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One of the most recent applications for tea as a health treatment is with lung cancer. The application is called Quantum Dots. 

What are Quantum Dots?

The measurement used to describe the size of quantum dots is nanometers. For example, the human hair is 40,000 nanometers thick. A quantum dot is only 10 nanometers. Particles measured in nanometers – nanoparticles – have been used in science and technology for many years. There are common scientific applications from imaging cancer tumors to creating solar cells to computer hardware. Creating quantum dots has also been possible using a chemical process but that is costly and produces a toxic product and byproducts.

National Institute of Standards and Technology [Public domain]

Much like in an old tube television where a beam of electrons moves over a phosphor screen to create images, the new microscopy technique works by scanning a beam of electrons over a sample that has been coated with specially engineered quantum dots. The dots absorb the energy and emit it as visible light that interacts with the sample at close range. The scattered photons are collected using a similarly closely placed photodetector (not depicted), allowing an image to be constructed.

The researchers we’re recognizing today have found a way to make these useful quantum dots using tea extract that is much less expensive and non-toxic than using chemicals.

Why do scientists make them from tea?

Green tea extracts are widely considered to contain healthy antioxidants and polyphenols and have proven to be effective partners in delivering cancer drugs to affected areas. This led the researchers to investigate it as an option to the toxic chemicals being used to manufacture quantum dots. In the scientific paper, Green-Synthesis-Derived CdS Quantum Dots Using Tea Leaf Extract: Antimicrobial, Bioimaging, and Therapeutic Applications in Lung Cancer Cells, the researchers identify three specific areas for their research; bio imaging, antibacterial treatment and apoptosis of cancerous cells in the lung. Searching for a less toxic to create these valuable particles, they combined a tea leaf extract with cadmium sulfate (CdSO4) and sodium sulfide (Na2S). The mixture is incubated to form quantum dots. Their expectation was that the fluorescent glowing qualities of the dots would be useful in the treatment of cancer to help locate and treat tumors. And the microscopic size would allow the particles to penetrate affected tissue more deeply and efficiently. 

Surprising Results Using Tea

The tea component – tea extract – added additional and unexpected results. Not only did it “light up” the lung cancer tumors, but it also inhibited the growth. They were able to penetrate the pores of the cancer cells and kill up to 80% of them. The work that these researchers are doing suggests other applications in healthcare for tea-generated quantum dots. 

Dr Pitchaimuthu outlined the next steps for research:


“Building on this exciting discovery, the next step is to scale up our operation, hopefully with the help of other collaborators.   We want to investigate the role of tea leaf extract in cancer cell imaging, and the interface between quantum dots and the cancer cell.

We would like to set up a “quantum dot factory” which will allow us to explore more fully the ways in which they can be used.”

Science In Our Teacups

Reading the latest scientific research tends to both inspire and caution us in discussing the health benefits of drinking our daily oolongs, whites, blacks, greens and dark teas. In making our tasty beverages, we are not using purified extracts in quantifiable doses. The compounds vary with nature. We cannot produce the same results in our daily practices that are possible in the laboratory. In other words, drinking several cups of green tea a day is not likely to kill a large percentage of lung cancer cells. 

The important take-away is that tea does offer many benefits, perhaps comparable benefits, as part of our daily diet. And these benefits are much broader than a single research project would suggest. 

Picture: Swansea University academics who worked on the research: l-r – Dr Catherine Suenne De Castro, Dr Matthew Lloyd Davies, Dr Sudhagar Pitchaimuthu


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