Tayloring functions in microcapsules: Responsiveness and ...

Coating colloids and Hollow capsulesResponsive capsules

Composite capsules - Remote activationTwo compartmental capsules

Capsules delivery in living systemsIntracellular sensing

Conclusions and Perspectives

�� Department of Materials, Queen Mary University of London, UK

Tayloring functions in microcapsules: Responsiveness and remote controlling

Hollow Capsule Fabrication

Hollow PolyelectrolyteCapsule

Organic and inorganic colloidal particles, Dye or drug nanocrystals, emulsion droplets

Gas bubbles, biological cells, protein aggregatesSize 50nm – 50 µm.

Cores

Core removal (decomposition)

Sukhorukov, et al (1998) Colloids and Surfaces A 137, 253.Donath, et al (1998):. Angew. Chemie 37 (16), 2202

Layer-by-layer Capsules

�� Size and shape are determined by Size and shape are determined by templating colloid particle.templating colloid particle.

�� Layer constituents: Layer constituents: �� synthetic polyelectrolytes and biopolymerssynthetic polyelectrolytes and biopolymers�� inorganic nanoparticlesinorganic nanoparticles

�� The Capsule Wall is tunable in The Capsule Wall is tunable in NanometerNanometer range range Thickness, composition and functionality are Thickness, composition and functionality are controlled by constituents and the layer numbercontrolled by constituents and the layer number

�� 1 layer of polyelectrolyte 1 layer of polyelectrolyte �� 11--2 nm2 nm

• Encapsulation �� micro- and nanoreactor engineering• Controlling permeability for wide class of molecules





External stimulus(ions, pH, temperature,

…)

Sharp physical or chemical modifications


Temperature induced capsule shrinkahe

Capsule diameter depends on incubation temperature

10 µm

B

10 µm

CA

10 µm

AB

C

10 20 30 40 50 60 70 80 90 100

1,5

2,0

2,5

3,0

3,5

4,0

4,5

C

apsu

le d

iam

eter

/ µm

Incubation temperature / °C

CLSM

PSS

SO3

n

Na

PDADMAC

N

n

Cl

Dr. Karen Köhler

Morphology of (PDADMAC/PSS)4 capsules

4,6 4,4 3,0 2,8 2,6 2,4 2,2 2,0 1,8 1,6 1,4 1,2

Capsule diameter / µm

1 µm

1 µm

1 µm 1 µm 1 µm

1 µm 1 µm 1 µm

SEM

1 µm

TEM

Temperature induced transition from a hollow shell to a full sphere

1 µm

pH-sensitive hollow capsules

Sodium Poly (Styrene Sulfonate)

n

SO3- , Na+

PSS PAH

m

NH3+, Cl-

Poly (Allylamine Hydrochloride)

NaOH 0.1 M

pH

HCl 0.1 M

pH

SHRUNK STATE

(8 µµµµm)

10 µµµµm

SWOLLEN STATE(18 µµµµm)

10 µµµµm

Christophe Dejugnat

Confocal fluorescence Laser Scanning

Microscopy10 µm

∆T, pH

10 µm

Impermeable„Closed gate“

10 µm

10 µm

Encapsulation and release

ReleaseEncapsulated

Permeable „Open gate“

pH, salt

PAH

PVP

Tuning of electrostatic interactions by pH

��

� ��

�

Poly(allylamine hydrochloride)

Poly(4-vinylpyridine hydrochloride)

PAA

PMA

OHO

m

OHO

p

CH 3

�

��

�

Poly(acrylic acid)

Poly(methacrylic acid)

Increasing hydrophobicity

NH3+

n

Cl-

N

o

H+Cl-

Weak polyelectrolytes

(PAH/PMA)5 capsules templated on SiO2

• thin shells

• d2L = (3 ± 0.2) nm

• smooth surface

NH3+

n

Cl-OH

O

p

CH 3

PAH PMA

Tatjana Mauser

1 2 3 4 5 6 7 8 9 10 11 123.0

3.5

4.0

4.5

5.0

5.5

6.0

caps

ule

diam

eter

, µm

pH

Influence of pH on (PAH/PMA)5 capsules

capsuledissolution

capsuledissolution

addition of HCl: pH < 2

t ~ 1 secswelling

t ~ 2 secdissolution

5 µm

5 µm

5 µm

Tatjana Mauser

Optically driven Encapsulation

Matthieu Bedard – Optically addressable microcapsules





Remote


TEM image

Magnetic NPs in shell

Targeted capsule delivery via magnetic field to tissues

Magnetite nanoparticles assembled in capsule wall

Capsules with Composite Shell are Susceptible to Remote Activation

Ag-nanoparticles doped capsules can be ruptured by Infrared Laser 830nm

� Optically activated release; � Infrared window for biomedical application

Andre Skirtach

Fluorescence Imaging

A.Skirtach et at, Nanoletters, 2005

Ultrasound stimulated release.

