New Biocompatible Polyurethanes: Synthesis, Structural Characterization and Cytotoxicity

Abstract

The synthesis of four samples of new polyurethanes was evaluated by changing the ratio of the diol monomers used, poly(propylene glycol) (PPG) and D-isosorbide, in the presence of aliphatic isocyanates such as the isophorone diisocyanate (IPDI) and 4,4′-methylenebis(cyclohexyl isocyanate) (HMDI). The thermal properties of the four polymers obtained were determined by DSC, exhibiting Tg values in the range 55-70 ºC, and their molecular structure characterized by FTIR, 1H and 13C NMR spectroscopies. The diffusion coefficients of these polymers in solution were measured by the Pulse Gradient Spin Echo (PGSE) NMR method, enabling the calculation of the corresponding hydrodynamic radii in diluted solution (1.62–2.65 nm). The molecular weights were determined by GPC/SEC and compared with the values determined by quantitative 13C NMR analysis. Finally, the biocompatibility of the polyurethanes was assessed using the HaCaT keratinocyte cell line by the MTT reduction assay method showing values superior to 70% cell viability.

Xanthan-Based Materials as a Platform for Heparin Delivery

“…This signal is due to the superimposition of –NH– stretching vibrations of the urethane group of the Pus, as well as to terminal Xn or XnOA groups. Furthermore, the presence of the carbonyl group from the PU structure was evidenced by the bands from the region of 1739–1625 cm −1 [ 32 ]. The presence of heparin in Xn–PU–Hep and XnOA–PU–Hep materials was confirmed by the appearance of signals between 1430 and 1404 cm −1 attributed to –COO - group.…”

LHC Upgrades in preparation of Run 3

“…The peak power density expected during operation in the TANB was estimated with FLUKA simulations [109] for two different crossing angle configurations and for the nominal instantaneous luminosity of 2 × 10 33 cm −2 s −1 (see figure 52) showing an adequate level of protection for D2 [110]. The power deposition on the TANB is not expected to exceed 25 W and, based on the results of a thermo-mechanical analysis [111], there will be no need of water cooling for this device [111].…”