Even if solutions don’t tend to fall from the sky, they do at times come from surprising directions. This is what happened when the Adolphe Merkle Institute (AMI) at the University of Fribourg, in collaboration with the Zurich University of Applied Sciences (ZHAW), came to develop an innovative method of characterising nanoparticles (NanoLockin) which will enable the optimisation of cancerous tumour treatment by means of thermal imaging – a technology which was originally intended for the quality control of aircraft spare parts.

The cancer treatment, known as magnetic hyperthermia, makes use of nanoparticles of iron oxide which are introduced into a tumour and then activated by a magnetic field. Exciting the particles in this way causes their temperature to rise and so destroys the cancerous cells.

Hyperthermia is considered by some clinicians to be the fourth pillar of cancer treatment beside surgery, radiotherapy and chemotherapy. In order to eliminate the tumour, however, an optimal dosage of particles is required. So the success of the treatment, approved in the European Union and applied in particular by doctors at the Charité hospital in Berlin, is dependant as much on the properties of the nanoparticles as on those of the magnetic field.

In order to increase the success rate, the researchers at AMI, specialists in the characterisation of the nanometric scale, wanted to get a better idea of the behaviour of the iron oxide particles when heated by a magnetic field. Current systems use an optic fibre immersed in a solution of nanoparticles. This is, unfortunately, not reliable enough, with measuring times being too long and the risk of data being skewed. So, together with their colleagues at ZHAW, they decided to use a thermal imaging technology called “lock-in”, originally developed for the quality control of aircraft spare parts.

Faster, better controlled and more effective
The NanoLockin team at AMI, comprising Dr Christoph Geers and Federica Crippa MSc, is led by Prof. Alke Fink of the Chair of BioNanomaterials. On the basis of the PhD thesis of Dr Christophe Monnier and in collaboration with Dr Mathias Bonmarin of the School of Engineering at ZHAW, the researchers applied this approach to developing the NanoLockin method which enables the precise measurement of the distribution of the nanoparticles and the heat they generate.  In this way, the production and dosage of nanoparticles can be optimised and nanoparticle producers have a precise and simple quality control tool. In the treatment of cancer, for example, one can be certain that the concentration of nanoparticles is in accordance with the therapeutic goal. This also enables the treatment to proceed more rapidly, with greater chances of success and at less cost.

The project is supported financially by the Federal Commission for Technology and Innovation. Other applications of the method are under development.

• www.nanolockin.com
• Monnier et al., A lock-in-based method to examine the thermal signatures of magnetic nanoparticles in the liquid, solid and aggregated states, Nanoscale, 2016, 8, 13321
• SRF, Einstein,  January 2016