Danish researchers at the UCPH (University of Copenhagen) created a sensor capable of detecting extremely low intensity magnetic fields generated by the activity of human cells, such as neurons and heart’s muscle cells. The human body, like those of all animals, overflows with electrical impulses, which generate weak magnetic fields. These fields are already used in medical tests, such as MRI, but their detection requires large and expensive equipment based on superconducting magnets cooled to cryogenic temperatures.
The new ultra-sensitive sensor is extremely small, operates at room (or body) temperature, and generates an optical reading of tiny magnetic fields. This highly versatile instrument can be used on a wide range of applications, especially in the medical field.
According to Kasper Jensen, Quantum Optics professor at Niels Bohr Institute, the device consists of a small-sized glass container filled with caesium vapour. Individual caesium atoms react to external magnetic fields. So by monitoring these atoms with laser light, magnetic readings can be inferred.
Caesium vapour is widely used in magnetometers owing to its high magnetic sensitivity.
The new “optical magnetic field sensor” measures only about 1 centimeter long and 1 millimeter wide. To read a magnetic field, it simply needs to be brought close to the nerve. The cells’ electrical activity generates a magnetic field, which changes the spin of the atoms within the sensor. This change is detected by a laser.
The sensor is so powerful that it can help calculate the speed of the nerve impulses, which is useful to detect diseases where nerve cells are damaged. Another advantage is that magnetic fields of nerve cells can be read several centimeters away by the sensor, hence the sensor does not need to touch the body.
Eugene Polzik, team member and director of Quantop at Niels Bohr Institute, explains that it could help diagnose and treat eye diseases, multiple sclerosis or even Alzheimer’s because of the way the nerve impulses degrade. Furthermore, cardiac activity in fetuses could be easily monitored by simply placing the sensor on the mother’s belly. Congenital heart problems could be diagnosed at an early phase.
Economic and practical imperatives propel a persistent search for increasingly automated and non-invasive diagnosis solutions in the medical industry. This new technology can drastically simplify and speed up the diagnosis of many diseases, and potentially help replace current equipment for simpler, cheaper and more portable devices in medical rooms.