Synthesis and properties of biodegradable network poly(ether‐urethane)s from L‐lysine triisocyanate and poly(alkylene glycol)s

Abstract

Biodegradable network poly(ether-urethane) films with different hydrophilicity were prepared from L-lysine triisocyanate (LTI) and poly(ethylene glycol) (PEG), poly(1,4-tetramethylene glycol) (PTMG) or poly (propyrene glycol) (PPG) with the molecular weights of 250-2000 g mol À1 . Prepolymers prepared by a melt-polycondensation were cast from tetrahydrofuran solution and heated at 65-80 C for 9 h, then postpolymerized at 150-180 C for 10-20 min to form a network. The resultant films were transparent to opaque and insoluble in water and organic solvents. These network films were fully characterized by FTIR, density measurement, wide-angle X-ray scattering (WAXS), differential scanning calorimetry, dynamic mechanical analysis, and tensile tests. WAXS intensity curves of LTI/PEG-1000 and LTI/PEG-2000 exhibited crystalline peaks due to PEG segments, while those of all other network films did amorphous halos. The molecular weights (M w ) between cross-links increased, while the cross-linking density decreased with increasing the M w s of the poly(alkylene glycol)s. Mechanical properties were strongly affected by the type and molecular weights of poly(alkylene glycol)s used. The weight losses of the LTI/ PEG series network films that were degraded in a phosphate buffer solution (pH 7.2) at 37 C and the equilibrium water content in distilled water at 20 C were much larger than those of LTI/PTMG and LTI/PPG series ones. In contrast, LTI/PTMG-1000 and LTI/PPG-1000 network films absorbed 150-216% of organic solvents such as benzene and toluene under equilibrium state at 20 C. The use of poly(alkylene glycol)s with different types and the M W s allowed the preparation of novel network poly(ether-urethane) films with a broad range of properties. V C 2012 Wiley Periodicals, Inc. J Appl Polym Sci 126: E358-E364, 2012

Fluorescent, online monitoring of PLGA degradation for regenerative medicine applications

“…Current methods utilised for the degradation proling of biomaterials include weight loss, high performance liquid chromatography (HPLC), gel permeation chromatography (GPC) and micro-computed tomography (microCT). [3][4][5][6] These techniques are however destructive end-point analyses which do not allow for real-time monitoring of degradation. Recent advances in the area have utilised non-invasive, uorescent techniques to tag biomaterials and assess degradation through subsequent changes in uorescence.…”