Multifunctional material aids brain imaging

Engineers are getting craftier and craftier about making one material that is capable of more than one function, especially in the realm of nanomaterials. It can be a little difficult to exactly understand what this is all about, but the basic idea is that if you are going to all the trouble to try to engineer a material to do behave in a certain way, why not add one or more other valuable behaviors to it?

Admittedly, one of the things that is allowing this kind of engineering to occur is the leaps in recent years in nanoscience and mathematics that provides precise construction and predictions of how a material will behave.

For a real-life example of multifunctional materials, consider the work of a group led by the University of Washington’s Miqin Zhang, Zhang’s group has been looking into how to improve the treatment of brain cancers, such as glioma. Because of the invasive nature of these cancers, getting all of the carcinogenic tissue removed without damaging healthy tissue is very difficult.

But Zhang and company think they have a new dual-function material that can improve both the surgical and post-surgical treatment. What they have is a nanomaterial that, first, can seek out cancer cells, and, second, can illuminate brain tumors (at this point, in mice). The immediate benefit of the nanoparticles is that they improve the contrast of the MRI and optical images that the surgeon uses to determine what areas are malignant.

“During the surgery, the surgeons can see the boundary more precisely,” says Zhang. “We call it ‘brain tumor illumination or brain tumor painting. The tumor will light up.”

She also says the superior resolution of the nanoimaging could also help with early cancer detection.

Getting a nanomaterial across the blood-brain barrier was a major challenge. She says that getting through the barrier depends particle size, lipid content and charge. After building a particle that could pass through the barrier, Zhang’s group used chlorotoxin to target the tumors, and then placed a small fluorescent molecule for optical imaging, and binding sites that could be used for attaching other molecules.

“This is the next generation of cancer imaging,” said team member Richard Ellenbogen, professor and chair of neurological surgery at the UW School of Medicine. “The last generation was CT, this generation was MRI, and this is the next generation of advances.”

Zhang’s Nanoparticle Lab is focused on building multifunctional materials to aid in cancer treatments. Specifically, they concentrate on the use of “nanoconjugates” or “multifunctional nanovectors.”

Her webpage provides some more detail about how a multifunctional material can aid in nonsurgical cancer treatments:

A nanoconjugate is a chemically modified nanoparticle serving as a “vehicle” that carries biomolecules to target cells. The term “nanovector” here refers to a nano entity that plays a function role in the perspective of therapeutics. A typical nanovector consists of a nanoparticle core coated with a targeting agent specific to the target cells and a biomolecule with designated functionality. The nanovector must be detectable by at least one characterization technique to validate its location in vivo and to evaluate its therapeutic effects in a time course. The nanovector specifically targets cancer cells and thus imposes minimal side effects to healthy tissue. For therapeutic payload delivery, a mechanism must be established to release the drug from the nanovector after entry to the target cell to induce cellular apoptosis or inhibit cell migration or proliferation. We develop new techniques to synthesize nanoparticles, modify nanoparticles with different chemistries, and functionalize nanoparticles with various targeting agents and therapeutic drugs.