Magnetic fluorescent nanoparticles highlight brain tumours for MRI and surgery

7 May 2010

Scientists at Ohio State University have combined two types of nanoparticle to create a 'nanocomposite' that is both magnetic and fluorescent.

The magnetic nanoparticle emphasizes colour contrasts within magnetic resonance imaging (MRI), allowing doctors to see potential or existing cancerous tumours before surgery. The fluorescent nanoparticle can change the colour that the tumour appears in the brain when seen under a special light during surgery.

“Our strategy is combining two particles that contain different properties to make one particle with multiple properties,” explained Jessica Winter, assistant professor in chemical and biomolecular engineering and biomedical engineering at Ohio State.

“We’re trying to develop a single nanocomposite that’s magnetic, so you can do preoperative MRI, and that’s fluorescent, so that when neurological surgeons go into surgery, they can shine a light on the tumour and it will glow a specific colour such as green, for example. Then, the surgeon can simply remove all of the green,” Winter said. “With traditional magnetic contrasting agents, you’ll get an MRI, but you won’t see anything during surgery."

Winter’s study provided convincing proof that a particle with dual properties can be formed. However, these multi-functional particles can’t be used for animal or human testing because the fluorescent particle, cadmium telluride, is toxic.

“We’re currently working on an alternative fluorescent particle which is composed of carbon. This will eliminate the complications that arise with ingesting the cadmium telluride particles,” Winter said.

Patients with a specific form of deadly brain tumour, glioblastoma, could benefit from Winter’s work. Glioblastomas are usually located in the temporal, or frontal lobe of the brain, and tumours located there are difficult to see and remove.

Combining the two particles could provide doctors with help both before and during the surgery to remove a brain tumour, Winter said.

One of the successes in creating the new nanocomposite particle was how they did it, Winter said. It is normally difficult to combine particles like these, a process known as doping.

The Ohio State researchers pursued an approach which had not been attempted before. They chose to bind their fluorescent particle on top of their magnetic particle at extremely high temperatures.

"The key is that our synthesis is done at pretty high temperatures — about 350 degrees Celsius,” Winter explained. “The synthesis was unexpected, but cool at the same time, and we were excited when we saw what we got.”

The primary neurological surgeon that collaborates with Winter and her team, an assistant professor with the Department of Neurological Surgery, Atom Sarkar, hopes to test the approach on animals at some point. But first they have to produce a particle that contains no toxic ingredients. If results continue to be encouraging, Winter is optimistic that similar multifunctional particles could become an innovative part of neurological surgery within the next five years.