Using bio-resources, scientists from the Indian Institute of Chemical Technology (IICT), Hyderabad, have synthesised eco-friendly gold nanoparticles which could be used as carriers for delivering anti-cancer drugs and also for diagnosing the disease.
Developed from leaf extracts, the biocompatible nanoparticles have shown promising results and inhibited cancer cells proliferation in lung and breast cancer cell lines. In the first instance, they have used leaves of Bhringaraj (Eclipta alba), a herbal plant.
While gold nanoparticles could be developed by chemical methods, the inherent problem in that approach was of toxicity. “But here we are using a green chemistry approach. It is environmental-friendly because the solvent we are using is water. It is a simple, clean, efficient and low-cost method,” said Dr. Chittaranjan Patra, Scientist, Ramanujan Fellow , IICT.
Explaining the importance of using gold, he said it has been used from time immemorial. “We have a long history of using gold as a medicinal agent in Ayurveda. More than 1,000 years ago it was used as a nanoparticle (swarnabhasma). At that time, there were no sophisticated instruments and that is why people did not know that it was a gold nanoparticle,” he observed.
He said the gold nanoparticle was bio-compatible, easy to synthesise and multiple cancer drugs could be loaded. It could reduce the toxicity of the anti-cancer drug, increase its efficacy and ensure better retention of the drug in the blood system. “When conjugated with gold nanoparticle, the anti-cancer drug could stay for more time in the tumour and enhance the therapeutic efficacy,” he added.
With the addition of a fluorescent molecule, it could be used to detect the position of the tumour.
Dr. Patra said the Bhringaraj-extracted bio-compatible gold nanoparticle was used to deliver an FDA-approved anti-cancer drug —Doxorubicin into lung and breast cancer cell lines. It showed that the drug inhibits tumour cells proliferation even at a low dose.
Besides Bhringaraj, the other leaf extract used was that of Olax scandens. The biomolecule present in the extract helped the nanoparticle to stabilise for more than a month. It was stable in different physiological media with different pH. “This plant extract contains some anti-cancer biomolecules which are conjugated with gold nanoparticles during synthesis. That nanoconjugate helps in inhibiting proliferation of tumour cells,” he added. The work was published in RSC Advances journal.
The O. scandens extract also contained some fluorescent molecules that enabled the scientists to see the shiny image in cancer cell lines. “This nano bio-conjugate could also be used for diagnosis in addition to delivering anti-cancer drugs,” he added.
IICT scientists now propose to use the gold nanoparticles in vivo in mice. “Biosafety of nanoparticles is very important for clinical trials. That’s why we are going to start in a mice model,” Dr. Patra said.