Characterization, degradation, and mechanical strength of poly(D,L‐lactide‐co‐ϵ‐caprolactone)‐poly(ethylene glycol)‐poly(D,L‐lactide‐co‐ϵ‐caprolactone)

Abstract

A series of three biocompatible P(CL-co-LA)-PEG-P(CL-co-LA) copolymers were synthesized using ring-opening polymerization and characterized by 1H-NMR, gel permeation chromatography, DSC, dynamic-mechanical analysis, and X-ray diffraction. The number of monomer units was kept constant, while the D,L-LA fraction was varied so as to constitute 0, 30, or 70% of the end segments. The molecular weights were sufficiently high to eventually permit 3D scaffold preparation. A degradation study was carried out over 26 weeks, and the effect of monomer composition on the rate of degradation as well as on changes in mechanical strength was investigated. Pure polycaprolactone (PCL)-poly(ethylene glycol) (PEG)-PCL copolymer, P(100/0), was a crystalline material displaying no measurable mass loss, a 30% reduction in mean molecular weight (Mn), and only very slight changes in tensile strength. The random incorporation of 30 and 70% D,L-LA into the end sections of the polymer chain, produced more and more amorphous materials, exhibiting increasingly high rates of degradation, mass loss, and loss of tensile strength. Compared with random P(CL-co-LA), the presence of the PEG block was found both to improve hydrophilicity and thus the rate of degradation and to infer a stabilizing quality, thereby pacing the decrease in tensile strength during degradation. The tested copolymers range from materials exhibiting low mechanical strength and high rate of degradation to slow-degrading materials with high mechanical strength suitable, e.g., for three-dimensional scaffolding.

Embroidered and Surface Modified Polycaprolactone-Co-Lactide Scaffolds as Bone Substitute: In Vitro Characterization

“…11,12,20,21,25,31,32 The using of embroidered scaffolds, with adequate pore size and porosity, were pervious described from Wollenweber et al 40 and Rentsch et al 30 Aliphatic polyesters such as poly(lactide) and poly (e-caprolactone) have attracted considerable attention in biomedicine because of their biodegradability and biocompatibility. 32 Copolymers of poly(lactide) and poly(e-caprolactone) have proved to be useful in a number of biomedical applications including surgical sutures, 37 drug delivery, 6 and nerve guide channels. 9 Cell adhesion to these artificial materials is affected by their surface properties such as wettability, roughness, surface charge, and chemical functionalities.…”

Blends as a strategy towards tailored hydrolytic degradation of poly(ɛ-caprolactone-co-d,l-lactide)–poly(ethylene glycol)–poly(ɛ-caprolactone-co-d,l-lactide) co-polymers

“…All co-polymers were synthesized according to Bogdanov et al [13] as described earlier [12]. Briefly, PEG diols and monomers (3-CL and D,L-LA) were introduced into a threeneck round-bottom flask at an ethylene glycol-to-monomer molar ratio of 1:4.2.…”

“…In a recent publication, P(CLeD,L-LA)ePEGeP(CL-co-D,L-LA) co-polymers, containing 100, 70 or 30 mol% of CL in the side chains, were characterized and their degradation profiles studied [12]. The resulting materials are referred to here as P100, P70, and P30, respectively.…”

“…Using melt-moulded films, it was found that by varying the LA content in the copolymers, mechanical properties and the rate of hydrolytic degradation could be controlled. However, the degradation profiles of the three tested materials covered a very large range, and in the case of P30, rapid degradation resulted in early loss of sample integrity [12]. In view of previous results, this study was designed to answer two main questions: (1) can intermediate degradation profiles be obtained by way of copolymer blending?…”

Recent Developments in Cyclic Acetal Biomaterials for Tissue Engineering Applications

“…The bulk degradation of PCL is a slow process on the order of one to three years. In an attempt to increase its degradation rate, PCL has been increasingly used in the synthesis of co-polymers and polymer blends with poly(ethylene glycol) (PEG), poly (ethylene oxide) (PEO), poly(hydroxybutyrate-co-hydroxyvalerate) (PHBHV), PLLA and PLGA (35)(36)(37)(38).…”