Synthesis and characterization of biodegradable elastomeric polyurethane scaffolds fabricated by the inkjet technique (original) (raw)
Related papers
Biodegradable polyurethanes: Comparative study of electrospun scaffolds and films
Journal of Applied Polymer Science, 2011
The development of elastomeric, bioresorbable, and biocompatible segmented polyurethanes (SPUs) for use in tissue-engineering applications has attracted considerable interest in recent years. In this work, nonporous films and microfiber/nanofiber scaffolds, which were prepared from two different poly(e-caprolactone)-based SPUs previously synthesized from 1,6-hexamethylene diisocyanate and novel chain extenders containing urea groups or an aromatic amino acid derivative, were studied. Their thermal properties were influenced by both the different chemical structures of the hard segments and the processing conditions. The mechanical properties of the scaffolds (the elastic modulus, ultimate strain, and tensile stress) were adequate for engineered soft-tissue constructs (e.g., myocardial tissue). The film samples displayed a low swelling degree (<2 wt %) in a phosphatebuffered solution at 37 C. The introduction of the amino acid derivative chain extender with hydrolyzable ester bonds contributed to greater degradation. The fibrous scaffolds exhibited higher hydrolytic stability than the films after short assay times because of their more crystalline structures and higher degrees of association by hydrogen bonding, but they also experienced higher mass losses under accelerated conditions (70 C). This suggested that the degradation rate was not constant but depended on the degradation time and the processing technique. V
Journal of Biomedical Materials Research Part A, 2007
The purpose of this research was to develop and characterize a novel, slowly degrading polyesterurethane. In this study, a polyesterurethane with a crystalline segment of poly((R)-3-hydroxybutyric acid)-diol linked by a diisocyanate to an amorphous segment of poly(e-caprolactone-co-glycolide)-diol was synthesized. Porous and nonporous scaffolds were processed using electrospinning and solvent casting respectively. The morphology, pore size, and filament diameter of the mesh and film were characterized using scanning electron microscopy (SEM). The thermal properties were examined using differential scanning calorimetry (DSC). A degradation study was initiated to characterize the change in mechanical properties, molecular weight, and surface morphology over 12 months using tensile testing, gel permeation chromatography (GPC), and SEM respectively. Concomi-tantly, cell morphology and viability on these variants were investigated using fibroblasts. The mechanical test data indicated a gradual decrease in the ultimate tensile strength and strain to break while the modulus of elasticity remained stable. GPC data suggested a slow decrease in the molecular weight while SEM examination revealed changed surface morphologies. The in vitro studies implied that the novel polyesterurethane was not cytotoxic and that the mesh was a more favorable scaffold towards cell viability. The summation of these results suggests that this polyesterurethane has the potential for tissue engineering applications.
Acta Biomaterialia, 2005
Many polyurethane elastomers display excellent mechanical properties and adequate biocompatibility. However, many medicalgrade polyurethanes are prepared from aromatic diisocyanates and can degrade in vivo to carcinogenic aromatic diamines, although the question of whether the concentrations of these harmful degradation products attain physiologically relevant levels is currently unresolved and strongly debated. It is therefore desirable to synthesize new medical-grade polyurethanes from less toxic aliphatic diisocyanates. In this paper, biocompatible segmented polyurethane elastomers were synthesized from aliphatic diisocyanates (1,4-diisocyanatobutane (BDI) and lysine methyl ester diisocyanate (LDI)), novel diurea diol chain extenders based on tyrosine and tyramine, and a model poly(ethylene glycol) (PEG) diol soft segment. The objectives were to design a hard segment similar in structure to that of MDI-based polyurethanes and also investigate the effects of systematic changes in structure on mechanical and biological properties. The non-branched, symmetric polyurethane prepared from BDI and a tyramine-based chain extender had the highest modulus at 37°C. Introduction of symmetric short-chain branches (SCBs) incorporated in the tyrosine-based chain extender lowered the modulus by an order of magnitude. Polyurethanes prepared from LDI were soft polymers that had a still lower modulus due to the asymmetric SCBs that hindered hard segment packing. Polyurethanes prepared from tyramine and tyrosine chain extenders thermally degraded at temperatures ranging from 110 to 150°C, which are lower than that reported previously for phenyl urethanes. All four polyurethanes supported the attachment, proliferation, and high viability of MG-63 human osteoblast-like cells in vitro. Therefore, the non-cytotoxic chemistry of these polyurethanes make them good candidates for further development as biomedical implants.
