Researchers at Caltech have been able to create a chip that mimics the properties of MRI, a very bulky machinery, so tiny that it can be injected in the body, through arteries, or can be swallowed to explore the gastrointestinal tract.
The micro chip is in shape of a cube, less than one cubic millimetre and contains magnetic sensors plus the radio systems to communicate with an external probe and can be equipped with specific sensors as needed.
The chip can either move inside the body following the flow of blood or food or it can be steered using magnetic fields to an exact location. It can be localised within a theoretical 0.3 mm space and in practice it has been shown to be localised with sub-millimetre precision.
The chip can be equipped with a battery, an extremely tiny one, or it can receive power from the external probe using frequencies in the range of 1GHz (your home wifi would be ok to power it…).
The localisation system is based on the detection of electronic spin, at the bases of the MRI working. This provides an extremely accurate localisation in a 3D space. Three magnetic fields emitted from different places provide the required spatial triangulation to detect the position. Additionally, they can be used to steer the chip in the desired position.
This sub-millimetric precision opens the door to very precise observation at cell level. So far it has been experimented in vivo on mice showing that it performs as expected.