Previously we wrote about the ground-breaking bio-sensors being developed to diagnose certain medical conditions. The proof-of-concept nanowire biological sensor (or nanochip) can identify any pathogen or bacteria such as e. coli, Salmonella or cholera in 10 to 15 minutes after being swallowed. This sensor can ultimately be used to accurately diagnose patients during an epidemic or outbreak using a combination of nanotechnology and microbiology. In layman’s terms, it means soon you will be able to swallow a nanochip that can diagnose a bacterial infection faster and more cost-efficient than traditional tests such as bloodwork and endoscopies and put less stress on the body’s immune system. You will be able to isolate specific bacteria to test for. For example, if your concern is water quality, you can set up the sensor to only look for e. coli.
The nanochip technology has been further refined with a view of using it in a very specific revolutionary application for the early detection of cancer that is currently being researched and developed.
Use this table of contents to navigate to the section that interests you most about our current article:
1. Revolutionary cancer markers
2. Adding engineering to the research
3. How does it work?
4. Changing the world
The innovative research focuses on a molecule in the blood system called serum amyloid A (SAA), a protein with the ability to signal cancer in its very early stages.
Revolutionary cancer markers
Every inflammatory condition, whether cancer, dementia, or diabetes has specific “inflammatory markers”. These proteins become upregulated or are produced in increased amounts where the condition is present. Prof Resia Pretorius explains it as follows: “Every disease has its own inflammatory profile or footprint, which is characterised by different markers. We have been studying various inflammatory molecules in order to identify different disease profiles, new treatment regimens and early identification techniques.” In other words, cancer is not something that develops unexpectedly; it builds up over months, even years based on factors such as your lifestyle, genetic predispositions and other bodily changes. SAA upregulation is one of those changes that can function as an early inflammatory disease marker. This research culminated in a revolutionary finger-prick test for SAA.
This breakthrough has the potential to save many lives in Africa’s most underprivileged areas. Rural Africa generally lacks pathology labs which means the cancer is often only diagnosed when already reaching stage 3 or 4 at which stages survival chances are not optimistic. Using the biosensors as a simple and affordable screening test can help identify these people much earlier. They can then be sent for further testing and hopefully life-saving treatment.
Adding engineering to the research
Once SAA was identified as a reliable cancer marker, Prof Perold’s electronic engineering expertise was required to detect the levels of specific molecules in a drop of liquid using a hand-held nano-electronic biosensor. To achieve this, a tiny electrical circuit is printed on a strip of paper – such as paper or an electrospun nanofiber – with a specific area that can bind to the molecule of interest. This testing strip is easy to use and inexpensive to produce, costing as little as R2 per test. For SAA this area contains protein SAA antibodies. Antibodies are the body’s main defence against bacterial infection. If a virus or bacterium, therefore, enters your body, your immune system will produce specific antibodies to identify and bind to the intruder, marking it for destruction. In the context of our research, Prof Perold explains “when a drop of blood is placed on the nanosensor, the SAA will bind to the antibodies and change the resistance of the circuit”. In addition, the SAA antibodies are specially produced by a small African company that manufactures artificially produced antibodies in Alpacas.
How does it work?
It works in a similar manner to the device reading blood-sugar levels. One of the strips containing the correct biorecognition element (such as SAA antibodies) is inserted into the hand-held nano-electronic biosensor that can be calibrated according to the molecule of interest and that provides the result within minutes. You simply put a drop of blood on it and get the result – an extraordinarily simple yet effective idea. This sensor has many advantages foremost that it is faster than conventional methods where blood samples have to be sent to a laboratory for analysis and because it is small and portable it is ideal to use in remote and rural areas.
Changing the world
The technology underpinning this research has been patented and within a few years, nanosensors could be actively used in early cancer detection in every mobile clinic in Africa and in state-of-the-art hospitals. “We want to treat people before they are sick or, at least, before they’re too sick to be treated. And we want to do it cheaply so that every mobile clinic in Africa can have access” concludes Prof Pretorius.
Read more about this exciting project or contact Prof Willie Perold by E&E dep Stellenbosch wjperold@sun.ac.za.
