Control the Mechanical Properties and Degradation of Poly(Glycerol Sebacate) by Substitution of the Hydroxyl Groups with Palmitates

Abstract

Mechanical properties and degradation profile are important parameters for the applications of biodegradable polyester such as poly(glycerol sebacate) in biomedical engineering. Here, a strategy is reported to make palmitate functionalized poly(glycerol sebacate) (PPGS) to alter the polymer hydrophobicity, crystallinity, microstructures and thermal properties. The changes of these intrinsic properties impart tunable degradation profiles and mechanical properties to the resultant elastomers depending on the palmitate contents. When the palmitates reach up to 16 mol%, the elastic modulus is tuned from initially 838 ± 55 kPa for the PGS to 333 ± 21 kPa for the PPGS under the same crosslinking conditions. The elastomer undergoes reversible elastic deformations for at least 1000 cycles within 20% strain without failure and shows enhanced elasticity. The polymer degradation is simultaneously inhibited because of the increased hydrophobicity. This strategy is different with other PGS modifications which could form a softer elastomer with less crosslinks but typically lead to a quicker degradation. Because the materials are made from endogenous molecules, they possess good cytocompatibility similar to the PGS control. Although these materials are designed specifically for small arteries, it is expected that they will be useful for other soft tissues too.

Fast photocurable thiol-ene elastomers with tunable biodegradability, mechanical and surface properties enhance myoblast differentiation and contractile function

“…The biodegradability of the ternary P(GTP- co -PP- co -BDBMP) elastomers was adjusted by varying the GTP content, which consequently changes crosslinking degree. These findings are corroborated by other studies that showed control of the biodegradation at the expense of the mechanical stiffness; less crosslinked elastomers degrade faster than more crosslinked elastomers [ 75 , 84 ].…”

“…First, the utilization of UV-induced thiol-ene crosslinking strategy permits quick gelation by photocuring and avoids elevated temperatures and/or long curing times often required in thermally-induced curing process, and can enable the addition of bioactive agents without causing denaturation. Second, elastomers with copolymeric structures can be readily targeted by selecting thiol-ene monomers with flexible aliphatic structures, because they are not expected to possess significant crystallinity that would hinder their elastomeric properties [ 75 ]. Third, the synthesized ester-based alkene monomers and the commercially available thiol monomers provide a solid basis to tune the structures and properties of the resulting thiol-ene elastomers.…”

Slow degrading poly(glycerol sebacate) derivatives improve vascular graft remodeling in a rat carotid artery interposition model

“…Compared to PGS, the PPGS with 9 and 16 mol.% of palmitate pendants reduced the elastic modulus from 838 ± 55 kPa to 441 ± 26 kPa and 333 ± 21 kPa, respectively. On the other hand, water contact angles of 9-PPGS and 16-PPGS significantly increased from 66.3 ± 1.2° (PGS control) to 72.0 ± 1.8° and 84.8 ± 1.6°, demonstrating a proportional increase in hydrophobicity [33]. Both the 9-PPGS and 16 PPGS elastomers demonstrated a sustained release of palmitates over time (Supplementary Fig.…”

“…In our previous study, we designed PPGS with appropriate contents of palmitate functionalities to make the elastomer softer with enhanced elasticity and at the same time increase hydrophobicity [33]. Compared to PGS, the PPGS with 9 and 16 mol.% of palmitate pendants reduced the elastic modulus from 838 ± 55 kPa to 441 ± 26 kPa and 333 ± 21 kPa, respectively.…”

Bead‐free and tough electrospun PCL/gelatin/PGS ternary nanofibrous scaffolds for tissue engineering application

“…Despite common polyesters, poly(glycerol sebacate) (PGS) is a synthetic bioresorbable material that is used for peripheral nerve regeneration due to mechanical and physio mechanical properties closer to peripheral nerves 23 . Furthermore, its good flexibility, linear degradation profile, and tunable mechanical properties in the range of soft tissues as well as excellent neural reconstruction properties make PGS preferable for nerve tissue engineering applications 24 . However, PGS because of low viscosity and inadequate chain entanglements, hardly has the potential to transform into nanofibers.…”