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Intelligent Micro- and Nanocapsules
Gleb SukhorukovMax-Planck Institute of Colloids and Interfaces,
Golm/Potsdam, Germany
Coating colloids and Hollow capsulesRelease properties
Encapsulation of macromoleculesOrganic dye precipitation by pH-gradientInorganic particles synthesis in capsules
Poor-water soluble dye precipitationCapsule based combinatorial libraries
Enzymatic reaction in capsules
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Polyelectrolyte Layer-by-layer assembly
3. Polycation Adsorption
4. Wash
1. Polyanion Adsorption
2. Wash
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Capsule preparation
Hollow Polyelectrolyte Capsule
Organic and inorganic colloidal particles,
drug nanocrystals, biological cellsCores
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The core (template) is a dissolvable colloidal particle, a drug particle a dye particle or
even a biological cell
Melamin resin coresMelamin resin coresInorganic cores, carbonates, oxidesInorganic cores, carbonates, oxidesDye and drug particles Dye and drug particles DropletsDropletsErythrocytes, others biological cellsErythrocytes, others biological cells
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Layer constituents
Synthetic polyelectrolytesSynthetic polyelectrolytesBiopolymers (proteins, polysacharides, nucleic Biopolymers (proteins, polysacharides, nucleic acids)acids)Lipids,Lipids,Inorganic nanoparticlesInorganic nanoparticlesThe wall can be tuned in thickness, composition The wall can be tuned in thickness, composition and functionality by choosing various constituents and functionality by choosing various constituents and adjusting the layer numberand adjusting the layer number
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Advantage of the technique
The size and shape of the The size and shape of the capsules is controlled by the capsules is controlled by the SIZE and SHAPE of the SIZE and SHAPE of the TEMPLATETEMPLATE
Rather monodisperse capsule Rather monodisperse capsule dispersions can be prepared
Templated on red blood cell
dispersions can be prepared
Templated on melamin particles
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0 1 2 3-80
-60
-40
-20
0
20
40
60
Fluorescently labeled polyallylamine concentration (microgram/ml)
0
5000
10000
15000
20000 supernatant flu
orecenceZe
ta-p
otentia
l
( )
NH3+
Poly(allylamine hydrochlorid) PAH
C l-
Poly(styrenesulfonat) PSS
( )
SO3-
N a +
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Next layerMatched concentration
Next layerCentrifugation
Next layerFiltration
Next layerGel-electro-phoresis
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Electrophoretic Mobility measurements as means to follow Layer Growth
Layer Number0 2 4 6 8
-80
-60
-40
-20
0
20
40
60
ζ - P
oten
tial [
mV
]
Various Polyelectrolytes: PDADMAC - PSS BSA - PDADMAC, PSS - PAH, DNA - PDADMAC
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Layer Thickness - Monitoring of Multilayer Formationby Single Particle Light Scattering
200 300 400 500 600 7000
500
1000
1500
2000
21 layers11 layers
control
Scattering Intensity (arb. units)La
yer T
hick
ness
[nm
]
0
5
10
15
20
25
0 2 4 6 8 10 12 14 16
Layer Number
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Scanning electron microscopy Atomic force microscopy
Layer-by-Layer approach
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Templating on biological cells - MICROREPLICA
Echinocyte cells
Confocal Scans through an Echinocyte templated polyelectrolyte shell
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Release Control by Multilayers
0 100 200 300 400 500 600 700 800 900 1000 1100
0
1x104
2x104
3x104
4x104
5x104
Uncoated Fluorescein particles 9 PSS/PAH layers 13 PSS/PAH layers 15 PSS/PAH layers 18 PSS/PAH layersFl
uore
scen
ce, a
.u.
Time, sec
0 2 4 6 8 10 12 14 16 18 20
0
1
2
3
4
5
6
7
Perm
eabi
lity
coef
ficie
nt, m
/sec
*10-8
Number of layers
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Permeability Coefficients: Ionic Strength
Ionic strength influencesdrastically (one order of
magnitude going from 1 to 500mM) the properties of
PEM.
0,0 0,1 0,2 0,3 0,4 0,50,0
0,5
1,0
1,5
2,0
2,5
3,0
Perm
eabi
lity
Coe
ffici
ent,
m/s
ec *1
0-8
Ionic strength, M
0 5 10 15 20 250
20
40
60
80
100
120
140
Fluo
resc
ence
, a.u
.
