A Conversation with Dr. Valeria Milam   by Andrew Kerr April 2006 Dr. Valeria Milam mentored GIFT teacher Pamela Gilbert Smith, who we interviewed last month. In this interview the Materials Science and Engineering professor talks about her work and the everyday challenges faced by science teachers everywhere. (To save this video to your computer, right-click on this link and "save target as".)

Transcript 00:10 You do a lot of research into colloids. What are colloids? I actually was talking to undergraduates this past Saturday as part of the undergraduate fair and trying to explain to them what is a colloidal suspenion. And we started off with the simplest example: milk. Milk is actually a suspension of particles. As opposed to just being a pure liquid it's actually a suspension. Other examples that I used were inks in pens for example, that's another example, the suspension of pigment which is being used to write material. And then another great example that I like because I'm particular to this gemstone are opals. Opals are another example of colloidal particles, but instead of being in a suspended state they're actually in a solid state. So if you actually were to take a microscope to an opal gemstone you would see this array of particles made up of silica. So they have different applications varying from your everyday food colloids to writing instruments like pens, to even gemstones like opals. [How do you define a liquid vs. a suspension? Why does ink not count [as a liquid]?] We do have solvent in there. We do have a liquid that's being used to suspend the particles, so it's actually the media to help support the colloids in a suspended state. But the particles themselves are the solid part. So they have characteristics of both a liquid and a solid, because you have a solid suspended within a liquid, so they have a more complicated set of properties that mimic the two states, somewhere in between a liquid and a pure solid. [It seemed that it was important at least to some people, web pages I was on, the surface area properties vs. the volume properties.] Yes, very much so. One way to think about it is if you were to take a cube and you were to think about the surface area associated with that cube it's just on the surface. Now if you break that cube into smaller cubes the volume is the same as before, but now you have more surface area that you've introduced by simply slicing it up. So that's why our surface area is so important as a feature. And actually it can be both a challenge and a problem as well as a benefit to working with colloidal particles because the surface area can drive all the association between the particles. For us because surface area dominates even the bulk properties of the materials we are choosing, we have to be very careful with the chemistry that we use to modify the surface of these particles. And so for example if we want the particles to not glue together, if we introduce the same charge type, like all negative charges to the surface of those particles, then like charges are repulsive, so the particles are less likely to come together, but if we introduce a positive charge to one particle and a negative charge to the other particle then they're very likely to connect together. So we have to be very careful as to how we balance the chemistry of those particles to tune the interaction between those particles to either be repulsive or attractive. And depending on the application we may want it to be repulsive, or we may want it to be attractive. And in a lot of cases for us instead of just using these electrostatic or these charges to drive association between particles we want to use specific attraction due to recognition between chemical functionalities. And that's why we're using DNA. Because DNA as part of our genome, what makes it so special is that DNA strands recognize its partner strand just due to the base pair matching between adenine and thymine and guanine and cytosine. So if you think of just those four bases you can come up with a rich variety of sequences just depending on how you put A's T's G's and C's on these strands. But so in order for it to find a partner strand it has to have the complimentary set of bases in that order in order to match up and find its partner strand. So what we're interested in doing is instead of just taking these DNA helixes that form in solution we want to put one on one bead, the complimentary strand on another bead, and see if we can connect those two surfaces together via the recognition of the DNA. So we're actually using the biological recognition that is specific to DNA to drive these particles to associate with one another in a very particular fashion. So A only recognizes the complimentary bead B, but not C if it doesn't have its complimentary strand on it. So it really gives us a lot of control over the order in which we want to assemble these particles; if we want to use several different particle types, like magnetic particles, or drug-loaded particles, or enzyme-loaded particles, we can actually direct those particles to assemble in a very specific manner. [Is this so that when you when you use certain medications and treatments it will target only those--the "bad guy" germs or the viruses themselves?] In order to do that we'd have to add, it wouldn't be enough just to have the DNA, because in our body, the way that our body fights infection is it generates antibodies, so if we could find the antibody and connect that to the surface of the particle then we could use the DNA to connect multiple particles but then use the antibody on the surface of those particles to then drive it towards the cell, which is one of the projects that we're very interested in pursuing, which we're currently pursuing in our lab. So we're using two modes of biological recognition, we're using the DNA to connect those particles together and then we're going to functionalize the outer layer of particles in that assembly with the recognition, with the biological recognition macromolecule known as an antibody in order to direct it towards a cancer cell for example. [Is cancer your primary research?] We're very interested in cancer because colloidal particles have these diverse properties in terms of their size, shape and even composition, we can use the colloidal particle as the drug-delivery vehicle, but if we use the DNA to connect those particles together and then the antibody to the cancer cell, then we can drive it towards the cancer cell. Cancer's one of our biggest interests, but we are interested in just general immunology concerns that we have in the body whether we're fighting infection, inflammation, any of these less than desirable conditions that humans find throughout their entire life unfortunately! 