1. Tissue Engineering: a new healthcare technology

2. Biomaterials Biomaterials science may be the most multidisciplinary of all the sciences which encompasses aspects of medicine, biology, chemistry, engineering and materials science. Biomaterials are : “Non-viable materials used in a medical devices intended to interact with biological systems ” [D.F. Williams, 1987]

3. Biomaterials: Examples Joint replacements Bone plates Bone cement Hip Joint Artificial ligaments and tendons Dental implants for tooth fixation Blood vessel prostheses Heart valves Skin repair devices Cochlear replacements Contact lenses Hip joint Heart valve Knee jointSkin

4. Biomaterials at Oxford Nano-SIMS characterization of Teeth Drug Delivery Systems Biomaterials Group Materials Dept. In vitro Testing Cell culture Tissue expander Tissue Engineering

5. 3-D scaffolds for tissue engineering

6. Example - Total Hip Replacement Computer GraphicActual femur head removed Osteoarthritis

7. Some Artificial Hips UHMWPE Alumina Ti 6Al4V, Co-Cr, 316L stainless steel

8. Implants – An X-Ray View New After 10 years Gap Bone is resorbed when not stressed. A gap forms around the blade of the insert.

9. 50,000 hip replacements (arthroplasties) in Britain each year. Hydroxyapatite porous coatings in orthopaedic prostheses: Bioactivity, Osteoconductivity. Problem: Infections in orthopedic surgery (10% of cases) Total Hip Joint Replacement

10. Bioreactor system Scaffold Biopsy mechanical stimuli electrical stimuli chemical stimuli Human Cell Suspension Nutrients, Growth Factors Implantation operation H

11. Variable Pore Size in Bone 4µm4µm220µm

12. Computer-Aided Design of Vasculature We need a structure which will be space saving, strong and yet porous to allow growth of blood vessels… Learn from nature and use a HONEYCOMB structure

13. 3-D printing From Dr. Chaozong Liu Printing video

14. 3D Printing of Biocompatible Molds Layers of wax and scaffold material build up in 3D

15. 3D Printing of Biocompatible Molds The wax is dissolved at high pressure and low temperature in liquid carbon dioxide… …this leaves a porous Scaffold

16. Why collagen? It is the ideal scaffold material:  is an important ECM molecule and is the major structural component in the body.  posses ideal surface for cell attachment in the body.  biocompatible and degrades into harmless products that are metabolized or excreted.  a very poor antigen, non-toxic.

17. Collagen processing This technique allow the control over pore size and porosity. Achieved through variation of freezing temperature and collagen dispersion concentration Dry collagen scaffold

18. Advantages of Scaffold formation Control of the external structure: Technology: CT/MRI CAD

19. Heart valve tissue engineering Valve cells Collagen scaffold of heart valve Heart valve post- implantation