In Vitro Examination of Poly(glycerol sebacate) Degradation Kinetics: Effects of Porosity and Cure Temperature
- PDF / 251,275 Bytes
- 6 Pages / 432 x 648 pts Page_size
- 49 Downloads / 205 Views
In Vitro Examination of Poly(glycerol sebacate) Degradation Kinetics: Effects of Porosity and Cure Temperature Nadia M. Krook,1 Courtney LeBlon,2 and Sabrina S. Jedlicka1,3,4 Lehigh University1 Materials Science & Engineering,2 Mechanical Engineering & Mechanics,3 Bioengineering Program,4 Center for Advanced Materials & Nanotechnology, Bethlehem, PA, 18015, U.S.A ABSTRACT Poly(glycerol sebacate) (PGS) is a biodegradable and biocompatible elastomer that has been used in a wide range of biomedical applications. While a porous format is common for tissue engineering scaffolds, to allow cell ingrowth, PGS degradation has been primarily studied in a nonporous format. The purpose of this research was to investigate the degradation of porous PGS at three frequently used cure temperatures: 120°C, 140°C, and 165°C. The thermal, chemical, mechanical, and morphological changes were examined using thermogravimetric analysis, differential scanning calorimetry, Fourier transform infrared spectroscopy, compression testing, and scanning electron microscopy. Over the course of the 16-week degradation study, the samples’ pores collapsed. The specimens cured at 120°C demonstrated the most degradation and became gel-like after 16 weeks. Thermal changes were most evident in the 120°C and 140°C cure PGS specimens, as shifts in the melting and recrystallization temperatures occurred. Porous samples cured at all three temperatures displayed a decrease in compressive modulus after 16 weeks. This in vitro study helped to elucidate the effects of porosity and cure temperature on the biodegradation of PGS and will be valuable for the design of future PGS scaffolds. INTRODUCTION Biocompatible and biodegradable poly(glycerol sebacate) (PGS) exhibits similar mechanical properties to those of soft body tissues [1,2]. Porous and nonporous PGS has been used in various applications of bioengineering, including drug delivery [3] and tissue engineering scaffolds to allow cell ingrowth [4-9}. Previous in vivo biodegradation of nonporous PGS shows that there was complete absorption in 60 days [1]. In vitro, nonporous PGS is almost completely degraded in 4 months in simulated body fluid (SBF) [10]. Very little is known about the degradation of porous PGS and data is limited to weight loss, chemical changes, and morphology for nonporous PGS [1,2,10]. Further in vitro research on the biodegradation will provide insight to the effects of degradation on material properties for better use of PGS in its biological applications. The purpose of this research was to investigate the degradation effects of SBF on porous PGS at three different cure temperatures: 120°C, 140°C, and 165°C. There is also a direct link to changing cure temperatures and differences in mechanical properties. Increased cure temperature of PGS correlates with an increased amount of cross-linking and thus a greater elastic modulus [1]. This research is designed to better understand the effects of SBF on the properties of biocompatible and biodegradable porous PGS and the specific effect of the
Data Loading...
