Cancer detection breakthrough
Have your oranges gone bad? No need to throw them in the bin because University of Sydney PhD student Pooria Lesani has developed a cancer detection technique made from the juice of rancid oranges.
In a study, published in Chemical Engineering Journal, Lesani described the orange-based, low-cost probe, which proved to be a useful nanobiosensor for screening cells that may be at risk of cancer.
The nanobiosenser is a tiny probe that “glows” fluorescently in human cells, and signals if those cells become acidic, indicating that cancer is not far off. This shows which cells are at greatest risk of cancer, so preventative measures can be taken.
“Many diseases start developing over many years – and even decades – before a person shows even the slightest of symptoms. With many diseases such as Alzheimer’s, once there are symptoms, it is too late to treat them,” says Lesani.
“Our device allows for a more accurate disease diagnosis before the onset of symptoms, as well as enabling the early detection of serious diseases associated with pH fluctuations.
“We hope this could lead to the early treatment and prevention of serious disease. Current testing methods can be complex, expensive and time-consuming, whereas our nanobiosensor can easily be produced on a large scale at low cost.”
Acidic cells and how oranges detect cancer
Rotten oranges were the key ingredient in the nanobiosensor and were integral for making fluorescent carbon dots – tiny blobs of carbon that are just one-billionth of a metre in length.
“The process for making these carbon dots for the nanobiosensor is similar to making a meal in a pressure cooker,” says Lesani.
“We throw all the ingredients together – in this instance rancid orange juice and some water – into a reactor which somewhat resembles a pressure cooker, tightly close the lid, and place it in a scientific oven heated to around 200℃.
“The increased temperature and pressure inside the reactor break down the initial molecular structure of the ingredients, helping them form a new material: carbon dots. These dots are then used to build the nanobiosensor.”
To use the biosensor, a small tissue biopsy is taken from a patient and put in a petri dish. The biosensor is applied to the cells and examined under a fluorescent microscope, which picks up tiny changes in light. Oranges are also high in ascorbic acid, which improves the function of the sensor.
If the cells are healthy, the biosensor shines brightly, but if the cells are more on the acidic side the light dulls and indicates the cells may be precancerous.
Super quick cancer detection
This doesn’t take very long and provides quick, accurate results.
“Dramatic fluctuations in the acidity of cells can lead to inappropriate cell function, growth and division, and can lead to serious diseases ” says Lesani.
“We have developed a sensitive and cost-effective nanobiosensor for real-time measuring of the degree of acidity of the cells.
“This nanobiosensor can also help us to gain a better understanding of how these diseases develop.”
The new technique also has the added benefit of diverting food waste from landfill.
Deborah Devis is a science journalist at Cosmos. She has a Bachelor of Liberal Arts and Science (Honours) in biology and philosophy from the University of Sydney, and a PhD in plant molecular genetics from the University of Adelaide.
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