Globally, males are affected by prostate cancer, with those over 65 being particularly at risk. One in eight males may receive a cancer diagnosis at some point in their lives, according to the American Cancer Society. Prostate cancer has one of the best overall prognoses of any cancer and can be treated with surgery as well as a range of other medicines; however, early detection of the disease can be challenging.
A novel sensor created by Chinese researchers may make early prostate cancer detection considerably simpler in the near future. Because of the excellent accuracy of their sensor, there may be a decrease in the future in the overdiagnosis and misdiagnosis of prostate cancer. Moreover, this accuracy would lessen or completely remove the requirement for invasive follow-up biopsies.
A two-biomarker approach
Sarcosine (SAR), another biomarker raised in the blood as prostate cancer develops, is detected by the recently invented biosensor in addition to prostate-specific antigen (PSA), which is the sole biomarker measured by standard testing for prostate cancer.
The range of PSA concentrations known as the “grey zone,” where the diagnosis is less certain, can be an early warning indication, but it can also be a sign of common, benign illnesses such prostatitis, an inflammation of the prostate gland, or urinary tract infections. By concurrently detecting SAR, the new sensor greatly increases the accuracy with which it can identify instances, hence decreasing the possibility of false alarms associated with conditions that are not critical.
Using a computational modelling technique called “molecular docking,” the researchers first designed the two biosensor probes, one for PSA and the other for SAR. Predicting how well tiny molecules, such proteins or possible drug candidates, attach to a receptor molecule with a known three-dimensional structure is done through the use of computer algorithms. It’s basically like searching for a key that fits into a lock.
The scientists set out to find short DNA sequences known as “aptamers” that bind PSA and SAR. They incorporated the ideal aptamers into the surfaces of the two probes—one made expressly to interact with PSA and the other with SAR—based on the molecular docking study.
Following the acquisition of each biomarker from a patient sample, these aptamers alter their molecular structures to generate electrical signals that are associated with the PSA and SAR levels. The group used a sensor design called a “solution-gated graphene field transistor” to identify these signals. This sensor combines two gate electrodes with graphene as a channel material, which they altered using their aptamers to identify PSA and SAR.
According to Jinhua Li, a professor in the School of Materials Science and Technology at Hubei University in China and one of the researchers who assisted in the development of the biosensor, “solution-gated graphene field transistor biosensors often exhibit high sensitivity and selectivity, meaning they can detect low concentrations of specific biomarkers with a minimal chance of interference from other substances.”
In comparison to traditional approaches, “they frequently require smaller sample volumes, which can be particularly advantageous when dealing with limited sample availability,” the speaker continued.
Accelerating the process of diagnosis
The output signals from the probe can then be wirelessly transferred to a tablet or smartphone for data processing, enabling the physician doing the test to provide the patient with the diagnostic results right away.
A patient may only have to wait a short while at the doctor’s office for their diagnosis, provided the biosensor receives regulatory approval. This is in contrast to the hour or two it usually takes for traditional prostate cancer diagnostic techniques to yield a result. The biosensor would further reduce waiting times and the number of medical personnel needed to analyse blood samples by doing away with the need to send samples to a lab for analysis.
Less than five minutes for PSA and less than fifteen minutes for SAR are the incredibly short detection durations of the sensor that the researchers credit to the electrical pulse they delivered between the electrodes during testing, which speeds up the interaction of the probes with the PSA and SAR targets.
Major benefits of the biosensor include its tiny size and easy to use operation, in addition to its excellent accuracy. Point-of-care testing would be possible with these capabilities in remote areas, at home, and outside of clinics. More significantly, the sensor would remove the need for expensive diagnostic tools and medical supplies, both of which are scarce in many parts of the world.
At this level of research, the biosensor prototype has some limitations despite its outstanding detection times and accuracy. According to Li, “device uniformity is a key issue in the fabrication process.” “Graphene doping is challenging to control because it is deposited onto a glass substrate via a wet chemical process.”
Before the sensor is put on the market, this problem needs to be resolved because the quality of the graphene can vary from batch to batch depending on the chemical source.