| I thought I would talk a little bit about how nature makes materials . I brought along with me an abalone shell . This abalone shell is a biocomposite material that 's 98 percent by mass calcium carbonate and two percent by mass protein . Yet , it 's 3,000 times tougher than its geological counterpart . And a lot of people might use structures like abalone shells , like chalk . I 've been fascinated by how nature makes materials , and there 's a lot of sequence to how they do such an exquisite job . Part of it is that these materials are macroscopic in structure , but they 're formed at the nanoscale . They 're formed at the nanoscale , and they use proteins that are coded by the genetic level that allow them to build these really exquisite structures . So something I think is very fascinating is what if you could give life to non-living structures , like batteries and like solar cells ? What if they had some of the same capabilities that an abalone shell did , in terms of being able to build really exquisite structures at room temperature and room pressure , using non-toxic chemicals and adding no toxic materials back into the environment ? So that 's the vision that I 've been thinking about . And so what if you could grow a battery in a petri dish ? Or , what if you could give genetic information to a battery so that it could actually become better as a function of time , and do so in an environmentally friendly way ? And so , going back to this abalone shell , besides being nano-structured , one thing that 's fascinating , is when a male and a female abalone get together , they pass on the genetic information that says , " This is how to build an exquisite material . Here 's how to do it at room temperature and pressure , using non-toxic materials . " Same with diatoms , which are shone right here , which are glasseous structures . Every time the diatoms replicate , they give the genetic information that says , " Here 's how to build glass in the ocean that 's perfectly nano-structured . And you can do it the same , over and over again . " So what if you could do the same thing with a solar cell or a battery ? I like to say my favorite biomaterial is my four year-old . But anyone who 's ever had , or knows , small children knows they 're incredibly complex organisms . And so if you wanted to convince them to do something they do n't want to do , it 's very difficult . So when we think about future technologies , we actually think of using bacteria and virus , simple organisms . Can you convince them to work with a new tool box , so that they can build a structure that will be important to me ? Also , we think about future technologies . We start with the beginning of Earth . Basically , it took a billion years to have life on Earth . And very rapidly , they became multi-cellular , they could replicate , they could use photosynthesis as a way of getting their energy source . But it was n't until about 500 million years ago -- during the Cambrian geologic time period -- that organisms in the ocean started making hard materials . Before that they were all soft , fluffy structures . And it was during this time that there was increased calcium and iron and silicon in the environment . And organisms learned how to make hard materials . And so that 's what I would like be able to do -- convince biology to work with the rest of the periodic table . Now if you look at biology , there 's many structures like DNA and antibodies and proteins and ribosomes that you 've heard about that are already nano-structured . So nature already gives us really exquisite structures on the nanoscale . What if we could harness them and convince them to not be an antibody that does something like HIV ? But what if we could convince them to build a solar cell for us ? So here are some examples : these are some natural shells . There are natural biological materials . The abalone shell here -- and if you fracture it , you can look at the fact that it 's nano-structured . There 's diatoms made out of SIO2 , and they 're magnetotactic bacteria that make small , single-domain magnets used for navigation . What all these have in common is these materials are structured at the nanoscale , and they have a DNA sequence that codes for a protein sequence , that gives them the blueprint to be able to build these really wonderful structures . Now , going back to the abalone shell , the abalone makes this shell by having these proteins . These proteins are very negatively charged . And they can pull calcium out of the environment , put down a layer of calcium and then carbonate , calcium and carbonate . It has the chemical sequences of amino acids which says , " This is how to build the structure . Here 's the DNA sequence , here 's the protein sequence in order to do it . " And so an interesting idea is , what if you could take any material that you wanted , or any element on the periodic table , and find its corresponding DNA sequence , then code it for a corresponding protein sequence to build a structure , but not build an abalone shell -- build something that , through nature , it has never had the opportunity to work with yet . And so here 's the periodic table . And I absolutely love the periodic table . Every year for the incoming freshman class at MIT , I have a periodic table made that says , " Welcome to MIT . Now you 're in your element . " And you flip it over , and it 's the amino acids with the PH at which they have different charges . And so I give this out to thousands of people . And I know it says MIT , and this is Caltech , but I have a couple extra if people want it . And