Before - encapsulated After – released

– Power of Ultrasound for capsule rupture is compared to medical use without damage of tissues

– Higher depth of operation inside the body

Skirtach, A.G., De Geest, B.G., Mamedov, A.A., Antipov, A.A., Kotov, N.A., Sukhorukov, G.B. J. Mater. Chem., 2007, 11, 1050-1054

Porous calcium carbonate microparticles (∅∅∅∅ 5µm)

��

CaCl2

Na2CO3

+

LbL-coating CoprecipitationCore-

dissolution

Encapsulation of macromolecules after incorporaton into calcium carbonate microparticles (�coprecipitation method�)1.1.

encapsulated biopolymer

Fabrication of multicompartment „ball-in-ball“particles calcium carbonate microparticles ��

CaCO3prec. 1

CaCO3prec. 2

��

ball-in-ball particle (type III)

PEM

SEM-images

ball-in-ball particle (type IV)

PEM

SEM-images

PEM

step 2 LbL-coati ng

CaCO3-extraction

initial core

single-shell-capsule (mixed components)

shell-in-shell-capsule (separated components)

step 5 LbL-coati ng

ball-in-ball particle (type III) ball-in-ball particle (type IV)

~ 8 µm

ball-in-ball particle (type I) ball-in-ball particle (type II)

+ +

step 4 magnetic separation

coproduct

initial core-shell-particle

step 1 Coprecipitation

coproduct

Rhodamin-HSA

magnetite

CaCO3

Alexa 488-HSA

~ 4 µm

CaCO3

PEM

PEMPEM

��

unpurified raw-product

�

step 3 Coprecipitation

� 10 µm

ball-in-ball particles after magnetic

separation

Product purification by an external magnetic field.

Oliver Kreft

�� !��

5 µm

+ E

DT

A

1 sec 2 sec 3 sec 4 sec 5 secB

ball-in-ball-particle IV

shell-in-shell capsulecore dissolution

!��

��

Oliver Kreft

OH

H

OHH

OH

OH

HH

CH2OH

OH

N

OOH O

OH

H

OHH

OH

OH

H

CH2OH

O N

OOH OH

O CH3

��

��

��

��

Amplex Red

ResorufinD-Glucose

D-Gluconic acid-5-lactone

Principle of a coupled assay using the Amplex Red reagent. Oxidation of glucose (GOD) by glucose oxidase results in generation of H2O2, which is coupled to converion of the Amplex Red reagent to fluorescent resorufin by peroxidase (POD).

OUTER CAPSULE COMPARTMENT

INNER CAPSULE COMPARTMENT

��

��

"�� #��$��%��&�� '()*+�� '")*+

IDEA:

+ A

mpl

ex R

ed 10 sec 11 sec 12 sec 13 sec

5 µm

Resorufin formation

GOD: �-D-glucose + H2O + O2 → D-gluconic acid-�-lactone + H2O2

POD: H2O2 + Amplex Red® + H+→ H2O + resorufin + CH3COOH

GODGOD

GOD

GODGOD

PODPOD

POD

Resorufin

+ G

luco

se

H2O2 formation

0 sec

�� ! "��# "�� #

� ��#��$

��%��&�� '()*+�� '")*+

Separate compartments for biochemical reactions

Kreft, O. et al. Angewandte Chemie Intern. Ed., 2007,46 (29), 5605-5608

!&��!&��,)��-$

Mixing of reaction partners by physical triggers:

mixing

LASER

Shell doped with NP

Release of inner capsules by external trigger:

LASER

Shell doped with NPs

!&��!&��,)��-$

AFM & SEM images of shell-in-shell microcapsules

Inner shell rupture

Outer shell rupture - release of nner capsule

O. Kreft et al, Advanced Materals, 2007, 19, 3142



Capsules delivery into living systems Intracellular sensing



Small 2005 1(2), 194-200

Capsules Uptake by Breast cancer cells

Capsules in cells - Artificial organellesReporting on cell interior

Targeted drug delivery - Use of polymer capsules as multifunctional (magnetic, labeled) carrier systems

B. Zebli, A. S. Susha, G. B. Sukhorukov, A. L. Rogach, W. J. Parak, Langmuir, 2005, 21, 4262

A

B C

distance AC: 11 mmdistance BC: 5 mm

Magnet

CBA

In cooperation with Dr. Wolfgang Parak, (LM Uni-München) Dr. Andre Skirtach

Capsules in cells - Artificial organellesRemote activation in the cells

In-house developed optical setup for remote release experiments

Various sources, CCD, real-time imaging, portable, easy tranferable to new location

