Using easily available, inexpensive natural polymers, researchers in Bengaluru have developed a gel for the skin to protect agricultural workers from harmful pesticide sprays. The gel does not just act as a simple physical barrier; it chemically deactivates pesticides.
Ripple effect
Organophosphate pesticides bring about the inhibition of important enzymes (AChE) of the body, which can, in turn, affect the functioning of nervous system, heart, immunity, and even the reproductive system.
Explains Ketan Thorat, a doctoral scholar at the Institute for Stem Cell Science and Regenerative Medicine (inStem), Bengaluru, “The base of the gel is chitosan, a natural substance extracted from the waste shells of crabs and shrimps, to which we added a nucleophile and few aqua reagents to get the consistency and desired pH.”
Dr. Thorat, who is also the first author of a paper on the subject published in Science Advances , adds, “The gel looks and feels like a cold cream and we can add suitable fragrance too.”
Since pesticides can inhibit enzymes in blood, different experiments were carried out using rat blood to see if the gel could prevent this. The gel was found to cleave a wide range of commercially available pesticides before they enter the bloodstream, thus reducing the pesticide-induced enzyme inhibition.
In-vivo studies were carried out using rat models. Even 96 hours after pesticide exposure, the gel-applied rats did not show any reduction in enzyme activity. The control animals (without gel) exposed to pesticides lost about 20% of their body weight by four days, whereas the protected rats had normal weight.
To understand pesticide-induced mortality, the researchers sprayed a higher concentration of pesticide on the rats for four consecutive days and monitored them. The rats without the gel showed signs of pesticide poisoning such as diarrhoea, trouble in breathing, tremors and died after five days. All the rats in the protected group survived and showed no signs of toxicity even after 30 days.
Post-mortem studies showed that the rats had decreased levels of the important enzyme in their system.
Safe to use
Explains Dr. Praveen K. Vemula, from inStem, and corresponding author of the paper, “We carried out pre-clinical toxicology studies and the gel was found to be safe for repeated applications. It had no side-effects even if inhaled, swallowed or if it comes in contact with the eye.” According to Dr. Vemula, when produced in bulk, the gel may cost less than ₹1,000 for an entire month.