Med Del Coat NET Meeting

8/2/2019 Med Del Coat NET Meeting

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www.meddelcoat.eu1

Multi-functional bioresorbable coatings

with biofilm inhibitionand optimal implant fixation

Project n NMP3-CT-2006-026501


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www.meddelcoat.eu2

LEMI

The MEDDELCOAT consortium

Project coordinatorIndustry (SME)

Research


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www.meddelcoat.eu3

Outline

1. Objectives

2. State-of-the-art

3. Innovative substrate materials

4. Innovative coating techniques

5. Advanced characterisation

6. Contact


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www.meddelcoat.eu4

1. Objectives

Combinatorial approach:

Design and engineer the structure of the implant surface to optimiseimplant fixation by osteointegration,

Promote osteointegration by the application of a bioactive top

coating,

Incorporate a biofilm formation inhibiting function into the coating.

Implant material

(Ti or Ti6Al4V)

Porous coating

(Ti + bioactive coating)

Metal

Bioactive and/or

biofilm inhibiting coating

Open porosity

Development of innovative,multi-functional bioactive and

anti-inflammatory coatingson Ti6Al4V


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The project focused on acetabular cups, glenoids and humeralbodies ofinverse shoulder implants and dental implants providedby LIMA and HeliPro.

1. Objectives

Glenoid

Humeral

body

Targeted coating:

Bioactive

Biofilm inhibiting

Targeted coating:

Porous

Bioactive

Biofilm inhibiting


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State-of-the-art vacuum plasma sprayed coatings were used as areference throughout the project. This technique is commerciallyapplied by Alhenia, a leading provider of medical instruments andimplants.

2. State-of-the-art

500 m500 m

State-of-the-art Ti vacuum plasma sprayed cup (left),

cross-sectional view (middle) and top view (right)


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An increased surface roughness improves the implant stability, butalso increases the risk of biofilm formation. Viable cells (green)tend to spread throughout the porous coating.

2. State-of-the-art

SEM top view (left) and CSLM cross-sectional (right) imageof staphylococcal biofilm formation on a VPS Ti surface


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A new biomedical grade titanium alloy was developed withadvantageous microstructure, excellent biocompatibility, andwithout aluminium or vanadium!

3. Innovative substrate materials

Nanostructured TNZ(X)

Negative control TNZ(X)

CSLM top view of human osteogenic cells ona TNZ(X) surface showing enhanced in vitro

cell adhesion and proliferation



Electrophoretic deposition (EPD)

EPD of particle stabilised emulsions and/or suspensions followed byclassical vacuum sintering or vacuum microwave sintering creates aporous Ti mask with an average porosity of 50% and pores ranging

from 10-60 m, improving mechanical interlocking, i.e. biologicalimplant fixation.


Porous Ti coating on dental screw and Ti6Al4V cup

100 m 100 m




EPD of particle stabilised emulsions and/or suspensions followed byclassical vacuum sintering or vacuum microwave sintering creates aporous Ti mask with an average porosity of 50% and pores rangingfrom 10-60 m, improving mechanical interlocking, i.e. biologicalimplant fixation.


SEM image and EDX compositional analysis of the bone

ingrowth in a porous Ti coating

100 m




Additional application of bioactive glass enhances the bioactivefixation of the implant


Bioactive glass coating on a Ti6Al4V humeral

body (left) and Ti dental implant (middle)

Hybrid microwave furnace

for vacuum sintering

(10-6mbar) of Ti alloys

100 m

100 m



Hydrothermal treatment

Provides a bioactive TiO2 layer, which promotes HAp formation,

exhibits a photocatalytic effect enabling sterilisation by UV-light andprevents leaching of metal ions into the body.


Hydrothermally treated dental Ti implant



Micro-arc oxidation(MAO)

Creates a titania-based amorphous coating with incorporated calciumphosphates, which acts as a biocompatible top coating for implantswith a porous Ti layer for cementless fixation. The highly hydrophylicnature of the coating reduces biofilm formation.


MAO coated cups



Sol-gel synthesis

Sol-gel synthesis of bioactive glass enables coating the internalsurface of a porous Ti coating without filling the voids completely(left). As an alternative, the porous structure can be infiltrated withbioactive glass prepared by the particulate sol-gel method (right).


100 m20 m

SEM images of VPS Ti surfaces impregnated with bioactive glass



Spraying of anti-microbial coatings

An active anti-microbial coating, which releases an antibiotic drugduring more than 2 weeks, was sprayed on top to avoid infection andbiofilm formation.


Submicron CT images of a VPS Ti surface without (left)

and with an additional anti-microbial coating (right)

revealing no difference in bone ingrowth

SEM image of a VPS Ti surface

with anti-microbial coating



Microbial interaction

Microbial interaction results in biofilm formation and thus difficult totreat biomaterial-related infections. The influence of various substrate-coating systems on biofilm formation was studied. The importance ofthe composition and physico-chemical properties of the coating likeroughness, porosity, interconnective pore channel size andhydrophobicity were analysed.


1m5 m

SEM pictures ofStaphylococcus epidermidis cells

adhering on a Ti coating and formation of biofilm



Mechanical characterisation of coating-substratesConstant Depth scratch procedure to measure the shear adhesionstress along thick substrate-coating interfaces (> 30 m). For thincoatings (< 5 m), AFM was successfully incorporated and combinedwith a mathematical model correlating the force deformation

components.


Platform

head

Diaphragm

load cell

Specimen

Scratch head

withintegrated

load cell

Scratch test setup (left) and micrograph

of a scratched specimen (right)



In vitro and in vivo evaluation

In vitro evaluation to investigate the biocompatibility and cell/materialinteractions of powders and various substrate-coating systems toevaluate the osteogenic potential. A short and long term in vivo study

was performed, to evaluate the bone response of porous Ti coatingscombined with different bioactive and anti-microbial coatings.


Collagen type I expression

1 3 9 15 27 days

Gene expression and cytoskeleton and focal

adhesion study of human osteogenic cells on a

porous Ti coating

Light microscopic image of a stained histological

section after 4 weeks of implantation and nano-CT

scan of a VPS-Ti coated implant after 12 weeks of

implantation showing bone ingrowth


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For further information:

Visit www.meddelcoat.eu

Project coordinator

Prof. Dr. Ir. Jef VleugelsKatholieke Universiteit Leuven

Department of Metallurgy and Materials Engineering (MTM)Kasteelpark Arenberg 44, B-3001 Heverlee (Belgium)

Phone: +32 16 32 12 44

Fax: +32 16 32 19 92E-mail: [email protected]

6. Contact

Documents

Med Del Coat NET Meeting