Poly(ester amide)s from Poly(ethylene terephthalate) Waste for Enhancing Bone Regeneration and Controlled Release

Abstract

The present study elucidates the facile synthesis and exceptional properties of a family of novel poly(ester amide)s (PEAs) based on bis(2-hydroxy ethylene) terephthalamide that was obtained from the poly(ethylene terephthalate) waste. Fourier transform infrared and H NMR were used to verify the presence of ester and amide in the polymer backbone. Differential scanning calorimetry data showed that the glass transition temperature decreased with as the chain length of dicarboxylic acids increased. Dynamic mechanical analysis and contact angle studies proved that the modulus values and hydrophobicity increased with as the chain lengths of dicarboxylic acids increased. In vitro hydrolytic degradation and dye release studies demonstrated that the degradation and release decreased with as the chain lengths of dicarboxylic acids increased. Modeling these data illustrated that degradation and release follow first-order degradation and zero-order release, respectively. The in vitro cytocompatibility studies confirmed the minimal toxicity characteristic of these polymers. Osteogenic studies proved that these polymers can be highly influential in diverting the cells toward osteogenic lineage. Alizarin red staining evinced the presence of twice the amount of calcium phosphate deposits by the cells on these polymers when compared to the control. The observed result was also corroborated by the increased expression of alkaline phosphatase. These findings were further validated by the markedly higher mRNA expressions for known osteogenic markers using real time polymerase chain reaction. Therefore, these polymers efficiently promoted osteogenesis. This study demonstrates that the physical properties, degradation, and release kinetics can be altered to meet the specific requirements in organ regeneration as well as facilitate simultaneous polymer resorption through control of the chain length of the monomers. The findings of this study have significant implications for designing cost-effective biodegradable polymers for tissue engineering.

Chemical upcycling of poly(ethylene terephthalate) waste: Moving to a circular model

“…The degradation and release of this material was also conditioned by the length of the dicarboxylic acid group, decreasing with increasing acid content in the chain. Moreover, the viability tests carried out confirmed the cytocompatibility of these polymers, essential for medical applications 49 …”

Recent Advances of Poly(ester amide)s-Based Biomaterials

“…Laura Elomaa et al reported a type of photo-cross-linkable PEAs derived from ε-CLO and l -Ala-derived depsipeptide that could boost the osteogenic activity of pluripotent cells to some extent likewise . Besides, other soybean oil- or bis­(2-hydroxy ethylene) terephthalamide-based PEAs were also successively developed by Janeni Natarajan et al and Krishanu Ghosal et al ,, Except for the outstanding physicochemical, mechanical, and biocompatible characteristics, osteogenic studies revealed that cells deposited on the PEAs could be more tendentiously diverted to osteogenic lineages with higher osteogenic marker mRNA expressions, increasing alkaline phosphatase expressions and more calcium phosphate minerals deposits than the control. And the PEAs could have tunable properties and supplementary functions such as eluting drugs and controlled release for optimally meeting the clinical demands.…”

Incorporation of Glutamic Acid or Amino-Protected Glutamic Acid into Poly(Glycerol Sebacate): Synthesis and Characterization

“…Poly(ester amide)s that integrate the excellent thermal and mechanical properties of polyamides with the biocompatibility and biodegradability of polyesters have gained increasing attention for medical applications, including use as scaffolds for tissue engineering [ 38 , 39 , 40 ]. In this study, L-glutamic acid was incorporated into a PGS network with an aim to retard the degradation rate of PGS through the formation of peptide bonds.…”