BIO-MATERIALS

1. BIO-MATERIALS

2. Syllabus - Chapters • STRUCTURE OF BIO-MATERIALS AND BIO-COMPATIBILITY • IMPLANT MATERIALS • POLYMERIC IMPLANT MATERIALS • TISSUE REPLACEMENT IMPLANTS • ARTIFICIAL ORGANS

3. STRUCTURE OF BIO-MATERIALS AND BIO-COMPATIBILITY • Definition and classification of bio-materials • Mechanical properties, visco elasticity • Wound-healing process, • Body response to implants, Blood compatibility.

4. Definition • A biomaterial is a synthetic material used to replace part of a living system or to function in intimate contact with living tissue • Commonplace examples include sutures, needles, catheters, plates, tooth fillings, etc

5. Classification of bio-materials • From the point of view of the problem area which is to be solved

6. By considering the levels of organisation

8. Classification based on materials

9. Mechanical properties • The behavior of the material under loading • Two important properties • STRENGTH • STIFFNESS

11. The load - deformation curve

12. Determinants of strength • The load that the structure can sustain before failing • Ultimate failure point • The deformation it can sustain before failing • Slope of the curve - Stiffness

13. The stress – strain curve (In tension)

14. Stress σ • Strain ε • Young’s modulus E = σ / ε • Elasticity of a material

15. A comparison

16. Mechanical properties of biomaterials

17. Visco elasticity

21. Viscoelasticity • The material is subjected to Constant load and its response varies with time • Combination of viscous fluid and elastic solid • Two fundamental responses • Creep • Stress relaxation

22. Creep & Stress relaxation • Constant load → rapid initial deformation → slow (time-dependent) progressively increasing deformation → till equilibrium is reached • Constant deformation → rapid initial stress → slow (time-dependent) progressively decreasing stress