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Estimation for diameter of superparamagnetic particles in Daphnia resting eggs

View Article: PubMed Central - PubMed

ABSTRACT

Ferromagnetic resonance (FMR) with an electron spin resonance (ESR) apparatus was investigated for super-paramagnetic particles within Daphnia resting eggs. High-field (HF) resonance lines near g=2 resulted from single superparamagnetic particles, were detected from ESR spectra of Daphnia resting eggs. The size of isolated superparamagnetic particles within Daphnia resting eggs was calculated to be approximately 13 nm in diameter by analysis of the temperature dependence of the HF line width. Small-angle X-ray scattering (SAXS) analysis of Daphnia resting eggs also showed that average size of superparamagnetic particles in diameter, equivalent to magnetite, was approximately 13 nm. The combination of FMR and SAXS measurement is very effective in estimating the size of superparamagnetic particles in biological organisms, with difficulties of preparing for samples for measurement by electron microscopy. However, Chlorella, with that Daphnia were raised, did not show FMR spectra, showing no magnetic particles within Daphnia resting eggs. Therefore, it suggested that superparamagnetic particles within Daphnia resting eggs, were mineralized in Daphnia as the result of biomineralization of Fe originated from Chlorella.

No MeSH data available.


Diameter distribution of superparamagnetic nanoparticles within Daphnia resting eggs.
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f5-6_53: Diameter distribution of superparamagnetic nanoparticles within Daphnia resting eggs.

Mentions: Figure 4 shows the SAXS scattering an intensity profile for Daphnia resting eggs and the results of curve fitting, on an assumption of small magnetite particles. Close fitting was seen in the region around two degrees for two theta in Figure 4, resulting from small deviation of SAXS measurement data with low angle of scattering X-ray. The results are summarized as the diameter-distribution curve in Figure 5. The average diameter of particles was estimated to be 13 nm, which is very near to the value from FMR study. Fitting curve in the very low angle in Figure 4 shows that there is a possibility of existing bigger particles in Daphnia resting eggs. More studies are needed to understand this in the near future.


Estimation for diameter of superparamagnetic particles in Daphnia resting eggs
Diameter distribution of superparamagnetic nanoparticles within Daphnia resting eggs.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC5036663&req=5

f5-6_53: Diameter distribution of superparamagnetic nanoparticles within Daphnia resting eggs.
Mentions: Figure 4 shows the SAXS scattering an intensity profile for Daphnia resting eggs and the results of curve fitting, on an assumption of small magnetite particles. Close fitting was seen in the region around two degrees for two theta in Figure 4, resulting from small deviation of SAXS measurement data with low angle of scattering X-ray. The results are summarized as the diameter-distribution curve in Figure 5. The average diameter of particles was estimated to be 13 nm, which is very near to the value from FMR study. Fitting curve in the very low angle in Figure 4 shows that there is a possibility of existing bigger particles in Daphnia resting eggs. More studies are needed to understand this in the near future.

View Article: PubMed Central - PubMed

ABSTRACT

Ferromagnetic resonance (FMR) with an electron spin resonance (ESR) apparatus was investigated for super-paramagnetic particles within Daphnia resting eggs. High-field (HF) resonance lines near g=2 resulted from single superparamagnetic particles, were detected from ESR spectra of Daphnia resting eggs. The size of isolated superparamagnetic particles within Daphnia resting eggs was calculated to be approximately 13 nm in diameter by analysis of the temperature dependence of the HF line width. Small-angle X-ray scattering (SAXS) analysis of Daphnia resting eggs also showed that average size of superparamagnetic particles in diameter, equivalent to magnetite, was approximately 13 nm. The combination of FMR and SAXS measurement is very effective in estimating the size of superparamagnetic particles in biological organisms, with difficulties of preparing for samples for measurement by electron microscopy. However, Chlorella, with that Daphnia were raised, did not show FMR spectra, showing no magnetic particles within Daphnia resting eggs. Therefore, it suggested that superparamagnetic particles within Daphnia resting eggs, were mineralized in Daphnia as the result of biomineralization of Fe originated from Chlorella.

No MeSH data available.