Magnetised particles mimic blood cells

When white blood cells are summoned to combat germs, they travel along blood vessels to their point of deployment, explained the Federal Institute of Technology (ETH) in a statement.

This behaviour inspired ETH postdoc Daniel Ahmed, who works in ETH Professor Bradley Nelson's research group, to develop a transport mechanism for nanodrugs. The mechanism involves injecting commercially available, biocompatible magnetic particles into an artificial vasculature.

The application of a rotating magnetic field encourages these particles to self-assemble into aggregates and start to spin around their own axes. Targeted application of ultrasound moves the aggregates in the desired direction. When the magnetic field is switched off, the aggregates disassociate into their constituent parts and disperse in the fluid stream.

The research group intends to use this transport mechanism to “deliver drugs in hard-to-reach sites within the body and integrate it with imaging modalities,” explained Ahmed in the statement. He cited as an example tumours that can be reached only via narrow capillaries.

To date, Ahmed has only tested this system in artificial channels. The researchers now want to study how magnetic microrollers behave under flow conditions with auxiliary particles, such as red and white blood cells, to uncover whether the magnetic particles can be persuaded to move against the flow. They also intend to test the system in animal models.