Phage + Metal = Battery?

By now, many people have read about Angela Belcher, a professor at MIT, and her lab's recent developments in the use of bacteriophages as a component of batteries. Having had a very distinct privilege to hear her speak yesterday, I wish to share what I have learned.

In a broad sense, the goal of her lab is to give inorganic compounds (batteries, medical devices, solar cells, etc), "genetic intelligence." That is, to give the power of evolutionary adaptation and self-correction to inanimate objects. Life evolved the ability to perfectly use the ions and metals present in its environment, things like calcium, silica, etc. However, she wants to know what happens when we allow life to evolve in the presence of technologically important compounds, like gold, silver, aluminum, platinum, etc.

One of the original goals was to develop a biological system that could recognize and mark atomic scale cracks in layered materials. She set to do this using a phage library. The phage, M13, is capable of having many of its parts replaced with random gene sequences, allowing us to add in peptides that allow recognition for any particle of our choosing. (A concept referred to as "phage display" and has been used for lots of detection assays)

She selected for attachment proteins that allowed the phage to attach to atomic scale cracks in the alloy used in engine blocks and computer parts. You can then propagate, mutate, and select for phages that have tail fibers with the strongest possible affinity for the substrate of your choosing. This was very successful, and from my impression, is being scaled up to allow identification of these atomic cracks in engine blocks, airplane wings, and helicopter blades. (She is now figuring out how to mesh the identification of the cracks via phage, to self-healing properties via metal nucleation)

She then found that the proteins in the phage body could be altered as well. Using similar techniques she found that metal ions could be nucleated in both poly crystalline and mono crystalline structures to the phage body. Thus allowing the creation of nanotubes (with a phage inside). By altering ratios of metal ions added, she can create very specifically composed alloys. Importantly, all of this is done at STP, with a rare exception (Ag-Pt tubes for fuel cells) requiring 80C temperatures. She can also rid the system of organic material by heating to >100C, but keep the inorganic structures intact.

Using phages with affinities for cobalt oxide, lithium, these scientists managed to create a functional battery that is only on the order of nanometers in thickness. Paper thin batteries that have the capacity and power to replace automotive batteries now. The batteries are capable of being charged and recharged numerous times without losing power or capacity. (This was a problem at first). They are very fast to produce (<6hrs)>
If you can think of any application for nanowire like phage nucleation of metals, her team is already working on it. This battery concept is definitely going to be an important milestone in development of new energy storage, usage, and production.

Normally when we think of applications of microbial genetic systems, we think of human health and perhaps fermentations. Now, we can truly see the power when genetics are applied to technologically challenging engineering applications.

---

Source:
Lee, Y., Yi, H., Kim, W., Kang, K., Yun, D., Strano, M., Ceder, G., & Belcher, A. (2009). Fabricating Genetically Engineered High-Power Lithium Ion Batteries Using Multiple Virus Genes Science DOI: 10.1126/science.1171541

---

Other Articles of Interest:
Utilizing Natural Killers: Phage-Based Antimicrobials
Evolution of Phage Capsid and Genome Size
How Far Do Those Phages Stretch?
Phages with Horns? What's Next?
I Got You Phage