A team of researchers at the University of Massachusetts Amherst have developed an electronic microsystem capable of responding to environmental stimuli without requiring external energy. These ‘green’ self-autonomous organisms are constructed from a novel type of electronics. They can process ultralow electronic signals and incorporate devices that can generate electricity “out of thin air” from the surrounding environment.
Jun Yao, an assistant professor of Electrical and Computer Engineering (ECE) and an Adjunct Professor of Biomedical Engineering, co-authored the study with Derek R. Lovley, a Distinguished Professor of Microbiology. The research was published in the journal Nature Communications.
Overcoming the challenge
The researchers found that incorporating neuromorphic electronics made from memristors in bioelectronic interfaces can provide intelligent responsiveness to environments. However, there is a substantial difference between the environmental stimuli and neuromorphic device’s driving amplitude.
The researchers’ key challenge was to construct sensor-driven, integrated neuromorphic interfaces capable of compensating for the inherent amplitude mismatch between sensing and computing signals. The basic approach was to boost sensing signal by carefully selecting sensor structure and stimuli. However, this technique frequently results in sensor form factor or operating environment constraints that preclude a compact or flexible integration, or both. Additionally, certain environmental or physiological signals are intrinsically limited in their amplitude. In comparison, biosystems take a different approach by restricting the computing signal to the thermodynamic limit, enabling bio-computation to respond to a considerably broader spectrum of environmental stimuli.
Properties of Protein Nanowires
To overcome this challenge, the researchers built the systems on three recently recognised properties of protein nanowires produced from the microbe Geobacter sulfurreducens:
- Protein nanowire memristors can be driven by impulses as low as 100 millivolts, opening the way for bio amplitude neuromorphic circuits and signal processing.
- The Protein nanowires-based devices can capture moisture from the environment, enabling the devices to act as a power source for computing, even if the environmental humidity goes down.
- It can operate as a sensing component in electronic sensors.
The microorganism Geobacter was Lovley’s discovery and has been previously used by the research team to demonstrate protein nanowire-based air generators or “Air-Gen” to generate electricity from the ambient environment.
The bio composition of the devices also reflects an exploration of “green” electronics made of renewable, biocompatible, and eco-friendly biomaterials. Additionally, adaptive microsystems are made possible by the protein nanowires, which allow for simple reconfigurable functionality. These qualities represent a significant step forward in the advancement of bio-emulated interfaces and microsystems.
Source (Self-sustained green neuromorphic interfaces research paper)
The Green components
First, components required for integration were examined in a bio-realistic environment, and protein nanowire memristors were fabricated on a flexible substrate. The device was a vertical structure with an insulating layer placed between two electrodes. In terms of programming voltage and current, the device operated at a power level comparable to that of a biological neuron. Devices without protein nanowires could not achieve bio amplitude switching, showing that protein nanowires play a crucial role in enabling bio-amplitude switching.
According to the US Army Combat Capability Development Command Army Institute, which funds the research, this research work will create a “Self-sustaining, intelligent microsystem.”
Efforts to find new energy sources have now advanced to the point where electronic microsystems can derive energy from their environment and support sensing and computation without the need for external energy sources such as batteries. The findings demonstrate that protein nanowires can be applied to actual purposes. Wearable and environmental applications both benefit from the biocompatibility and eco-friendliness of the “green” material composition. Other neuromorphic functionalities that work in different contexts will be achievable, resulting in a diverse set of self-supported microsystems or intelligent sensors for widespread deployments to support the Internet of Things. In the future, however, further investigations will be needed to discover the total capacity of protein nanowire devices.
Access the complete research here.