Design, Preparation and Characterization of 3D ...
Transcript of Design, Preparation and Characterization of 3D ...
Tessuti connettiviMateriali e tecnologie per la realizzazione di scaffolds per l’ingegneria dei tessuti
Osso trabecolareOsso compattoDentinaSmaltocemento Menisco
TendiniLegamentiIVDTMJ disc
MINERALIZZATI
DENSI
•The medial meniscus is somewhatC-shaped and occupies approximately51% to 74% of the medial tibial plateau.•The lateral meniscus is almostO-shaped and occupies approximately75% to 93% of the lateral tibial plateau.
The two major phases of meniscus are:
1) a fluid phase containing water and electrolytes;
2) a solid phase containing collagen (type I), proteoglycans, glycoproteins and chondrocytes.
Tissue Water Collagen ProteoglycansMeniscus 60-70% 55-65% (type I, dry weight) 1-3%
Materiali e tecnologie per la realizzazione di scaffolds per l’ingegneria dei tessuti
Pig meniscus
MENISCO
fibrocartilaginous tissue
Materiali e tecnologie per la realizzazione di scaffolds per l’ingegneria dei tessuti
Cellular componentsChondrocytes and fibroblasts.
Matrix componentsElastin (0.6% dry weight)Proteoglycans (1-3%)GlycoproteinsCollagen:1) primarily type I (55-65% dry weight), also types II, III, V, VI (5-10%
dry weight);2) the superficial layer consists of a thin layer of randomly oriented fibers;3) the lamellar layer also consists of randomly oriented fibers, but in the
peripheral portions the fibers are oriented radially;4) the deep zone consists of circumferentially oriented fibers with a small
amount of radially oriented fibers.
Materiali e tecnologie per la realizzazione di scaffolds per l’ingegneria dei tessuti
Functions•Enable the femoral condyles to articulate congruently;•Distribute compressive and shear forces;•Act as “shock absorbers”;•Prevent synovial impingement;•Disperse synovial fluid for lubrication and proper nutrition;•Limit extremes of flexion and extension;•Facilitate complex movements;•Control rotating instability.
Materiali e tecnologie per la realizzazione di scaffolds per l’ingegneria dei tessuti
A) Rolling;B) Sliding;C) Rolling + sliding.
Menisci movements:a) extension;b) flexion.
Menisci movements:a) External rolling;b) Neutral rolling;c) Inner rolling.
Materiali e tecnologie per la realizzazione di scaffolds per l’ingegneria dei tessuti
Examples of tearing
Longitudinal tear Horizontal tear
Arthroscopic repairsuturing.
Materiali e tecnologie per la realizzazione di scaffolds per l’ingegneria dei tessuti
Rigenerazione del MeniscoBlend di PCL/HYAFF (derivati dell’acido ialuronico)
PCL/THF 80/20 miscelato a 45°C
Fase solida
93.9% (w/w) cloruro di sodio (granulometria 315–400 µm)
3.5% (w/w) bicarbonato di sodio (granulometria 140–315 mm)
2.6% (w/w) acido citrico (granulometria inferiore a 200 mm)
Scaffold Materials
Reverse engineering e rapid prototyping del menisco di pecoraStampo
Soluzioni PCL e HYAFF-11p75 HE (PCL/HYAFF 70/30 (w/w) miscelati con la fase di sale (rapporto polimero/salt di 1/10)
Solvent Casting & Salt Leaching
Innovative materials and technologies for a bio-enginneredmeniscus substitute”, FP5
Materiali e tecnologie per la realizzazione di scaffolds per l’ingegneria dei tessuti
Sheeplateral meniscus
Sheepmedial meniscus
Sheep meniscus section
Lateral and MedialTeflon moulds
LateralMeniscusMIMICS
MedialMeniscusMIMICS
Reverse engeneering del menisco di pecora
3D x-Ray
Materiali e tecnologie per la realizzazione di scaffolds per l’ingegneria dei tessuti
Lateral meniscus with net