Time, min
0,0 0,5 1,0 1,5 2,0 2,5 3,00
20
40
60
80
100
120
140
1mM 10mM 25mM 50mM 100mM 250mM 500mM
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Permeability behavior of annealed shells
20 30 40 50 60 70 80 90 1001E-9
1E-8
1E-7
1E-6
1E-5
Perm
eabi
lity
[m/s
]
Temperature [ °C]
Annealing time = 30 min
10 min
Capsules 8 layers PAH/PSS
Heat Treatment can close defects
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The Presence of the Lipid Bilayer Decreases the Permeability
Capsules with 8
Polyelectrolyte LayersCapsules with a Phospholipid Bilayer
The fluorescent polar marker 6-carboxyfluorescein is excluded
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Encapsulation via Permeability RegulationDextran-FITC
pH >7.5, closed state pH <6.5, open state pH>7.5 Encapsulated
1 2 3 4 5 6 7 8 9 10 11 12
open capsules
closed capsules
pH
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Encapsulation of Enzymes
0
20
40
60
80
100
50210%
of a
ctiv
ity fr
om n
ativ
e[BPTI] / [α-chymotrypsin], mol/mol
free α-chymotrypsin encasulated α-chymotrypsin
0 1 2 3 4 5 6 7 80
20
40
60
80
100 pH8.0 , 25oC Native chymotrypsin Encapsulated chymotrypsin
Res
idua
l act
ivity
, % fr
om T
ime=
0
Time, days
Inhibitor
Enzyme
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Encapsulation of Urease in Polyelectrolite Multilayer shells
Ethanol/Water 1:1In WaterIn Water.
Encapsulated
5 mµ5 mµ
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Calcium carbonate growth into polyelectrolytecapsules by urease catalyzed reaction
A final stage of precipitation
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Polymer Synthesis inside Capsules
pH = 1
Monomers
80°CS O2 8
2-
Polymerisation Washings
Broken and Empty Capsules
Swelling as a result of osmotic pressure increase.•The capsules were filled with a fluorescent
(rhodamin) copolymer
•The permeability difference between substrate and product is always employed
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Encapsulation of macromolecules. 1. Controlled precipitation of polymers on colloidal particles
Precipitating condition
Solvent or complex-ion
10µm
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Encapsulation of macromolecules. 2. Inner shell decomposition
non-chargedpolyanion Me3+
charged
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Reversible shrinkage - swelling of the loaded with polyelectrolyte (PSS) capsules induced by osmotic
pressure
Reversabl e shrinkage - swelling of the loaded with polyelectrolyte (PSS) capsules induced by osmotic pressure
681012
Diameterofthecapsules(µm)
0 1 2
6
8
10
12
Dia
met
er o
f the
cap
sule
s (µ
m)
PSS concentration in bulk solution (monoM)
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Organic dye precipitation by pH-gradient
Electroneutrality (C = C )yields pH = 7
OH H
neutralacid
H+
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pH- difference through capsule wall established by Donnan equilibrium
Polycationpolyanion
neutral
basic
neutral
acid
acid
neutral
basic
neutral
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Organic dye precipitation by pH-gradient
Polyelectrolyte Shells as templatesfor controlled crystallization and
precipitation of small organic molecules. Model of drug loading pH-difference
Fluorescence Confocal Image (self-quenching) Transmission Image
Scanning electron microscopy image of carboxytetra-methylrhodamine precipitates 6-carboxy-fluorescein
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Organic dye precipitation inside capsules caused by pH-gradient
solubility, nucleus sites, pH-difference
6-CF 5(6)-TAMRAM X U EI T R
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Inorganic particles synthesis inside capsules
pH-difference
Selective pH-induced formation of Iron oxide crystals into capsule
filled with polycation
23
Optical microscopy
TEM
Hematite Fe2O3-particles
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Magnetite particles synthesis in capsule interior
Fe3+Fe2+
pH-difference
OH- Fe3O4
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Selective polymer/light-induced Silver particles formation into PSS and dextran filled capsules
Light
Ag+
Optical microscopy image of dextran filled capsules
in AgNO3 solution
TEM image of dextran filled capsules in AgNO3 solution
