Viruses Engineered to Construct Batteries

An anonymous reader writes "Researchers at MIT have modified the M13 virus to create very small batteries. With the viruses building wires 6 nanometers in diameter, the research team hopes to 'build batteries that range from the size of a grain of rice up to the size of existing hearing-aid batteries.'"

Environmental disaster looms

[AsciiNaut]

Note that M13 is a bacteriophage, a kind of virus that can only infect bacteria. M13 gets into E. coli via long proteinaceous protuberances known as pili, such as those encoded by the fertility factor F. In a crude analogy, M13 is to E coli what Herpes simplex is to humans. And another thing. I hope these guys are working on rechargeable versions: I don't want to see landfills getting choked with literally millions of discarded M13-batteries. Won't somebody think of the children?

Lemme see here..

[k98sven]

First, the viruses aren't making any batteries, they're making wires which may be used in batteries?

Second.. it seems unclear that the virus is actually doing any work..

They modified the M13 virus' genes so its outside layer, or coat, would bind with certain metal ions. They incubated the virus in a cobalt chloride solution so that cobalt oxide crystals mineralised uniformly along its length.

They added a bit of gold for the desired electrical effects.

So basically, it seems they're pulling an Auric Goldfinger on those poor viruses, smothering them with conducting gold metal. Seems a bit misleading to characterize that as making the virus produce wire (much less a battery).

Rather, the viruses were modified to form a suitable substrate to cover with metal and turn into a wire, which is something a bit different.

Re:Environmental disaster looms

[mavi_yelken]

There are some basic rules when you are making recombinant viruses. one of them is making sure that the virus cannot reproduce in any other thing except the specific strand of bacteria you are using and there are still more safeguards in place. so don't worry about self powered virus overlords.

details.

[hometoast]

A more in depth writeup at swoogylee.tripod.com/resume/Lee-jps-B-2004.pdf. For the interested or very bored.

The original article in Science

[mapkinase]

original article in science [sciencemag.org]

um, no! for all sooo many reasons.

[Ancient_Hacker]

Plating gold or other metals onto a virus is not new, not that difficult, and unlikely to ever be useful as a "battery". Many reasons:

• Scientists have been depositing metal onto bilogical specimens for 60 years or so. (it's very useful for showing off contrast in electron-micrographs).
• A "battery" is a bunch of somethings. In common usage, a bunch of electrochemical generators. A electrochemical battery is made up of electrochemical "cells". These guys are plating metal onto viruses, which are, strictly defined, a type of "cell", So they're making CELLS, not batteries.
• Putting wires onto a microscopic electrochemical CELL is wildly unuseful, for oh so many reasons:
  • A virus is unlikely to have more than a millivolt of EMF from end to end.
  • A virus isnt designed to be a good EMF generator, so its amps and volts will be extremely miniscule.
  • The power available goes down as the third power of the linear dimensions. A virus has about the smallest linear dimension of just about anything. When you take about the smallest number one can imagine, and cube it, you get a breathtakingly small number. That's the watt-hour capacity of a virus, down in the microwatt-microsecond range. Just stunningly small.
  • The leakage from terminal to terminal of a electrochemical cell goes down as the first and second powers of the linear dimensions, while as mentioned above, the power capability goes down as the CUBE. Long before you get down to the size of a virus, the leakage dwarfs the power capacity-- in other words the cell "runs down" almost immediately.
• Viruses use their EMF as a large part of their tools for invading a cell. If you plate a virus, it probably loses that ability, so it's not going to be able to grow or replicate.

Thats about all the objections for now. Hope that's enough.

Ah, brings back the memories...

[SB9876]

Ah, I used to work on this sort of stuff. Although TFA is very information poor, I'm guessing that this research was done by Angela Belcher's group. She and a few other folks (including my former prof) have been working with proteins that bind to specific organic surfaces for several years now. She's been at the lead of this particular field for quite a while now. It's a very interesting and promising field of research.

Here's some background for the interested:

M13 is a filamentous bacteriophage. It infect E. coli bacteria and creates a latent infection where the E. coli ends up pumping out hundreds of new M13. Unlike most bacteriophage, the infection is not lethal to the host. The M13 phage itself is thread-like in structure. At the core is the a circular, single-stranded DNA genome arranged in a linear shape. (imagine grabbing a rubber band at both ends and stretching it out so that it's a very elongated and narrow oval) There are 5 types of coat proteins that then coat and protect this DNA. Here's a link to a decent site about M13: http://www.biosci.ohio-state.edu/~mgonzalez/Micro5 21/Lambda/M13.html [ohio-state.edu]

One, G8P, is present in thousands of copies and coats the DNA in a spiral fashion. A pipe cleaner is a fairly good representation of what the phage looks like. At the ends, the other 4 types of proteins form end caps. On the end that infects bacteria, a protein known as G3P is present in 5 copies and mediates the atachment of the virus and its incorporation into the bacterium for infection. G3P is important because it's fairly exposed at the end of the virus. Also, experimentation over the years has found a 'permissive' region in G3P. A permissive region of the protein structure that is tolerant to the addition of new amino acid sequences that do not badly disrupt the normal protein function. Therefore, one can genetically engineer M13 to put a small chunk of new protein into this site and the virus is still capable of infecting bacteria and replicating. The inserted bit of protein is also known to be exposed at the end of the virus.

M13 is available in commercially generated libraries where tens of millions of randonly generated DNA sequences have been inserted into M13. These 'libraries' are then infected into bacteria and amplified. The resulting phage are then sold to researchers who want to find pecific protein sequences that bind to certain targets. Mostly, these targets are biological in nature. For example - to try and find peptide-based drugs that bind to and inactivate a particular cellular receptor. Here is a link to a commonly used commercial library (I used to use it and I know Belcher's group did too) http://www.neb.com/nebecomm/products/productE8120. asp [neb.com] The link also has lots of pretty pictures and the like about how phage display screening works in more detail that I've got below.

Essentially, what you do is take a substrate of interest, in this case, cobalt oxide and mix it with a sample of the library. You use incubation conditions where regular M13 doesn't stick to the CoO. If any of the library phage stick you know it is probably because those particular phage have a protein insert which binds specifically to CoO. You do a few rounds of binding and washing to get the strongest binders and then sequence the cobalt oxide binding proteins you've recovered.

You can churn out hundreds of sequences this way and start building up a library of proteins very specific to a particular inorganic substrate. You can, for example, create proteins that bind to only platinum versus gold and palladium, cupric oxide versus cuprous oxide, etc. There is even evidence that you can discriminate various sizes of nanoparticles and bind to particular crystalline faces of materials this way. I even heard a rumor a few years back of being able to distinguish p and n-doped