Lecture-9SS-modified

Lecture-9SS-modified - Biomaterial Classifications –...

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Unformatted text preview: Biomaterial Classifications – Lecture Slide Set 9 Lecture Dr. Anthony Brennan University of Florida Tel: 352.392.6281 Email: abrennan@mse.ufl.edu University of Florida - EMA 6580 Science of Biomaterials - Copyright Protected University 1 Lecture Slide Set 9 – Surface Modification Strategies Modification • Learning Objectives 9: – Surface Coating • Separate, distinct phase • Requires adhesion layer – Surface gradients • IPNs, Semi-IPNs • Ion implants • Limited by phase compatibility – “Chemical modification” of surface • Distinct from adding another material • Wide range of opportunities – Oxidation, reduction, etching, roughening, etc • Potentially unstable – Multilayering creates interfaces/interphases – Physical and Chemical Patterning University of Florida - EMA 6580 Science of Biomaterials - Copyright Protected 2 Section 1 – Lecture Slide Set 9 SURFACE MODIFICATION STRATEGIES STRATEGIES University of Florida - EMA 6580 Science of Biomaterials - Copyright Protected 3 Strategies Strategies • Generally accepted: – Degradation: irreversible chemical change in Degradation: covalent bond structure (metal, ionic) resulting in by-products resulting • Biodegradation is a biologically mediated, Biodegradation irreversible chemical change in bond structure irreversible – Erosion: change in physical structure that Erosion: normally involves degradation of chemical structure. structure. • Bioerodible polymer: a water insoluble polymer Bioerodible converted “biologically” into a water soluble polymer, i.e., biochemical degradation of structure polymer, – Bioresorbable & Bioadsorption: labeled Bioresorbable “superfluous” by author “superfluous” University of Florida - EMA 6580 Science of Biomaterials - Copyright Protected 4 Surface Modification Strategies Surface University of Florida - EMA 6580 Science of Biomaterials - Copyright Protected 5 Surface Modification Methods Surface • Coatings – Non-reactive – – – – Solvent based LB Films Surface active Vapor deposition • Carbon coatings – heart Carbon valves, stents valves, • Parylene • Coatings – Reactive – Radiation grafted polymer • • • • E-beam Gamma UV Corona Discharge – Gas Phase Deposition • • • • Coatings – Reactive – Coatings cont’d cont’d • Chemical Chemical – – – – Ozonolysis Surface nucleated grafting Silanization Protein Protein immobilization/grafting immobilization/grafting • Material Ablation – – – – Metallization Anodization Redox Mechanical/Chemical • Polishing • Grinding Ion beam sputtering CVD Flame spray deposition University of Florida - EMA 6580 Science of Biomaterials - Copyright Protected 6 Section 2 – Lecture Slide Set 9 RADIO-FREQUENCY GLOW DISCHARGE DISCHARGE University of Florida - EMA 6580 Science of Biomaterials - Copyright Protected 7 RFGD RFGD (Radio-Frequency Glow Discharge) • High energy – High Ablation Ablation • Grafting – – – UV-initiated RF-plasma initiated Composition • Controllable • Gradients – “Conformal” – Void free • Applicable to most Applicable surfaces surfaces • Adhesion • Higher purity • Chemically complex – Radicals – Anions – Cations • High cost University of Florida - EMA 6580 Science of Biomaterials - Copyright Protected 8 Structure Relaxation – Plasma/Corona Plasma/Corona University of Florida - EMA 6580 Science of Biomaterials - Copyright Protected 9 Surface Energy Temporal Response Response University of Florida - EMA 6580 Science of Biomaterials - Copyright Protected 10 Kinetics of Recovery - PDMSe Kinetics University of Florida - EMA 6580 Science of Biomaterials - Copyright Protected 11 Strain Response - Morphology Strain University of Florida - EMA 6580 Science of Biomaterials - Copyright Protected 12 Surface Elastic Modulus Surface Material Bulk Elastic Bulk Modulus [MPa] Modulus Surface Elastic Surface Modulus [MPa] Modulus RMS Roughness RMS [nm] [nm] Polystyrene ~3,000 ~3,000 4.4 ± 1.4 9.1 ± 8.0 9.1 PDMS Elastomer 1.4 ± 0.1 1.5 ± 0.8 26.9 ± 5.6 PT PDMS PT Elastomer Elastomer 1.4 ± 0.1* 3.0 ± 0.9 6.8 ± 4.5 University of Florida - EMA 6580 Science of Biomaterials - Copyright Protected 13 Surface Reorganization “The Mechanisms of Hydrophobic Recovery of Polydimethylsiloxane Elastomers Exposed to Partial Electrical Discharges,” Jongsoo Kim,¤ Manoj K. Chaudhury, Michael J. Owen and Tor Orbeck, J ournal of Colloid and Interface Science 244, 200– 207 (2001) University of Florida - EMA 6580 Science72 Biomaterials - Copyright Protected 14 of of 14 Surface Roughness Surface RMS University of Florida - EMA 6580 Science of Biomaterials - Copyright Protected 15 PT - Hydrophilic PDMSE Lamellae-like Morphology Morphology University of Florida - EMA 6580 Science of Biomaterials - Copyright Protected 16 Section 3 – Lecture Slide Set 9 SURFACE GRAFTING SURFACE University of Florida - EMA 6580 Science of Biomaterials - Copyright Protected 17 HPX Grafting HPX University of Florida - EMA 6580 Science of Biomaterials - Copyright Protected 18 Example Silanes Example University of Florida - EMA 6580 Science of Biomaterials - Copyright Protected 19 Coupling Agents Coupling • Methacryloxymethyl triethoxy silane [MAMTES] combined with Methacryloxymethyl Methyl triethoxysilane [MTES] (60% Silica of Bioglass Particulate) Particulate) University of Florida - EMA 6580 Science of Biomaterials - Copyright Protected 20 Parylene (para-Xylylene) Parylene • Unique conformal Unique coating coating • Simultaneous Simultaneous vaporization, pyrolysis and polymerization polymerization • High purity High polymerization polymerization • Tough, thermally Tough, stable polymer stable H2 C CH2 H2C CH2 Pyrolysis Polymerization C H2 University of Florida - EMA 6580 Science of Biomaterials - Copyright Protected C H2 n 21 Section 4 – Lecture Slide Set 9 SURFACE PATTERNING – SURFACE PHYSICAL TOPOGRAPHY University of Florida - EMA 6580 Science of Biomaterials - Copyright Protected 22 Surface Science Model (Kasemo and Lausmaa)1 Epithelial topo-directed morphology • Geometric structures interact at all size scales Surface Biological Geometry mm Tissue µ-roughness µm Cells Grains Membrane roughness nm MB-Proteins Dislocations Proteins Oxide Peptides Defects Å Amino acids Atoms Water 70x400x600 nm Smooth SiO2 1900x4000x600nm 1. Kasemo B, Lausmaa J. Surface science aspects on inorganic materials. CRC Crit Rev Biocomp 1986;2:335–80 Brennan Biofouling Group – Investor Presentation Copyright Protected University of Florida Brennan Biofouling Group – Investor Presentation Copyright Protected University of Florida 12/15/2008 9:49 AM 6 Freshly Harvested Porcine Pulmonary Arterial Segment Contact Guidance Lumen • Harrison (1914) Tunica Intima – Neurons on spider silk • Cell morphology depends on underlying substrate (Weiss, 1945) • Grooved substrates Tunica Media Tunica Adventitia – Alignment increased by • decreased spacing • increased depth – Kidney cells, fibroblasts and ECs • • 5 0 µm Wilkerson WR. [MS Thesis]. Brennan Group, University of University of Florida University of Florida - EMA 6580 Science Brennan Biofouling Group – Investor Presentation Copyright Protected Florida; 2001 ECs grow as a monolayer on the vessel lumen The monolayer is continuous with a well developed actin cytoskeletal network and a cell density of ~3,161 cells/mm2 of Biomaterials - Copyright Protected GRC - Chemistry at Interfaces, Waterville Valley, July 2008 23 Methods – Methods Photolithography/Replication Photolithography/Replication • Modeling Mold Production – T2 Silastic – Engineered Roughness Index – Settlement Maps – Force Gradients • • • • Pattern Design Mold Production Sample Casting Chemical Treatments • Stamping • Bioassays Sample Casting Positive Replication Negative Replication Silicon Wafer PDMSe University of Florida - EMA 6580 Science of Biomaterials - Copyright Protected University SBS Copolymer 24 Sharklet™ Engineered Surface Topographies Sharklet™ Disclosure: Professor Brennan is Chief Technology Officer, Co-Founder and an Owner of Sharklet Technologies University of Florida - EMA 6580 Science of Biomaterials - Copyright Protected 25 Contact Guidance Contact Silastic T2 PDMSe University of Florida - EMA 6580 Science of Biomaterials - Copyright Protected 26 Section 5 – Lecture Slide Set 9 SURFACE PATTERNING – SURFACE CHEMICAL TOPOLOGY University of Florida - EMA 6580 Science of Biomaterials - Copyright Protected 27 Fabricating Microengineered Surfaces Surfaces University of Florida - EMA 6580 Science of Biomaterials - Copyright Protected 28 Chemical Patterning Chemical University of Florida - EMA 6580 Science of Biomaterials - Copyright Protected 29 Visualizing Cell Structures Visualizing University of Florida - EMA 6580 Science of Biomaterials - Copyright Protected 30 Chemical Patterning Chemical University of Florida - EMA 6580 Science of Biomaterials - Copyright Protected 31 EC Coverage on Patterns EC University of Florida - EMA 6580 Science of Biomaterials - Copyright Protected 32 Cell Density and Area – Fn Patterns Patterns University of Florida - EMA 6580 Science of Biomaterials - Copyright Protected 33 Remodeling of Chemical Patterns Remodeling University of Florida - EMA 6580 Science of Biomaterials - Copyright Protected 34 Observations Observations University of Florida - EMA 6580 Science of Biomaterials - Copyright Protected 35 Summary University of Florida - EMA 6580 Science of Biomaterials - Copyright Protected University 36 Additional References University of Florida - EMA 6580 Science of Biomaterials - Copyright Protected University 37 ...
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