(Nanowerk News) Engineers from UNSW Sydney have found a way to make flexible electronic systems in materials as thin as skin.
These developments allow entire 3D stretchable structures to operate like semiconductors and could help significantly reduce the need for animal testing by making so-called organ-on-chip technology more effective.
In later tracks, the technology could also be used in wearable health monitoring systems or implantable biomedical applications, such as systems to alert people with epilepsy about imminent seizures.
The research team, led by Dr Hoang-Phuong Phan from UNSW’s School of Mechanical and Manufacturing Engineering, have published their findings in Advanced Functional Materials (“Engineering Routes for Stretchable 3D Microarchitecture of Broadband Gap Semiconductors for Biomedical Applications”).
Their new process involves using lithography – a technique that uses light to print tiny patterns – to fabricate wide-bandgap semiconductors such as silicon carbide and gallium nitride onto extremely thin, flexible nanomembranes on a polymer substrate.
The semiconductor membrane provides sensing, recording, and stimulation functionality even when stretched and twisted into any imaginable 3D shape.
They could be an important component of organ-on-chip technology, which is a cutting-edge approach that involves manufacturing miniature versions of human organs on tiny chips.
These chips replicate the function and structure of organs, allowing scientists to study their behavior and test the effects of drugs or diseases in a more accurate and efficient way.
And because organ-on-chip technology allows researchers to replicate the complexity of human organs in laboratory conditions, it could potentially eliminate the need to use animals for multiple tests and experiments.
“Many people are interested in turning to medical testing on replicated versions of human cells rather than live animals for legal, ethical and moral reasons,” said Dr Phan.
“You can grow 3D cell organs that mimic organs in real bodies, but we also need to develop 3D electrodes to help facilitate the organ-on-chip process.
“Our process allows electronic systems to be fabricated on membranes that can be stretched into any 3D shape around an organ-on-chip.”
The work is the culmination of interdisciplinary and cross-institutional collaboration between UNSW, Griffith University, UQ, QUT, and their international partners such as Kyung Hee University, University of Southern California, and Northwestern University.
Wide band gap material for easier observation
UNSW Scientia Lecturer Dr. Thanh Nho Do, the project’s chief investigator, added: “We used a wide bandgap material, which unlike traditional semiconductor materials does not absorb visible light. That means that when scientists want to observe an organ-on-chip through a microscope, they can do so, which is not possible otherwise.
“The electronics in the membrane also allow a lot of data to be collected while monitoring how the artificial organ reacts to various things when tested.”
For this application, the researchers believe it could become a commercial product within three to five years, though they aim to carry out further work to upgrade the device even further and integrate additional components such as wireless communications.
In terms of leveraging the technology in wearable health monitoring systems, Dr Phan said there was exciting potential for new processes to significantly improve the quality of monitoring, diagnosis and therapy.
One such function could be in the form of wearable shields to help detect and signal a warning about the level of UV radiation a person experiences during the day, which in turn could help reduce cases of skin cancer.
“Wide bandgap materials are important in such applications because traditional silicon semiconductors have narrow bandgaps and do not absorb UV light,” said Dr Phan.
The UNSW team also proposed their new material could be further developed to create implantable biomedical devices in which electrical systems can monitor, and influence, neuron signals in real-time.
Although such a device likely won’t be available for at least 10 years, researchers are already planning further tests with the aim of potentially helping people with epilepsy — a neurological disorder in which sudden, uncontrolled bursts of electrical activity in the brain can cause seizures. .
“For people with epilepsy, when a seizure is about to happen, the brain will send an unusual signal which is the trigger,” said Dr Phan.
“If we can build implantable electronic devices that can detect those abnormal patterns, they could potentially also be used to apply electrical stimulation to bypass seizures.”
One of the main challenges that need to be overcome with implanted devices is how to power these electronic systems.
Therefore, researchers at UNSW are also trying to develop a magnetic resonance coupling system that can be integrated with wide-bandgap 3D electronic membranes to transfer power wirelessly through the body via external antennas.