Imagine a world where our electronic devices are powered by living microbes and naturally break down after use, leaving no harmful waste behind.
This is the exciting potential of "bioelectronics" -- a new field of research focused on using microbes to create sustainable, biodegradable electronics.
Microbes play a huge role in the Earth's natural cycles, but scientists recently discovered some microbes can also generate electricity.
Known as "electroactive" microbes, these tiny organisms use a unique energy strategy to survive in places with little or no oxygen.
Instead of breathing oxygen, they "breathe" minerals, transferring electrons onto them and generating electricity as they do so.
For over a decade, scientists have studied microbes like Shewanella and Geobacter for their ability to produce electricity, using them in experimental systems that turn microbial activity into usable power.
This process is called a bioelectrochemical system, where electrodes act as a substitute for the minerals that these microbes would typically use.
While these systems have been used for applications like wastewater treatment and metal recovery, they're limited by the short distances over which they transfer electrons.
In 2012, scientists discovered a new type of electroactive microbe called "cable bacteria," which takes electron transfer to a whole new level.
Unlike other microbes, cable bacteria can move electrons over distances of several centimeters through a thin, conductive "wire" within their structure, similar to an electric cable. This long-distance electron transfer has huge potential for bioelectronics.
Researchers are now exploring how electroactive microbes like Geobacter and cable bacteria could be used in electronics.
For example, nanowires from Geobacter can be produced on a large scale and incorporated into electronic circuits to conduct electricity.
These microbial nanowires have already been used in thin-film circuits that generate electricity from humidity. Since they're biodegradable and non-toxic, they could be used to create electronics that break down naturally, reducing electronic waste.
Some microbes, including Geobacter and cable bacteria, even produce conductive mineral layers along their filaments, like iron and manganese oxides.
Scientists think these mineral coatings could help store and release energy, creating "microbial batteries" or biological capacitors that could power small devices, such as sensors for deep-sea or space exploration.
Bioelectronics is especially promising for its sustainability benefits. Traditional electronics create a huge amount of toxic e-waste, and less than 20% of it is recycled.
Bioelectronics, on the other hand, could reduce our reliance on rare and harmful materials, offering a greener alternative. Since devices made from microbial materials could break down naturally, they would leave no trace, unlike the e-waste piling up in landfills today.
While there are still challenges in making this technology practical -- like the difficulty of growing cable bacteria in the lab and ensuring long-term device stability -- the future of sustainable electronics looks bright.
With continued research, bioelectronics could pave the way toward eco-friendly devices powered by nature's tiniest creatures.