Bioceramics: Multiscale Engineering of Advanced Ceramics ... · Universität Bremen ......

www.bioceramics.uni-bremen.deUniversität [email protected]

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ETH Ceramics20 years5.9.2008

Bioceramics: Multiscale Engineering of Bioceramics: Multiscale Engineering of Advanced Ceramics at the Biology InterfaceAdvanced Ceramics at the Biology Interface

Kurosch RezwanKurosch Rezwan

krezwan@[email protected]

Bioceramics, FB4Bioceramics, FB4UniversitUniversitäät Brement BremenAm Biologischen Garten 2, IW3Am Biologischen Garten 2, IW3D D -- 28359 Bremen28359 BremenTel: +49 421 218 4507Tel: +49 421 218 4507Fax: +49 421 218 7404Fax: +49 421 218 7404

www.bioceramics.uniwww.bioceramics.uni--bremen.debremen.de


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Global ChallengesGlobal Challenges

Filters, Sensors, CatalystsFilters, Sensors, CatalystsClean Air & Clean WaterClean Air & Clean Water

EnvironmentEnvironment

500 µm500 µm

HealthHealthGrowing and Ageing Growing and Ageing PopulationPopulation

Orthopaedic ImplantsOrthopaedic ImplantsBone Replacement MaterialBone Replacement Material

EnergyEnergy

BioreactorsBioreactorsSustainabilitySustainability

150 µm150 µm150 µm

www.bioceramics.uni-bremen.deUniversität [email protected] Ceramics

20 years5.9.2008

LongLong--term implants in Orthopaedics or Dentistryterm implants in Orthopaedics or Dentistry

Degu Dent

Complete Dental Bridge: ZrO2

Pearson Dental Group

Crowns

Hip implants: Al2O3 and ZrO2Ceramtec


20 years5.9.2008

Use of Zirconia (ZrOUse of Zirconia (ZrO22) for dental bridges) for dental bridges

Wax model of a ceramicdental bridge

800

N80

0 N

800

N


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How to fix implants inside bone?How to fix implants inside bone?

A bioactive coating is necessary to stimulate the bone connection

QUESTION:Which parameters are pivotal for bone connection?

dental implant

artificial hip joint

ww

w.z

fz.d

e

ww

w.m

unni

ch.c

l

HA coatedtitanium implant

ww

w.li

feco

re.c

om


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Investigation of bone cell interactions with materials surfaceInvestigation of bone cell interactions with materials surface

Key Factors

→ geometry, microstructure

→ composition of material

→ roughness

→ porosity

→ biofunctionalisation

→ type of cells

biomoleculescells geometry

material


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Microstructures by Microstructures by ““AirbrushAirbrush”” methodmethod

microchannels generated by M3D

height = ca. 20 µm

Cooperation withFraunhofer Institute forManufacturing Technology and Applied Materials Research(IFAM)


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How do Bone Cells behave in these Microchannels?How do Bone Cells behave in these Microchannels?Tumorousbone cells in calcium phosphate microchannels (SEM)


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Orientation of Bone Cells in MicrochannelsOrientation of Bone Cells in Microchannels

Ceramics without Microstructures

Ceramics with Microstructures


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Orientation of Bone Cells in MicrochannelsOrientation of Bone Cells in Microchannels

• laser ablated HA surface

MG-63→ grew in all microchannels 40-220 µm→ disordered growth in 100 & 220 µm channel → cell alignment due to strut direction

HOB→ no cells in microchannels 40-100 µm→ disordered growth in 220 µm channel → prefered growth on the struts (100 µm)

Focus in microchannel Focus on strut 200 µm

Day 7: HOB40 µm

40 µm

40 µm

100 µm

100 µm

100 µm

220 µm

Focus on strut

Day 7: MG-63

Focus on microchannel 200 µm

40 µm

40 µm

100 µm

100 µm

100 µm

220 µm

40 µm


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FurtherFurther Key Key QuestionsQuestions

• How do healthy and tumorous cells behave in these microchannels?

