Micro-CT: a powerful tool for the characterization and evaluation of the bone forming capacity of CaP stem cells TE constructs

Transcription

1 Micro-CT: a powerful tool for the characterization and evaluation of the bone forming capacity of CaP stem cells TE constructs Greet Kerckhofs SJ. Roberts, M. Wevers, F. Luyten and J. Schrooten Department of Metallurgy and Materials Engineering Materials Performance and Non Destructive Evaluation

2 Bone Tissue Engineering Bone defect 19/07/

3 Bone Tissue Engineering Bone defect 19/07/

4 Bone Tissue Engineering Patient-own cells + growth factors Bone scaffold Cell seeding Bone defect Incubation (bioreactor) Implantation (surgery) Healing (in-vivo) 19/07/

5 Bone Tissue Engineering CaP grains Polymeric network 19/07/

6 Bone Tissue Engineering Composite CaP-polymer Material-specific variability Patient-specific variability + 19/07/

7 Strategy Patientspecific cell source (hpdcs) Characterization Scaffold characterization IN OUT Production Polymer (network) Cell behaviour Modelling EMPIRICAL MODEL + CaP particles Bone forming capacity Composite scaffold : parameter to be optimised 19/07/

8 Objectives Scaffold characterization Bone forming capacity 19/07/

9 Methods Composite CaP-polymer scaffold 19/07/

10 Methods + Patient-own hpdcs + growth factors Composite CaP-polymer scaffold Cellularized scaffold 19/07/

11 Methods + Cellularized scaffold 19/07/

12 Methods 19/07/

13 Objectives Scaffold characterization Volume fraction grains Specific surface grains Average grain thickness Grain thickness distribution Bone forming capacity 19/07/

14 Scaffold characteristics NuOss 19/07/

15 Scaffold characteristics BioOss 19/07/

16 Scaffold characteristics Collagraft 19/07/

17 Scaffold characteristics CopiOss 19/07/

18 Scaffold characteristics VitOss 19/07/

19 Scaffold characteristics Volume fraction grains (%) Before implantation After explantation 25% 20% 15% 10% 5% 0% Nu Bio Coll Cop Tut Vit SSA grains (1/mm) Before implantation After explantation Nu Bio Coll Cop Tut Vit 19/07/

20 Frequency (%) Scaffold characteristics 200 Average grain size (µm) Before implantation After explantation Nu Bio Coll Cop Tut Vit Grain size distribution before implantation Grain size (µm) NuOss BioOss Collagraft CopiOss TutoBone VitOss 19/07/

21 Frequency (%) Frequency (%) Frequency (%) Frequency (%) Frequency (%) Frequency (%) Scaffold characteristics 10 NuOss Before After 10 BioOss Before Series1 10 Collagraft Before After Grain size (µm) Grain size (µm) Grain size (µm) 50 CopiOss Before After 10 TutoBone Before After 20 VitOss Before After Grain size (µm) Grain size (µm) Grain size (µm) 19/07/

22 Objectives Scaffold characterization Volume fraction grains Specific surface grains Average grain thickness Grain thickness distribution Bone forming capacity Volume fraction newly formed bone Amount of bone spicules (bone interconnectivity) Newly formed bone volume distribution 19/07/

23 Bone forming capacity NuOss (Nu) Bone BioOss (Bio) Scaffold Bone Collagraft (Coll) Scaffold Bone Scaffold 19/07/

24 Bone forming capacity CopiOss (Cop) TutoBone (Tut) VitOss (Vit) 19/07/

25 Bone forming capacity Volume fraction newly formed bone 18% 16% 14% Micro-CT Histology 12% 10% 8% 6% 4% 2% 0% Nu Bio Coll Cop Tut Vit Correlation THE TOTAL VOLUME FOR HISTOLOGY IS SMALLER THAN FOR THE MICRO-CT!!! THE 3D CHARACTER OF MICRO-CT REDUCES THE STANDARD DEVIATION!!! 19/07/

26 Bone forming capacity NuOss (Nu) 2 different interconnected bone speckles Light grey = CaP grains Blue = Bone speckle 1 Yellow = Bone speckle 2 19/07/

27 Bone forming capacity NuOss (Nu) 3D visualization White = CaP grains Yellow = Bone speckle 1 Orange = Bone speckle 2 Red = Bone speckle 3 19/07/

28 Bone forming capacity NuOss 9% 8% 7% 6% 5% 4% 3% 2% 1% 0% Volume fraction newly formed bone Core Middle Edge NuOss BioOss Collagraft VitOss CopiOss TutuBone Middle Core Edge Middle Core Edge Core Middle Edge 19/07/

29 Bone forming capacity 9% 8% 7% 6% 5% 4% 3% 2% 1% 0% 12% 10% 8% 6% 4% 2% 0% Volume fraction newly formed bone Core Middle Edge Volume fraction grains Core Middle Edge NuOss BioOss Collagraft VitOss CopiOss TutuBone NuOss BioOss Collagraft VitOss CopiOss Tutubone BioOss 19/07/

30 Objectives Scaffold characterization Volume fraction grains Specific surface grains Average grain thickness Grain thickness distribution Bone forming capacity Volume fraction newly formed bone Amount of bone spicules (bone interconnectivity) Newly formed bone volume distribution 19/07/

31 Discriminant analysis Discriminant analysis based on biomaterial characteristics. (A) Canonical plot showing clear separation between the different bone forming classes. ( : Bio-Oss ; ο: Vitoss ; : CopiOs ; Δ: Collagraft ; x: NuOss. +: class multivariate mean.). Circle size corresponds to a 95% confidence limit for the mean (significantly different groups have non-intersecting circles). (B) Based on canonical plot, the first two canonical vectors can be defined as (1) bone forming vs. non bone forming and (2) influence of scaffold morphology. 19/07/

32 Conclusions and future perspectives Patientspecific cell source (hpdcs) Characterization Scaffold characterization IN OUT Production Polymer (network) Cell behaviour Modelling EMPIRICAL MODEL + CaP particles Bone forming capacity Composite scaffold : parameter to be optimised Quality control & validation 19/07/

33 Thank you for your attention!!! Questions??? Department of Metallurgy and Materials Engineering Materials Performance and Non Destructive Evaluation