Nature's Tiniest Screening Technology: a Big Challenge to Analytical Chemistry
Our cells' portals are smart indeed. They can recognize incoming molecules, like proteins, bind to just the right one and grant entry as needed. That skill helps keep us alive. Such a passageway, called a nuclear pore complex (NPC), is in essence a powerful hole in the wall, one that really knows its molecular biology. For Lane Baker, that's a model well worth translating from nature to synthetic systems. Baker, an analytical chemist at Indiana University, plans to study how to create technology that would work in much the same way as the NPC's in our cells. The synthetic portal would be smart and selective, with what Baker compares to a Velcro-like lining, just strong enough to briefly cling to the protein molecule, long enough to recognize its chemistry and usher it inside. Each of our cells has about 2,000 such portals, and they can conduct business about 1,000 times a second. In his lab at the University of Indiana, Baker hopes to combine ideas from analytical chemistry and bioscience with practical insights from his days on a farm in Missouri to improve our understanding of biological pores like the NPC. Applications might be found in creating sensors or separation technologies in which an opening the size of a protein molecule, about 10 nanometers (a human hair is perhaps 3,000 times as wide as a nanometer), can exert chemical control on what passes through. The portal could provide a selective membrane to separate out, say, a small molecule of a drug in an industrial process. Ultimately these holes could be contained in small portable devices and could be operated with low power and very simple read-out electronics. "For me, it's a conceptually simple idea," said Baker, an assistant professor of chemistry at Indiana University. "It's a hole in a wall, with the ability to recognize what's moving through it. We want that hole to do some work for us." Baker grew up on family farm in central Missouri and tried a range of fields, from biology to physics to medicine. "Then one day a light came on," he said. "All those fields can show how things work, but none of them explains things at the deeper, practical level that chemistry provides." In doctoral work at Texas A&M, Baker says he fell in love with electrochemical sensors. "I knew as an undergraduate that I liked instruments and building things. At A&M I learned the molecular side, how to let molecules do the work." As a postdoc at the Naval Research Laboratory in Washington, D.C., he began work with semiconductors using solid state physics. "We were doing scanning probe microscopy, looking at semiconductor wafers, silicon chips," he said, referring to the scanning tunneling microscope, a device that can read a surface at the atomic level. Then, during a second post doctoral fellowship, at the University of Florida in Gainesville, he began to put together all those fields. "I was studying nanopores, and I realized I could combine my experience with scanning probes in my work on these pores." Now, in his work at Simon Hall, Indiana's flagship multidisciplinary science center, Baker is trying to, in essence, cut out pieces of the proteins from a natural pore and make them work in synthetic pores. Ideally each pore will be selective, specific to certain kinds of molecules, like a membrane protein. "We've taken some first steps, but we don't yet have the level of control we need to do everything we'd like to do," Baker said. One day such a synthetic pore could be able to pull out one molecule at a time from a sample for analysis. "If you put a drop of blood on a membrane, and the pore lets you look for one molecule, one protein at a time, you can determine if that molecule is there, and you can estimate the concentration," Baker said. "Then you can take it a step further, you can start to think: What else it is interacting with? This is where it really gets interesting." Perhaps not so far removed from that Missouri farm, the goal is still to get some work done, with some essentially simple ideas.
Lane Baker's Teaching Plans
In his education efforts Baker plans to focus on using modern media technologies to engage students with science early in their careers. He hopes to build media bridges to science for women and ethnically diverse groups including African-Americans and Hispanics, using tools like Podcasting and video conferencing, and to use Skype, an application that permits voice calls via the Internet, to add a more personal dimension to the web-based teaching programs. One target school, with a diverse student body, he has selected is in Mobile, Alabama. "There are lots of people in small towns, out of the way places, where new technology can reach students now," Baker said. "We hope to bridge those geographic gaps. We can package scientific content into what kids want to listen to with an IPod. We will make it palatable for high-school kids." He plans to involve graduate students in his research group at Indiana to help shape the media materials to reach younger audiences. "I want every kid to have the exposure to chemistry, and not to be afraid of it," Baker said. He said he hopes that involving his graduate students will help fulfill a goal of "teaching students to teach," and to ultimately help recruit more U.S. students to careers in science.