Nanoparticles get in shape for drug delivery

Polymeric nanoparticles are expected to play a vital role in the future of medicine, carrying drugs to exactly where they are needed to help attack and kill cancer cells. Now, UNSW researchers have answered a longstanding question that could lead to better drug delivery vehicles: how does a nanoparticle’s shape affect its voyage through the cell?

In a study published in the journal Nature Nanotechnology, UNSW engineers fabricated four types of nanoparticles — one shaped like a rod, one like a worm and two that were spherical — which were labelled with fluorescent tags and incubated in cancer cells. Using pair correlation microscopy, the researchers were able to track the movement of the differently shaped nanoparticles through a single cultured cancer cell, with very high temporal and spatial resolution.

“You need to know how things arrive at their final destination in order to target them there,” noted lead author Dr Elizabeth Hinde.

While the spherical particles got blocked by the nuclear envelope, the rod- and worm-shaped particles were able to pass through. Furthermore, the researchers found that the cancer drug doxorubicin was most effective when it could breach the strong yet porous cellular barrier protecting the nucleus — the cell’s control centre.

“Cancer cells have different internal architecture than healthy cells,” said Dr Hinde. “If we can fine-tune the dimensions of these rod-shaped nanoparticles, so they only pass through the cellular barriers in cancer cells and not healthy ones, we can reduce some of the side effects of chemotherapies.”

Professor Justin Gooding, a co-author on the study, said its impact on the field will be huge. “It gives us the ability to look inside the cell, see what the particles are doing and design them to do exactly what we want them to do,” he said.

“And this isn’t just thanks to the microscope, but the information and data we can extract from the new analysis procedures we’ve developed. If other research groups can learn how to do this analysis, they can use the equipment already in their labs and get started tomorrow.”