Inorganic Nanoporous Nanoparticles for Tooth Bleaching

and Drug Delivery System

Kevin C.-W. Wu

吳嘉文Associate Professor

Department of Chemical Engineering

National Taiwan University

E-mail: kevinwu@ntu.edu.tw

Russian-Taiwanese Symposium on Nanobiology and Nanomedicine

3-5 November 2015, Novosibirsk, Russia

About National Taiwan University

2

Kevin C.-W. Wu

吳嘉文

Associate Professor

Department of Chemical Engineering

National Taiwan University

E-mail: kevinwu@ntu.edu.tw

Facebook: mesoporous

Pore = Empty = Useless?

Inorganic Nanoporous Nanoparticles for Tooth Bleaching

and Drug Delivery System

無用之用: The Usefulness of The Useless

Space has its usefulness with functionality

Pore Diameter (nm)2

Mesoporous

Materials

Zeolite

MOF

ZIF

Porous glass

Classification of Porous Materials According to IUPAC

Microporous

Materials

Macroporous

Materials

MCM

SBA

FSM

Lamellar Hexagonal Cubic

50

FDU

CMK

CAR

Inorganic Nanoporous Materials

Study in my group

Intracellular drug delivery

Tooth bleaching

Why do we need drug carriers?

Some clinical limits of direct delivery of conventional

diagnostic and therapeutic drugs

1. Less solubility

2. Rapid clearance

3. Poor pharmacokinetics

4. High dosage

5. High side effects

6. Nonspecific targeting

1. High solubility

2. Slow clearance

3. Good pharmacokinetics

4. Low dosage

5. Low side effects

6. Specific targeting

Drug delivery systems (DDS) are designed to enhance

the availability of various therapeutic reagents to its

target site and reduce the adverse side effect.

What is Metal-Organic-Framework (MOFs)?

‘Linking Inorganic and Organic Units by Strong Bonds’

COOH

COOH

H2BDC

+

Zn4O

Metal connector Organic linkers

FunctionalityDesignabilityDirectability

Physical propertiesof metal ion

Pore sizepore shapesurface functionality

Yaghi et al. Nature 1999, 402, 276

Zn4O(bdc)3 (MOF-5)

Ditopic linker

The synthesis of MOF is like playing LEGO

Library of organic linkers

Di-topic Tri-topic Poly-topic

Library of inorganic metal connectors

Our recent contribution to MOF

Zeolitic Imidazoate Framework-90

(ZIF-90)

H2O-based

systems

Zn(NO3)2

ICA

5 μm

200 nm

Microparticles

Nanoparticles

Water-based Synthesis of ZIF-90 with Controlled Sizes!!

Our recent contribution to MOF JACS, in press, (2015)

Introduction of Prussian blue

Dark blue pigment with idealized

formula Fe7(CN)18 xH2O

Widely used in painting, medicine, and

laboratory histopathology stain for iron.

In medicine, PB is used as an anitdote for heavy metal

poisoning (e.g., Cs and Tl)

The US FDA determines that 500 mg of PB is safe and

effective for treating internal contamination with heavy

metal

poisons.

Prussian blue is potential as an anticancer drug carrier

Control of particle size of Prussian blue (PB)

Preparation of PB particles by adding polyvinylpyrrolidone (PVP)

K3[Fe(CN)6]

Partial

decomposition

Fe3+ Fe2+Reduced by PVP

K3[Fe(CN)6]Fe4[Fe(CN)6]3

Growth mechanism of PB particles

CrystEngComm, 2012, 14, 3387.

Synthesis of solid Prussian blue (SPB) NPs

SPB

HCl

Self-

assembly

PVP

coating

Self-

etchingPVP

removal

HPB

Blue precipitates (SPB)

PVP

K3[Fe(CN)6]·3H2O

HCl solution (0.01M)

Dried@80℃

Controllable particle size: 110 nm

Interior micropores

Single-crystal of Prussian blue17

Synthesis of hollow Prussian blue (HPB) NPs

SPB

HCl

Self-

assembly

PVP

coating

Self-

etchingPVP

removal

HPB

Interior hollow cavity

Mesopores in shell

Single-crystal of Prussian blue

HPB

SPB

PVP

HCl (1 M)

Hydrothermal

treatment@140℃

Space group: (Fm3m)

18

Angew. Chem. Int. Ed., 2012, 51, 984.

