Abelmann, Leon

Chul Park, Bum

Keun Kim, Young

Pan, Lijun

ten Haken, Bernard

van de Loosdrecht, Melissa Mathilde

English

NARCIS 

Differential magnetometry on Fe2O3 nano-clustered particles

University of Twente Research Information

International Workshop on Magnetic Particle ImagingDifferential miagneommeoro mn e2O3 nianm-clusoered piartclesLemn Abelmiann ia,b*, Melissia vian de Lmmsdrecho b, Bennie oen Hiaken b, Lijun Pian c, Bum Chul Piark c, Ymung Keun Kim ca KIST Europe, Saarbrücken, Germanyb University of Twente, Enschede, The Netherlandsc Department of Materials Science, Korea University, Seoul, Korea* Corresponding author, email: l .a  belmann  @  kist-europe  . de  , ykim97@korea.ac.krI. InormductmnModern contrast agents for Magnetic Particle Imagingconsist of clusters of superparamagnetic iron-oxide par-ticles,  rather  than  individual  particles  [1,2].  Thesemulti-granule  nanoclusters  (MGNCs)  have  theadvantage  that  the  size  of  clusters  can be increased,without  sacrificing  the  superparamagnetic  responsethat  is  necessary  to  avoid  magnetic  attraction  andunwanted agglomeration.Previously, we have investigated the suitability of thesenanoclusters for Magnetic Particle Imaging [3]. In thiscontribution  we  optimize  these  particles  for  use  indifferential  magnetometry,  a  technique  that  can  forinstance be applied to detect sentinel lymph nodes inlaparoscopic procedures [4].II. Miaoeriial iand MeohmdsThis  type  of  magnetic  multi-granule  nanoclusters(MGNCs) can be easily formed by the simple reactionof FeCl3 in ethylene glycol, which serves as both thesolvent  and  reductant,  in  the  presence  of  sodiumacetate  [5].  By  adjusting  the  process  condtions,  thegranule size as well as the number of granules can beadjusted.  Two formulations  were  used,  one  with  anaverage granule size of 15 nm, and one with 23 nm.The average number of granules per cluster was variedso that the cluster size varies from an average diameterof 25 to 43 nm. The smallest clusters with the biggergranules are composed of only one or two granules. The magnetic  response for differential  magnetometrywas  measured  by  a  home  built  susceptometer(superparamagnetic  quantifier,  SpaQ),  with  a  drivefield of 1.3 mT at a frequency of 2.5 kHz. The samplevolume was 200±10 μL of a 1 mg(Fe)/mL suspension.The bias field was applied with a maximum value of14 mT.III. ResulosFig.  1  shows  a  subset  of  the  range  of  suspensionsinvestigated. The label “small” (black curves) refers togranules in the order of 15(2) nm, the label “big” (redcurves) to granules of about 23(3) nm, as measured bytransmission  electron  microscopy.  Of  eachformulation,  two  different  cluster  sizes  are  shown(continuous and dashed lines). As can be observed, thesignal varies considerably with formulation as well ascluster  size.  The  effect  of  cluster  size  appears  to  bemuch stronger when using bigger granules. Even withthis first initial parameter sweep, we can reach signalsthat  are  20%  higher  than  a  commercial  solution(ResovistTM,  Bayer  Schering  Pharma  GmbH))  withidentical iron content. It should be noted however thatthe  commercial  solution  was  in  water,  whereas  oursuspensions are still in ethanol. (Suspensions in waterhave  been  prepared,  and  will  be  shown  at  theconference).The maximum peak height and width of the particleresponse  function  at  half  the  maximum  signal  areshown in table 1. The width of the Resovist curve issignificantly  larger  than  that  of  the  nanoclustersuspensions.  