Structure, properties, and in vitro degradation behavior of biodegradable poly(L‐lactic acid)‐trimethylene carbonate‐glycolide terpolymer

Abstract

For biodegradable medical implants, it is critical to match the degradation rate of the material with the lesion healing rate of the tissue defect. Here, we report the synthesis of poly(L-lactic acid) (PLLA)-trimethylene carbonate (TMC)glycolide (GA) terpolymers with various monomer feeding ratios of L-lactide, TMC, and GA. The terpolymers were prepared through ring-opening polymerization with the purpose to improve degradation and mechanical properties of the terpolymers for biomedical applications. The influence of various GA contents in PLLA-TMC-GA terpolymers on the chain structure and their in vitro degradation performances were evaluated by using gel permeation chromatography, differential scanning calorimetry, X-ray diffraction, 1 H nuclear magnetic resonance, and tensile tests. Compared with pure PLLA, the degradation rate of terpolymers increased with the increase of GA content, because GA segments, which have a faster hydrolysis rate, not only effectively disrupt the regularity of LLA segment, but also increase the probability of chains scission during the degradation process. In a 28-week long degradation study, the mass loss of PLLA-TMC-GA terpolymers was about 36%, which is a faster rate than reported for pure PLLA. Therefore, it is possible to tailor the copolymer chain structures by varying the ratio of GA in the terpolymer to balance its degradation rate with body's lesion healing rate.

Elastomeric Polyesters in Cardiovascular Tissue Engineering and Organs-on-a-Chip

“…Poor biological integration, low biocompatibility, and a high chance of fibrosis often hinder application of engineered scaffolds in vivo . − Given the low elastic modulus of human myocardium during the diastole and systole cycles (10–300 kPa), an ideal elastomer for implantable patches should possess a similar Young’s modulus, as well as high elongation and tensile strength in order to support the contractile behavior of cardiac tissue. ,,, Implementation of cardiac patches with better physiological integration has raised a great interest toward restoring the functionality of the heart upon injury . Patches could be made of a combination of synthetic polymers and natural hydrogels. − ,,− A landmark study by Zimmermann et al demonstrated that the use of cardiac patches, made of heart cells incorporated in collagen I and Matrigel, on the epicardial surface of the heart can result in functional improvement post-MI .…”