Uniquely shaped magnetic nanoparticles offer a breakthrough in cancer therapy

Uniquely shaped magnetic nanoparticles offer a breakthrough in cancer therapy

New magnetic nanoparticles shaped like a cube between two pyramids represent a breakthrough for the treatment of ovarian tumors and possibly other cancers, according to the Oregon State University researchers who developed them.

The scientists say the study highlights the importance of shape in magnetic nanoparticle design and that the results may revolutionize treatments that use heat to damage or kill cancer cells.

The nanoparticles are made of iron oxide and doped with cobalt. Doping refers to the addition of something as a means of adjusting characteristics.

When the particles accumulate in cancer tissue after intravenous injection, they can quickly rise to temperatures that weaken or destroy cancer cells.

The mouse model study, published in advanced functional materials, is part of ongoing nanomedical research by scientists at the OSU College of Pharmacy.

Nanoparticles are as tiny as a billion meters, which have special properties due to their small size and high surface area to volume ratio.

Magnetic nanoparticles have shown anticancer potential for years, the scientists said, but currently magnetic hyperthermia can typically only be used for patients whose tumors are accessible through a hypodermic needle — that is, if the particles can be injected directly into the cancer.

With currently available magnetic nanoparticles, the required therapeutic temperatures – above 44 degrees Celsius – can only be achieved through direct injection. And these nanoparticles only have moderate heating efficiency, meaning they need a high concentration in the tumor - higher than systemic administration normally - to generate enough heat. “

Oleh Taratula, Professor of Pharmaceutical Sciences, Oregon State University

Taratula and collaborators at Oregon State, Oregon Health & Science University and the Indian Institute of Technology Mandi used a novel heat-decomposition method—a two-step process they call seeding and growth—to make cobalt-doped iron oxide nanoparticles in a cubic bipyramid shape. Their paper is the first report of this type of nanoparticles with this specific shape.

“These nanoparticles exhibit a remarkable ability to heat rapidly, increasing temperatures by 3.73 degrees Celsius per second under an alternating magnetic field,” said Prem Singh, a postdoctoral fellow in the College of Pharmacy. “This is twice as high as the heating power of our previously published cobalt-doped iron oxide nanoparticles.”

This means that an ovarian cancer patient could receive an intravenous injection and have their tumor stop after a 30-minute, non-invasive magnetic field session. Short treatment sessions improve patient comfort and compliance, researchers say.

A cancer targeting peptide helps the nanoparticles in the tumor, and because the heating efficiency of the particles is so strong, the necessary concentration of nanoparticles can be achieved without high dosage, limited toxicity and side effects.

“This is the first time that systemically injected nanoparticles heat tumors beyond 50°C, significantly exceeding the therapeutic threshold of 44°C for effective treatment at a clinically relevant dose,” said Olena Taratula, associate professor of pharmaceutical sciences at OSU. “There is now great potential to apply magnetic hyperthermia to a variety of difficult-to-reach populations, making the treatment more versatile and widely available.”

Karthickraja Duraisamy at Oregon State, Constanzraitmayr, Shitaljit Sharma, Tetiana Korzun, Abraham Moses, Vladislav Grigoriev, Ananiya Demessie, Youngrong Park, Yoon, also Babak Mamnoon and Ana Paula Mesquita Mesquita.

The National Cancer Institute of the National Institutes of Health and the Eunice Kennedy Shriver National Institute of Child Health and Human Development supported this research.

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