SIGNALS Department of Electrical and Computer Engineering 2011 Summer, Vol. XI, Issue 1 Harnessing nanostructures for new applicati ons Light is a versatile carrier of information but is con- strained by diffraction limits. The emerging fi eld of plasmonics—using the surface plasmon waves of metal nanostructures to manipulate optical energy at the nanometer scale—works to overcome the constraints and involves engineering metals such as gold, silver, and copper for diverse applications. Department of Electrical and Computer Engineering Prof. Sang-Hyun Oh and his research team work to ad- dress the challenges of plasmonics and harness nano- structures for a number of applications in biosensing, spectroscopy, and solar cells. “In 1998, researchers at NEC laboratory showed that nanoscale holes in gold and silver fi lms provided unusu- ally strong optical transmission,” says Oh. “Building on those fi ndings, many researchers like us began develop- Above is a conceptual illustrati on of cell-mimicking lipid membranes formed on a me- ing techniques to engineer gold and silver fi lms and to drill tallic nanopore biosensor by the rupture of spherical shaped lipid membranes, called tiny holes in these structures. Eventually, in the University lipid vesicles. The nanopore plasmonic biosensor can detect molecular binding to the membrane in real-ti me to study dynamic interacti ons between anti bodies and lipid of Minnesota Nanofabrication Center, we developed a membranes. (Illustrati on by post-doctoral researcher Nathan Lindquist.) successful recipe to turn these structures into functional biosensors.” Oh’s work led to collaborations with research- ers both at the University and in industry. structure allows cellular membranes to adhere to the chip surface. Using a microfl uidic device, antibody molecules are delivered to the Investi gati ng biomolecular interacti ons membrane surface. “Reconstituting cell membrane on the metal- Oh entered into collaboration with Mayo Clinic’s Dr. Moses Ro- lic surfaces was a challenge, but postdoctoral researcher Nathan driguez to study antibody interaction with cell membranes using Wittenberg and PhD candidate Hyungsoon Im* developed the the nanopore sensor technology. With funding from the Minnesota chemistry and instrumentation techniques to overcome these issues Partnership for Biotechnology and Medical Genomics, the re- step by step,” says Oh. “Now that we have new technology to study searchers hope to better understand the mechanism of new antibody dynamic interactions between antibodies and cell membranes, this molecules that potentially could treat multiple sclerosis. will play an important role in new drug discovery.” In order to provide precise measurement of the antibody mol- With preliminary results from therapeutic antibodies, Oh and Rodri- ecules binding with the cell surface, the device’s metallic nanopore guez wrote a grant proposal for nanopore biosensor research and re- Faculty Research - conti nued on page 2 In this issue Centaurus II wins Formula Sun REU - Readying students for Graduate Research ..............................3 Grand Prix Ph.D. candidate Gysler Castelino Top CSE TA ....................................4 College of Science and Engineering Solar Vehicle Project Team wins Nati onal Cheung Kung University Students ......................................5 race at Daytona Motor Speedway............4 A long-ti me supporter of the University of Minnesota Solar Vehicle News Briefs - Students & Faculty....................................................6-7 Project Erland Persson helped with the design of a motor to propel the solar car. Persson died Feb. 22, 2011................................................7 U of MN Economic Fast Facts............................................................8 Faculty Research - conti nued from page 1 ceived an R01 grant from the National Institutes of Health. Further studies will be made on how antibodies and other drug molecules react on cell membranes. Solar fi lm enhancement It turns out that these metallic nanostructures also can benefi t the performance of thin-fi lm solar cells. Oh’s team has ongoing col- laborations with Department of Chemical Engineering’s Prof. Rus- sell Holmes to combine metallic nanostructures with organic solar cells for more effi cient operations. Thin fi lm solar cells can reduce materials and processing cost, but cannot absorb large amounts of light energy effi ciently. Nanostructured metallic electrodes can ef- fi ciently capture light in the form of surface plasmon waves, which Dr. Oh’s Research Team - (from left ) Dr. Nathan Witt enberg, Sudhir Cheru- kulappurath, Luke Jordan, Prof. Sang-Hyun Oh, Shailabh Kumar, Dr. Nathan can lead to enhanced power conversion effi ciency. ACS Petroleum Lindquist, Xiaoshu Chen, Timothy Johnson, Si Hoon Lee, Hyungsoon Im. Research Fund has been supporting Oh’s research with a Doctoral New Investigator Award grant. Working with Oh on this project are postdoctoral researcher Nathan Lindquist ** (Ph.D. ’10) and doctoral candidate Tim Johnson. Making smooth patt erned metals In 2009, the University’s