Recently, researchers have developed a sensor that can be used to detect signs of infection in wounds. What challenges do current medical testing systems face, what did the researchers develop, and how will it help doctors fight against infections?

What challenges do medical tests face?

Medical testing is one of the central pillars of modern medicine and allows doctors to better diagnose patients. The range of medical tests available to doctors is extraordinary, with a few common examples including MRI, CAT, blood tests, biopsies, and PCR. With such a wide range, doctors often face multiple challenges when selecting tests and consider tests that will most likely provide a result.

The first challenge with medical testing is the cost; some tests are costly to run, and this can be either because the equipment itself is expensive or the testing method itself is in short supply. A typical example is an MRI machine; the NHS will only issue such a test if they believe that the test is warranted and that patient symptoms suggest there are problems internal to the body.

The second challenge with medical testing stems from the first challenge; missing symptoms and misdiagnosing. If a doctor could justify using every single test known to man, then the chances of misdiagnosing would be extremely small. However, doctors have to be selective with their choice of tests, which means that they can (and often do) miss conditions or misdiagnose illnesses.

The third challenge with medical testing is that some tests can take an extended amount of time to complete. While this may not be a problem for conditions like diabetes or Alzheimer’s, it can be problematic for situations that can worsen in hours (such as sepsis). As such, tests that can return results promptly are often highly valued.

Researchers develop sensors that can detect infection

Recently, researchers from the University of Strathclyde and NHS Ayrshire and Arran developed screen-printed sensors to detect signs of infection from samples before commercial equipment could. Typical commercial testing systems can take up to 48 hours to see signs of infection from infected tissue, but the new sensor could produce reliable results within half an hour.

Specifically, the sensor was designed to detect traces of the bacteria Proteus Mirabilis. This bacterium is commonly found in the digestive tract of humans (its natural habitat in humans) but is often found in infected tissue. To detect the bacterium, researchers developed their sensor to measure impedance over a range of different frequencies. These impedances are then fed into an algorithm that can identify patterns related to the impedances found in samples containing the bacterium.

The researchers demonstrated their sensors with samples taken from ulcers found on the feet of diabetics. This test case is important as diabetics lose sensation in their limbs, which can lead to cuts and sores forming. From there, these wounds can become infected, which results in infection, and this infection can require amputation if not caught early.

How will such technology help doctors?

While rapid, low-cost testing is always advantageous in the medical field, one of the most significant advantages of such rapid testing is the ability to catch infections early. A patient who has been found to have sepsis and/or a bacterial infection often requires antibiotics at the earliest time possible to prevent the infection from spreading. Unlike many other diseases, bacterial infection spread can also lead to the loss of limbs and necrotic tissue (i.e. dead flesh).

Considering that standard medical testing equipment can take up to 48 hours to process samples, using a sensor that can detect such conditions up to 48 hours earlier could be the difference between death and full recovery while retaining all limbs. Being able to detect infections cheaply and effectively could also reduce the spread of superbugs such as MRSA that are immune to most forms of antibiotics.

Overall, sensors utilising exciting materials and nanostructures will pave the way for next-generation medical testing and diagnosis. Such sensors will also help reduce the cost of medical testing while simultaneously reducing the number of secondary conditions caused by misdiagnosed symptoms.