The study, published in the journal Applied Nano Materials, outlines a new method of producing a type of nanoparticle called quantum dots.
“Our research confirmed previous evidence that tea leaf extract can be a non-toxic alternative to making quantum dots using chemicals,” said Sudhagar Pitchaimuthu from Swansea University in the UK, who led the study. “The real surprise, however, was that the dots actively inhibited the growth of the lung cancer cells. We had not been expecting this,” Pitchaimuthu said.
Quantum dots can be made chemically, but this is complicated and expensive and has toxic side effects. The team, including researchers from K S Rangasamy College of Technology and Bharathiar University in Tamil Nadu, explored a non-toxic plant-based alternative method of producing the dots, using tea leaf extract.
Tea leaves contain a wide variety of compounds, including polyphenols, amino acids, vitamins and antioxidants. The researchers mixed tea leaf extract with cadmium sulphate (CdSO4) and sodium sulphide (Na2S) and allowed the solution to incubate, a process which causes quantum dots to form.
They then applied the dots to lung cancer cells. They found that tea leaves are a simpler, cheaper and less toxic method of producing quantum dots, compared with using chemicals, confirming the results of other research in the field.
The study found that quantum dots produced from tea leaves inhibit the growth of lung cancer cells. The researchers penetrated into the nanopores of the cancer cells and destroyed up to 80 per cent of them.
The CdS quantum dots derived from tea leaf extract showed exceptional fluorescence emission in cancer cell bioimaging compared to conventional CdS nanoparticles. Quantum dots are therefore a very promising avenue to explore for developing new cancer treatments, researchers said.