Functionalities of hollow PB nanoparticles

Nanoparticle (~100 nm)

Easily uptaken by cancer cell

Passive targeting (EPR effect)Hollow

interior

Large space to store drug

Micropores

Absorb guest molecule by

large surface area

1. Nanoparticle morphology

3. Micropores in shell

2. Hollow cavity

Fe4[Fe(CN)6]319

Porous structure of HPB NPs

Macropore

MicroporeMesopore

SBET = 324 m2/g

Macropore: 80 nm

Mesopore: 3-20 nm

Micropore: ~0.5 nm

20

In-vitro drug loading & release

Cisplatin

(~0.5 nm)

Fast adsorption Drug got stuck in shell 21

Confocal fluorescent images

T24 cancer cell

Healthy cell: elongated shape

HPB & cis@HPB accumulate in cytoplasm

Cell death induced by cis@HPB

22

Stability & MTT assay

40%

BladderStomac

h

Endosome Blood None

High biocompatibility of HPB

Cytotoxicity of cis@HPB

High stability of HPB in pH 2-8.6

Biocompatibility of HPB Cytotoxicity of cis@HPB

70%

23

Inorganic Nanoporous Materials

Study in my group

Intracellular drug delivery

Tooth bleaching

Synthesis of mesoporous materials

Hexagonal

ArraySurfactant

Micelle

Self-assembly

Inorganic

Spices

Si(OR)4

Sol-Gel process

(OR)3Si-OHCooperative

assemblyDrying &

Calcination

Self-assembled

organic/inorganic hybrid

(Mesostructured materials)

Mesoporous

materials

A variety of inorganic species

• Siliceous

Silicon alkoxides: Si(OR)4

Layered silicate: Kanemite

Silsesquioxanes: (RO)3Si-R’-Si(OR)3

• Non-siliceous

Transition metal alkoxides: M(OR)n

Transition metal salts: MXn

Carbon: Glucose

Si +OR H2O

hydrolysis

Si +OH ROH

Si +OR

H2O

alcohol

condensation Si +O ROHSiHO Si

Si +OHwater

condensation Si +OSiHO Si Uniform and tunable pore size (2 ~ 50 nm)

High surface area (> 1000 m2/g)

Hydrophilic head

Hydrophobic tail

Cationic: CnH2n+1(CH3)3N+

Anionic: CnH2n+1R, R=COO-, SO3-

Neutral : CnH2n+1NH2

Cubic2D-HexagonalLamellar

Highly-ordered mesostructure

Gyroid

Electrostatic interaction Hydrogen-bonding

Interaction between surfactants (S) and inorganics (I) Functionalization

-COOH

-NH2

-SH

-SO3H

Mesoporous Silica Nanoparticles (MSN)

50 - 300 nm2-5 nm

Advantages of mesoporous silica nanoparticles (MSN)

High surface area (>1000 m2/g)

High pore volume (~1.0 cm3/g)

Uniform and tunable pore size (2-40 nm)

Abundant silanol groups (~30 %)

: Si-OH

Rigid framework

Tunable particle shape and size

External and internal surface

Multifuncationalization

: organic group A

: organic group B

: organic group C

Integratied with other NPs (e.g. Fe3O4)

A unique 2D hexagonal pore structure

: Caps

They love you !!!

Endocytosis

Uncapping

Drug release

Intracellular Drug Delivery System

Cell membrane

: Caps

: MSN

: Drug

V

V

V

Nano-vehicle

• Chemistry-A European Journal. 2012, 18, 7787-7792.

• Chemical Communications. 2012, 48, 6532-6534.

