Tracking new cancer-killing particles with MRI

Dec 14, 2009
Tracking new cancer-killing particles with MRI
This is Naomi Halas from Rice University. Credit: Rice University

Researchers at Rice University and Baylor College of Medicine (BCM) have created a single nanoparticle that can be tracked in real time with MRI as it homes in on cancer cells, tags them with a fluorescent dye and kills them with heat. The all-in-one particle is one of the first examples from a growing field called "theranostics" that develops technologies physicians can use to diagnose and treat diseases in a single procedure.

The research is available online in the journal Advanced Functional Materials. Tests so far involve laboratory cell cultures, but the researchers said MRI tracking will be particularly advantageous as they move toward tests in animals and people.

"Some of the most essential questions in nanomedicine today are about biodistribution -- where particles go inside the body and how they get there," said study co-author Naomi Halas. "Noninvasive tests for biodistribution will be enormously useful on the path to FDA approval, and this technique -- adding MRI functionality to the particle you're testing and using for therapy -- is a very promising way of doing this."

Halas, Rice's Stanley C. Moore Professor in Electrical and Computer Engineering and professor of chemistry and , is a pioneer in nanomedicine. The all-in-one particles are based on nanoshells -- particles she invented in the 1990s that are currently in human clinical trials for cancer treatment. Nanoshells harvest laser light that would normally pass harmlessly through the body and convert it into tumor-killing heat.

In designing the new particle, Halas partnered with Amit Joshi, assistant professor in BCM's Division of , to modify nanoshells by adding a fluorescent dye that glows when struck by near-infrared (NIR) light. NIR light is invisible and harmless, so NIR imaging could provide doctors with a means of diagnosing diseases without surgery.

In studying ways to attach the dye, Halas' graduate student, Rizia Bardhan, found that dye molecules emitted 40-50 times more light if a tiny gap was left between them and the surface of the nanoshell. The gap was just a few nanometers wide, but rather than waste the space, Bardhan inserted a layer of iron oxide that would be detectable with MRI. The researchers also attached an antibody that lets the particles bind to the surface of breast and ovarian cancer cells.

In the lab, the team tracked the fluorescent particles and confirmed that they targeted and destroyed them with heat. Joshi said the next step will be to destroy whole tumors in live animals. He estimates that testing in humans is at least two years away, but the ultimate goal is a system where a patient gets a shot containing with antibodies that are tailored for the patient's cancer. Using NIR imaging, MRI or a combination of the two, doctors would observe the particles' progress through the body, identify areas where tumors exist and then kill them with heat.

"This particle provides four options -- two for imaging and two for therapy," Joshi said. "We envision this as a platform technology that will present practitioners with a choice of options for directed treatment."

Eventually, Joshi said, he hopes to develop specific versions of the particles that can attack cancer at different stages, particularly early stage cancer, which is difficult to diagnose and treat with current technology. The researchers also expect to use different antibody labels to target specific forms of the disease. Halas said the team has been careful to choose components that are either already approved for medical use or are already in clinical trials.

"What's nice is that every single component of this has been approved or is on a path toward FDA approval," Halas said. "We're putting together components that all have good, proven track records."

More information: Nanoshells with Targeted Simultaneous Enhancement of Magnetic and Optical Imaging and Photothermal Therapeutic Response, DOI:10.1002/adfm.200901235

Source: Rice University (news : web)

Explore further: Dye-sensitized solar cell absorbs a broad range of visible and infrared wavelengths

add to favorites email to friend print save as pdf

Related Stories

Rice University researchers create 'nanorice'

Mar 14, 2006

Who better to invent "nanorice" than researchers at Rice University? But marketing and whimsy weren't what motivated the team of engineers, physicists and chemists from Rice's Laboratory for Nanophotonics (LANP) ...

Study shows nanoshells ideal as chemical nanosensors

Jan 11, 2005

'Nanoshells' enhance sensitivity to chemical detection by factor of 10 billion New research published in the Proceedings of the National Academy of Science finds that tailored nanoparticles known as nanoshells can enhanc ...

Nanoparticles Designed for Dual-Mode Imaging

Dec 18, 2006

Nanoscale, inorganic fluorescent imaging agents such as quantum dots have become an important tool for researchers studying key biomolecules involved in cancer. At the same time, magnetic iron oxide nanoparticles are proving ...

Recommended for you

A new way to make microstructured surfaces

23 hours ago

A team of researchers has created a new way of manufacturing microstructured surfaces that have novel three-dimensional textures. These surfaces, made by self-assembly of carbon nanotubes, could exhibit a ...

Tough foam from tiny sheets

Jul 29, 2014

Tough, ultralight foam of atom-thick sheets can be made to any size and shape through a chemical process invented at Rice University.

Graphene surfaces on photonic racetracks

Jul 28, 2014

In an article published in Optics Express, scientists from The University of Manchester describe how graphene can be wrapped around a silicon wire, or waveguide, and modify the transmission of light through it.

User comments : 0