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Precipitation poor-water soluble dyes in capsules caused by polarity gradient
Filled capsules
Suspension of capluces with precipitated drug in water
Capsules+drug suspension in acetone/water mixture (high acetone content)
DR-1
0,0 0,3 0,6 0,9
0,0
0,3
0,6
0,9
Acet
on c
once
ntra
tion
insi
de th
e sh
ells
Aceton concentration in outer solution
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LbL of Thermosensitive Polyelectrolytes
use of charged PNIPAM derivativesfor the preparation of thermosensitive microcapsules
anionicblock copolymer(SS24-NIPAM76)
cationicblock copolymer
(DEAEMA34-NIPAM66)
C=O
NH
H3C CH3
66
C2H5
C=O(CH2)2
H5C2
34
NH+, Cl-
H3C
C=O
NH
H3C CH3
7624
, Na+SO3-
LCST = 31.9ºC LCST = 31.8ºC(determined by DSC measurements)
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Influence of the Temperature on the Capsule
size measured by confocal microscopy (8 deposited layers)
-the thickness of the wall measured by AFM increases with the temperature-Ratio of thickness ≈ 0.5
⇒ decrease of the permeability of the wall
R
e << R ⇓
V = 4πeR2
volume Vat 25°C
x
increaseof the
temperature
e’ volume V'at 60°C
R’x
e’ << R’ ⇓
V = 4πe’R’2
V = V’ ⇒ (e/e’) = (R’/R)22.2
2.0
1.8
1.6
1.4
Radi
us (µ
m)
6050403020100Temperature (ºC)
R25
R’60
shrinking of the hollow capsules with the increase of the temperature
ratio R’60/R25 = 0.77
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Combinatorial library based on Doping of Capsules with Fluorescent nanoparticles (quantum dots) and their mixture
500 600 700
1:1PL
inte
nsity
[a.u
.]
500 600 700
1:2
Wavelength [nm]500 600 700
2:1
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Combinatorial library based on particle signing
Reduction of Ag in film by laser beam on surface of colloidal particles
Ag/PSS film was assembled on colloid particles
5 µm
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Enzymatic reactions inside capsule
Ca2+ Chymotrypsine
Dextran sulfate/ protamine capsules filled with alginate
5 µΜ
Chymotrypsine embedding in capsules containing alginate gel
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Enzymatic reactions inside capsule
Kinetic scheeme of chymotrypsime function
C hym o tryp sin
NH2
COO-
Rhodamine 110
Exc ita tio n - 498 nm
Em issio n - 521 nm
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Enzymatic reactions inside capsule
Capsules with embedded chymotrypsine
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Bi-enzyme system incorporated in the capsule
Pe ro xid a se fluo re sc e in la b e lle d
10µΜ
G luc o se o xid a se
Pe ro xid a se
Re d
Exita tio n 563 nme m issio n 587 nm
A m p le x fo r g luc o se a ssa y, c o lo rle ss
G luc o se o xid a se rho d a m ine la b e lle d
10µ 10µΜ Μ
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Shell with defined Size, thickness, stability,
composition,Affinity properties
Controlling Uptake and release
Drug formulationDrug carriers
Sustained releaseTargeting
Microreactor,CatalysisSensing
MacromoleculeEncapsulation
Hollow particle
Precipitation,Product collection in capsule interior
Colloidal particle
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Biological Functions onBiological Functions on PolyelectrolytePolyelectrolyte Capsules Capsules --TowardToward ArtificialArtificial CellsCells?
Lipid-Polyelectrolyte Interaction
Tuning the Lipidproperties Tuning of the polyelectrolyte
Layer properties
Do the membrane proteins work?
Additional Functions: Nanoparticles, Fluorescent
Reporter Molecules, Magnetic Particles, etc.
Synthese
Capsule or Colloidal Core
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Acknowledgments.
Prof.Dr.Helmuth Möhwald Collaborators:Prof.Edwin Donath
Prof.Yuri Lvov,Prof.Olga Vinogradova
Prof.Natalia I. Larionova,Dr.Andrei Rogach
Dr.Alexander Petrov,Dr.Dmitry Shchukin,
Yuri Fedutik Michelle Prevot
Capsulution NanoScience AG
Postdoctoral researchers:Dr.Karine Glinel,Dr.Olga Tiourina,
Dr.Dinesh Shenoy,Dr. Claire Peyratout
Dr.Radostina Georgieva
Ph.D.Students:Alexei Antipov,
Igor Radtchenko,Ana Cordeiro,Wenfei DongAnja Günther,
Technical staff: Carola Gaudl, Anne Heilig, Heidi Zastrow
Financial supportSofia Kovalevskaya Programm of Alexander von Humboldt Foundation,
BMBF- Investment for Future Programm, EU-project „Nanocapsules“