Contactless magnetic heating may sound scary, but it is part of your daily life experience. Every time you heat-up your morning coffee mocha with an induction cooker, you are using magnetic fields and magnetic materials. But can this kind of heating also be used to solve high-tech problems? This is the question that scientists are trying to answer in the H2020-FETOPEN project HOTZYMES.

In this project, the scientists focus on enzymes. Enzymes are biological molecules that activate or speed up industrial processes like the production of biofuels, cosmetic products or antitumoral drugs. They are becoming more and more important in biotechnological industry. However, there are still some technical problems that hamper the progress of different biotechnological sectors.

Since enzymes are biological molecules, they operate at characteristic temperatures. Some of them like to operate at body temperatures, others are more efficient at high temperatures. For this reason, processes that involve many enzymes become complicated and, in some cases, enzymes with very different operational temperatures cannot be used together. The solution proposed in HOTZYMES is to control the local temperature of enzymes using magnetic nanoparticles and high frequency magnetic fields. This approach is not only technologically advantageous but also more efficient than conventional heating systems, offering the possibility of creating different temperatures in the same reactor by using magnetic nanoparticles.

Magnetic nanoparticles: how small can we heat?

Magnetic materials – like your inductive mocha – are able to absorb the magnetic fields and transform them to heat in a very efficient manner. A deeper understanding of the process will help us to find innovative ways to exploit this technique. If a magnetic field is applied in the presence of a magnetic material, the magnetic moments of the material will align in the direction of the field, just like atomic compasses. When the magnetic field is reversed, the magnetic moments will reverse too but with a certain delay. Such delay is dissipated in the magnetic material as heat. In the case of magnetic nanoparticles, due to their tiny size, this only happens when the applied field is switched very fast (high frequencies). Thus applying alternating magnetic fields to solutions containing MNPs could trigger their activation as nanoheaters.

Enzymes and magnetic nanoparticles: better together

The key idea of this project is the combination of enzymes involved in multi-enzymatic processes with magnetic nanoparticles that regulate their temperature. Attaching “hot-spicy” enzymes to powerful nanoheaters and “chill-out” enzymes to weaker nanoheaters, both enzymes can operate comfortably together and increase the yield of the process.

An alternative approach studied also in the project consist on using different field conditions to trigger one enzyme at a time to create a sequential process. Some technological difficulties that the scientists are facing is the control of the enzyme orientation on the surface of magnetic nanoparticles, the aggregation of magnetic nanoparticles in the presence of a magnetic field or the effect of enzymes in the heating performance of the nanoparticles. But, despite these challenges, the preliminary results obtained so far indicate the great potential of this technology to improve the efficiency of many processes in biotechnological industry.

The research for this work has received funding from the European Union (EU) project HOTZYMES (grant agreement n° 829162) under  EU’s Horizon 2020 Programme  Research and Innovation actions H2020-FETOPEN-2018-2019-2020-01