Medial meniscus with oriented fiber
section
section
3D x-Ray imaging
scaffold di menisco basato su PCL
Materiali e tecnologie per la realizzazione di scaffolds per l’ingegneria dei tessuti
rigenerazione del menisco•Semina e coltura di condrociti articolari di pecora
•Implantaziuone in pecora
Scaffold non seminato Scaffold seminato
Le strutture sono entrambeintegrate
Il follow-up istologico a 4 mesiindica che la deposizione dimatrice cartilaginea avvienesolo negli scaffold seminaticon cellule
Kon et al., Tissue Engineering for Total Meniscal substitution: Animal Study in Sheep Model. Tissue Engineering: Part A 6, 2008,1067-80
Materiali e tecnologie per la realizzazione di scaffolds per l’ingegneria dei tessuti
Materiali e tecnologie per la realizzazione di scaffolds per l’ingegneria dei tessuti
Proprietà biomeccaniche del disco intervertebrale naturale e del disco con nucleo polposo artificiale iniettabile, D. Ronca, A. Gloria, R. De Santis, F. Causa, G. Guida, L. Ambrosio, L. Nicolais. Giornale Italiano di Ortopedia e Traumatologia. Vol. XXXII, Suppl. 1, Ottobre 2006.
Both partial and total functional disorders of spine constitute one of the most disabling, common and costly problem of
current surgery.The surgical treatment may involve the partial or total
resection of the Intervertebral Disc (IVD).Thus, implants for vertebral fusion are often required in
order to immobilize the diseased column.
AGEING DEGENERATION
Materiali e tecnologie per la realizzazione di scaffolds per l’ingegneria dei tessuti
Materiali e tecnologie per la realizzazione di scaffolds per l’ingegneria dei tessuti
DISCO INTERVERTEBRALE
LEGAMENTO
braidingfilament winding
Filament WindingLAB101
Nucleus pulposus consists of a network of delicate collagenous fibers in mucoprotein gel, rich in polysaccharide (high water content like gel)
Annulus fibrosus makes up peripherical portion of disc structure, composed of fibers running obliquely in layers with crossing angle of 45-60 deg
End–plate contains no fibrillar connection with collagen of subchondral bone of the vertebrae
Microstructure
J. J. Cassidy, A. Hiltner, E. Baer,. J. Mater. Sci.: Mater. in Med. 1 (1990) 69-80.
Visco-elastic propertie of natural IVD
Biomechanics
Ela
stic
mod
ulus
[MPa
]
Cervical Thoracic ThoracicLumbar
Lumbar
Materiali e tecnologie per la realizzazione di scaffolds per l’ingegneria dei tessuti
…the design is driven using the mimiking approach: learn from nature
MatrixHydrophilic Semi-Interpenetrating Polymer Network:
poly(2-hydroxyethyl-methacrylate) (PHEMA)poly(methyl-methacrylate)PHEMA/PMMA 80/20w/w
ReinforcementPolymers Fiber
Poly(ethylene-terephtalate) PET40% by volumeWinding angle: from 45 to 65 degrees
Filament Winding &Radical polymerization
AIBNEGDMA90°, 2hrs
45°
65°
Hydrogel
Composite Hydrogel
ϑ
L. Ambrosio et al. J. Proc. Instn. Mech. Engrs., 212H, 1998, 93-99
Materiali e tecnologie per la realizzazione di scaffolds per l’ingegneria dei tessuti
Static properties•J-shaped stress-strain curve•Compressive modulus 80-110 MPa•Maximum stress 12-20 MPa
0
5
10
15
20
25
0 0.1 0.2 0.3 0.4 0.5 0.6
sample 1sample 2sample 3sample 4
Strain [mm/mm] cervical thoracic lumbar
Natural DiscArtificial Disc
Stre
ss [M
Pa]
Tailoring of mechanical properties• Composition of the matrix• Volume concentration of the fibers• Winding angle of the fibers…to obtain IVD Device for a specific spine location
Materiali e tecnologie per la realizzazione di scaffolds per l’ingegneria dei tessuti
