IISc study backs chemically-modified nanosheets for drug delivery

Researchers from the Department of Organic Chemistry and Materials Research Centre (MRC) at the Indian Institute of Science (IISc) have, in a recent study, found surface modifications made to two-dimensional molybdenum disulphide (2D-MoS2) nanosheets to be highly effective in applications like delivering drugs to diseased cells.

The efficiency of nanomaterials is, typically, improved through a process called functionalisation, which involves attaching ligands (small or large molecules) to the surface of the nanomaterial.

As part of the study, the researchers modified the surface of 2D-MoS2 nanosheets with thiol (sulphur-containing) ligands and found that these thiols can be exchanged with naturally occurring thiols in biological systems, which can allow drugs attached to these nanosheets to be released. These chemically modified nanosheets were also found to be safe to use inside living cells, IISc said on Thursday.

Mrinmoy De, associate professor at the Department of Organic Chemistry and senior author of the study, said the nanomaterial was stable in the presence of various biomolecules. “This is an important observation as it will make this nanomaterial highly beneficial for biomedical applications like drug delivery,” he said. The study has been published in the scientific journal, ACS Nano.

The team attached anti-cancer drug doxorubicin (DOX) to the nanosheet surface and found that thiol exchange could also happen between Glutathione (GSH) – a naturally occurring thiol found in abundance in cancer cells – and DOX, allowing DOX to get released at the disease site. The exchange happens only in the presence of high GSH concentrations in diseased cells, helping delivery of drugs like DOX specifically to cancer cells, without affecting normal cells and potentially reducing side effects.

Pradipta Behera, a postdoctoral research scholar at IISc and the first author of the study, said 2D-MoS2 nanosheets could substitute gold nanoparticles in such biomedical applications. The researchers said gold nanoparticles are an expensive option with limited efficiency. The work can be developed into an alternative to RNA and DNA delivery applications, with potential use in detecting and treating infections, including Covid-19, Behera said.