Dozens, if not hundreds, of research teams around the world are developing nanoparticles that can deliver targeted forms of therapy directly to the cancer. One issue with bringing this technology to the clinic involves identifying when the particles have arrived at their target so that therapy can begin. Researchers from Rice University and Baylor College of Medicine (BCM) have now created nanoparticles that can be monitored as they move through the body in real-time on MRI.
The all-in-one particles are based on nanoshells — particles [Naomi Halas, Rice Professor in Electrical and Computer Engineering] 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 Molecular Imaging, 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 cancer cells 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 nanoparticles 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.
Press release: Tracking new cancer-killing particles with MRI…
Abstract in Advanced Functional Materials: Nanoshells with Targeted Simultaneous Enhancement of Magnetic and Optical Imaging and Photothermal Therapeutic Response
Image credit: Wellcome Library
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