|Novel Polymers, Novel Scaffolds -- A Framework for Tissue Engineering |
Chemistry and Chemical Biology
|Buddy Ratner, University of Washington Engineered Biomaterials (UWEB)|
11:00 AM, BME-102 (Auditorium)
Porous, interconnected structures are widely observed in nature. In the human body, trabecular bone and extracellular matrix are examples of porous systems that are intrinsic to the functionality of tissues and organs. Porous polymeric scaffolds for tissue engineering serve to provide anatomical shape, attach cells, direct cell growth/differentiation and finally provide an environment for tissue formation. Ultimately, they must biodegrade and leave behind functional tissue. In this talk, a number of scaffold technologies will be addressed, along with the biomaterials that they are fabricated from.
Specific technologies useful for creating scaffolds for tissue engineering include salt leaching, gas foaming (e.g. NH4(CO3)2 or high pressure CO2), sintering, microsphere templating, solvent precipitation, freeze-induced phase separation, aphrons and foams, electrospinning, spinaret fabrication methods, inkjet printer rapid prototyping and decellularization of tissue. Gels can also be used as scaffolds, though their porosity is described at the molecular scale rather than the micro scale. A central question in engineering scaffolds is what pore sizes, pore shape, pore orientation and interconnectivity is best for tissue engineering. Though definitive answers to these questions are not yet available, some contemporary thinking on this subject will be discussed. A special focus in this talk will be on a porous material made by sphere templating that rapidly induces angiogenesis and minimizes fibrotic outcomes. A special variant of this material will have long, parallel pores for heart muscle cells and spherical pores to induce angiogenesis. A scaffold prepared by aphron technology will also be discussed. Electrospun scaffolds will be briefly discussed. Finally work on decellularized natural tissue will be presented.
Many biodegradable polymers, both natural and synthetic have been used in the fabrication of scaffolds. There are special requirements for such polymers that are often not met with existing polymers. Two unique polymers will be discussed. A poly(hydroxyethyl methacrylate) gel that is biodegradable through precision-integrated polycaprolactone oligomers will be presented. Also, a new class of polymers using amino acid anhydrides as the biodegradable unit will be described.
Hosts: Profs. Kathryn Uhrich (CCB) and Prabhas Moghe (BME)