Department of Chemical Engineering Prof. David Norris’s*** team and Oh’s team joined efforts to develop a new nanofabrication technique called template stripping. In this process, one fi rst creates silicon patterns, which have the desired property of smoothness (plasmon waves are very sensitive to surface roughness.) Using gold or silver, the pattern is replicated and peeled off of the silicon mold. This method can solve many challenges of reproducible plasmonic devices. Oh notes, “I’ve been fortunate to work with many talented students, postdocs and collaborators over the last fi ve years. Now we have powerful new technologies to engineer metallic nanostructures, and we look forward to demonstrating a series of devices and instru- ments for practical applications in drug discovery, nanoscale imag- ing, and photovoltaics.” *Recently the Materials Research Society (MRS) selected Im to receive the 2011 MRS Graduate Student Award based on his biosensor research, which was presented at the MRS Spring Meeting in San Francisco in April. **Lindquist will join Bethel University as an Assistant Professor of Phys- ics beginning fall 2011. ***Dr. Norris now works at ETH Zurich in Switzerland. (Right - graphs) The plasmonic biosensors can measure real-ti me binding kineti cs of diff erent concentrati ons of anti bodies to their binding partners embedded in lipid membranes. From these curves the rate and strength of molecular binding can be determined. This informati on is essenti al to un- derstand the behavior of anti bodies and to develop new drug molecules. (Right, bott om) An image of a plasmonic nanopore sensor. A scanning electron microscope allows imaging of nanometer-scale structures. 2 In the Classroom REU: Enhancing students’ research careers The University of Minnesota’s Research Experience for Under- “I recalled our conversation in which I pointed out how important it graduates (REU) program, funded by the National Science Founda- was for him in deciding to pursue graduate school,” she says. “He tion (NSF), is a 10-week summer experience for sophomore- or was interested, but did not have anyone to encourage him to take it junior-year undergraduate students from across the United States. seriously. When we talked he was considering going into industry The program focuses on encouraging a culturally-diverse group of but wanted to have some research experiences.” individuals to pursue successful careers in science and engineering. By providing women and under-represented minority undergradu- Franklin met Roach again in 2002 at UIUC where he was pursu- ates and undergraduates from non-research universities with a ing his master’s degree and where eventually he would receive his challenging and rewarding introduction to research in electrical and Ph.D. degree. computer engineering, our REU program seeks to motivate these students towards obtaining advanced degrees. “For me it was really comforting and reassuring to know that one conversation made such an impact on the life of a student,” says ECE’s REU program successes Franklin. “Over the years, it is a conversation I have had with This is the 14th summer for the ECE REU program that has run ev- many undergraduates who I think have what it takes though to get a ery summer since 1997, except for the summer of 2010. Our current doctorate. For the ones I have targeted, the results are just starting to NSF grant will support the summer program through 2013. show.” During the past 13 summers, 156 undergraduate students drawn Tyron Roach, Research Engineer II, Georgia from more than 50 higher education institutions across the U.S. and Tech Research Insti tute Puerto Rico have participated in the program. Of these, 59 were “In the last year or two of my undergraduate women and 97 men. Ten students are participating in the summer studies, I wanted to do something different 2011 program, two women and eight men. for the summer,” says Roach.“Why not study abroad? My advisor suggested I seek out a sum- “Based on a recent survey of our past program participants, nearly mer undergraduate research experience since 90 percent have completed an advanced degree (M.S., M.A., or I had expressed an interest in attending gradu- M.B.A.), with about 60 percent having completed or currently are ate school. I am glad I went down that path completing a Ph.D. in a STEM discipline,” says Prof. Douglas because, ultimately, I landed an REU opportu- Ernie, director of the ECE REU program. “Sixty-six percent of past nity with U of MN. The program brought great participants indicated that their REU experience in our program 2000 REU student excitement and challenge to my life; it opened motivated them to continue on to graduate school. This is a good Tyrone Roach a door to possibilities for my career from that indicator of success in accomplishing our goal of persuading these (above) and today point forward.” students to continue to pursue advanced degrees, given that only (below). about 50 percent of them expressed a strong interest in graduate He adds, “The REU program ran perfectly; school when they fi rst came to our program.