Blinking microbubbles for early cancer screening take grand prize at Research Expo 2012

(Nanowerk News) Carolyn Schutt, a Ph.D student in bioengineering at the University of California, San Diego is developing a new imaging technique that could lead to highly-sensitive light imaging deeper inside the body, improving the way we diagnose breast cancer. Schutt's research received the grand prize April 12 at the Research Expo, the annual research and networking event of the UC San Diego Jacobs School of Engineering.
Schutt's aim is to build a bridge between optical imaging and ultrasound imaging, in order to get the benefits of both technologies: the chemical sensitivity of visible light and the tissue penetrating properties of ultrasound. Such a "smart particle contrast agent" would render biological tissue effectively transparent to light and enable highly sensitive light imaging deeper inside the body, improving the way we diagnose cancer. Conventional X-ray mammography can only show the density of tissue, indicating the presence of a mass, but cannot determine any of the biochemical differences between a benign mass and a malignant tumor.
Bioengineering graduate student Carolyn Schutt
Bioengineering graduate student Carolyn Schutt won the Rudee Outstanding Poster Award for her research into a new imaging technique for breast cancer research.
"There is a very high false positive rate with just X-ray mammography," said Schutt, who was honored with the best poster award for the Department of NanoEngineering and the Jacobs School-wide Rudee Outstanding Poster Award. "By being able to extract chemical information we hope to avoid unnecessary biopsies that are done on benign lesions."
For example, because of their rapid growth, cancerous tumors consume a lot of oxygen so the area around a tumor is likely to be hypoxic or depleted of oxygen. Cancer cells also require increased blood flow to fuel their growth creating a region of new blood vessel formation. The use of this technique could allow this sort of biochemical information to be determined for tumor diagnosis.
Schutt's work, advised by nanoengineering Professor Sadik Esener, focuses on the use of gas-filled microbubble contrast agents that change their fluorescence intensity, or "blink", only in response to focused ultrasound. A solution of these microbubbles would be injected into the body to circulate through the blood stream. When gas microbubbles encounter an ultrasound pressure wave, they contract and expand their outer surface in response to the pressure peaks and troughs. By loading the microbubble surface with a fluorescent dye that turns off when it is very close to other dye molecules the ultrasound creates a blinking signal. Initially, less than 10 percent of the bubbles produced this modulating fluorescence. Analysis of the nanostructure by super-resolution microscopy showed that most of the dye partitioned into isolated clusters, which were likely preventing the dye from blinking in response to ultrasound. Schutt was able to manipulate the bubble nanostructure by heating the bubbles to melt their outer surface and distribute the dye more evenly, and then rapidly cooling them to lock in this distributed state. This melting and quick cooling process increased the fraction of blinking microbubbles to over 50 percent, making this a more viable imaging platform.
This blinking light can then be used to build up an image of the ultrasound-scanned tissue (a suspected tumor, for example) with the sensitivity and contrast offered by optical imaging. This is a new and powerful capability that could significantly improve present diagnostics as well as image guided therapeutic capabilities.
Schutt is also active in campus outreach and leadership programs. As a Gordon Scholar, Schutt participates in the Gordon Engineering Leadership Center's engineering leadership programs, a course of study she takes seriously. In her current position as outreach chair of the Bioengineering Graduate Student Society, Schutt organized the group's exhibit at the recent San Diego Festival of Science and Engineering as well as a festival-wide science challenge for K-12 students to learn and discuss key science concepts. Read our chat with Schutt about organizing the Home Run Science Challenge.
Schutt was one of more than 230 graduate students who presented at Research Expo, which was sponsored by Qualcomm, ViaSat and SAIC . Judges were impressed by the students' high level of technical proficiency and their ability to communicate their ideas.
Three-time Research Expo Judge Silvia De Dea, a staff scientist at Cymer, which is a member of the Jacobs School Corporate Affiliates Program, was impressed by the entrepreneurial mindset of many of the students she met who already had some experience with the patent process, including thinking about how their technology could be eventually sold or licensed to industry. "Realizing that they had that type of mindset was very interesting," said De Dea, a Jacobs School alumna who earned a masters (2004) and doctorate (2008) in chemical engineering.
Judge Greg Kusinski, DeepStar Director with Chevron Energy Technology Company, who serves on the Industrial Advisory Board for the Department of NanoEngineering, said the winners demonstrated a unique capacity to explain the relevance of their research. "The students had the ability to present the big picture," said Kusinski. "That's why they stood out." He said that they did a great job at showing the problem they were trying to solve, steps taken during the research process and the next steps in their research.
Source: University of California, San Diego
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