Tiny robots can track down and kill cancer cells

It might sound like sci-fi, but it's real.

The sci-fi future we’ve been waiting for is almost here.

Tiny robots that can target and kill cancer cells have been created by scientists in an exciting breakthrough for future treatments.

The nanorobots work by activating the cell’s ‘death receptors’, helping to shrink tumours.

However, because all cells have death receptors, the challenge has been finding a ‘kill switch’, ensuring the nanorobots only target the cancer.

The team, from the Karolinska Institutet in Sweden, had previously discovered how to create miniscule robots made of amino acids that could be injected and activate death receptors.

Think the 1987 cult classic Innerspace, but without a tiny Dennis Quaid at the controls.

‘This hexagonal nanopattern of peptides becomes a lethal weapon,’ said Professor Björn Högberg, who led the study, published in the journal Nature Nanotechnology.

‘If you were to administer it as a drug, it would indiscriminately start killing cells in the body, which would not be good. To get around this problem, we have hidden the weapon inside a nanostructure built from DNA.’

Building miniscule, or nanoscale, structures from DNA is known as DNA origami, something Professor Högberg’s team has been working on for many years.

Now, by combining the DNA and peptides, they have discovered how to create the essential kill switch, so it only targets cancerous cells, not healthy ones.

The key is in the pH level. The pH, or potential of hydrogen, scale is a measure of how acidic or alkaline a substance is. Pure water has a pH of seven, and is neutral. Anything from zero to six is acidic, and eight to 14 is alkaline.

In most parts of the human body, the pH level is around 7.4, also neutral (although stomach acid is, luckily for us, very strong). However, the areas surrounding tumours are typically slightly acidic. In lab tests, the team found the nanorobots were inactive at pH 7.4, but began killing cells at pH 6.5.

‘We have managed to hide the weapon in such a way that it can only be exposed in the environment found in and around a solid tumor,’ said Professor Högberg. ‘This means that we have created a type of nanorobot that can specifically target and kill cancer cells.’

Further testing on mice revealed the robots helped shrink breast cancer tumours by up to 70% compared to those given an inactive version.

First author Yang Wang said: ‘We now need to investigate whether this works in more advanced cancer models that more closely resemble the real human disease.

‘We also need to find out what side effects the method has before it can be tested on humans.’

The team also hopes to make the nanorobots even more specific and able to target certain types of cancer.