected patient real samples. The sensitivity of the DNA chip based sensor was found 951.34 (μA/cm2)/ng DNA and lower limit of detection (LOD) was 130 fg/6 μL samples. The DNA chip based sensor is highly specific and takes only 30 min for identification of specific pathogen.