Teabots, Ahoy!

Pfizer, Sun Pharma, Biocon, Sanofi, Glaxo you name them and they all are working on drug delivery. Safety, Affordability, Efficacy, and Ease of drug administration are the major concerns in Pharmacotherapy leading to exploration of better drug delivery systems. Very recently, there has been a shift into engineered microscopic particles such as nanobots that can navigate through the body to deliver drugs with precision.

The recent robotic age has made each and every task possible with just a few clicks. It’s the era of AI. Scientists too have tried to benefit from this by developing safer and easier methods that can transform the therapeutics. One can also go on to design Mini Robots (nano size) which could delve into our body, reach the diseased site and deliver the drug without harming the surrounding tissues. Researchers at IIT-G did something similar to this, they fabricated Bio-compatible Vit C fortified robotic antioxidant molecules from tea extracts. The novelty here is that these Teabots are Eco-friendly, safe and navigate fuel-free.

Free radicals are the by-products produced during the metabolism in our cells, they can damage our cellular components. This phenomenon is known as Oxidative stress. This is where the Teabots come into play, they are propelled by the sound waves and swim towards the free radicals neutralizing them in the process. Now even though these bots are bio-compatible they still have to pass through the body’s defense mechanism which can reject it as a foreign element. Hence a lot of research is being put into synthesizing nanobots from non toxic sources such as plants which can pass through the intestinal layer and the blood brain barrier without alarming the immune system.

The IITG team zeroed in on white buds of Camelia sinensis (tea buds) for their high antioxidant content and bio compatibility. They used a method to avoid the use of toxic chemicals for synthesizing the product which is knows as the Green Chemistry Principle, they distilled 100-200 nm sized purified pellets from the tea extract, to derive the Teabots. Their surface is mesh-like with a negative charge on them. Now the next challenge faced by the team was piloting the particles, for which they took advantage of the existing studies which has proved that nanoscale particles can be driven by ultrasound waves (3-10 MHz) which has been deemed safe by the medical community for diagnostic purpose.

Tamanna Bhuyan, the first author of the study said that “The nanomotors absorbs the sound energy converting it to mechanical energy. By altering the direction of the waves falling on the Teabots, the direction of motion can be changed. This way, the Teabots can move about without any fuel.”

The cells which were grown were first subjected to oxidative stress and then the Teabots were added into the culture. When they were exposed to the optimized sound waves, they moved towards the diseased cells and when these nanoscale bots reached the site they neutralized around 65% of the free radicals.

Since their efficacy was quite low, the team decided to load the Teabots with Ascorbic -Acid(AA) or Vit C which is another potent antioxidant . However unlike the tea extracts, Vit C is a very unstable molecule and to overcome this hurdle and deliver stable molecules inside the cells, they made use of the electrostatic interaction between them. Electrostatic interaction is an attractive or repulsive interaction between objects having electric charge. As mentioned earlier these bots have a charged mesh like structure which encapsulates the positively charged Vit C molecules preventing them from degrading.

At the diseased cell, the acidic conditions of the cell fluids gradually broke down the Vit C loaded Teabots to release the antioxidant molecules. The AA-teabots could now scavenge up-to 90% of the free radicals and could also protect the HEK-293 cells from the oxidative injury alongside preventing protein aggregation derived diseases. Which means they could effectively breaking down toxic amyloid fibres which form in neurodegenerative disorders like Alzheimer’s disease.

Further, Bhuyan said “Our study offers a scope for on-site acoustic control of Teabots for drug delivery using safe hand-held ultrasonic probes, which is an attractive alternative to regular oral or injected drug formulations.” Very soon, these AA-Teabots are envisioned to provide an attractive approach in proficient delivery and controlled release of therapeutic payloads at targeted zones.