Rute Pereira, a PhD student of the University of Aveiro, Portugal, and her research group could synthesize magnetic nanoparticles with ability to change drastically their magnetic behaviour in response to small temperature fluctuations, around the room temperature. Interestingly, such magnetic nanoparticles can have valuable biomedical applications, such as in anti-cancer hyperthermia.
Are you curious to know why these nanoparticles are so special and how they can open new pathways in the biomedical field? Here, we’re going to explain you everything!
Magnetic nanoparticles are particles smaller than 1 micrometre of diameter, which have received a special attention due to their ability to be manipulated or even located using external magnetic fields. Such particles are commonly composed of two components:
(1) a magnetic material, often iron; (2) and a chemical component that has functionality.
Rute’s nanoparticles are composed of iron and selenium, called iron selenids (Fe3Se4), and have a distinctive and quite unique behaviour: they can dramatically change their magnetic properties close to room temperature (between 40 ºC and 47 ºC), while the remaining magnetic particles explored so far have magnetic properties almost constant around this temperature. In a practical way, such particles act as “temperature nano-sensors”, answering Yes or No to the question: “Did the system locally exceed a certain temperature threshold?”.
Representation of an Fe3Se4 nanoparticle.
Source - DOI: 10.1039/c8mh01510d.
Given these results, Rute and her research group asked: What are the possible biomedical applications of these nanoparticles? Since the nanoparticles are temperature-sensitive in the range of 40-47 ºC, they probably could be useful in anti-cancer hyperthermia.
Hyperthermia is a type of cancer treatment, in which the body tissue is exposed to high temperatures (> 45 ºC), occurring the damage and death of cancer cells, usually with minimal injury to normal cells/tissues. In order to evaluate the potentiality of the nanoparticles for monitoring temperature during anticancer hyperthermia, researchers designed a testing platform, as shown in the figure below.
Design of the testing platform. Source - DOI: 10.1039/c8mh01510d.
After magnetization of the nanoplatelets, they used irradiation to increase the temperature and observed that when temperature raised above 42ºC (threshold), the nanoparticles changed suddenly their magnetic behaviour, which was correlated with the death of cancer cells (red cells), as shown in the next figure.
Scheme showing the use of the nanoparticles to possibly detect a temperature change (above 42 ºC) during different irradiation doses. Images B1-B9 were obtained by fluorescence microscopy of irradiated cells. B1-B3 correspond to images of non-irradiated cells; B4-B6 correspond to irradiated cells with the record temperature bellow 42ºC; and B7-B8 correspond to irradiated cells with the record temperature above 42ºC.
Source - DOI: 10.1039/c8mh01510d
The authors end up by saying: “We further expect that the switching behaviour of the nanomagnets developed here can inspire biosensing in general”. Actually, this study opened new doors, opened new pathways to other emergent applications.
Meanwhile, we will keep waiting for the next episodes of this promising story!
References:
Oliveira-Silva, R., et al. (2019). Temperature-responsive nanomagnetic logic gates for cellular hyperthermia. Materials Horizons, 6(3), 524–530. DOI: 10.1039/C8MH01510D
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