Researchers have developed new superparamagnetic crystals that could zip down drugs around your body, revolutionising drug delivery to tumours and other sites in the body that need to be targeted precisely.

In the past, this was thought to be impossible - the crystals, which have special magnetic properties, were so small that scientists could not control their movement.

However, in the new study, a team of Chinese researchers developed a method of producing superparamagnetic crystals that are much larger than any that have been made before -- a discovery which has opened new applications that could use these crystals to improve and perhaps even save many lives.

"These larger crystals are easier to control using external magnetic fields, and they will not aggregate when those fields are removed, which will make them much more useful in practical applications, including drug delivery," Kezheng Chen from Quingdou University of Science and Technology in Quingdou, China.

Further, Chen's crystals might, be useful in the many engineering projects that need "smart fluids" who change their properties when a magnetic field is applied.

They can also be used to build more comfortable and realistic prosthetic limbs, the researchers said, in the paper published in the journal Physics Letters A.