You have it inside, under your skin, it’s as thin as a postage stamp and for five days it keeps your pH under control. Like a miniaturized laboratory that takes the necessary information and gives the result in real time, without being minimally invasive. What could be better than a sensor that evaluates important parameters of our body? The term is known above all in computer science, while in medicine we are at the beginning of a tool that could revolutionize the diagnostic methodology hitherto entrusted to the sampling of blood and other body fluids. The only device we are familiar with is the transdermal patch which sticks to the surface of the skin and slowly releases a certain drug into the body.
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A minimally invasive tool
The sensor we are talking about instead, which is inserted with a micro-incision, probably the first of its kind, biocompatible and bioabsorbable, for now has a limited range of action to determine the pH, that fundamental parameter that reveals the degree of acidity of the our blood. The results of the research, conducted by the team of the Department of Information Engineering of the University of Pisa, coordinated by Giuseppe Barillaroin collaboration with the University of Modena and Reggio Emilia together with Surflay Nanotec GmgH of Berlin, were published on May 26 in the magazine Advanced Science .
Why the pH value is important
But why is it important for a doctor to know the numerical quantity that identifies pH? Barillaro replies: “From the detected level, a possible acidification of the tissues may emerge. And, among other things, it provides important information on the onset and progression of a tumor, as well as being a predictor of heart problems. The pH has so far been measured through the withdrawal of body fluids, but this method has a gray area: it is unable to measure the possible acidification of a specific area with high accuracy which, instead, our sensor is able to detect “.
But the potential is many, even in view of surgery or for the control of a wound, adds the professor: “If a patient needs to be operated on or is under control for an infected wound, the pH value of the wound can be obtained. which is indicative of various diseases: when it is acidified it starts from 7.4 to go down to 5 and beyond “.
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How the sensor works
Consisting of a porous membrane of nanostructured silicon, in turn covered with a fluorescent polymer, it provides an immediate, accurate and above all continuous result over time of the pH level in the affected tissue. “It is sufficient to illuminate the area of the skin where the sensor is implanted with a green light. The sensor will, in turn, emit a red light, the greater or lesser intensity of which reveals the pH level with a range between 4 and 7.5, running for up to 100 hours in a row. Eventually, the sensor will degrade and, after a week or so, there will be no trace of it in the body, without the need for surgical removal. “
How the research was carried out in the laboratory
For in vivo studies, mice were used in which the sensor was implanted under the skin of the back, obtaining real-time monitoring of the local pH level through the skin.
“Usually implantable devices are protected by a suitable coating – he adds Alessandro Paghi, researcher in the same department – so as not to be attacked and knocked out by our immune system. This makes it very difficult to make implantable chemical sensors, impossible to protect because they only work if they chemically interact with our body. Our study has shown that it is possible to make a chemical sensor, not only implantable, but also biodegradable, a discovery that opens the door to countless applications in the biomedical field “.
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The Resorb project: the clinical phase on humans soon
If for now the sensor has shown on animal models its effectiveness in monitoring values such as pH and evaluating the effectiveness of the drugs administered, facilitating the arrival of new clinical and diagnostic procedures, the transition to the clinical phase on humans. The European project is called Resorb and is included in the Horizon Europe program for research and innovation (2021-2027), with the aim of further developing the sensor, adding bioreceptors for the quantification of target molecules.
“The only obstacle is represented by funding to carry out tests on humans – underlines Barillaro – At the moment we are working on the dosage of the chemotherapy doxorubicin, which today is evaluated (and determined) based on body weight. But in this way we know the amount of drug absorbed throughout the body, while we ignore how much is absorbed by the tumor. Of course, it is a fact that the neoplastic cells are more perfused and therefore better reached by the chemotherapy. But we do not know how much. And instead, having more precise parameters , we could also evaluate drug toxicity. So we could measure the dose of a substance that targets cancer cells and tune it as needed. “