Ion-Sensitive Transistors Developed For Cancer Detection

Recently, researchers from Japan have demonstrated an ion-sensitive transistor that can detect trace amounts of cancer cells in blood samples. What challenges does traditional cancer screening present, what did the researchers demonstrate, and why are transistor gates amazing for sensory detection?

What challenges does cancer screening present?

When screening for cancer, there are numerous challenges faced by both medical professionals and patients. By far, one of the biggest challenges is catching cancer at its early stages, as many cancers can develop over time without any apparent symptoms. Unfortunately, it is at the early stages that cancers are easiest to eliminate, which means that those who are susceptible need to undergo routine check-ups. One such example is breast cancer where it is recommended that women over 50 get a mammogram at least once every two years. Another example is prostate cancer, whereby men over 50 should consider taking yearly blood tests (interestingly, prostate cancer is relatively easy to treat and itself does little harm. It is metastasised cancer originating from the prostate that is lethal).

This leads us to the next major challenge faced by cancer screenings; they can sometimes be invasive. While scans can show up large tumours and growths, they are not always the best solution for finding initial cancer cells due to the low resolution offered by medical scans (cell masses smaller than a pea are incredibly hard to find). Therefore, other tests often must be done, such as biopsies and blood tests, which are extremely unpleasant procedures to undergo.

Even though blood tests can be used to identify cancer cells, current testing methods are not able to catch all cancers. Some tests involve identifying specific chemical markers, but these same markers can often be made by healthy cells, and in some cases, cancer cells won’t even provide any kind of chemical marker. Worse, routine blood tests are unable to identify signs of cancer as specialised tests are required to identify suspicious patterns.

Researchers develop ion-sensitive FET for cancer screening

Recognising the challenges faced with traditional screening methods, researchers from Japan recently announced the development of a new ion-sensitive transistor that is able to detect specific cancer cells in blood work. To make the sensor, the researchers took advantage of the reaction between cancer cells and antigen receptors when in the presence of glucose oxide. The resulting reaction causes a change in pH levels which ion-sensitive FETs can detect, thus allowing the researchers to detect the presence of cancerous cells. If healthy cells are present, the reaction doesn’t occur, resulting in no change in pH and, thus, no change in the conductivity of the FET.

But what makes the sensor technology particularly interesting is that it can be scaled down to the size of individual cells, and this would allow for an array of sensors to react to specific cells instead of a generalised reaction (i.e., localisation testing). This will enable researchers to truly understand the distribution of cancerous cells via an accurate count, which can help identify the type of cancer and its progression. Furthermore, it is possible for a sensor array to have transistors responsive to different cancer cells, enabling spectrum tests that can look for the most common cancers while simultaneously identifying their concentration and progression.

Why are transistors amazing for biochemical detection?

There is no doubt that transistors have provided many benefits, but transistors with biochemical-sensitive gates are by far some of the most interesting. The ability to tune a transistor to only respond to specific chemicals not only allows for accurate detection but also allows for increased sensitivity as the output of a single transistor can be made to change upon the detection of a single molecule. Furthermore, the ability to detect single molecules allows for observing reactions on the atomic scale, albeit an electrical observation.

In addition to research testing, biochemical-sensitive transistors also have the possibility to be integrated into everyday products such as smartphones and wearables. If tuned to detect pathogens and toxic compounds, it could allow users to immediately identify the presence of dangerous environments, whether it is a COVID risk or a chemical attack.

Overall, transistors sensitive to biomarkers and other chemical compounds offer engineers and researchers numerous possibilities, and what the researchers from Japan have demonstrated could very well lead to a future where all blood tests can be done with a few drops of blood.