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Biodegradable Fumarate-Based Polyhipes as Tissue Engineering Scaffolds

Elizabeth Christenson1, Wafa Soofi1, Neil Cameron2, and Antonios G. Mikos1. (1) Bioengineering, Rice University, Mail Stop 142, P.O. Box 1892, Houston, TX 77251-1892, (2) Chemistry, University of Durham, South Rd., DH1 3LE, Durham, United Kingdom

It is widely recognized that scaffold architecture (porosity, pore size, interconnectivity) can profoundly influence the behavior of cells on tissue engineering constructs. High internal phase emulsion (HIPE) polymerization affords tremendous control of scaffold morphology. In particular, pore size and interconnectivity may be readily optimized using this technology to facilitate cellular ingrowth, influx of nutrients and transport of waste throughout the scaffold. In this study, a range of highly porous, biodegradable scaffolds were prepared by polymerization of the continuous phase of HIPEs containing poly(propylene fumarate) and the crosslinker propylene fumarate diacrylate. The biodegradable macromers were synthesized and combined with a suitable diluent and surfactant prior to emulsification. The aqueous solution was gradually dispersed in the organic phase and contained the initiator potassium persulfate. Crosslinking of the macromer chains during cure locked in the emulsion geometry. Subsequent removal of the aqueous phase by extraction and drying resulted in monolithic polyHIPEs with interconnected cellular architectures. Scanning electron microscopy was used to characterize the resulting monoliths and correlate experimental parameters with scaffold morphology. Pore sizes ranging from 20 microns to 100 microns and interconnect sizes up to 30 microns were generated by varying the chemical composition of the emulsions. Specifically, the effect of diluent concentration, crosslinker concentration and surfactant on emulsion stability and subsequent scaffold morphology will be presented.

Web Page: www.ruf.rice.edu/~mikosgrp/