Science & Technology, Australia (Commonwealth Union) – Scientists at the University of New South Wales have engineered filaments capable of generating electricity from atmospheric moisture. Originally produced by bacteria, these protein filaments have been altered by researchers for the conduction of electricity. Published in the journal Small, a recent study reveals that these modified protein nanowires, enhanced with a single compound, can efficiently conduct electricity over short distances and utilize moisture in the air to generate energy.
Lead author Dr. Lorenzo Travaglini emphasizes the significance of these findings, stating, that their discoveries pave the way for the creation of sustainable and eco-friendly electrical components and devices, utilizing protein-based materials. These engineered nanowires offer potential for advancements in energy harvesting, biomedical applications, and environmental sensing.
The intersection of protein engineering and nanoelectronics holds promise for groundbreaking technologies that integrate biological systems with electronic devices, fostering interdisciplinary developments with far-reaching implications.
“Ultimately, our goal is to modify the materials produced by bacteria to create electronic components. This could lead to a whole new era of green electronics, helping to shape a more sustainable future,” says explained Dr Travaglini, supervised by Dr Dominic Glover in the SYNbioLAB from the School of Biotechnology and Biomolecular Sciences.
Researchers drew inspiration from the intricate dance of electrons in nature, electricity emerges from the dynamic movement of these tiny charged particles between atoms.
According to Dr. Travaglini, nature’s myriad phenomena, such as the electron-shuttling process within chlorophyll during photosynthesis, offer fertile ground for innovative electricity generation methods.
In a fascinating parallel, certain bacteria utilize conductive nanowires to ferry electrons across their membranes. These natural nanowires hold promise for interfacing with biological systems, potentially revolutionizing biosensing technologies.
Yet, while these bacterial nanowires possess inherent capabilities, their direct extraction presents challenges. They are inherently difficult to manipulate and offer limited functionality.
To overcome these hurdles, Dr. Travaglini’s team embarked on a groundbreaking endeavor, genetically engineering E. coli bacteria to produce custom-designed proteins. These proteins were meticulously crafted into nanowires within the laboratory environment.
Recognizing that the conductivity of these bacterial-produced proteins was insufficient on its own, the team introduced a crucial additional component.
Researchers of the study focused on the utilization of humidity for Energy Generation.
Haem, a circular molecular structure known as a porphyrin ring, houses an iron atom at its core. It plays a crucial role in transporting oxygen in red blood cells from the lungs to various parts of the body.
Recent investigations propose that when haem molecules are closely arranged, they facilitate electron transfer. Thus, Dr. Travaglini and his team embarked on incorporating haem into the filaments produced by bacteria, hypothesizing that electrons could leap between haem molecules if positioned in proximity.
In their laboratory experiments, the team assessed the conductivity of the engineered filaments by applying a film of the material onto an electrode and subjecting it to an electric potential. As anticipated, they noted that the addition of haem to the filament rendered the protein conductive, while the bare filament lacking haem exhibited no electrical current as indicated by Dr. Travaglini.
Though initially aiming to modify a naturally occurring material into a conductive wire, Dr. Travaglini and Dr. Glover stumbled upon unexpected findings.
“We ran the conductivity testing in a chamber where you can control the external conditions,” added Dr Travaglini. “We started to notice that under what is considered ‘ambient conditions’, between 20 – 30 per cent humidity, the electric current was stronger.”
The team opted to conduct additional tests, utilizing thicker layers of the material placed between two gold electrodes. Dr. Travaglini explains, that they hypothesized that humidity induces a charge gradient within the material’s depth. Consequently, this charge disparity across the film facilitates a short current, obviating the need for external potential.
Upon confirming the material’s responsiveness to humidity, they devised a rudimentary humidity sensor to gauge the current’s sensitivity to atmospheric moisture, simply by exhaling onto the device. They observed that each conductivity peak in the fiber correlated with an exhalation according to Dr. Travaglini.
This investigation presents a promising avenue towards the development of electrical devices crafted from sustainable and non-toxic materials, requiring minimal power consumption.
“The electronics we tend to use are created through processes that require high temperatures and are very energy-demanding. They’re not green, and the materials they are sourced from can be toxic,” explained Dr Travaglini. “Using biomaterials to create electricity is far more environmentally friendly. We can produce these filaments from bacteria, and it’s scalable.”