Compression testing inWater environment at 37°C
Methods
Loops around:•Creep fatigue•DMA•Creep recovery
MTS858 Bionix dynamometerLoading cell 25KN
δcos*EE =′
δsin*EE =′′
Storage modulus
Loss modulus
Complex modulus0
0*
εσ
=E
Dynamic-mechanical and fatigue
Materiali e tecnologie per la realizzazione di scaffolds per l’ingegneria dei tessuti
E′ increases with the increasing mean load level
and with the increasing number of cycles (cyclic
hardening)
Dynamic-mechanical and fatigue
0.102
0.104
0.106
0.108
0.11
0.112
0.114
0.116
0.118
0 5000 1 104 1.5 104 2 104 2.5 104
after 1 cycleafter 10 cyclesafter 1000 cyclesafter 100000 cyclesafter 1000000 cyclesafter 10000000 cycles
Stra
in (m
m/m
m)
Time (sec)
Creep-recovery steps of 8 hours (sleeping time) at
200 N (horizontal position) suggest high mechanical
stability after fatiguing
Materiali e tecnologie per la realizzazione di scaffolds per l’ingegneria dei tessuti
Dynamic-mechanical properties of a novel composite intervertebral disc prosthesis, A. Gloria, F. Causa, R. De Santis, P.A. Netti and L. Ambrosio. Journal of MaterialsScience: Materials in Medicine. 2007, vol. 18, no11, pp. 2159-2165
Materiali e tecnologie per la realizzazione di scaffolds per l’ingegneria dei tessuti
Protesi totale biomimetica
•PEI is dissolved in chloroform (15% ww of PEI)•Carbon fibers impregnated with the PEI/Chloroform solution are wound with an angle of ± 45°
•Chloroform is removed under vacuum at 58°C•The composite system is hot pressed (35bar, T=240°C, t=15min)
Composite cages filament winding and hot compression molding technologyComposite cage geometry (di=4mm; de=8mm; L=16mm)
Materiali e tecnologie per la realizzazione di scaffolds per l’ingegneria dei tessuti
Porcin model
Composite Cages
12 large white-duroc race of 50-55 Kg by weight and 1.9-2.1 months old
Titanium cagesMod. Inter Fix Ti, (Ti6Al4V) D=10mm L=20mmSOFAMOR Danek
Cages
PEI/carbonHA coated
Materiali e tecnologie per la realizzazione di scaffolds per l’ingegneria dei tessuti
Southerland SR, Remedios AM, McKerrell JG, Litwin D: Laparoscopic approaches to the lumbar vertebrae. An anatomic study using a porcine model. Spine. 1995 Jul 15;20(14):1620-3
Preliminary skills concerning the cage implantation into L4-L5 discs of pig’s carcasses suggested that the posterior-peritoneal approach was the less invasive treatment
A hole is made in the disc using a stainless threaded tool (diameter of 8mm)
The composite device is screwed into the disc using a screwdriver tool whose tip was designed in order to be perfectly inserted in the special groove on the top of the composite cage.
Materiali e tecnologie per la realizzazione di scaffolds per l’ingegneria dei tessuti
Spine sectioning
Specimen of two half adjacent vertebral body (L4-L5)IVD treatment:Control (8months)Composite (5months)Titanium (10 months)
Pigs were sacrificed at an age of 5, 8 and 10 months (average weight of 110±32 Kg)
Materiali e tecnologie per la realizzazione di scaffolds per l’ingegneria dei tessuti
Pathological anatomy investigation
diamond saw low speed microtome slicesth=5mm chilled water
Normal-conformed bone tissue is well evident around the
composite cage
Materiali e tecnologie per la realizzazione di scaffolds per l’ingegneria dei tessuti
L. Manto, R. De Santis, G. Carrillo, G. Ambrosio, L. Ambrosio, L. Nicolais. Novelcomposite intervertebral disc cage for spine fusion. Journal of Bone And Joint Surgery - British Vol 87-B, Issue SUPP_I, 68, 2005