1. Francesca Re
Nanomedicine Seminar - Synthesis of nano-biomaterials, modelling, and applications

2. common issues
in the treatment/diagnosis of different diseases
worse for the treatment of diseases affecting the central
nervous system (neurodegeneration and cerebral tumors)
There are increasingly high
expectations for the delivery of
drugs to the brain using
NANOPARTICLES

3. to develop drug delivery strategies that will allow the
passage of drug molecules from the blood to the brain
in a safe and effective manner
Considerable efforts have been made to enhance the
delivery of therapeutic molecules to the CNS
BUT
after two decades of research, nanotechnology approaches
to brain drug delivery remain yet underdeveloped

4.  Biological hurdles
 Modifications of the NP’s surface that occurs after
administration in biological environment
 Physical hurdles
SMART DESIGN OF NANOPARTICLES

5. the problem

6.  Highly selective barrier
 Lack of specific/exclusive molecules on the BBB
 Presence of transport mechanisms on the BBB
2-3 nm
X

7. potential solutions
Functionalized nanoparticles
+
Lipoproteins
[Fernandes C. Pharm Res. 2010]

8. Transwell system for BBB model in vitro
Brain capillary endothelial cells
CELLULAR UPTAKE
MONOLAYER PERMEABILITY (cm/min)

9. CHARACTERIZATION OF BBB MODEL
BIOELECTRICAL PROPERTIES
FUNCTIONAL PROPERTIES
TRANS-ENDOTHELIAL ELECTRICAL RESISTANCE
140
TJ: CLAUDIN
RATIO PROPRANOLOL
SUCROSE PROPR/SUCR = 1,3
AJ: CADERIN
TEER = 114.3Ωxcm2
TEER (Ohms x cm2)
120
100
80
60
40
20
0
10
11
12
13
14
15
16
17
18
Days after seeding (day)
[Re F.; Andreozzi P]

10. Adsorptive pathways:
 Cationic proteins: cationic albumin
 Cell-penetrating peptides: modified TAT-1 from HIV
Receptor-mediated pathways:
 A modified receptor-binding domain peptide of ApoE
(CWLRKLRKRLLR or its tandem dimer) for LDLR
 Anti-TfR antibodies (OX-26, RI-7217)

11. NP-Cationic albumin
[Liu X. Biomaterials. 2013]
IN VIVO
NP-TAT-1 peptide
[Gregori M. J Nanomed Nanotech. 2013]
IN VITRO

12. IN VIVO
NP + modified peptide of the receptor-binding domain of ApoE
IN VITRO
[Re F. Nanomedicine. 2011]
[Bana L. Nanomedicine 2013, submitted]
[Balducci C. PNAS 2013, submitted]

13. NP
NP + anti-TfR antibody
IN VITRO
[Salvati E. Int J Nanomed. 2013]
[Markoutsa E. Eur J Pharm Biopharm. 2011]

14. THE NP CHEMICAL DESIGN AFFECTS THE BBB CROSSING:
ligand density on the NP surface
LIGAND DENSITY IN THE NP SURFACE
[Re F. J Biotechnol. 2010]

15. THE NP CHEMICAL DESIGN AFFECTS THE BBB CROSSING:
method of ligand conjugation on the NP surface
NP-b/s-anti-TfR antibody
NP-cov-anti-TfR antibody
[Salvati E. Int J Nanomed. 2013]

16. NANOPARTICLES
[Re F. Nanomedicine. 2011]
DRUG

17.  Biological hurdles
 Modifications of the NP’s surface that occurs after
administration in biological environment
 Physical hurdles
SMART DESIGN OF NANOPARTICLES

18. the problem
Targeting
moieties
adsorption of biomolecules to the NP surface
Y
Adsorption of plasma proteins to the NP surface

NP
NP with new biological identity
Protein corona
 NP cellular uptake and trafficking
 Biodistribution in vivo
The formation of protein corona depend of NP:
 SIZE
 SURFACE CURVATURE
 SURFACE CHEMISTRY
NP-cell membranes interaction
[Krol S. J Control Rel. 2012]

19. potential solutions
SMART SURFACE ENGINEERED APPROACHES
TO AVOID PROTEIN CORONA
Design a NP surface that exhibits
minimal interaction with
biological environment
TO EXPLOIT PROTEIN CORONA
Design a NP surface that exhibits a
specific interaction with biological
environment
 Apolipoproteins (ApoE)
 Tween 80
 Human serum albumin
NP
[Mahon E. J Control Rel. 2012]

20. Striped gold NP
#
3,0E-04
IN VITRO
Permeability (cm/sec)
1,2E-04 2,5E-04
Permeability (cm/sec)
PB
**
1,0E-04 2,0E-04
[unpublished data]
#
#
IN VITRO
M
#
8,0E-05 1,5E-04
*
[Verma A. Nat Mater. 2008]
6,0E-05 1,0E-04
4,0E-05 5,0E-05
2,0E-05
0,0E+00
PBS
2 % FBS
10% FBS
[unpublished data]
0,0E+00
ST1
Au NANOPARTICLES
(prime preparazioni di striped)
ST2
MUS1
Au NANOPARTICLES
MUS2
all-MUS
[Verma A. Nat Mater. 2008]

21. [unpublished data]

22.  Biological hurdles
 Modifications of the NP’s surface that occurs after
administration in biological environment
 Physical hurdles
SMART DESIGN OF NANOPARTICLES

23. the problem
brain
nanoparticles
1 step: NP dilution into the blood
2 step: NP dilution into CSF
potential solutions
An increased retention of the nanoparticles in the brain blood capillaries combined with
an adsorption to the capillary walls. This could create a higher concentration gradient
that would increase the transport across the endothelial cell layer and as a result
enhance the delivery to the brain.
[Krol S. J Control Rel. 2012]

24. Drugs bound to NP for brain delivery
The development of delivery system to transport drugs into the
brain in a safe and effective manner and in a non-homeopathic
doses are still under exploration
[Kreuter J. Adv Drug Del Rev. 2013]

25. AD MICE MODEL TREATED WITH AMYLOSOMES
(functionalized with mApoE as BBB ligand)
TREATED WITH PBS
TREATED WITH LIP
-40%
*
Immunohistoch. Cortex + Hippocampus (Ab 6E10)
[Balducci C. PNAS 2013, submitted]

26. The BBB represents the main
mechanism of defense of the CNS
The risk-benefit balance due
to NP accumulation in the
CNS should be carefully
evaluated
Some NP (e.g. gold, TiO2 and silica NP) are able to reach the brain even in the absence of
any specific functionalization [Sousa F, 2010 Nanoscale; Wu J, 2011 ACS Nano]