Biomaterials in Medical device design

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1 Biomaterials in Medical device design 1 Dr Joseph Buhagiar B. E n g ( H o n s. ) P h D ( B h a m ) D e p a r t m e n t o f M e t a l l u r g y a n d M a t e r i a l s E n g i n e e r i n g U n i v e r s i t y o f M a l t a What is a biomaterial? 2 A biomaterial is a nonviable material used in a medical device intended to interact with biological systems (Williams, 1987) 1

2 What is a biomaterial? 3 medical removed from definition: growing cells in culture processing biomolecules for biotechnology diagnostic gene arrays aquaculture of oysters What is a biomaterial? 4 nonviable removed from definition: tissue engineering hybrid artificial organ applications living cells that are used as materials 2

3 What is a biocompatibility? 5 Biocompatibility is the ability of a material to perform with an appropriate host response in a specific application (Williams, 1987) What is a biocompatibility? 6 host response : resistance to blood clotting resistance to bacterial colonization normal (uncomplicated) healing 3

4 What is a biocompatibility? 7 specific application : haemodialysis membrane (blood 3hrs) urinary catheter (inserted for a week) hip-joint replacement (life of a patient) Biomaterial performance requirements 8 Performance requirements : mechanical performance mechanical durability physical properties biocompatibility 4

5 Biomaterial a multidisciplinary endeavour 9 Medicine Biology REQUIREMENTS Chemistry Manufacturing Family of biomaterials 10 Ceramic Al 2 O 3 ZrO 2, TiO 2 Composite Metallic Polymeric 5

6 Metallic biomaterials Titanium Alloys Shape Memory Alloys Cobalt- Chromium Austenitic Stainless Steels Zirconium Alloys 11 Alumina (Al 2 O 3 ) Zirconia (ZrO 2 ) Calcium Phosphate Hydroxyapatite (HA) Bioactive Glasses Glass-Ceramics Ceramic biomaterials 12 6

7 Toxic surrounding material dies Ceramic biomaterials Nontoxic and biologically inactive (inert) fibrous tissue of variable thickness forms Nontoxic and biologically active (bioactive) interfacial bond forms Nontoxic and dissolves surrounding tissue replaces it 13 Polymeric biomaterials 14 Ultra High Molecular Weight Polyethylene (UHMWPE) Polymethyl-methacrylate (PMMA) Silicone Biomaterials 7

8 Nanotechnology in biomaterials 15 Silver Antimicrobial protection Biotextiles and dressings Handles in hospitals Medical devices Degradation of biomaterials 16 Pitting and crevice corrosion Fretting and corrosion-wear Fatigue Deformation Release of toxic elements Nickel Chromium (VI) Cobalt Vanadium 8

9 Surface engineering of biomaterials Coat or alloy the surface for: hardness corrosion-wear resistance fatigue resistance corrosion properties biocompatibility osseointegration hydrophilicity antibacterial properties 17 Research in biomaterials (DMME) Surface engineering of biomaterials Medical grade austenitic stainless steels Ni-Ti Shape memory alloys Development of dental biomaterials Dental cement in collaboration with Dr. J Camilleri Degradation evaluation of biomaterials Crevice Corrosion Pitting Corrosion Fretting-wear Corrosion-wear 18 9

10 Collaboration interests (DMME) Biocompatibility In-vitro and in-vivo testing Wet chemical analysis Ni and Cr content in solution Clinical studies Analysis of implant retrieval Design and manufacturing Prototypes manufacture and mechanical testing 19 Surface nano analysis and characterisation Low Energy Electron Diffraction Scanning Electron Microscope Secondary Ion Mass Spectroscopy X-Ray Photoelectron Spectroscopy Auger Electron Spectroscopy Scanning Tunnelling Microscope Atomic Force Microscope Time of Flight 20 Funding ERDF: Setting up a material testing & rapid prototyping R&D facility 10

11 Confocal laser scanning microscope 21 Biological Samples High Resolution Image Requisition True Spectral imaging 32 Channels of fluorescence Gentle on living cells Funding ERDF: Setting up a material testing & rapid prototyping R&D facility Scanning Electron Microscope (SEM) 22 Field Emission Energy Dispersive Spectroscopy (EDS) Wave Dispersive Spectroscopy (WDS) Electron Backscattering Diffraction (EBSD) Funding ERDF: Setting up a material testing & rapid prototyping R&D facility 11

12 Nano Indentation: Nano-indentation and hardness Hardness Testing of thin films Hot stage Cold Stage (-30 C) Liquid Cell Impact testing Scratch testing 23 Other hardness testing: Macro-hardness Vickers micro-hardness Shore hardness Funding ERDF: Setting up a material testing & rapid prototyping R&D facility Phase determination Stress Analysis Thin film analysis Hot Stage Funding ERDF: Setting up a material testing & rapid prototyping R&D facility 4 th Italian Protocol X-Ray Diffraction 24 12

13 Mechanical and corrosion testing 25 Tensile Tester Compression Tester Rotary Fatigue Tester Tribometer (pin-on-disc) Impact tester Potentiostat (corrosion) Salt spray cabinet Funding ERDF: Setting up a material testing & rapid prototyping R&D facility 4 th Italian Protocol joseph.p.buhagiar@um.edu.mt Tel: Room: 107: Engineering Building Biomedical Device Design & Manufacture 26in Malta - 1st June 2010, Dolmen, Qawra 13