URI engineers develop drug-delivery system

The team has developed nanoparticles embedded in a liposome that can be triggered by electromagnetic fields.

According to URI professor Geoffrey Bothun, liposomes are spherical structures made of lipids that can trap different drug molecules inside them for use in delivering those drugs to targeted locations in the body.

Superparamagnetic iron-oxide nanoparticles embedded in the shell of the liposome release the drug by making the shell leak when heat activated in an AC electromagnetic field operating at radio frequencies.

‘We’ve shown that we can control the rate and extent of the release of a model drug molecule by varying the nanoparticle loading and the magnetic-field strength,’ said Bothun. ‘We get a quick release of the drug with magnetic-field heating in a matter of 30 to 40 minutes and without heating there is minimal spontaneous leakage of the drug from the liposome.’

Bothun said that the liposomes self-assemble because portions of the lipids are hydrophilic and others are hydrophobic. When he mixes lipids and nanoparticles in a solvent, adds water and evaporates off the solvent, the materials automatically assemble themselves into liposomes. The hydrophobic nanoparticles and lipids join together to form the shell of the liposome, while the hydrophilic molecules are captured inside the spherical shell.

‘The concept of loading nanoparticles within the hydrophobic shell to focus the activation is brand new,’ Bothun said. ‘It works because the leakiness of the shell is ultimately what controls the release of the drugs.’

The next step in the research is to design and optimise liposome/nanoparticle assemblies that can target cancer cells or other disease-causing cells. In-vitro cancer-cell studies are already underway in collaboration with URI pharmacy professor Matthew Stoner.