0 5 10 15 20 25 30-15 -10 -5  0  5  10  15Abs(Z) [mV]Bias Field [mT]2500 Hz'small' 30 nm'small' 42 nm'big' 25 nm'big' 33 nmResovistAbstract – IWMPI 20181International Workshop on Magnetic Particle ImagingFigure 1: Particle response function for multi-granulenanocluster suspensions with variation in size of thegranules (black and red curves) as well as the diameterof the total cluster. For comparison, Resovist withidentical iron content is shown in blue.Peak (mV) FWHM (mT)Small 30 nm 10±1 2.90±0.05Small 42 nm 9±1 2.62±0.05Big 25 nm 13±1 2.92±0.05Big 34 nm 6±1 2.77±0.05Big 43 nm 7±1 2.53±0.05Resovist 10±1 3.55±0.05Table 1: Peak signal at 0 mT and width at half maximum forsuspensions with different granule size (“small” vs “big”) and clustersize. For comparison, Resovist with identical iron content is shown.Fig. 2 shows the transmission electron microscopy imageof the suspension with the highest signal (“Big” 25 nm)and the lowest signal (“Big” 34 nm). Apart from the size,there is no apparent  difference.  Also the coercivities ofboth suspensions are identical (0.9 kA/m), indicating thatthe origin of the signal difference might be related to thehydrodynamic radius. Further research is in progress.100 nmBig 25 nm Big 34 nmFigure 2: Transmission electron micrograph of the suspension withthe highest (left) and the lowest signal (right) IV. CmnclusimnsWhen using multi-granule nanoclusters, one can tune thesize of the granules relatively independently from the sizeof the clusters. This offers an extra degree of freedom intuning magnetic  particles  for  differential  magnetometryand Magnetic Particle Imaging. We have shown that thehighest  signal  can  be  obtained  when  using  biggergranules,  but  that  the relation between  cluster  size  andmagnetic signal increases when using big granules.These  promising  first  results  encouraged  us  to  realizesuspensions in water  by proper  surface  modification ofthe nanoclusters, and to further optimize their response.REERENCES[1] F.Ahrentorp, A.Astalan, J.Blomgren, C.Jonasson, E.Wetterskog, P. Svedlindh, A. Lak, F. Ludwig, L.J. Van Ijzendoorn, F. Westphal, C.Gruttner, N. Gehrke, S. Gustafsson, E. Olsson, and C. Johansson. Effective particle magnetic moment of multi-core particles. Journal of Magnetism and Magnetic Materials, 380:221–226, 2015. doi:10.1016/j.jmmm.2014.09.070..[2] D.Schmidt, F.Palmetshofer, D.Heinke, U.Steinhoff, and F.Ludwig. A phenomenological description of the MPS signal using a model for the field dependence of the effective relaxation time. IEEE Transactions on Magnetics, 51(2), 2015. doi:10.1109/TMAG.2014.2345192.[3] Pan, L., Park, B. C., Ledwig, M., Abelmann, L., & Kim, Y. K. (2017). Magnetic Particle Spectrometry of Fe3O4 Multi-granule Nanoclusters. IEEE transactions on magnetics, 53(11), [5101004]. DOI: 10.1109/TMAG.2017.2701904[4] Pouw, J. J., Grootendorst, M., Klaase, J. M., van Baarlen, J., & ten Haken, B. (2016). Ex vivo sentinel lymph node mapping in colorectal cancer using a magnetic nanoparticle tracer to improve staging accuracy: a pilot study. Colorectal disease, 18(12), 1147-1153. DOI: 10.1111/codi.13395[5] J. Cha, J.S. Lee, S.J. Yoon, Y.K. Kim, and J.-K. Lee. Solid-state phase transformation mechanism for formation of magnetic multi- granule nanoclusters. RSC Advances, 3(11):3631–3637, 2013. doi:10.1039/c3ra21639j.Abstract – IWMPI 20182

Differential magnetometry on Fe2O3 nano-clustered particles

Abstract

Similar works

Full text

Available Versions

NARCIS

University of Twente Research Information