1. Nanoparticle-mediated brain drug delivery for the treatment of Alzheimer's disease
Gyeong Won Lee
Supervised by Prof. Seung Yun Yang
Functional Soft Nanomaterials Lab.

2. What is dementia? Dementia? Cause of dementia Caused by brain damage
Continuous and overall decline of cognitive function
Increased incidence rate due to increasing the aging population
Alzheimer’s disease 69 %
Vascular dementia 21 %
Parkinson’s disease dementia 4%
Alcoholism
Injury

3. Alzheimer’s disease (AD)
Symptom of AD
Cause of AD
Difficult to learn new things and to remember new information
Normal concentration
Neurofibrillary tangles, senile plaques
Reduction of acetylcholine function
Deposition of the senile plaques mainly composed of amyloid plaque in brain cells
Formation of neurofibrillary tangle based on hyperphosphorylated tau protein

4. Target of AD therapies Acetylcholine Amyloid plaque Tau protein
Neurotransmitters secreted from the nerve terminal
Decreased acetylcholine secretion causes Alzheimer's disease
Deposition of insoluble amyloid plaques on brain cells
Necrocytosis of brain cells by deposited insoluble amyloid plaques
Microtubule-associated protein in neuron cells
Formation of neurofibrillary tangle by hyperphosphorylated tau protein

5. Blood-brain barrier; gate keeper of brain
Blood-brain barrier (BBB)
A gateway that limits the transfer of moleculars from blood to brain tissue
Interfering with the transport of intercellular molecules by tight junction
Permeable material
Liposoluble material
Non Permeable material
Polar material, strong electrolyte, polymer, water soluble molecule
The upper limit of pore size in the BBB that enables passive flow of molecules across : <1 nm particles
Diameter of several nanometers can also cross the BBB by mediated transport. 
Need to develop targeted drug delivery to BBB and AD region
for penetrating into BBB and minimizing side effect

6. Nanoparticles for drug delivery across the BBB
Nanoparticles (NPs)
Particulate dispersions or solid particles with sizes ranging from 1 to 1,000 nm.
Advantage of NPs
Permeable into BBB without damaging
Sustained release
Improving permeability to BBB
The transport mechanism of NPs across the BBB
An increased retention of the nanoparticles in the brain blood capillaries.
Inhibit the efflux system. especially P-glycoprotein
A general surfactant effect characterised by the solubilisation of the endothelial cell membrane lipids.
Endocytosis by the endothelial cells.

7. Type of NPs for drug delivery
Polymer nanoparticle
Thin membrane trapping oil core with drug or polymeric chains trapping drug
Liposome
Consisting of one or more phospholipid bilayers
Around an aqueous compartment that serve as carriers of lipophilic or hydrophilic drugs
Solid lipid nanoparticle
Solid lipid core matrix with lipophilic molecules or solid liquid trapping oil core with drug
나노파티클 제조 방법
Bruno Fonseca-Santos, et al., Int. J. Nanomedicine, 10, (2015)
Bruno Fonseca-Santos, et al., Int. J. Nanomedicine, 10, (2015)

8. Coated NPs for improving permeability
Surface modification
Coating with specific material for penetration of BBB
Requires low toxicity and biocompatibility
Coating material
Surfactant
Lead to membrane fluidisation and to an enhanced drug permeability across the blood–brain barrier
Inhibit the efflux system, especially P-glycoprotein (ex. polysorbate 80)
Ligand
Targeted drug delivery to disease region
Combination with specific receptor on BBB surface
A. Zensi, et al., J. Control. Release, 137, (2009)
The nanoparticles (dark spheres indicated by arrows) were observed inside the endothelium cells

