A discovery by Chinese researchers may soon change the way drugs are delivered in your body, making it possible for doctors to target diseased organs for quick recovery.
In the past, microscopic crystals with special magnetic properties were so small that scientists could not control their movement. However, Kezheng Chen and Ji Ma from Quingdou University of Science and Technology, Quingdou, China have now published a new method of producing superparamagnetic crystals that are much larger than any that have been made before.
If some magnetic materials, such as iron oxides, are small enough — perhaps a few millionths of a millimetre across, smaller than most viruses — their magnetisation randomly flips as the temperature changes.
By applying a magnetic field to these crystals, scientists can make them almost as strongly magnetic as ordinary fridge magnets. It might seem odd, but this is the strongest type of magnetism known. This phenomenon is called superparamagnetism.
In theory, superparamagnetic particles could be ideal for drug delivery, as they can be directed to a tumour simply by using a magnetic field.
“The largest superparamagnetic materials that we have been able to make before now were clusters of nanocrystals that were together about a thousand times smaller than these,” said Dr. Chen.
“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,” he added.
Chen and Ma were able to produce crystals that grow under high stresses and strains, giving them unusual pock-marked appearance on the surface that are responsible for their unusual magnetic properties.
This method of making larger superparamagnetic crystals paves the way for the development of superparamagnetic bulk materials that can be reliably controlled by moderate external magnetic forces, revolutionising drug delivery to tumours and other sites in the body that need to be targeted precisely.