Forget about dipping lobsters in butter. UBC chemist Mark MacLachlan has other plans for the tasty crustacean. The scientist is experimenting with the shell, or exoskeleton, of lobsters to make batteries as well as biomedical materials and plastics.
Why, and how, could you turn lobster shells into batteries?
The exoskeletons of arthropods – crabs, shrimp, lobsters – are largely made up of chitin, a biomaterial. If you take a lobster shell and you remove its calcium carbonate and protein, you’re left with a “film” of chitin nanocrystals. When it is heat-treated, the nitrogen, hydrogen and oxygen of the chitin burn away. What’s left is high surface-area carbon, an essential component of many batteries.
The benefit of using chitin is that it is one of the most widely available biomaterials on the planet. It is also found in insects, mushrooms and other fungi. Chitin is biodegradable and renewable, and currently discarded as waste from the shellfish industry.
What other uses for chitin are you exploring?
Chitin can be used to make biomedical materials, such as dressings for wounds or surgical thread. The advantage of chitin over plant-based materials, such as cotton, is that it can be modified for different applications. It also has considerable strength, which could be important for sutures and other applications.
Chitin can also be used to make biodegradable plastics. You could make eco-friendly ‘lobster’ or ‘shrimp’ coffee cups. We have been constructing colourful materials out of crab shells, as the chitin in the shells is naturally iridescent. Real applications will depend on whether these materials can be economically scaled up.
What does your lab look like?
We have piles of different types of shells all over the place. We don’t have any live lobsters, we only work with discarded shells. We collect them from restaurants, and I have a post-doc who eats shellfish and then brings the shells into the lab.