(220f) Using a Triple Co-Cultured in Vitro Blood- Brain Barrier Model
 to Characterize Magnetic Nanoparticle Permeability

Shi, D., Northeastern University
Mi, G., Northeastern University
Webster, T. J., Northeastern University

Using a Triple Co-cultured in
vitro Blood- Brain Barrier Model
 to Characterize Magnetic Nanoparticle

Di Shi1, Gujie Mi1, and Thomas J

1Department of Chemical Engineeging,
Northeastern University, Boston, USA.



several intriguing nanoparticles, superparamagnetic iron oxide nanoparticles
(SPIONs) have been extensively studied because of their ability to be
controlled by magnetic fields. For instance, magnetic fields and nanomaterials
have been identified to locate and target nucleic acids within the last decade. Moreover,
SPIONs have also been
discovered as an excellent contrast agent which can potentially increase image
contrast and improve MRI sensitivity [1]. Under normal conditions in
the body and outside of the brain, the accumulation of magnetic nanoparticles
can be removed by several detoxification and antioxidant mechanisms. But, if
the SPIONs cross the blood brain barrier and have not been efficiently cleared,
the accumulation of those iron oxide nanoparticles may cause neurodegeneration and be harmful to normal brain function
in the long term [2].

As there are concerns about both the
delivery of drugs across the blood-brain barrier and the accumulation of SPIONs
in the body, this study established a triple co-cultured in vitro blood-brain barrier model to test the ability of a new
type of magnetic material (magnetic nanoliposome) to
pass through the blood-brain barrier. We tested several variations of magnetic nanopliposom in an effort to both increase blood-brain
barrier passage (for neural drug delivery applications) and decrease
blood-brain barrier passage (to minimize toxicity).
Materials and Methods

A.   Material Characterization

The collagen coated nanoliposome and PEG coated
nanoliposom were prepared and encapsuled with iron oxide [3]. The nanoparticles
will then be characterized by zeta potential to determine their charge and
dynamic light scattering for hydrodynamic diameter. SEM was used to characterize
their surface morphology and TEM was used to assess the iron oxide inner core
B.   Experimental Samples Tested
Through the Blood-Brain Barrier Model

For the in vitro blood- brain barrier model, pericytes
were cultured and seeded on the bottom side of the collagen-coated Transwell¨
inserts with 104 cells/cm2 density and astrocytes with same density were seeded
on the bottom of the 24-well plates separately. After 12 hours of adhesion,
murine brain endothelial cells were seeded onto the upper side of the inserts
with 105 cells/cm2 density and the inserts would then be placed in the 24-well
plates containing astrocytes. The model would be evaluated and confirmed using
TEER and FITC-Dextran transport. Then, the model was used to test the
permeability of the various nanoparticles after confirmation. The in vitro
model would be exposed to nanoparticles for 2 hours. After 2 hours, a 100
μL solution was taken from each well and an iron assay kit was used to
determine the iron concentration that passed through the model. Each experiment
was conducted in triplicate and repeated at least three times.
Results and Discussion

A.   Material Characterization

Dynamic light scattering revealed that the hydrodynamic
diameters of the samples ranged from 20nm to 200nm. TEM images show that the
iron core was about 5-10nm for all of the samples.
B.   Experimental Samples Tested
Through the Blood-Brain Barrier Model

The permeability of FITC-Dextran across the model
confirmed that the model was successfully established and the TEER value of
this triple co-cultured model was around 350 Ohms/cm2. Previous results
of samples showed that the highest permeability was obtained from collagen
coated nanoparticles. This result suggest that nanoliposomes coated with
collagen had better permeability across the blood-brain barrier than
nanoliposomes coated with PEG. Through such experiments, magnetic nanomaterials
(such as megnetic nanoliposome) suitable for MRI use which are less permeable
to the blood brain barrier to avoid neural tissue toxicity and magnetic nanoliposomes
suitable for brain drug delivery since they were more permeable to the
blood-brain barrier were created [4,5].



An in vitro model of blood-brain barrier
was established using triple co-culture method. The model was confirmed by
comparing the permeability trend of FITC-dextran in serum-free medium and the
TEER value with previous research. The results
suggest a possibility to manipulate magnetic nanoparticle penetration across
the blood–brain barrier by controlling bioactive coatings. Such data lay
the foundation for the modification of ferrofluids to be either coated with
collagen to pass through blood-brain barrier, or to be coated with glycine and
glutamic acid to avoid penetration.

The authors would like to thank Northeastern University for funding
this research.


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