Septicemia (or, sepsis) is the leading cause for deaths in hospitals worldwide and they have long battled this scourge without much success. According to a paper published in October 2015 in the journal Analytical Chemistry, there are about 200,000 cases of sepsis deaths each year in the U.S. alone. Most solutions to control this agent of death have proved to be too expensive or time-consuming. Until now that is.
Prof. Shalini Gupta from the Department of Chemical Engineering, IIT Delhi and Dr. Venkataraman Sritharan from Hyderabad have developed a low-cost, disposable, point of care device for bedside use for sepsis diagnosis reports The Hindu. This device detects the endotoxin levels in human serum sample when a commonly used antibiotic colistin is combined with (conjugated) gold nanoparticles to bind endotoxin. Since at a nano level the gold particles are red, when the endotoxin is bound to it, it appears red. The higher the levels of endotoxin, more nano particles are bound and the tinge of red deepens. Prof. Gupta explains further,
We used the drug to detect endotoxin as we did not want to use the antibody detection method and it also reduces the cost of testing. The drug has a specific affinity to endotoxin. More the endotoixin, the redder it becomes, because more gold nanoparticles get absorbed. It works on a concentration-dependent manner, and so we get to know the degree of infection.”
A patient not suffering from Sepsis lacks endotoxin in their blood and so the colour of the membrane or device does not change. This innovative device also called a colorimetric rapid card test eliminates the need for trained scientists and a sophisticated microbiology laboratory. This also makes the device a viable option for detecting and treating sepsis in a timely manner in rural areas, where there are a lack of such medical staff and facilities.
So far the test has been used on 80 samples with more validation on blind samples to be carried out. The device which took about three years to develop won the Gandhian Young Technology Innovation Award this March.