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Antibacterial Polyelectrolyte Multilayers (PEMs). Team X Maricela Delgadillo Kay Furman Yushan Kim. Industrial Application. Implantable Medical Devices: Pacemakers treat Bradycardia (slow heart rhythm) Size: 45x48x8 Defibrilators treat Tachyarrhythmia (fast heart rhythm)
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Antibacterial Polyelectrolyte Multilayers (PEMs) Team X Maricela Delgadillo Kay Furman Yushan Kim
Industrial Application • Implantable Medical Devices: • Pacemakers treat Bradycardia (slow heart rhythm) • Size: 45x48x8 • Defibrilators treat Tachyarrhythmia (fast heart rhythm) • Size: 62x51x15mm • Potential for Bacterial Exposure • 6% of all vascular surgeries result in surgery site infection (Health Protection Agency) • Packaged and handled sterilely • 1-2 hr surgical procedure Images from http://www.medtronic.com/
Brief PEM Background • Layer-by-layer fabrication • Polycation - Poly(allylamine hydrochloride) PAH • Polyanion - Poly(acrylic acid) PAA • Easy to control pH and number of bilayers • Polyelectrolyte pH affects: • Film Thickness • Interpenetration between layers • Highly ionized polyelectrolytes (pH~6.5) result in thin films • Possible cell adhesion applications • pH~3.0 loopy conformations
Project Plan sepidermidis.mlst.net/ Berg, 2000
PEM Design • TiO2 substrate: + charge • 1st PEM layer: PAA • PAH/PAA bilayers • Incorporation of antibacterial active by use of electrostatic charge • Other design considerations • Porosity • Cross-linking
Ti disk Staph aureus Potential Material Issues • Metal substrate and PEM processing • Titanium use in implantable devices • Previously published studies with metal • PEM on device stimulation electrodes (Patent 5964794, 1999) • PEMs for corrosion-resistant metals (Patent 027011, 2003) • Necessitates (-) PAA layer deposition first • Imaging Issues • Microscopy requires transparent substrate • TEM or SEM availability
Further Issues and Questions • Feasibility of bacteria/eukaryote selectivity