February 22, 2011

Peer Review: Student Works to Improve Drug Delivery to Tumors

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Once an undergraduate student without any concrete post-graduation plans, Zachary Schulz, ’10, M. Eng. ’11, is now a part of a potentially life-saving team of researchers, working on methods to improve drug delivery to the brain for devastating illnesses, such as brain tumors.

As a child growing up in Aberdeen, South Dakota, Schulz became interested in science because of his father.

“My dad would show me all the cool things that science could do,” Schulz said.  “He taught me about the process of discovery and finding out about nature all around you.”

Schulz did well in most science and math classes, but it was his AP Chemistry class in high school that truly sparked his interest. At Cornell, Schulz says he wanted to study chemistry, but research was “not on his radar.” It wasn’t until a meeting with his advisor sophomore year that the idea crossed his mind.

After learning that Schulz was interested in things like nanofabrication, his advisor recommended that he email Prof. William Olbricht, chemical and biomolecular engineering, who was doing research on drug delivery to the brain. Schulz emailed the professor, but didn’t hear back for months, and decided to give up on the idea of doing research.

One day, Olbricht emailed Schulz back, and invited him to a meeting. Olbricht introduced Schulz to George Lewis, who was working on an ultrasound device for drug delivery.

“[Lewis’] enthusiasm for the research was just boiling over. It was really inspiring and made me want to work with them.” Schulz has been working with them ever since.

The core of Schulz’s research deals with one of the main problems of drug delivery to the brain for the treatment of tumors. The brain is made of porous material; the individual pores are very small. Chemotherapy drugs used to kill tumors are made up of large molecules, which are not able to permeate the brain effectively. Because of this, chemotherapy drugs are delivered systemically. “But when the drugs are administered this way, they kill off your whole body. They’re poison,” Schulz explained.

The patent pending ultrasound device Schulz has been working on with Lewis could be the solution to the permeability problem.  “By applying low intensity ultrasound to the brain tissue using various mechanisms, we are making the tissue more receptive. The pores are opening up, and allowing the large drug molecules to flow through directly to the brain,” Schulz explained.

The groundbreaking device has been delivering promising results so far.  In one experiment a control rat was administered dyed fluid made up of large molecules directly to the brain, and the other rat was administered the same fluid, but with the use of the ultrasound device. The volume distribution of the fluid in the rat that received it via the ultrasound device was nearly two to three times the volume distribution of the fluid in the control rat.

“This is really promising because one of the problems with brain tumors is that if you don’t get them all, you have a recurrence.  The more volume distribution of the drug you have, the more likely you are to get all of the tumor cells and avoid the recurrence,” Schulz said.

Schulz believes that even though the results have been impressive so far, the device can be improved to be even more effective, and the volume distribution can be increased without detriment to a potential patient.

“We need to push the boundaries. I think we can get it to be higher than 2 to 3 times. We don’t want to shoot ultrasound into brain tissue but we want to push up that ultrasound power, increase the flow rate of the drug and push the different parameters to see how much we can get out of it because we want to make it the best possible treatment that it can be,” Schulz said.

Though Schulz currently has a job offer in the chemical engineering field that isn’t related to his current work, Schulz says he wants to go back to doing this type of research. “We found out that ultrasound is really doing something, and it can actually be clinically relevant in 5 or 10 years,” Schulz said. “I want to go back to research because being able to potentially help people is amazing.”

Original Author: Maria Minsker