BME416-Biocompatibility [Compatibility Mode]

BME416-Biocompatibility [Compatibility Mode] - BASICS OF...

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BASICS OF BIOMATERIALS & BIOCOMPATIBILITY erald E Loeb M D Gerald E. Loeb, M.D. Professor of Biomedical Engineering niversity of Southern California University of Southern California gloeb@usc.edu http://ami.usc.edu AMI-USC
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issues vs Materials Tissues vs ± Constantly replaced ± Gradually deteriorate ± Trophic plasticity efended from infx ± Fixed properties ideaway for bacteria ± Defended from infx ± Mechanically tough amiliar to surgeons ± Hideaway for bacteria ± Mechanically fragile eed instructions ± Familiar to surgeons ± Need instructions AMI-USC
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Biocompatibility or Biotolerance ± Foreign Body Reactions ² ody attacks implant Body attacks implant ² Implant damages body afety vs Efficacy ± Safety vs. Efficacy ² failed device present unexpected hazard ² life-critical function is lost ² device replacement leads to morbidity AMI-USC
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Voyage at Sea A Voyage at Sea altwater ± Saltwater ² permeation orrosion ² corrosion ± Seasickness nsile failure ² tensile failure ² stress fatigue harks ± Sharks ² macrophage urgeons AMI-USC ² surgeons
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ater water everywhere Water, water everywhere… iffusion ± Diffusion ± Condensation apillary Flow ± Capillary Flow ± Osmotic pressurization ± Adhesive hydrolysis ± Dissection ± Short circuits ± Corrosion AMI-USC ± Dendrite formation
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on- ermetic Packaging Non hermetic Packaging leaning ± Cleaning ± Adhesion ressure ± Pressure ? Low-permeability AMI-USC
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ermetic Packaging Hermetic Packaging etals ± Metals ² welds eramics ± Ceramics ² brazes ± Glasses ² melts ± Wax? AMI-USC
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Strategies for Neuromuscular Stimulation Conventional Technology vs. BION® Wireless Injectable Modules AMI-USC
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ermeticity Testing Hermeticity Testing implantable CLARION TM cochlear cardiac BION TM 50% vol., 6% water vapor 10% vol. getter defibrillator implant pacemaker VOLUME cc 10 2 1 0 -1 -2 -3 high pressure bomb - 100 atm He sniffer LEAK RATE cc atm/s mil spec typ. prod. max. sens. -9 -4 -5 -6 -7 -8 -11 -12 -13 -10 trapped He detector conventional bubble test LIFE TIME 1day 1mo. 1yr. 30yr. 10yr. AMI-USC s 5 6 7 8 9 10
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BION1 Hermetic ackage Assembly Ferrites oil Package Assembly CO2 laser welds: ASIC Capacitor Wire bonds Coil 3) Glass bead to Ta tube 5) Glass beads to capillary Substrate 1) ) 5) ) 5) 6) He leak test 2) 4) 3) 7) Nd-YAG laser welds: 2) PtIr Washer to Ta stem Vacuum furnace seal: 1) lass bead to Ta Electrode AMI-USC ) a s eoa s e 4) Spring to Ta tube 7) Ta tube seal/cut & Ir Washer ) G ass bead o a ec ode
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lectrical Interfaces Electrical Interfaces ± electrons in metal ions in water ± reversible reactions ² double layer charging M 0 + e - + H + M 0 e - H + ² ion adsorption M 0 + H 2 O M ++ O -- + 2H + + 2e - ± irreversible reactions ² electrolysis of water 2H 2 0 + 2e - H 2 + 2OH - ² corrosion of metal M M + + e - + ² chelation of metal M + 2Cl - M ++ Cl - 2 + 2e - ² organic denaturation, e.g. C 6 H 12 O 6 + 6 H 2 0 CO + 24H + + 24e - AMI-USC 6CO 2 e
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harge density limits ( /cm 2 Charge density limits ( μ C/cm ) harge Q(C) = current I(A) x phase duration t(s) ± charge Q(C) = current I(A) x phase duration t(s) ±
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This note was uploaded on 06/08/2009 for the course BME 416 taught by Professor Loeb during the Spring '08 term at USC.

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BME416-Biocompatibility [Compatibility Mode] - BASICS OF...

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