2007 Graduate Student Awards

Biomedical Engineering Boasts Three Award Winners for Graduate Student Research

Bone fractures, blood cell counting and brain imaging are the topics for this spring’s recipients of the Graduate Student Research Awards in the biomedical engineering department. Graduate students Marie Tupaj, Cherry Greiner, and Leonardo Angelone are the winners of $500 grants awarded on April 27, 2007. All award-winners are working on non-invasive technologies and techniques to improve human health.

Though their studies of white blood cells and bone marrow stem cells are different, developing their own experimental design unites Tupaj and Greiner, both members of assistant professor Irene Georgakoudi’s lab.

Greiner, a third-year doctoral candidate, says having no previous system in place can be tough however the experience can be rewarding at the same time. “It was a great engineering experience building something from scratch, but it does take up a lot of your research time before you can start actual experiments,” says Greiner. The flipside is that “you can control the project yourself, and it takes your own motivation to keep the project going,” says Tupaj, a second-year master’s of science candidate.

Tupaj, who has a background in electrical engineering, had always been interested in tissue engineering, but was galvanized by a study on how direct current stimulated the growth and development of bone cells. Though the phenomenon is well-known, guidelines such as type, duration and intensity of those electric currents aren’t well-defined, says Tupaj. “In the current systems that are out there, they don’t know the molecular level effects on the cells,” Tupaj says. In the United States, five to 10 percent of bone fractures have difficulty healing, according to Tupaj. Understanding these parameters will help design more effective treatments and aid in the development better techniques for bone tissue engineering.

Tupaj modified a chamber system originally designed by graduate students at MIT in which she monitors the growth of adult bone marrow stem cells exposed to an alternating current. Tupaj looks at how the AC field affects cell growth, gene expression and metabolic activity. “My overall goal is to see an increase in metabolic activity in the chamber versus the control and hopefully we can discover new genes involved in the process along the way,” says Tupaj. Once she has these nailed down, Tupaj’s next step is to assess affects on direct current versus alternating current on stem cells, and move from two-dimensional cells to a three-dimensional structure of cells and silk scaffolding.

But, as Greiner knows, getting the experimental setup to work and recording reliable signals are the first, and often harder, steps. “We’ve gone through four stages of design,” said Greiner of the micro-fluidic system she designed to mimic cells flowing through a blood vessel. Greiner is studying non-invasive methods to monitor the body’s number of circulating white blood cells, key players in the body’s immune system. She designed a system similar to commercially available technology called fluorescence-activated cell-sorting, or FACS.

The difference between her research system and FACS is two-fold. FACS typically count and sort cells by evaluating differences in fluorescence from cells excited by a laser. Greiner instead looks for light scattered back by the cells, possibly eliminating the use of fluorescent dyes. Greiner said she believes differences in the form and structures of sub-types of white blood cells will result in differences in back scattered light. “My goal is to look at white blood cells and see if their scattering is different” from each other and from the major component of blood—red blood cells.

The second difference between Greiner’s system and the FACS involves the use of the technology to monitor the cells directly in the body’s circulation, as opposed to drawing a patient’s blood and then analyzing the sample in the lab. “The system is clinically applicable for monitoring diseases, infection and patient’s response to therapy,” says Greiner. “Patients, especially infants and those with cancer and AIDS, will benefit in the development of a non-invasive or minimally invasive system for blood cell counting.

Non-invasive techniques and patient safety are on award-recipient Leonardo Angelone’s mind as well. With assistant professor Giorgio Bonmassar, Angelone has focused on the safety concerns raised when clinicians use MRI to look at the brain in conjunction with monitoring the brain’s electrical activity with electroencephalography, or EEG.

Patient safety is paramount when bringing an electrical field close to the radio-frequency fields used to elicit the MRI signal. When using MRI/EEG technology, the goal is optimize safety while providing clinically useful information. “You want to provide the clinicians with a good image they can use, and you want to provide a good EEG signal as well,” says Angelone, who is in his final year of doctoral dissertation research.

This past year, as an extension of his research on monitoring radio-frequency levels during MRI, Angelone has looked at safety issues of electrical leads implanted in the brain to control tremors in Parkinson’s disease, epilepsy, and multiple sclerosis.

“It was a similar problem to the EEG in that you have these leads in a radio-frequency field of the MRI,” Angelone says, “It’s different because these leads are inside the head;” and they aren’t monitoring what’s happening in the brain, they’re therapeutically stimulating it as well.

Angelone models the distribution of electromagnetic field during MRI to see what may cause changes in the tissue area around the implant. Many factors including the type of lead material, position and length of the lead all play a role in the amount of energy, or potential damage, the surrounding tissue may be absorbing.

But for deep brain stimulation to be effective, says Angelone, you have to send enough current through the leads. However, Angelone says, “You may have a patient who needs the MRI to clinically find out what’s going on with his Parkinson’s. If you care too much about ‘safety,’ you’re not going to obtain any clinically relevant signal.”

Angelone, along with Grenier and Tupaj, will continue their biomedical engineering research through the summer. Their recent Graduate Student Research Award will get them one step closer to clinically important biomedical engineering discoveries.

–Julia C. Keller, Tufts School of Engineering Communications

To find out more about the Graduate Student Research Grants, please visit: http://ase.tufts.edu/GradStudy/research/

Application is open to any graduate student enrolled in a doctoral or masters program in the Graduate School of Arts and Sciences and the School of Engineering. Awards are competitive and decisions will be based on clarity of the proposal, significance of the proposal to the scholarly activities of the applicant, and need. The maximal amount for an award is $500. Students are limited to one award per academic year.