Interesting Study Uncovers The Confusing Behaviors Concerning ZD6474
Inner views of the scaffolds were obtained after cryofracture. The results for the thermal characterization of the scaffolds are shown in Figures ?Figures55 (DSC) and ?and66 TRIB1 (TGA). None of the polymeric scaffolds showed evidence of crystallinity. PLDLA-TMC was amorphous and DSC thermograms showed a decrease in the glass transition temperature (Tg) of PLDLA-TMC (51.7��C) compared to PLDLA (57.9��C) (Figure 5). Similar tendencies were observed for the Tg values for poly(L-lactide-co-TMC) and poly(D,L lactide-co-TMC) [24]. Davachi et al. [29] showed that an increase in the TMC content of poly(lactide-TMC-glycolide) resulted in a decrease in the glass transition temperature. Since the crystalline phase is poorly ZD6474 accessible to water and other permeants, the presence of crystallinity reduces polymer permeability and the rate of biodegradation by chain scission because of a decrease in accessible hydrolysable bonds. With regard to the use of these polymers for biomedical applications, it is worth remembering that crystalline debris formed during degradation may cause an undesired late inflammatory response, thereby negatively influencing tissue growth and normal function [30]. Hence, little or no crystallinity is desirable [31]. Figure 5 DSC thermograms showing the glass transition temperature of PLDLA and PLDLA-TMC scaffolds. Figure 6 TGA thermograms of PLDLA and PLDLA-TMC scaffolds. The thermal stability of PLDLA-TMC was measured with a thermogravimetric analyzer (TGA). Figure 6 shows typical TGA traces of weight loss as a function of temperature. This analysis showed that both polymers decomposed ON-01910 in vitro in a single-stage degradation and that the addition of TMC reduced the polymer thermal stability; that is, the addition of TMC to L/D,L-lactide resulted in greater degradation of the polymer. The onset temperature of PLDLA decreased from 333.2��C to 322.6��C when TMC was present. The maximum decomposition temperature of PLDLA was 362.8��C, whereas that of PLDLA-TMC was 342.1��C. 3.3. Osteoblast Cell Culture on Scaffolds The MTT assay showed that the viability of SaOS-2 osteoblasts increased with time (Figure 7), an indication of cell proliferation on the porous scaffolds. The presence of TMC in PLDLA did not affect cell viability compared to scaffolds containing only PLDLA. After 1 and 7 days, cells grown on PLDLA and PLDLA-TMC scaffolds showed greater viability than those grown in control wells (P