I was really fortunate to have President Obama visit my lab this year on his visit to MIT , and I really wanted to give him a periodic table . So I stayed up at night , and I talked to my husband , " How do I give President Obama a periodic table ? What if he says , 'Oh , I already have one , ' or , 'I 've already memorized it ' ? " And so he came to visit my lab and looked around -- it was a great visit . And then afterward , I said , " Sir , I want to give you the periodic table in case you 're ever in a bind and need to calculate molecular weight . " And I thought molecular weight sounded much less nerdy than molar mass . And so he looked at it , and he said , " Thank you . I 'll look at it periodically . " ( Laughter ) ( Applause ) And later in a lecture that he gave on clean energy , he pulled it out and said , " And people at MIT , they give out periodic tables . " So basically what I did n't tell you is that about 500 million years ago , organisms starter making materials , but it took them about 50 million years to get good at it . It took them about 50 million years to learn how to perfect how to make that abalone shell . And that 's a hard sell to a graduate student . " I have this great project -- 50 million years . " And so we had to develop a way of trying to do this more rapidly . And so we use a virus that 's a non-toxic virus called M13 bacteriophage that 's job is to infect bacteria . Well it has a simple DNA structure that you can go in and cut and paste additional DNA sequences into it . And by doing that , it allows the virus to express random protein sequences . And this is pretty easy biotechnology . And you could basically do this a billion times . And so you can go in and have a billion different viruses that are all genetically identical , but they differ from each other based on their tips , on one sequence that codes for one protein . Now if you take all billion viruses , and you can put them in one drop of liquid , you can force them to interact with anything you want on the periodic table . And through a process of selection evolution , you can pull one of a billion that does something that you 'd like it to do , like grow a battery or grow a solar cell . So basically , viruses ca n't replicate themselves , they need a host . Once you find that one out of a billion , you infect it into a bacteria , and you make millions and billions of copies of that particular sequence . And so the other thing that 's beautiful about biology is that biology gives you really exquisite structures with nice link scales . And these viruses are long and skinny , and we can get them to express the ability to grow something like semiconductors or materials for batteries . Now this is a high-powered battery that we grew in my lab . We engineered a virus to pick up carbon nanotubes . So one part of the virus grabs a carbon nanotube . The other part of the virus has a sequence that can grow an electrode material for a battery . And then it wires itself to the current collector . And so through a process of selection evolution , we went from having a virus that made a crummy battery to a virus that made a good battery to a virus that made a record-breaking , high-powered battery that 's all made at room temperature , basically at the bench top . And that battery went to the White House for a press conference . I brought it here . You can see it in this case -- that 's lighting this LED . Now if we could scale this , you could actually use it to run your Prius , which is my dream -- to be able to drive a virus-powered car . But it 's basically -- you can pull one out of a billion . You can make lots of amplifications to it . Basically , you make an amplification in the lab . And then you get it to self-assemble into a structure like a battery . We 're able to do this also with catalysis . This is the example of photocatalytic splitting of water . And what we 've been able to do is engineer a virus to basically take dye absorbing molecules and line them up on the surface of the virus so it acts as an antenna , and you get an energy transfer across the virus . And then we give it a second gene to grow an inorganic material that can be used to split water into oxygen and hydrogen , that can be used for clean fuels . And I brought an example with me of that today . My students promised me it would work . These are virus-assembled nanowires . When you shine light on them , you can see them bubbling . In this case , you 're seeing oxygen bubbles come out . And basically by controlling the genes , you can control multiple materials to improve your device performance . The last example are solar cells . You can also do this with solar cells . We 've been able to engineer viruses to pick up carbon nanotubes and then grow titanium dioxide around them -- and use as a way of getting electrons through the device . And what we 've found is that , through genetic engineering , we can actually increase the efficiencies of these solar cells to record numbers for these types of dye-sensitized systems . And I brought one of those as well that you can play around with outside afterward . So this is a virus-based solar cell . Through evolution and selection , we took it from an eight percent efficiency solar cell to an 11 percent efficiency solar cell . So I hope that I 've convinced you that there 's a lot of great , interesting things to be learned about how nature makes materials -- and taking it to the next step to see if you can force , or whether you can take advantage of how nature makes materials , to make things that nature has n't yet dreamed of making . Thank you . |