March 20, 2011
A team of scientists including researchers from the University of Toronto and Princess Margaret Hospital have created an organic nanoparticle that is completely non-toxic, biodegradable and nimble in the way it uses light and heat to treat cancer and deliver drugs. (A nanoparticle is a minute structure with novel properties).
The findings, published online today in Nature Materials (DOI: 10.1038/NMAT2986) are significant because unlike other nanoparticles, the new nanoparticle has a unique and versatile structure that could potentially change the way tumours are treated, says principal investigator Professor Gang Zheng
, of the Institute of Biomaterials & Biomedical Engineering (IBBME) at the University of Toronto and Senior Scientist, Ontario Cancer Institute (OCI), Princess Margaret Hospital at University Health Network.
“In the lab, we combined two naturally occurring molecules (chlorophyll and lipid) to create a unique nanoparticle that shows promise for numerous diverse light-based (biophotonic) applications,” Professor Zheng said. “The structure of the nanoparticle, which is like a miniature and colourful water balloon, means it can also be filled with drugs to treat the tumor it is targeting.”
It works this way, explains first author Jonathan Lovell
, a doctoral student at IBBME and OCI: “Photothermal therapy uses light and heat to destroy tumours. With the nanoparticle’s ability to absorb so much light and accumulate in tumours, a laser can rapidly heat the tumour to a temperature of 60 degrees and destroy it. The nanoparticle can also be used for photoacoustic imaging, which combines light and sound to produce a very high-resolution image that can be used to find and target tumours.”
Once the nanoparticle hits its tumour target, it becomes fluorescent to signal “mission accomplished,” he added.
This nanomaterial is also non-toxic, explained Professor Warren Chan
of IBBME, another author of the paper. “Jon Lovell and Gang Zheng created a material that doesn't have metals, [which] means no toxins, but with similar tunable properties to its metal nanostructure brother,” he said. This is the first reported organic nanostructure with such a unique feature, he noted, and so provides a significant opportunity to explore unique designs of organic nanostructures for biomedical applications without concerns regarding toxicity.
“There are many nanoparticles out there, but this one is the complete package," said Professor Zheng, "a kind of one-stop shopping for various types of cancer imaging and treatment options that can now be mixed and matched in ways previously unimaginable. The unprecedented safety of this nanoparticle in the body is the icing on the cake. We are excited by the possibilities for its use in the clinic.”Read the full research article on Nature Materials online.
Collaborators on this research were: Jonathan F. Lovell (Institute of Biomaterials & Biomedical Engineering, University of Toronto; Ontario Cancer Institute, University Health Network), Chen S. Jin (IBBME; OCI), Elizabeth Huynh (OCI; University of Toronto Department of Medical Biophysics); Honglin Jin (OCI; U of T Medical Biophysics); Chulhong Kim (Department of Biomedical Engineering, Optical Imaging Lab, Washington University), John L. Rubinstein (U of T Medical Biophysics; Hospital for Sick Children), Warren C. W. Chan (IBBME, CCBR), Weiguo Cao (Department of Chemistry, Shanghai University), Lihong V. Wang (Biomedical Engineering, Washington University), Gang Zheng (IBBME; OCI; U of T Medical Biophysics)
The research was financially supported by grants and fellowships from the Ontario Institute for Cancer Research, the Canadian Cancer Society, the Natural Sciences and Engineering Research Council of Canada, the Canadian Institute of Health Research, the Joey and Toby Tanenbaum/Brazilian Ball Chair in Prostate Cancer Research, and in part from the Campbell Family Institute for Cancer Research and the Ministry of Health and Long-Term Care , and The Princess Margaret Hospital Foundation.