Version 2 2022-12-28, 16:03Version 2 2022-12-28, 16:03
Version 1 2022-12-19, 20:03Version 1 2022-12-19, 20:03
journal contribution
posted on 2022-12-28, 16:03authored byErin S. Grant, Liam T. Hall, Lloyd C. L. Hollenberg, Gawain McColl, David A. Simpson
Ferritin is the primary storage protein in our body and
is of significant
interest in biochemistry, nanotechnology, and condensed matter physics.
More specifically within this sphere of interest are the magnetic
properties of the iron core of ferritin, which have been utilized
as a contrast agent in applications such as magnetic resonance imaging.
This magnetism depends on both the number of iron atoms present, L, and the nature of the magnetic ordering of their electron
spins. In this work, we create a series of ferritin samples containing
homogeneous iron loads and apply diamond-based quantum spin relaxometry
to systematically study their room temperature magnetic properties.
We observe anomalous magnetic behavior that can be explained using
a theoretical model detailing a morphological change to the iron core
occurring at relatively low iron loads. This model provides an L0.35±0.06 scaling of the uncompensated
Fe spins, in agreement with previous theoretical predictions. The
necessary inclusion of this morphological change within the model
is also supported by electron microscopy studies of ferritin with
low iron content. This provides evidence for a magnetic consequence
of this morphological change and positions diamond-based quantum spin
relaxometry as an effective, noninvasive tool for probing the magnetic
properties of metalloproteins. The low detection limit (ferritin 2%
loaded at a concentration of 7.5 ± 0.4 μg/mL) also makes
this a promising method for precision applications where low analyte
concentrations are unavoidable, such as in biological research or
even clinical analysis.