Imitating nature to build a more sustainable world

Proteins could be used to produce biodegradable solar cells

What could be greener than solar panels? They generate renewable energy, a key to fighting climate change. Yet the components that go into them often include toxic or non-sustainable materials.

McGill University scientist Noémie-Manuelle Dorval Courchesne hopes to change that. She’s investigating the conductive properties of certain naturally occurring proteins – a line of research that could someday lead to biological and biodegradable solar cells.

Nature is rife with eco-friendly biological materials with properties that enable them to assemble into complex shapes and bind molecules or particles. Increasingly, scientists are trying to imitate these processes—a field known as biomimicry—in order to create green solutions to a number of ecological challenges.

“We’re trying to replicate what we can find in nature. I’ve always been interested in bio-derived materials,” says Dorval Courchesne, who grew up in Quebec’s Outaouais region and studied biotechnology at the University of Ottawa before earning her PhD at MIT. “In the past, I looked into using proteins or microorganisms to coat them with an inorganic layer that could be used to conduct electricity or harvest light. These inorganic particles, however, remain toxic, so during my postdoc (at Harvard’s Wyss Institute for Biologically Inspired Engineering), I began working on biological, environmentally friendly materials that could be conductive by themselves.”

The Dorval Lab has created conductive protein nanowires inspired by naturally occurring bacteria.

Since she arrived at McGill in 2017 as an assistant professor, the Dorval Lab in the Department of Chemical Engineering has been working on developing protein-based materials with novel properties, such as absorbing or emitting light, or conducting electricity. She has found an unlikely ally in this quest: bacteria that naturally produce wire-like proteins capable of conducting electricity. “These nanowires have inspired us to design our own protein wires,” she says.

Most proteins can’t conduct electricity. But scientists in recent years have discovered unusual bacteria -- (Geobacter sulfurreducens and, Shewanella oneidensis) -- with naturally occurring extracellular, wire-like proteins that transmit electrical currents to oxidize certain metals, such as iron, and generate by-products for their oxygen-deprived metabolism.

It’s early days for Dorval Courchesne’s protein wires, but she and collaborators from Harvard recently demonstrated that it is possible to have electricity pass through them. Though their conductivity still doesn’t measure up to the naturally occurring protein wires, she is confident that they can be tweaked to make them useful for a wide variety of applications. One day, she hopes to use them to build green solar cells.

“We already know they conduct electricity, now we’re trying to see how they can be modified to absorb light and store energy so as to use them to replace some of the toxic and non-sustainable components—like certain nanomaterials—used in solar panels today.”

Thanks to this device, Dorval Courchesne has recently demonstrated that her nature inspired proteins can conduct electricity.

The production of the modified proteins could also easily be scaled up and would offer a cost efficient alternative to the traditional materials that go into making solar cells, says Dorval Courchesne, who is a member of McGill’s Trottier Institute for Sustainability in Engineering and Design and the Québec Center for Advanced Materials

Dorval Courchesne’s team is also looking into how their proteins can be modified to bind to other small molecules or proteins, such as biological markers and environmental contaminants, which would make them useful in creating efficient and environmentally friendly sensing technologies.

“Biologically derived materials have tremendous potential to be used in a wide range of energy, environmental, and biomedical applications,” she says. “If we’re going to create a more sustainable world, there’s no better source of engineering inspiration than nature, itself.”