A team of scientists around Dr. Gang Zheng and Jonathan Lovell, Ontario Cancer Institute (OCI), Princess Margaret Hospital at University Health Network, Canada, have created porphysome nanovesicles by porphyrine bilayers that are completely non-toxic, biodegradable and nimble in the way they use light and heat to treat cancer and deliver drugs.
Two naturally occurring molecules, chlorophyll and a lipid, were combined to create this unique nanoparticle that shows promise for numerous diverse light-based (biophotonic) applications. The polysomes are nanovesicles formed from self-assembled porphyrin bilayers that generate large, tunable extinction coefficients, structure-dependent fluorescence self-quenching and unique photothermal and photoacoustic properties. Similar to liposomes or like a miniature and colorful water balloon, the large aqueous core of the porphysomes can be loaded passively or actively, e.g. with drugs to treat the tumor it is targeting.
Photothermal therapy uses light and heat to destroy tumors. With the nanoparticle’s ability to absorb so much light and accumulate in tumors, a laser can rapidly heat the tumor to a temperature of 60° 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 tumors. Once the nanoparticle hits its tumor target, it becomes fluorescent to signal “mission accomplished”.
- Porphysome nanovesicles generated by porphyrin bilayers for use as multimodal biophotonic contrast agents,
Jonathan F. Lovell, Cheng S. Jin, Elizabeth Huynh, Honglin Jin, Chulhong Kim, John L. Rubinstein, Warren C. W. Chan, Weiguo Cao, Lihong V. Wang, Gang Zheng,
Nature Mat. 2011.