Biodegradable biosensor
Sensors that monitor the patient's condition during and after medical procedures can be expensive, inconvenient, and even dangerous. An international team of researchers has developed a highly sensitive flexible gas sensor that can be implanted into the body. At the end of the work, it decomposes safely into materials that are absorbed by the body.
During the study, a group from the University of Pennsylvania, the Korean Institute of Science and Technology and the University of Cambridge reported that a new flexible implantable sensor is able to detect various forms of nitric oxide (NO) and nitrogen dioxide (NO2) in the body.
Nitric oxide, which is naturally produced in the human body, plays an important role because it participates in relaxing the walls of blood vessels to increase blood flow, allowing oxygen and nutrients to circulate freely through the body. On the other hand, exposure to nitrogen dioxide from the environment is associated with the progression of conditions such as chronic obstructive pulmonary disease. Nitric oxide has a high reactivity and can be converted into nitrogen dioxide upon contact with oxygen.
The new sensor is made of materials that are not only safely implanted, flexible and stretchable, but also biodegradable. This is very important, since implantable devices must be removed somehow, and safe self-destruction will avoid additional surgical intervention.
What is the implantable sensor for? For example, during heart surgery, when a monitor outside the body may not be enough and there is a need to monitor the level of gas on the surface of the heart or other internal organs. The implantable gas sensor is able to measure the necessary indicators, and if the patient no longer needs it, the device decomposes into constituent substances that are absorbed by the body.
The sensor components are biodegradable in water or body fluids, but are stable enough to collect information about the level of various gases. The elements conducting electricity are made of magnesium, and silicon, which is very sensitive to nitrogen oxide, was used as functional materials.
Thus, all materials used in the device are safe for humans. An additional advantage of the design is that the materials dissolve slowly, which allows the sensor to function in the body for a long time, sufficient, for example, for the patient to recover after surgery.
To create a sensor capable of detecting even minor fluctuations in the concentration of gases, the researchers used the computing resources of the ICDS Roar supercomputer. The sensor has been tested in high humidity conditions and in aqueous solutions, which proves its stability in a living organism.
The sensor is based on the measurement of resistance, which can vary depending on the absorption of gas. But it can also change due to deformation; if you use sensors that detect contentation on the surface of the skin, stretching and deformation will cause a change in resistance, and it will be impossible to understand whether it is the result of exposure to the determined gas or the environment.
The researchers say that their efforts will be directed to the development of integrated systems that will be able to monitor other body functions for healthy aging and the presence of various diseases.
Article by G.-J.Ko et al. Biodegradable, flexible silicon nanomembrane-based NOx gas sensor system with record-high performance for transient environmental monitors and medical implants is published in the journal NPG Asia Materials.
Aminat Adzhieva, portal "Eternal Youth" http://vechnayamolodost.ru according to Penn State: Implantable sensor could measure bodily functions - and then safely biodegrade.