Engineering Research Expo Winners

Congratulations to this year’s winners of the Literature Review prize at the Jacobs School of Engineering Research Expo.  Aaron and Roy will each receive a $125 giftcard for the UCSD Bookstore, and their posters (along with others from the Expo) will be on display in the S&E Library.

SOLAR FUEL FROM CO2: A STAND-ALONE OFF-GRID DEVICE
Aaron John Sathrum, Department of Mechanical & Aerospace Engineering & Graduate Program in Materials Science & Engineering
Faculty Advisor: Clifford P. Kubiak (Dept of Chemistry & Biochemistry)

Capturing energy from the sun to facilitate the renewable conversion of CO2 into useful chemical commodities creates a carbon neutral cycle. This cycle is currently out of balance on a global scale and new approaches to reducing CO2 levels are needed. CO2 conversion is not a foreign reaction; plants successfully accomplish this on a global scale of more than 100 billion tons per year via photosynthesis. Homogeneous electrocatalysis presents a unique opportunity to convert and store electrical energy in CO2 derived products at low input energy. A device built at UCSD using sunlight, commercial solar cells, an electrolysis cell, and an electrocatalyst for converting CO2 to CO is demonstrated. The integration, power matching, and optimization of the components is essential for maximum fuel generation. The goal is an overall conversion efficiency of at least 3%. The importance of this work will be to demonstrate that reduction of a greenhouse gas and the production of a chemical fuel can be accomplished using a renewable energy source using electrocatalysis.

Aaron’s strategy for searching the literature:   (The UCSD Libraries license and pay for most of the journal articles that our faculty, students and staff locate via Google Scholar)

I like to start with Google Scholar because it is quick and easy. Next I usually use Web of Science or SciFinder to get more specific resources. If I have a field/topic and it is new to me, I usually look for a good review paper and follow the references therein.

Aaron Roy
Aaron Sathrum Roy Lefkowitz

AN EARLY POINT-OF-CARE SHOCK DIAGNOSTIC: CLINICALLY RELEVANT DETECTION OF PROTEASE ACTIVITY IN WHOLE BLOOD
Roy Brian Lefkowitz, Department of NanoEngineering (and the department’s best poster winner)
Faculty Advisors: Michael Heller (Depts of NanoEngineering, Electrical & Computer Engineering, Bioengineering) and Geert Schmid-Schönbein (Dept of Bioengineering)

Proteases are potential biomarkers for physiological shock, various types of cancer, cardiovascular disease, and for many other diseases. The measurement of their activity in blood is important for the development of point-of-care diagnostics and for biomedical research. It is particularly important for possible early diagnosis of physiological shock, which has a 52% hospital mortality rate and which can be fatal within hours. Unfortunately, current protease assays require sample preparation, making them time-consuming, costly, and less accurate. Furthermore, sample preparation makes these assays more complex, resulting in the requirement that they be performed in federally approved (CLIA) laboratories. This requirement precludes these assays from point-of-care applications. We have recently overcome this major limitation of protease detection by developing a technique that eliminates the need for sample preparation and that allows the measurement of clinically relevant levels of protease activity directly in whole blood [Electrophoresis 2010, 31(2), 403-410; Patent: PCT/US2009/033584].

Specifically, we developed charge-changing fluorescent peptide substrates that produce positively charged fluorescent cleavage fragments upon cleavage by the target enzyme. Thus far, we have developed specific substrates for α-chymotrypsin, trypsin, elastase, and MMP-2/9. These fragments are separated from the negatively charged components of whole blood by electrophoresis into an “extraction” gel. Upon further electrophoresis, the fluorescent cleavage product is transported from the extraction gel to a higher density, polyanion-doped “focusing” gel, which greatly concentrates the fluorescent signal and improves the detection sensitivity. As an example illustrating the overall process, we cast a 3 mm-long 12% polyacrylamide extraction gel on top of a 5 mm-long 25% polyacrylamide focusing gel doped with 0.5% 21,500 MW poly-L-glutamic acid (both 1 mm-thick). After a 1 hour reaction of substrate with various concentrations of spiked trypsin followed by 10 minutes of electrophoresis, we achieved a detection limit of 2 pg protease in 6 μL (0.3 ng/ml) in human whole blood, which is 50- to 200-fold better than estimated reference levels (15-60 ng/ml).

To further support the clinical relevancy of this detection, subsequent experiments demonstrated the measurement of baseline trypsin-like activity directly from healthy human whole blood. Efforts are now underway to test for protease activity in plasma and in whole blood samples for type II diabetes, pancreatic cancer, and physiological shock. This straightforward technique now enables the rapid measurement of clinically relevant levels of protease activity in microliter volumes of unprocessed whole blood, opening the door for the development of a point-of-care early shock diagnostic.

Ray’s strategy for searching the literature:   (The UCSD Libraries license and pay for most of the journal articles that our faculty, students and staff locate via Google Scholar)

My main strategy for researching the literature is to first search relevant key words in Google Scholar. I then, in this order, skim through the abstract, then skim through the article, and then slowly read, with greater attention to details, the full article. I do this to save time and to systematically and efficiently track down articles that will support my research. For references that are books or older journal articles, and not available online, I will search UCSD’s Roger and Melvyl to track down a hard copy.

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