• Which Biomolecules affect cell growth (A-D) ?

• Which other type of ceramic materials can affect cell proliferation?

sketch of a biofunctionalized µ-structured substrate

A B

C D


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Investigation of bone cell interactions with materials surfaceInvestigation of bone cell interactions with materials surface

Key Factors

→ geometry, microstructure

→ composition of material

→ roughness

→ porosity

→ biofunctionalisation

→ type of cells

biomoleculescells geometry

material


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Hydroxyapatite doped with Silica: Influence on Cell ViabilityHydroxyapatite doped with Silica: Influence on Cell Viability

with SiO2

Ra= 6.1±0.8µm Ra= 4.9±0.6 µm


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Cell ProliferationCell Proliferation

After 7 days we obtain the same cell density.


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BUT: Different expression of collagen type IBUT: Different expression of collagen type I

3-st

aini

ngco

llage

n I

HA doped with SiO2 increases cell expression of proteins that are relevant for bone formation!

[S. Blindow,K. Rezwan, Biomaterialssubmitted]


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ButBut: : HowHow to to healheal bonebone defectsdefects??


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CompositionComposition and and StructureStructure of Boneof Bone

Composition:Bone apatite (~ 70 wt.%) + Collagen (~ 30 wt.%)

CO32-Hydroxyapatite

Macroscopicbone

Osteons(d ~ 100 µm)

Collagen fiber(d ~ 5 µm)

consisting of Collagen fibrils

Collagen fibril (d ~ 500 nm)consisting of collagen molecules

with embedded HAp-crystals(blue, d ~ 20 nm)

Collagen triple helix(d ~ 1.5 nm)

Structure(Compact bone)

1 cm 1 mm 1 µm 100 nm 1 nm


20 years5.9.2008

What happens without Collagen?What happens without Collagen?

Mechanical testing of bone without Collagen

[AG Prof. Grathwohl, Universität Bremen]


20 years5.9.2008

What happens without calcium phosphate?What happens without calcium phosphate?

Mechanical testing of bone without calcium phosphate

[AG Prof. Grathwohl, Universität Bremen]


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Challenges• Open Porosity ingrowth of cells• Bioactivity bone bonding and bone healing • Degradability long-term replacement by bone

Further Requirements• Sufficient mechanical properties• Near-net-shape fabrication• Cost effectiveness

1 cm

Bone replacement material: Adjusting mechanicalBone replacement material: Adjusting mechanicaland functional properties to bone materialand functional properties to bone material


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Adaption of Bone MicrostructureAdaption of Bone Microstructure

Goal: Near-net-shape fabrication of calciumphosphate/collagen composites

Freeze Casting Polymer Replica Method

Cortical BoneDense bone with

small pores (~50 µm)

Cancellous Bone (Spongiosa)Spongy bone with

larger pores (~200-500 µm)


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20 µm

500 µm

20 µm

200 µm

Bone(Spongiosa)

Porous Components of Calcium phosphate

2 cm 2 cm

Fabrication of bone replacement material:Fabrication of bone replacement material:Polymer Replica Method and SpongiosaPolymer Replica Method and Spongiosa


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HAp-Ceramic(1wt.% SiO2)

200 µm

Microstructure of unsintered ceramic (ABET= 64.4 ± 0.38 m²/g)

Microstructure of sin-tered ceramic (1100°C) (ABET= 2.6 ± 0.08 m²/g)

Microstructure of Bone(Bio-Oss®, ABET= 88.0 ± 0.12 m²/g)

200 µm

200 µm

20 µm

2 cm

FabricationFabrication of Bone of Bone ReplacementReplacement Material:Material:Freeze Freeze CastingCasting and and CorticalCortical bonebone


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[Deville, et al., Acta Mater., 55, 6]

Casting Freezing and crystal growth

Δ T

- H2O

Drying

Δ T

Sintering

Fabrication method: Freeze CastingFabrication method: Freeze Casting

Water as dispersion medium: Layering of particles between growing column- or lamella shaped ice crystals

