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Magnetic nanoparticles are already being characterized during the manufacturing process

PTB News 2.2021
Especially interesting for

manufacturers of nanoparticles

physico-chemical testing laboratories

PTB has developed a measuring instrument that can already characterize the magnetic properties of magnetic nanoparticles reliably during their synthesis. The demonstrator developed within the scope of PTB’s technology transfer program titled TransMeT has now undergone its first functional testing. With this device, it is planned to support the manufacturing of new reference materials for magnetic nanoparticles.

The new inline detector for process control can be used directly during microreaction synthesis. This allows, for instance, a change in the magnetic signal (due to changes in temperature) to be measured in real time during synthesis.

Magnetic nanoparticles (MNPs) are industrially manufactured particles that usually consist of an iron oxide core and an organic shell. They are used in a wide range of applications, such as for biomedical diagnostics or in the loudspeakers of cell phones. Controlling (and therefore measuring) their magnetic properties is important for them to work well in any given application area.

Specific reference materials and robust measurement procedures are required to obtain reliable and trustworthy measurement results. These procedures are not yet commercially available. The reason for this is that in established chemical synthesis procedures, the exact size of the iron oxide cores and their magnetic properties are difficult to adjust. One of the main problems is the lack of suitable measuring instruments to determine the magnetic properties of MNPs directly during their synthesis or directly afterwards.

The Fraunhofer Institute for Microengineering and Microsystems (IMM) has developed a microreaction system that allows the production of nanoparticles whose core size can be controlled at laboratory scale and thus meets one of the major prerequisites for manufacturing reference nanomaterials. PTB has supported the development of this manufacturing process by providing the magnetic measurement technology. To investigate the extensive parameter range of the synthesis conditions (e.g., flowrate and temperature) systematically and effectively, efficient inline measurement procedures should be used instead of sequential measurements on individual samples. In this way, it should become possible to manufacture MNPs of well-defined sizes and magnetic properties.

Within the scope of the TransMeT program, PTB, together with Postnova Analystics GmbH, developed a detector to control the magnetic inline processes. This detector can be used directly during the microreaction synthesis. It is planned that this new measuring instrument will be made available to a large circle of users (e.g., for particle synthesis, in medical diagnostics or in laboratory analysis) for the fast and accurate measurement of MNPs. In particular, manufacturing certified reference nanomaterials for MNPs is to be furthered in this way.

The TransMeT program serves the promotion of pre-competitive joint research and development by PTB and its external partners. This program is designed to validate PTB’s existing metrological know-how for market purposes with a view to enhancing its utilization. At the same time, TransMeT aims to strengthen the current research base and competitiveness – of small and medium-sized enterprises (SMEs) in particular – by transferring this know-how to industry. On PTB’s website, you will find more information about the program as well as the contact persons: Opens external link in new windowhttps://www.ptb.de/cms/en/ptb/fachabteilungen/abt9/ref-911/funding-programme-transmet.html


Norbert Löwa
Department 8.2
Phone: +49 30 3481-7736
Opens local program for sending emailnorbert.loewa(at)ptb.de

Scientific publications

N. Löwa, D. Gutkelch, E. A. Welge, R. Welz, F. Meier, A. Baki, R. Bleul, T. Klein, F. Wiekhorst: Novel benchtop magnetic particle spectrometer for process monitoring of magnetic nanoparticle synthesis. Nanomaterials 10, 2277 (2020)