Using this method Magnetic nano-particles are triggered by an alternating current to “shoot” their heat at a tumor cell effectively frying the cancer and leaving healthy cells in tact. It is meant to target small tumors and metastatic cancer cells where surgery is impossible
In the past unsuccessful clinical trials were conducted on cancerous human brain tissue.
Due to the bodies natural all encompassing heat source carried around by blood flow smaller tumors get “lost in the noise” and so are harder to target – requiring more heating power from magnetic particles.
Previous studies focused on adjusting the shape/morphology of the magnetic nano-particle in order to better “aim” the magnetic field. In so doing they created these nano-particles with high “specific loss power” and high magnetic field strength. However, it still wasn’t enough.
Loss power depends on magnetic anisotropy (MA) which is a term used to describe the difficulty of magnetizing material in a specific direction, so when a nano-particle has high specific loss power, a lot of power is being lost due to “missing the target”.
Scientists thought that by wrapping a bunch of particles with different MA in a shell, or by changing the geometry of the particle itself, they could increase the field strength enough to target small tumor cells. However the problem was that much of this extra heat and magnetism was too chaotically dispersed i.e. high specific loss power.
In this new study published in the journal “Small” scientists discovered that the density of the outer layer is more important rather than the position or shape of each particle.
All this team did was swap out the top layer for a harder more magnetic alloy. What they ended up with was a soft less magnetic core wrapped in a harder more magnetic surface. They discovered that by “painting on” just the right amount of hard alloy magnetic nano-particles can be “tuned at will” to fry a particular size of cancer tumor.
These nano-particles also possess low toxicity. Even lower than FDA approved magnetite nanoparticles used in MRIs.
Scientists have essentially achieved what was previously thought to be impossible – a high heating rate at a low field amplitude and frequency that is several times to a whole order of magnitude higher than any particles previously synthesized. In so doing they’ve past a milestone that makes the nanoparticles suitable for clinical applications.
Zeng states, “The mechanism of ac field heating of nanoparticles is not different from that of an induction oven, except that the size of each individual particle used to fry cancer cells is ten million times smaller than a typical frying pan. As such, it would allow heat to be released locally on cancerous cells and spare healthy tissues.”
As far as the experiment itself is concerned scientists mixed in nanoparticles with bone cement for grafting on to a surgically removed tumorous pig bone.
The next step to implantation requires conducting human clinical trials.
Image courtesy of Small Issue 29, 2018.