A friendly graphene

It can widen the use of nanotechnology in healthcare

By Biplab Das
Published: Wednesday 31 August 2011

IT’S been a couple of years since scientists proposed that graphene, the new rockstar of the nano-world, is capable of revolutionising the healthcare sector.

The one-atom-thick sheet of carbon can be used as an efficient vehicle to deliver drugs precisely to the target tumour or cancer cells. Its intrinsic optical properties can be used for cellular imaging.

cellsLast year, scientists of IIT Kharagpur showed that the nanomaterial, when tweaked a bit, can kill drug-resistant bacteria, tetracycline-resistant strain of Escherechia coli for example. Their study was published in the International Journal of Pharmaceutical Sciences and Drug Research in 2010. But till now hardly any study has paved the way for actual application. Reason: graphene in its pristine form is toxic to biological cells. Instead of entering the cell, it can accumulate on the cell surface and suffocate the cell to death. A team of scientists from Amrita Vishwa Vidyapeetham University (AVVU) in Ernakulam and Jawharlal Nehru Centre for Advanced Scientific Research in Bengaluru have recently devised a way to make graphene friendly to cells.

They followed the method scientists use to make carbon nanotubes compatible with cells. It is the only carbon nanostructure whose properties have been explored in great detail. In its pristine form, this cylindrical molecule of carbon is hydrophobic (water-hating) and so fails to penetrate the cell surface. Scientists add a functional group (a group of atoms that can induce the molecule for a particular reaction) to change its nature so that it enters the cell to carry out its designated job.

The team followed the theory to control the nature of graphene. They did it by mildly treating the pristine graphene (p-G) with acid and referred to it as functionalised graphene (f-G). Kidney cells of a monkey were then exposed to both the forms of graphene.

The researchers used kidney cell culture because previous studies had shown that functionalised carbon nanotubes are capable of entering the kidney cells. They observed that pristine graphene being water-hating in nature accumulated on the cell surface. “Such accumulation blocked the exchange of nutrients and ions, starving the cell to death,” says lead researcher Manzoor Koyakutty from AVVU.

On the other hand, functionalised graphene being hydrophilic (water-loving), safely entered the cells and spread inside them without disrupting any cellular activities. The researchers found that around 89 per cent of functionalised graphene treated cells remained viable, whereas around 68 per cent of the pristine graphene treated cells died. The researchers published their findings in the June 8 issue of Nanoscale. They are now studying the effects of functionalised graphene on human cells.

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