‘Time bomb’ liquid marbles with Nanoclay for controlled drug delivery

New Delhi: Researchers at the Indian Institute of Technology Guwahati
have developed liquid marbles using nano clay that can be pre-programmed for drug
delivery and cascade chemical reactions. Conventionally for treating any disease we
take medicines in the form of tablets, capsules, syrups, ointments, etc.

A controlled drug delivery system is a more efficient technique to deliver the required dose at the specific site gradually over the desired period of time. Loading and release of drug in its soluble form is another important aspect—which can be achieved with this liquid marble.

A Research team from the IIT Guwahati led by Dr. Uttam Manna, Associate Professor,
Department of Chemistry and Centre for Nanotechnology, IIT Guwahati has used the
liquid marbles approach for the controlled release of drugs and programmed chemical
reaction. The team has engineered liquid marbles to have a ‘time bomb’ type release
effect and to carry out a spontaneous chemical reaction.

Unlike normal droplets, a liquid marble is a non-sticking, non-wetting droplet. It is created
by wrapping a droplet with fine hydrophobic particles i.e., water-repelling particles.
Liquid marbles can be rolled, squeezed, and even float without spilling when put in a
water pool. In nature gall-forming aphids create liquid marbles by coating the honeydew
they secrete in a powdery wax. Liquid marbles are soft spherical solids that can be used
for multiple applications by replacing the liquid inside them. Some examples are in the
field of sensor platforms, soft robotics, healing agents, biosystems, etc.

Explaining the research challenge Dr. Manna said, “Release of drugs from a liquid marble
in response to a stimulus for instance light, temperature, electricity has been reported
earlier. But the time-programmed release was not yet achieved. We have chemically
modified the lifetime of a floating liquid marble on a water pool.”

The nano clay marbles were made of a shell of nanoclay that holds the liquid. To
programme the marbles for timed release of the content, the researchers modified the
nanoclay with chemical groups that were either water-loving (hydrophilic) or waterhating (hydrophobic). A water droplet was laid on a powder bed consisting of
hydrophilic and hydrophobic nanoclay powders. The properties and stability of the liquid
marbles changed according to the relative amounts of the water-hating and waterloving groups on the nanoclay surface.

Explaining further, Dr Manna said, “The surface modifications on the nano clay changed
the time taken for the liquid marble to break and release its contents when put in a pool
of water. We were able to control the timing of the release of the content from seconds
to hours by changing the nature of the surface groups. This is the time bomb type collapse
of LMs.”

The details on the formation of the NC liquid marbles and their programmed drug release
application have been published in Advanced Functional Materials. The paper has been
co-authored by Nishanta Barman, Arpita Shome, Saurav Kumar, Priyam Mondal, Karan
Jain, Mizuki Tenjimbayashi and Dr. Uttam Manna.

This project was funded by the Science and Engineering Research Board
(CRG/2022/000710) and Ministry of Electronics and Information Technology (no.
5(1)/2022-NANO) and the Department of Biotechnology.