• ACS Applied Materials & Interfaces. 2012, 4, 6720-6727.

• Chemistry-A European Journal. 2013, 19(15), 4812-4817.

• Journal of Materials Chemistry B. 2013, 1(19), 2447-2450.

• Journal of Biomedical Materials Research: Part B - Applied Biomaterials. 2013,

102(2), 293-302.

• Chemical Communications. 2014, 50, 4148-4157. Selected as Back Cover.

• International Journal of Nanomedicine. 2014, 9(1), 2767-2778.

Our contribution in the mesoporous inorganic nanoparticles

Hollow HAp NPs Mesoporous

TiO2 NPs

Au

nanoflowers

In vivo visualization of biodistribution of MSNs in a

see-through medaka fish (Oryzias latipes)

In vivo toxicity and biodistribution of MSNs

Mouse is used an animal model

MRI or NIR agents are necessary Lo et al., Adv. Funct. Mater., 2009, 19, 215.

Observation of MSNs in a see-through medaka fish as a rapid

screening model for in vivo toxicity and biodistribution

Exposure medaka fishes with FITC-MSNs

Exposure for 7 days Exposure for 28 days

Exposure for 28 days

Excretion for 2 days

Liver

Gill Kidney

Comparison in liver

Color of Tooth

Tooth structure

The tooth color is determined by

1. The color of dentine

2. The thickness of enamel

3. The color of blanket on

the enamel (hydroxyapatite)

The tooth color is yellowish

grey in general

Removal of tooth discoloration

Mechanical polishing for

extrinsic stain

Tooth bleaching for intrinsic

stain

Hydrogen peroxide

Bleaching agents

H2O2

(Strong free radicals can

attack stain)

OH or HO2. .

Carbamide peroxide

Sodium perborate

Side effects of tooth bleaching:

Tooth Hypersensitivity

Alter the structure of both dentin and enamel

Damage pulp tissues

Objectives

Mn+ + H2O2 →M(n-1)+ + HOO• + H+

M(n-1)+ + H2O2 →Mn+ + HO • + OH-

Use transition metal ions to catalyze H2O2 without UV light

Preparation of metal ion-histidine complex MSN

N

N OHNH

O

N

NOH

NH

O

Fe2+

Preparation of tooth samples

low speed saw sonication to

remove

impurities

store it in saline

solution

0.15mM

Orange II

4,24,48,72 hrs

image analysis

400 500 600

0

2

Ab

s

Wavelength [nm]

Orange II

Estimation of tooth color

Spectrophotometer

Colorimeter

Image analysis technique

1 h

6 h

0 h

H2O2 MSNhis-MSN

Fe(II)-his-MSNMn(II)-his-MSN

Result: Orange II discoloration in test tubes

Bleaching for 6 h

Only H2O2H2O2+

Fe(II)-his-MSN

Result: Orange II discoloration in tooth

H2O2+Mn(II)-his-MSN

Bleaching for 1 h

Before stain

After stain

＊ P<0.05

Result: Orange II discoloration in enamel

Mn+ + H2O2 →M(n-1)+ + HOO• + H+

M(n-1)+ + H2O2 →Mn+ + HO • + OH-

Mechanism: Fenton reaction

H2O2 + 2H+ + 2e- → H2O

H2O2 → O2 + 2H+ + 2e-

Eored = 1.776 V (1)

Eoox = -0.682 V (2)

Mn2+ + 2H2O → MnO2 + 4H+ + 2e- Eoox = -1.23 V (3)

Fe2+ → Fe3+ + e- Eoox = -0.77 V (4)

Mn2+ + H2O2

(1) + (3) = 0.546 V <

Fe2+ + H2O2

(1) + (4) = 1.006 V

Fe3+ + H2O2

(2) + (-4) = 0.088 V

Technology Transfer

Inorganic Nanoporous Materials

Conclusion

Intracellular drug delivery

Tooth bleaching

Acknowledgement

Research funding

Students