12 Magnetic Force Microscopy and Magnetic …
295
proposed, for instance, for the development of stimuli-responsive systems for application in biocompatible devices for the controlled release of drugs [67].
The detection of magnetite NPs with diameter ranging 10 nm 100 nm embedded
in polymer films using MFM was demonstrated by Krivcov et al. [60]. In particular,
while bigger NPs with diameter 80 nm could be detected under about 300 nm thick
polymer layer, superparamagnetic NPs with diameter of 10 nm and 20 nm could
be detected under polymer layers of 40 nm and 130 nm, respectively [60]. Slabu
et al. [68] reported the use of MFM to detect superparamagnetic iron oxide NPs
containing both magnetite and maghemite on the surface and into polyvinylidene
fluoride (PVDF) based fibers. Alosmanov et al. [69] used MFM to study magnetic nanocomposites containing iron oxide nanoparticles formed in situ within a
phosphorus-containing polymer matrix. Silva et al. [70] used iron-doped bismuth
sulphide nanocrystals embedded in glass matrix. Marín et al. used MFM to detect
magnetite NPs embedded in gelatin [71] or zein [67] based stimuli responsive films
to control drug release triggered by the application of an external magnetic field.
Arredondo et al. [72] recently proposed a method for the evaluation of enzyme activity, in which MFM images are used to real time monitor the degradation of enzyme
responsive layer constituted by gelatin films loaded with magnetite NPs.
Among the different class of magnetic nanocomposites, vesicular systems loaded
with magnetic NPs attract growing interest for their potential applications in theranostics. Passeri et al. [50] demonstrated the capability of MFM to distinguish
between empty niosomes and niosomes encapsulating magnetic NPs. Dong et al.
[59] attempted the determination of the diameter of magnetic NPs from MFM images
using a phenomenological calibration procedure.
12.3.2.2 Nanoparticle Detection in Cells and Tissues
MFM has been also proposed as a diagnostic tool in biology and nanomedicine, i.e.,
as a nanoprobe for the detection of magnetic NPs in biological systems such as cells
or tissues.
Taking advantage of its high spatial resolution and sensitivity, which allows one
to detect a single magnetic NP, MFM has been demonstrated capable to probe the
presence of ferritin by sensing its nanometer sized iron core [73]. In this field, they
are worth mentioning the extensive and thorough studies by Agarwal and coworkers,
who demonstrated the unique capability of MFM as a diagnostic tool to detect and
evaluate the presence of ferritin in biological samples. First Nocera et al. [74] used
MFM to distinguish ferritin from apoferritin, on the basis of the absence of the iron
core in the latter, and to quantitatively evaluate the amount of ferritin in a sample.
Then, Blissett et al. used MFM to evaluate the presence of ferritin in animal tissues,
i.e., in spinal cord [75] or spleen [76].
Different works have been reported in which MFM is used to detect magnetic
NPs on the surface as well as inside cells. In a first study, Shen et al. [77] detected
silica-coated magnetic iron NPs coupled with antisense oligonucleotide in human
leukemia (HL-60) cells. Wang and Cuschieri [78] successfully labeled human cancer
295
proposed, for instance, for the development of stimuli-responsive systems for application in biocompatible devices for the controlled release of drugs [67].
The detection of magnetite NPs with diameter ranging 10 nm 100 nm embedded
in polymer films using MFM was demonstrated by Krivcov et al. [60]. In particular,
while bigger NPs with diameter 80 nm could be detected under about 300 nm thick
polymer layer, superparamagnetic NPs with diameter of 10 nm and 20 nm could
be detected under polymer layers of 40 nm and 130 nm, respectively [60]. Slabu
et al. [68] reported the use of MFM to detect superparamagnetic iron oxide NPs
containing both magnetite and maghemite on the surface and into polyvinylidene
fluoride (PVDF) based fibers. Alosmanov et al. [69] used MFM to study magnetic nanocomposites containing iron oxide nanoparticles formed in situ within a
phosphorus-containing polymer matrix. Silva et al. [70] used iron-doped bismuth
sulphide nanocrystals embedded in glass matrix. Marín et al. used MFM to detect
magnetite NPs embedded in gelatin [71] or zein [67] based stimuli responsive films
to control drug release triggered by the application of an external magnetic field.
Arredondo et al. [72] recently proposed a method for the evaluation of enzyme activity, in which MFM images are used to real time monitor the degradation of enzyme
responsive layer constituted by gelatin films loaded with magnetite NPs.
Among the different class of magnetic nanocomposites, vesicular systems loaded
with magnetic NPs attract growing interest for their potential applications in theranostics. Passeri et al. [50] demonstrated the capability of MFM to distinguish
between empty niosomes and niosomes encapsulating magnetic NPs. Dong et al.
[59] attempted the determination of the diameter of magnetic NPs from MFM images
using a phenomenological calibration procedure.
12.3.2.2 Nanoparticle Detection in Cells and Tissues
MFM has been also proposed as a diagnostic tool in biology and nanomedicine, i.e.,
as a nanoprobe for the detection of magnetic NPs in biological systems such as cells
or tissues.
Taking advantage of its high spatial resolution and sensitivity, which allows one
to detect a single magnetic NP, MFM has been demonstrated capable to probe the
presence of ferritin by sensing its nanometer sized iron core [73]. In this field, they
are worth mentioning the extensive and thorough studies by Agarwal and coworkers,
who demonstrated the unique capability of MFM as a diagnostic tool to detect and
evaluate the presence of ferritin in biological samples. First Nocera et al. [74] used
MFM to distinguish ferritin from apoferritin, on the basis of the absence of the iron
core in the latter, and to quantitatively evaluate the amount of ferritin in a sample.
Then, Blissett et al. used MFM to evaluate the presence of ferritin in animal tissues,
i.e., in spinal cord [75] or spleen [76].
Different works have been reported in which MFM is used to detect magnetic
NPs on the surface as well as inside cells. In a first study, Shen et al. [77] detected
silica-coated magnetic iron NPs coupled with antisense oligonucleotide in human
leukemia (HL-60) cells. Wang and Cuschieri [78] successfully labeled human cancer