of 8
Biophysical Journal, Volume
118
Supplemental Information
Nanoscale Heat Transfer from Magnetic Nanoparticles and Ferritin in an
Alternating Magnetic Field
Hunter C. Davis, Sunghwi Kang, Jae-Hyun Lee, Tae-Hyun Shin, Harry Putterman, Jinwoo
Cheon, and Mikhail G. Shapiro
Supplementary Information for
“Nanoscale Heat Transfer from Magnetic Nanoparticles and
Ferritin in an Alternating Magnetic Field”
Hunter C. Davis, Sunghwi Kang,
Jae-Hyun Lee, Tae-Hyun Shin, Har
ry Putterman, Jinwoo Cheon,
Mikhail G. Shapiro (mikhail@caltech.edu)
Supplementary Figures
FIGURE S1. Fluorescence emission
spectra of Dylight 550-conjuga
ted nanoparticles (NP) and
DY-521XL. Spectra were measured in a Molecular Devices spectrop
hotometer. Excitation was
set at 532 nm.
FIGURE S2. Additional hyperthermia
trials with separate batches
of magnetic particles. Surface
and fluid temperatures measured for each nanoparticle type duri
ng RF-AMF application. Mean
and SEM temperature for particle surface (red) and surrounding
fluid (blue) are plotted for each
sample, with frequency and field parameters specified above the
plot. RF-AMF application
period is denoted by grey shading. Each trace denotes the mean
± S.E.M. of 20 runs of RF-AMF
stimulation.
FIGURE S3. Artifact from backgr
ound temperature variation due t
o the toroid.
As stated in
Fig.
3
in the main text, our 400-700 kHz toroid did not completely co
ol in between stimuli, resulting
in a slow apparent cooling at the beginning of the averaged plo
t. The ferrofluid easily reaches
thermal equilibrium with its surroundings over the nine minutes
between stimuli, such that this
slow cooling behavior of the toroid should be identical irrespe
ctive of the presence of
nanoparticles in the sample. (a)
Thermometry of 20 nm magnetite
nanoparticle ferrofluid during
RF-AMF application from
Fig. 3d
(b) Thermometry of DY-521XL in PBS during RF-AMF
application matching the field parameters in (a) establishes th
e background thermal variation of
the sample due to the toroid. (c) Subtracting this background v
ariation from the thermometry
measurement of the ferrofluid under RF-AMF stimulus eliminates
the slow cooling at the
beginning of the trace. Mean and SEM temperature for particle s
urface (red) and surrounding
fluid (blue) are plotted for each sample, with frequency and fi
eld parameters specified above the
plot. RF-AMF application period
is denoted by grey shading. Eac
h trace denotes the mean ±
S.E.M. of 20 runs of RF-AMF stimulation.
FIGURE S4. Background temperatur
e variation in low frequency fe
rritin experiment. (a) Surface
and fluid temperature of ferritin solution during RF-AMF applic
ation. Incomplete cooling of the
toroid between stimuli leads to a slow cooling through RF-AMF s
timulation in the ferritin
ferrofluid. (b) Thermometry of D
Y-521XL in PBS during RF-AMF ap
plication matching the
field parameters in (a) establis
hes the background thermal vari
ation of the sample due to the
toroid. (c) Subtracting backgr
ound thermal variation from therm
ometry of ferritin under RF-
AMF stimulation reveals no measurable heating from ferritin on
the protein surface or in the
surrounding fluid. Mean and SEM te
mperature for particle surfac
e (red) and surrounding fluid
(blue) are plotted for each sample, with frequency and field pa
rameters specified above the plot.
RF-AMF application period is denoted by grey shading. Each trac
e denotes the mean ± S.E.M.
of 20 runs of RF-AMF stimulation.
FIGURE S5. Characterization of cor
e-shell nanoparticles. (a) Tr
ansmission electron microscope
(TEM) image and (b) magnetic measurement of core-shell nanopart
icles. TEM observation were
made using the JEM-2100Plus (JEOL) under the acceleration volta
ge of 200 kV. Magnetic
property was measured using vibra
ting sample magnetometer (Lake
Shore Cryotronics, Inc.) and
mass of metal was measured using inductively-coupled plasma opt
ical emission spectroscopy
(Thermofisher).
FIGURE S6. Size distribution of
20 nm magnetite nanoparticles.
(a) Representative transmission
electron microscope (TEM) image of SHA20 nanoparticles from Oce
an Nanotech. (b) Particles
detected and sized using a custom imaging processing script. (c
) Distribution of particle radii
taken from a total of 289 partic
les. Scale bar is 100 nm.
FIGURE S7. Size distribution of
12 nm magnetite nanoparticles.
(a) Representative transmission
electron microscope (TEM) image of SHA10 nanoparticles from Oce
an Nanotech. (b) Particles
detected and sized using a custom imaging processing script. (c
) Distribution of particles radii
taken from a total of 291 partic
les. Scale bar is 100 nm.
Supplementary Tables
TABLE S1. Error from dye release for 20 nm magnetite (20 nm), 1
2 nm magnetite (12 nm), and
MnCoFe core-shell nanoparticles (CS). A small amount of nonspec
ifically bound Dylight 550
was released from the nanoparticle surface during stimulus. Due
to the strong quenching of dye
conjugated to the nanoparticle surface, this released Dylight 5
50 could account for a non-
negligible fraction of the overa
ll measured Dylight 550 fluores
cence. In order to ensure that this
did not confound our results, we measured the fractional contri
bution of released Dylight 550 to
the overall Dylight 550 signal. We did so by separating the nan
oparticle-bound dye from
dissolved dye after completion of
the standard RF-AMF stimulus
(20 one-min stim
uli at 420 kHz
and 25 kA/m with 9 min in between stimuli) for each synthetic m
agnetic particle sample type
using 10 kDa size exclusion filters (Amicon). The retentate was
diluted with PBS to match the
original particle conc
entration. An equivalent concentration of
unlabeled nanoparticles was
added to the flow-through to account for the nanoparticle’s opt
ical attenuation. The fluorescence
of the retentate and flow through
(FT in table) were then measu
red at 570 nm (530 nm
excitation) using a Molecular De
vices spectrophotometer. Assumi
ng the nanoparticle surface and
surrounding fluid maintained two distinct temperatures, the ove
rall Dylight 550 signal would be
a weighted average of the two environments. As a result, it is
possible to approximate the error
induced by the released dye:
Here
Dylight 550 Temp.
is the Dylight 550 temperature measured in our fluorometer dur
ing RF-
AMF application,
Released Frac.
is the fraction of the total D
550 signal in the flow through a
fter
size-exclusion filtration,
DY521 Temp.
is the DY-521XL temperature measured during RF-AMF
application, and
Surface Temp.
is the actual temperature at
the nanoparticle surface.