06:59 Describe your collaboration with high school teachers Pam Gilbert Smith and Anne Marie Johnson. Materials science really got its start with metallurgists and ceramic engineers, and then they started to pull in chemists to bring in the polymer science, and then they started bringing in electrical engineers to bring in the electronic materials aspect. So we already have a very diverse group of people making up materials science engineering departments across the U.S. And so what Pam's trying to do is actually right at home with the materials science engineering department because she's also trying to pull from diverse sets of people for a diverse set of needs actually with the high school students. [What's your involvement in that? You were going to be doing some talking...] I'm going to be conducting some visits there both with Pam and Anne Marie to do some demonstrations of how does materials science play into our daily life and so going back to the milk and the colloidal ink and the gemstone, materials science is actually an inherant part of our everyday life whether we realize it or not. So with these students what we're trying to do is show them how you can use materials science engineering principles to design your material and even characterize your material. So we're going to go with something as simple as a hydrogel, which we're going to use jello as our hydrogel mimic, and see how can we stiffen jello? What if we take away some of the water, does that make the jello stiffer or softer? And so using what are very simple principles to actually tune the properties of these materials that we're going to be playing with her students. 08:35 How did you get interested in materials science and engineering? It was basically because from my personal experience I actually became a materials science engineer almost by accident. I had never heard of it until my father had proposed looking into this. I had thought about doing pharmacy and after taking organic chemistry I said, "No way!" So I started looking into materials science engineering as a possible major, and from that stemmed this idea I had no idea this was around, I kind of stumbled upon this major as an accident, and so I was very interested from my own personal experience to introducing high school students to materials science. And the fact that we already had an RAU and RAT program already running with participants from local high schools like Pam and Anne-Marie it was actually just a natural connection to make. 09:26 Where did you grow up? I actually grew up in Birmingham, Alabama, so I stayed in the south for my undergrad and went to the University of Florida. And then did all my graduate work at the University of Illinois in Urbana-Champaign. [Where is the University of Florida?] Gainesville. So it's basically in central Florida, close to Orlando. [Why did you choose that school, how did you make that decision?] For me I really wanted a lot to choose from. I was thinking of going into pharmacy but I wasn't sure. And Florida was a big state school, which was very appealing to me in terms of having a lot of choices of majors. And so it really worked out well for me, and it also worked out financially well for my parents because I was the oldest and they still had some other siblings to put through school, and so those were some big motivations for me to go to Florida. And I was very happy there, a lot of choices as I said, and I stumbled into materials science almost by accident, but it was a great choice for me. I encourage students to start thinking about where they want to go to school. Around the end of their junior years is usually when people start to think about it, but keeping in mind what different schools have to offer in terms of majors is I think a very important thing to consider. And people need to consider the fact that they may change their mind after their freshman year and they want to have something else or a pool of options to choose from as opposed to going to one school because it has one good program and not much else to offer. 11:03 In looking back at your own education, were there any subjects you wish had been taught differently? I think overall my science and math in high school I thought was very strong, with the exception of physics. And for some reason I'm really glad to hear that Anne Marie and Pam are so involved in both the chemistry and physics aspects because these are often areas in high school which are weak, and its very hard to motivate people to return to high school to teach because it really is a labor of love. That is just all there is to it. So for me I thought I thought I had a very good chemistry teacher but my physics teacher unfortunately was very weak and so I really didn't go into college with a good physics background. [Because [the physics teacher's teaching] was dry or...?] I don't think she was as interested in the topic herself and so I think that that kind of, didn't help to motivate the students to really learn the material. And I think physics in a sense gets a bad rap because immediately when you say the word "physics" everyone sort of [cringes] "I don't ever want to have take that topic!" But my father's a physicist and it actually is a very straightforward set of principles. Now I would never go into graduate work with physics, but I think from the high school and the college perspective it really is I think a very elegant science, and I wish that people weren't scared away from it as much as they are. 12:32 What are some of the challenges faced by science teachers in the classroom? Well that's part of the challenge that I think Pam is trying to overcome is you have to sit at a blackboard and explain topics in a timely manner. You can't have every learning experience be a hands-on experience in which it's a fifty to an hour and a half lab involved. You have to be able to sit down at a blackboard and explain these issues. But if you have some hands-on experience coupled with it along the way I think it helps to reinforce the concepts and make them more tangible to students. And with chemistry it's a little more challenging because we are dealing with we're starting off with electrons and protons and neutrons, and we've just started being able to image atoms not too long ago, and so it isn't quite as tangible as some of the physics experiments that you get to do, in which you are just observing the friction, how it affects the velocity of a block sliding down an incline plane for example. So she has a different challenge I think. But she is very interested in trying to keep it hands-on and trying to get the students to ask the questions as opposed to her just dispensing information as a teacher she's really interested in involving the students in the critical thinking that's involved in learning material.