Monday June 18, 2012, 9:00 am - 5:00 pm, Santa Clara, California
Historically, synthetic materials have not served as sufficient implants. For example, the current average lifetime of an orthopedic implant is only 15 years. Similarly, for the vascular community, small diameter vascular grafts are only functional 25% of time past 5 years of use. Clearly, conventional materials have not invoked proper cellular responses to regenerate tissue that allows for these devices to be successful for long periods of times. In contrast, due to their ability to mimic the dimensions of constituent components of natural tissues, nanophase materials may be an exciting successful alternative. This is not only due to their ability to simulate dimensions of proteins that comprise tissues, but also because of their higher reactivity for interactions of proteins that control cell adhesion and, thus, the ability to regenerate tissues.
This is an introductory course suitable for anyone interested in the design of the next-generation of better biomaterials and, in particular, at the intersection of nanotechnology and tissue engineering.
This course will focus on the creation of better tissue engineering through concepts in nanotechnology, i.e. the use of materials with constituent components less than 100 nm in at least one dimension.
First, we will define current problems with various implants and learn why current materials fail in the device systems.
Orthopedic: • Current Materials Used • Current Modes of Failure: Poor bonding to surrounding bone; Generation of wear debris; Stress and strain imbalances at the tissue implant interface • Current Statistics on Orthopedic Implant Failure
Dental: • Current Materials Used • Current Modes of Failure: Poor bonding to surrounding bone; Generation of wear debris; Stress and strain imbalances at the tissue implant interface • Current Statistics on Dental Implant Failure
Cartilage: • Current Treatment Methods and Materials Used • Current Modes of Failure: Poor regeneration of cartilage tissue; Generation of wear debris; Stress and strain imbalances at the tissue implant interface • Current Statistics on Cartilage Implant Failure
Vascular: • Current Materials Used • Current Modes of Failure: Poor bonding to surrounding vascular; Endothelium removal due to shear stress; Generation of stenosis; Stress and strain imbalances at the tissue implant interface; Current Statistics on Vascular Implant Failure
Bladder: • Current Materials Used • Current Modes of Failure: Poor bonding to surrounding tissue; Stress and strain imbalances at the tissue implant interface • Current Statistics on Bladder Implant Failure
Central and Peripheral Nervous System: • Current Materials Used • Current Modes of Failure: Poor bonding to surrounding tissue; Build-up of glial scar tissue; Poor maintenance of electrical properties; Stress and strain imbalances at the tissue implant interface • Current Statistics on Central and Peripheral Nervous System Implant Failure
Next, we will learn how cells interact with implanted materials to generate a biological response. We will discuss both desirable and undesirable reactions of the body with implanted materials.
Protein Interactions with Implanted Materials: • Properties of Proteins • Adsorption • Conformation/Bioactivity
Cellular Recognition of Proteins Adsorbed on Materials Surfaces: • Adhesion • Migration • Differentiation
Cellular Extracellular Matrix Deposition Leading to Tissue Regeneration: • Bone • Dental Tissue • Cartilage • Vascular • Bladder • Central and Peripheral Nervous System
Wear Debris Response
How can nanophase materials be used as better implants? What are their promising properties and what experimental evidence exists? We will sort through the experimental data and separate promise from “hype”.
Mechanical Properties - Theoretical and Experimental Evidence: • Ceramics: Increased grain boundary sliding • Metals: Dislocation source • Polymer Composites
Surface: • Biologically-inspired Surface Roughness • Increased Surface Reactivity
Various Techniques to Synthesize Nanophase Materials
Experimental Evidence of Increased Tissue Regeneration: • Orthopedic • Dental • Cartilage • Vascular • Bladder • Central and Peripheral Nervous System
Lastly, we will discuss the most promising future directions for the use of nanophase materials in biological applications. We focus on key unanswered questions such as the immunological response to nanoparticles.
Immune System Response: • Basics of Immune System and Particle Size • Limited Experimental Evidence
Nanophase Materials Coatings: • Various Conventional Coating Methods • Limited Experimental Evidence
Wear Debris: • Size Relationships for Wear Debris • Limited Experimental Evidence
Intelligent Nanoparticle Systems: • Basics of Drug Delivery • Limited Experimental Evidence
Thomas J. Webster, Ph.D., Associate Professor, Division of Engineering, Brown University, Providence, RI, USA. Professor Webster’s research designs, synthesizes, and studies nanophase materials for various implant applications. Among many awards, Dr. Webster was the 2002 recipient of the Biomedical Engineering Society Rita Schaffer Young Investigator Award, the 2004 recipient of the Outstand Young Investigator Award for the Schools of Engineering at Purdue University, the 2005 Coulter Early Career Award, and the 2005 Finalist for the American Society for Nanomedicine Young Investigator Award. He also serves on several grant review panels for the NIH and NSF in the area of nanobiotechnology.
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