A new method of delivering drugs on the nanoscale, developed at University of Rhode Island, uses spherical liposomes to ferry chemicals to disease sites and an electromagnetic field to release them at appropriate time. According to the researchers, the next big step is getting the liposomes to actually hone in on correct disease targets, which would combine precise targeting with carefully regulated drug delivery
The superparamagnetic iron oxide nanoparticles the researchers embed in the shell of the liposome release the drug by making the shell leaky when heat-activated in an alternating current 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,” explained 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 – they have a strong affinity for water – and others are hydrophobic – they avoid water. 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 water-loving drug 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.”
Press release: URI researchers develop drug delivery system using nanoparticles triggered by electromagnetic field …
Abstract in ACS NANO: Controlled Release from Bilayer-Decorated Magnetoliposomes via Electromagnetic Heating
