A new, implantable sensor, made from materials that can safely biodegrade into the body, has been developed to monitor patients’ conditions.
A team of international researchers have designed the highly sensitive and flexible gas sensor that monitor forms of nitric oxide and nitrogen dioxide gas in the body. The sensor is made from materials that are implantable, flexible, and stretchable, which biodegrade and are safely absorbed by the body.
Monitoring these gases in the body is vital as they are important markers of health. For example, nitric oxide relaxes blood vessels to enhance blood flow, and exposure to nitrogen dioxide from the environment is linked to the progression of conditions such as chronic obstructive pulmonary disease.
The findings have been published in NPG Asia Materials.
Monitoring health with implantable sensors
Current devices are used outside of the body to monitor gas levels; however, they are bulky and potentially not as accurate as an implantable device, but implantable devices need to be removed, which could mean another operation. The researchers set out to investigate a design that does not need to be removed.
Huanyu “Larry” Cheng, Dorothy Quiggle Career Development Professor in the Penn State Department of Engineering Science and Mechanics and an affiliate of the Institute for Computational and Data Sciences, said: “Let’s say you have a cardiac surgical operation, the monitor outside of the body might not be sufficient to detect the gas.
“It might be much more beneficial to monitor the gas levels from the heart surface, or from those internal organs. This gas sensor is implantable, and biodegradable, as well, which is another research direction we’ve been working on. If the patient fully recovers from a surgical operation, they don’t need the device any longer, which makes biodegradable devices useful.”
The materials of the sensor are all biodegradable in water or in bodily fluids whilst also remaining functional – able to capture the information on the gas levels. The device’s conductors –are made from magnesium, and for the functional materials, they used silicon, which is also highly sensitive to nitric oxide – all of which can be safely absorbed by the human body.
The scientists highlight that an added benefit of the design is that the materials dissolve at a slow enough pace in order to allow the sensors to function during a patient’s recovery period.
“Silicon is unique – it’s the building block for modern electronics and people consider it to be super-stable,” said Cheng. “Silicon has been shown to be biodegradable, as well. It can dissolve in a really slow manner, at about one to two nanometers a day, depending on the environment.”
The sensor was tested in humid conditions and aqueous solutions to show that it could stably perform in the harsh conditions of the body, and the team used computational resources of ICDS’s Roar supercomputer to create the computer simulations that can calculate extremely small changes caused by slight changes of shape, or deformations, of the material.
The researchers say future work could look at designing integrated systems that could monitor other bodily functions for healthy ageing and various disease applications.