Andre Skirtach

Optically induced release inside cells

Before

After

Skirtach, A.G., Muñoz Javier, A., Kreft, O., Köhler, K., Piera Alberola, A., Möhwald, H., Parak, W.J., Sukhorukov, G.B. Angewandte Chemie Intern. Ed., 2006, 45, 4612-4617

Towards Intracellular Capsule Delivery to Neurons

In cooperation with Prof. Jo Martin and Dr. D.Davidson (Queen Mary, Neuroscience Center)

PSS/PAH capsules filled with labelled BSA



Capsules delivery in living systemsIntracellular Sensing Systems

Conclusions and perspectives


SNARF dyeRatiometric pH measurement. The dye shifts the maximum of the fluorescence emission from green to red color upon increasing the pH.

Emissionspectra (Fluorescence) of SN A RF-D extrane in Solution (pH 2 to 11)

0

2000

4000

6000

8000

10000

12000

510 520 530 540 550 560 570 580 590 600 610 620 630 640 650 660 670 680 690 700 710 720 730 740 750

nm

pH 2.0

pH 3.0

pH 4.0

pH 5.0

pH 6.0

pH 7.0

pH 8.0

pH 9.0

pH 10.0

pH 11.0

wavelength (nm)

inte

nsity

acidic pH: green fluorescence alkaline pH:

red fluorescenceEmissionspectra (Fluorescence) of SN A RF-D extrane in Solution (pH 2 to 11)

0

2000

4000

6000

8000

10000

12000

510 520 530 540 550 560 570 580 590 600 610 620 630 640 650 660 670 680 690 700 710 720 730 740 750

nm

pH 2.0

pH 3.0

pH 4.0

pH 5.0

pH 6.0

pH 7.0

pH 8.0

pH 9.0

pH 10.0

pH 11.0

wavelength (nm)

inte

nsity

acidic pH: green fluorescence alkaline pH:

red fluorescence

Polymer Microcapsules as Mobile Local pH-Sensor

SNARF-loaded capsules change from red to green fluorescence upon internalization by MDA-MB435S breast cancer cells.

(A) SNARF-fluorescence 30 min after adding the capsules to the cell culture. (B) The same cells after another 30 min of incubation.

On-line monitoring of capsule internalisation

Kreft, O., Muñoz Javier, A., Sukhorukov, G.B., Parak, W.J. J. Mater. Chem., 2007, 42, 4471-4476

Intracellular Sensors Encapsulated pH – sensor, SNARF-based dye

BeforeUptake

After Uptake

Green – low pHEmission 580nm

Inside cell endosomeRed – high pHEmission 650 mn

Outside cell

Kreft, O., Muñoz Javier, A., Sukhorukov, G.B., Parak, W.J. J. Mater. Chem., 2007, 42, 4471-4476




Conclusions and perspectives


Research strategies Research strategies

-- Design of NanoDesign of Nano--engineered shellengineered shell on colloidal particles/capsuleson colloidal particles/capsulesinc. inc. Emulsion, microEmulsion, micro-- and nanocrystals, bubblesand nanocrystals, bubblesTuning release, delivery systems into cells and tissuesTuning release, delivery systems into cells and tissues, ,

Cellreporters

enzyme functions

-- StimuliStimuli--responsive capsules responsive capsules RemoteRemote (IR(IR--, US, MW) activated release, US, MW) activated release

-- Diagnostics/Sensing using encapsulated materialDiagnostics/Sensing using encapsulated material

-- Modelling Modelling biological cellsbiological cells and organelles. and organelles. Cell residing reporters.Cell residing reporters.

Macromolecule encapsulationMacromolecule encapsulation

Cell-/Tissue-Targeting

Cell-/Tissue-Targeting

Visualization, Sensors

Visualization, Sensors

Controlled release

Controlled release Remote activationRemote activation

A+B

C

MicroreactorsMicroreactors

MagnetismMagnetism

��

ProtectionProtection

AcknowledgementsDr. Andre Skirtach

Dr. Oliver Kreft Dr. Christophe Dejugnat

Dr.Dmitry ShchukinDr. Tatjana Mauser Dr. Karen KöhlerDr. Alexei Antipov

Dr. Alexander PetrovDr. Tatyana Borodina

Matthieu Bedard

Prof. Dr. Helmuth Möhwald

University of Marburg – Prof. Dr. Wolfgang Parak, Dr. Almudena Muñoz Javier

University of Ghent – Dr. Bruno de Geest

NeuroScience Centre, QMUL – Prof. Jo Martin, Dr. D.Davidson

Tayloring functions in microcapsules: Responsiveness and ...

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