Chemotherapy is frequently used to treat cancer patients, often successfully, but there is usually a price to pay in the form of unpleasant side effects. This is because the strong drugs used to attack the cancer cells can attack healthy cells as well. It is therefore crucial to design delivery systems that take the drugs right to the tumour, without interfering with the rest of the body on the way.

Professor Steve Armes and his team from The University of Sheffield are developing a drug delivery method for a particularly aggressive type of cancer. Professor Armes explains:

"So-called 'triple-negative' (TN) breast cancer is hard to treat: it is highly aggressive and does not respond to conventional targeted therapies based on estrogen, progesterone or Her-2 receptors. The only option in such cases is chemotherapy, which has well-known unpleasant side-effects.

"Our in vitro experiments suggest that anti-cancer drugs can be delivered into hard-to-treat cancer cells more selectively, i.e. with fewer side effects for neighbouring healthy cells."

Drug delivery methods normally take the form of tiny nanoparticles that hold the drug inside and are designed to open when they arrive at the tumour. In designing nanoparticles to target this particular cancer, Professor Armes and his team took inspiration from an unusual source – the dengue virus.

The dengue virus possesses a pH-sensitive surface, which causes it to change its structure when it senses a change in pH. The researchers have taken inspiration from the pH-sensitive dengue virus to design their own pH-sensitive nanoparticle with a similar structure. The breast cancer cells are more acidic than healthy cells, so when the nanoparticle reaches the cancer cells it changes in structure, releasing the drug.

So far this approach has only been used in vitro – the next step is to make a similar structure out of biodegradable nanoparticles, so the system could be used in the body.

This article is free to read in our open access, flagship journal Chemical Science: Charlotte J. Mable, Irene Canton, Steven P. Armes et al., Chem. Sci., 2019, Advance Article. DOI: 10.1039/C8SC05589K. You can access our 2019 ChemSci Picks in this article collection.