20 µm


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Adjustment to Bone MorphologyAdjustment to Bone Morphology

Long bone

1. Variation of pore sizes

2. Polymer-Replica-Method

+ Freeze Casting

2 cm2 cm

2 cm

Micro-CT for MicrostructureVisualisation


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VisualisationVisualisation of 3of 3--D D CeramicCeramic StructureStructure

Mic

ro-C

ompu

terto

mog

raph

y

Scanning Electron Microscopy


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1 Freeze Casting

2 Polymer-Replica-Method

HAp

1.2 HAp

1.1 HAp + Protein

Functionalisationwith Protein

No Sintering2 cm

2 cm Sintering

Fabrication of Ceramic/Protein NanocompositesFabrication of Ceramic/Protein Nanocomposites


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Protein Interaction with Calcium PhosphateProtein Interaction with Calcium Phosphate

Charge distribution of the proteins and particles at adsorption pH and the preferred adsorption directions.


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Mechanical properties of Bone vs. available BiomaterialsMechanical properties of Bone vs. available Biomaterials

[Rezwan et al. Biomaterials. 2006]

0,0001

0,001

0,01

0,1

1

10

100

1000

0,01 0,1 1 10 100 1000 10000Compressive Strength [MPa]

Ela

stic

Mod

ulus

[GP

a]

DenseBiodegradable Polymers

Cortical Bone

SpongiosaBone

Porous Biodegradable Polymers

Porous Biodegradable Composites

Porous Bioactive Ceramics

DenseBioactive Ceramics


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Global Global ChallengesChallenges

Filters, Sensors, Filters, Sensors, CatalystsCatalystsClean Air & Clean WaterClean Air & Clean Water

EnvironmentEnvironment

500 µm500 µm

HealthHealthGrowingGrowing and and AgeingAgeingPopulationPopulation

Orthopaedic ImplantsOrthopaedic ImplantsBone Bone ReplacementReplacement MaterialMaterial

EnergyEnergy

BioreactorsBioreactorsSustainabilitySustainability

150 µm150 µm150 µm


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Biological Contamination of surfacesBiological Contamination of surfaces

Water pipe

Biofilm on indwelling medical device

20 µm 10 µm

Biofilm on a chip

Effects• Material break down• Growth of harmful microorganisms (e. g. Bacteria)

Technical Problems

- Water transport systems- Food Industry- Pharmaceutical / Medical Industry- Shipping


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high durabilityself cleaningantibacterialnon polluting

Strategy for Strategy for selfcleaningselfcleaning surfacessurfaces

Ceramics- Hardness (α-alumina)- Chemical Stability

Natural Biomolecule

- Specific Enzyme withantibacteriel Activity

200 nm

α-Alumina Powder

Lysozyme


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Mikrostructuring with α-Aluminiumoxide = abrasion consistency Biofunctionalisation with Lysozyme = antibacterial surface

Approach: Microstructured surface and BiofunctionalisationApproach: Microstructured surface and Biofunctionalisation

α-alumina surface

α-aluminamicrostructures

Active agent A

Active agent B

SEM images of α-Al2O3 sintered M3D-microstructures


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αα--AlAl22OO33 Microstructure: Test Abrasion Consistency Microstructure: Test Abrasion Consistency

200 µm

After

200 µm

100 µm

Before

100 µm

SEM images of α-Al2O3 sintered microstructures

100 µm

100 µm

Sintered 1000°C

Sintered 1500°C


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M. luteus grown on µ-structured α-Al2O3 surface

Dynamic conditions, after 40 hours

100 µm20 µm

Growth of Growth of BacteriaBacteria WITHOUT WITHOUT antibacterialantibacterial EnzymeEnzyme

Fluorescence microscopy images of bacteria biofilm grown on µ-structured alumina surface, Dead/Live Test

