December 2017: Magnetic Measurement of Nerve Signals

A highlight, especially for the team of the projects B2 and B6 of the CRC 1261, was the magnetic measurement of nerve signals with a 304 SQUID vector magnetometer at the PTB in Berlin. For further development and also for optimization of our uncooled magnetoelectric (ME) sensors, a better understanding of spectral power distribution and signal strength of nerve signals is of particular interest. Since the magnetic field of human nerve pulses is quite low, only signal amplitudes in the fT range from the deep nerve are measurable. The project B6 intensively prepared these measurements, since an earlier attempt at measuring the signals had completely failed. Finally, Christin Bald and Eric Elzenheimer succeeded in measuring nerve signals magnetically, which also fits to the current electrical gold standard (electroneurography). Signal amplitudes were subject dependent and ranged from 17 fT to 60 fT in a frequency range from 100 Hz to 1 kHz. The required averaging time was in the range of minutes, while for current ME sensors significantly longer averaging times are expected to be necessary.

 

February 2017: News from our Central Project Z2

Alexander Teplyuk (project Z2) had improved the head scanner with respect to scanning speed, robustness, and saftety means. It is ready now to be used for patient measurements. First evaluations have been performed in close cooperation with our medical project B5.

The scanner has reached the next level ...

 

Furthermore, a head phantom for emulation of a network of connected sources in the brain has been designed in close cooperation with the rearchers from project B3. Small coils can be arbitrarily placed at designated postions. This allows us to generate a variety of source configurations and we are able now to create the corresponding magentic fields on the surface of our artifical head.

July 2017: Localization of Magnetic Nanoparticles

Ron-Marco Friedrich recently reported on great progress the project project B7. Here, the aim is the detection of magnetically labeled cells for biomaterial scaffold characterization and first measurements of the magnetic field and localization of magnetic nanoparticles were successful. For the measurement, an ME sensor samples space over a surface with magnetic nanoparticles (Fig. 1). The magnetic field is measured and the inverse problem is solved to localize the sources of that magnetic field (Fig. 2).

Fig. 1: Sampling of the surface with magnetic nanoparticles using an ME sensor. The magnetic moment is aligned with the AC magnetic field.

 

   
Fig. 2: a) Reference sample with magnetic nanoparticles (red), b) Measured magnetic field (red – positive, blue - negative), c) Reconstructed sources of the magnetic field.

July 2017: New Sensor Characterization form Central Project Z2

Good news from our central project Z2. Alexander Teplyuk (project Z2) has finished a new scheme for mounting and characterization of our cantilever-based ME sensors. Instead of of permanenty fixing the cantilevers on a mouning plate (as we did it so far), we can contact the cantilevers now in a non-permanent manner. This allows to adjust the resonance frequency of our sensors in an easy way. Consequently, sensor characterisation with a predetermined center frequency is possible now.

The video above shows how easy it is to install and contact the ME cantilevers with the new measurement setup. By using a simple torque wrench, it is possible to ajust the claming force which dircetly influcenes the resonance frequency. This allows to characterize a large set of sensors with exactly the same resonance behaviour.

Financial Support

The Collaborative Research Center 1261 is funded by the German Research Foundation (DFG).

SFB1261 Microsite

Click here to visit our Microsite with information for students, teachers and the public (German and English version available).

Contact

sfb1261@tf.uni-kiel.de

Chairman:

Prof. Dr. Eckhard Quandt

Kiel University
Institute for Materials Science

 

Interner Server

 

CAU

Christian-Albrechts-Universität zu Kiel (CAU)

Christ.-Albrechts-Platz 4
D-24118 Kiel

UKSH

University Hospital Schleswig-Holstein, Campus Kiel (UKSH)

Arnold-Heller-Straße 3
D-24105 Kiel

ISIT

Fraunhofer Institute for Silicon Technology, Itzehoe (ISIT)

Fraunhoferstrasse 1
D-25524 Itzehoe  

IPN

IPN - Leibniz-Institut für die Pädagogik der Naturwissenschaften und Mathematik an der Universität Kiel

Olshausenstraße 62 
D-24118 Kiel

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