9. Improve permeability of water-soluble drug (doxorubicin)
Doxorubicin brain concentration after intravenous injection of one of the following preparations.
●, doxorubicin [5 mg/kg] solution in saline
■, doxorubicin [5 mg/kg] solution in saline plus 1% polysorbate 80
▲, doxorubicin [5 mg/kg] bound to poly(butyl cyanoacrylate) nanoparticles
◇, doxorubicin [5 mg/kg] bound to poly(butyl cyanoacrylate) nanoparticles + 1% polysorbate 80.
A.E. Gulyaev, et al., Pharm. Res., 16 (1999)
Viability of in vitro cultured bovine brain blood vessel endothelial cells in percent of untreated control cells by the MTT test after addition of poly(butyl cyanoacrylate) nanoparticle (NP) preparations or of polysorbate 80 alone.
100 oP=100 μg/ml NP without polysorbate 80
100 mP=100 μg/ml NP with polysorbate 80
20 oP=20 μg/ml NP without polysorbate 80
20 mP=20 μg/ml NP with polysorbate 80
10 oP=10 μg/ml NP without polysorbate 80
10 mP=10 μg/ml NP with polysorbate 80
P 1000=1000 μg/ml polysorbate 80
P 100=100 μg/ml polysorbate 80
P 10=10 μg/ml polysorbate 80
A.E. Gulyaev, et al., Pharm. Res., 16 (1999)

10. Ligand-conjugated NPs for Targeted drug delivery
Coating with specific ligand which has good affinity with disease region
Delivering drug specifically to disease regions
Minimizing side effects from taking medication
Maximizing drug efficiency
Receptor-mediated endocytosis
Process by which cells absorb metabolites, hormones, other proteins by the inward budding of plasma membrane vesicles containing proteins with receptor sites specific to the molecules being absorbed

11. Maleimide groups on NPs can conjugate with thiol groups on ligand
Ligand-conjugated NPs for BBB targeting
Phage display for find specific ligand
Fusion of peace of DNA and bacteriophage coat protein gene for displaying specific peptide on phage surface
Selection of phage passed through BBB after injecting the phage displaying the peptide into mouse
Ligand-conjugated NPs
Select ligand specifically binding to BBB
Covalently coupled onto the surface of NPs
Increasing selective permeability to BBB
Ligand 붙이는 방법
Karsten Ulbrich, et al., Eur. J. Pharm. Biopharm., 72, (2009)
Maleimide groups on NPs can conjugate with thiol groups on ligand

12. Distribution of ligand-conjugated NPs
Concentrations-time curves of coumarin 6 in cerebrum
In vivo and in vitro test
Enhanced brain accumulation efficiency Covalently coupled onto the surface of NPs
Lower accumulation in liver and spleen
Does not increase cytotoxicity
Ligand 붙이는 방법
Jingwei Li, et al., Biomaterials, 32, (2011)
 In vitro cytotoxicity
In vivo distribution
Jingwei Li, et al., Biomaterials, 32, (2011)
In vivo distribution of TGN-NP. (I) blank nude mice as blank control. (II) NP; (III) TGN-NP (1:1); (IV) TGN-NP (1:3)
Jingwei Li, et al., Biomaterials, 32, (2011)

13. Targeted drug delivery to AD region
Concentration vs. time curves of coumarin-6 in the cerebrum
Dual-functional NPs
Conjugated with BBB targeting ligand and AD region targeting ligand
Direct drug delivery to AD region is possible
Minimizing side effects (ex. NGF)
이중 리간드
The ex vivo imaging and fluorescent intensity of the brains from nude mice treated with NP
Cerebellum
Hippocampus
Hippocampus of
the AD model mice

14. Summary
Drug delivery using NPs can overcome the limitations of drugs that could not penetrate the BBB, thus broadening the range of AD medication and enabling sustained release drug delivery system
NPs coated with a ligand targeting the BBB and AD regions can minimize drug side effects by delivering drugs specifically to the BBB and AD regions
NPs conjugated with targeting ligand can be used to treat a wide range of diseases because they can be used for various CNS treatments besides AD therapy.

15. Thank you
for your attention