Light microscopy images of sintered (1500°C) α-aluminamicrostructures

50 µm

α-Al2O3 µ-structures on α-Al2O3 surface

--Formation of a dense Formation of a dense biofilm of living Bacteriabiofilm of living Bacteria

Bacteria stream: 500 µl/min

Alive Dead


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Bacteria stream: 500 µl/min

50 µm

Fluorescence microscope images of dead bacteria on µ-structured alumina surface with lysozyme, Dead/Alive Test

Dynamic conditions, after 40 hours

20 µm

Dead bacteria Dye

Dead bacteria

20 µm

Dye

Aliv

eD

ead

Microstructures protect Lysozyme from Microstructures protect Lysozyme from abrasive components and sustain abrasive components and sustain

antibacterial Activity!antibacterial Activity!

WITH WITH antibacterialantibacterial Enzyme: NO growth of Enzyme: NO growth of bacteriabacteria


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PorousPorous BacteriaBacteria filtersfilters withwith large large surfacesurface and high and high PermeabilityPermeability

AntibacterialAntibacterial

EnzymeEnzyme Oxi

de S

urfa

ceO

xide

Sur

faceShort

PeptideLinker

10 µm

nm µm cm

1 cm

Length Scale

200 µm

Scheme of the Molecular Surface Design


EnzymeEnzyme Oxi

de S

urfa

ceO

xide

Sur

faceShort

PeptideLinker


EnzymeEnzyme


EnzymeEnzyme Oxi

de S

urfa

ceO

xide

Sur

faceShort

PeptideLinker

10 µm10 µm10 µm

nm µm cm

1 cm1 cm

Length Scale

200 µm200 µm

Scheme of the Molecular Surface Design


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Multiscale Design of BioceramicsMultiscale Design of Bioceramics

Materials S

cienceM

aterials Science Li

fe S

cien

ces

Life

Sci

ence

s

Bridging the Gap between Materials Science and Biology:Fabrication and Multiscale Interface Engineering of Bioceramics

Colloidal Processing/Sol Gel Technology/

Fabrication of Advanced Ceramics

Biofunctionalisation/ Protein Immobilisation

Investigation ofCell & Bacteria

Responses

Complex Shaping/ Microstructuring/

Solid/Porous Ceramic Components

200 nm





Responses



200 nm200 nm

Materials S

cienceM

aterials Science Li

fe S

cien

ces

Life

Sci

ence

s

Bridging the Gap between Materials Science and Biology:Fabrication and Multiscale Interface Engineering of Bioceramics





Responses



200 nm





Responses



200 nm200 nm

Bioceramics = Ceramics at the Biology InterfaceBioceramics = Ceramics at the Biology Interface


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The Bioceramics GroupThe Bioceramics Group


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Collaborations and FundingCollaborations and FundingUniversity of Bremen

Prof. Grathwohl, CeramicsProf. Blohm, Biotechnology and Molecular GeneticsProf. Thöming, Environmental SciencesProf. Frauenheim, Bremer Centrum for Computational Materials ScienceProf. Lang, Institute for Microsensors, -actuators and -systems

Jacobs University, BremenProf. M. Zacharias, Bioinformatics and Computational BiologyProf. M. Fernandez-Lahore, Biochemical Engineering

Fraunhofer Institut für Fertigungstechnik und Materialforschung, BremenM. Maiwald, Dr. Zöllmer, Dr. Grunwald, Dr. Rischka, Prof. M. Busse

Max Planck Institute for Polymer Research, MainzDr. N. van der Vegt, Computational Chemistry

Imperial College London, UKProf. Dr. A. R. Boccaccini, Materials Department

Funding• European Research Council (Young Investigator Award 2008)• Deutsche Forschungsgemeinschaft (DFG)• Bundesministerium für Bildung und Forschung (BMBF)• Volkswagen Stiftung• Bundesministerium für Wirtschaft und Technologie (BMWi)• Investitionssonderprogramm, Bundesland Bremen

Bioceramics: Multiscale Engineering of Advanced Ceramics ... · Universität Bremen ......

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