Multi-tasking nanoparticle both seeks and destroys cancerous cells
By Nick Lavars
August 27, 2014
Nanoparticles hold great potential as a way of both detecting cancer cells and delivering the drugs to treat them. One hurdle that has proven difficult to overcome is incorporating these properties into one multi-purpose device, as nanoparticles are generally engineered with either goal in mind. In what appears a promising development, researchers at the University of California Davis (UC Davis) Cancer Center have created a multi-tasking nanoparticle shown to be effective both in the diagnosis of a tumor and attacking its cells – a flexibility that could lead to new treatment options for cancer patients.
Nanoparticles are constructed using either inorganic or organic compounds, each with strengths of their own. Inorganic nanoparticles, such those made from gold, are effective in imaging and diagnostics. Particles made from organic compounds on the other hand, are biocompatible and provide a safe method of drug delivery, but without the great imaging potential.
The nanoparticles developed at UC Davis are built on a polymer made from a common organic compound called porphyrin and cholic acid, which is produced by the liver. The researchers then added cysteine to create a fluorescent carbon nanoparticle (CNP). This final ingredient is an amino acid serving to stop the particle prematurely releasing its payload as it moves through blood proteins and other barriers.
The team then put its new nanoparticle to the test, observing its effects across a range of tasks, both in vitro and in vivo. They found the particle was effective in delivering cancer-fighting drugs such as doxorubicin (commonly used in chemotherapy). Furthermore, applying light (known as photodynamic therapy) causes them to release reactive molecules called singlet oxygen that destroy tumor cells, while heating them with a laser (known as photothermal therapy) provided another way for the particles to destroy tumors.
One notable finding was that the release of a payload sped up as the particle was exposed to light. The researchers claim this ability to manipulate chemotherapy release rates from inside the tumor could help to minimize toxicity.
In relation to imaging and phototherapy, the nanoparticle remained in the body for extended periods and bonded with imaging agents. And because CNPs are drawn more to tumor tissue than normal tissue, it helps to improve contrast and light them up for MRI and PET scans.
"This is the first nanoparticle to perform so many different jobs," says Yuanpei Li, research faculty member from the UC Davis Cancer Center. "From delivering chemo, photodynamic and photothermal therapies to enhancing diagnostic imaging, it’s the complete package."
The team is now focusing on further pre-clinical studies, with a view to advancing to human trials if all goes to plan.
The research was published in the journal Nature Communications.
Source: UC Davis