Polymer Degradation and Stability, 2019
Studies described in this work were related to the bulk synthesis and characterization of polyurethanes (PURs) obtained with the use of cyclic 4,4'-methylene bis(cyclohexyl isocyanate) (HMDI) or linear 1,6-hexamethylene diisocyanate (HDI), amorphous α,ω-dihydroxy(ethylenebutylene adipate) macrodiol (PEBA), 1,4-butandiol (BDO) chain extender and dibutyltin dilaurate (DBTDL) catalyst. Obtained PURs were modified with L-ascorbic acid (AA). Raw materials and modifier improving biocompatybility were carefully selected due to the planned use of obtained PURs as a tissue scaffold fabrication material. Performed chemical structure studies (FTIR, ATR-IR, 2D NMR), morphology observations (SEM, TEM and AFM) and characterization of degradation profile revealed that PURs obtained by using HDI were representing a significantly better characteristic than those obtained by using HMDI. Thus, the HDI-based PURs were suggested for further development as a materials useful for tissue scaffolds fabrication in the field of tissue engineering.
Colloid and Polymer Science, 2020
Polyurethane (PU) elastomers were synthesized by the reaction of HDI or IPDI diisocyanates and poly(ε-caprolactone) (PCL or poly(ethylene adipate) (PA) diols and ethylene glycol as a polymer chain extender. IR, 1H, and 13C NMR spectroscopy and X-ray analysis were used for the structural analysis of the formed films. The molecular weight distribution was examined by GPC chromatography. Based on the measured contact angles, free surface energy parameters were calculated. The obtained results were analyzed for the possible use of these polyurethanes as biomaterials. The most promising in this respect was PU-3, which was synthesized from IPDI and PCL. This was due to its high molecular weight of approximately 90,000, the presence of a crystalline phase, and the relatively high hydrophobicity, with a SEP value below 25 mJ/m2. These films showed a good resistance to hydrolysis during incubation in Baxter physiological saline during 6 weeks. Both Gram-positive (Bacillus sp.) and Gram-negat...
Pharmaceutical Research, 2008
Purpose-The purpose of this work was to investigate the effects of triisocyanate composition on the biological and mechanical properties of biodegradable, injectable polyurethane scaffolds for bone and soft tissue engineering. Methods-Scaffolds were synthesized using reactive liquid molding techniques, and were characterized in vivo in a rat subcutaneous model. Porosity, dynamic mechanical properties, degradation rate, and release of growth factors were also measured. Results-Polyurethane scaffolds were elastomers with tunable damping properties and degradation rates, and they supported cellular infiltration and generation of new tissue. The scaffolds showed a two-stage release profile of platelet-derived growth factor, characterized by a 75% burst release within the first 24 h and slower release thereafter. Conclusions-Biodegradable polyurethanes synthesized from triisocyanates exhibited tunable and superior mechanical properties compared to materials synthesized from lysine diisocyanates. Due to their injectability, biocompatibility, tunable degradation, and potential for release of growth factors, these materials are potentially promising therapies for tissue engineering.
Journal of materials science. Materials in medicine, 2016
The development of elastomeric, bioresorbable and biocompatible segmented polyurethanes (SPUs) for use in tissue-engineering applications has attracted considerable interest because of the existing need of mechanically tunable scaffolds for regeneration of different tissues, but the incorporation of osteoinductive molecules into SPUs has been limited. In this study, SPUs were synthesized from poly (ε-caprolactone)diol, 4,4'-methylene bis(cyclohexyl isocyanate) using biologically active compounds such as ascorbic acid, L-glutamine, β-glycerol phosphate, and dexamethasone as chain extenders. Fourier transform infrared spectroscopy (FTIR) revealed the formation of both urethanes and urea linkages while differential scanning calorimetry, dynamic mechanical analysis, X-ray diffraction and mechanical testing showed that these polyurethanes were semi-crystalline polymers exhibiting high deformations. Cytocompatibility studies showed that only SPUs containing β-glycerol phosphate suppor...
Macromolecular Bioscience, 2013
Hyperbranched polyurethanes are synthesized using TDI, PCL diol, butanediol, and pentaerythritol (1-5 wt%) as the B 4 reactant with and without the monoglyceride of sunflower oil. The biodegradation, physico-mechanical, and thermal properties are found to be tailored by varying the percentage weight of the branching unit. An MTT/hemolytic assay and subcutaneous implantation in Wistar rats followed by cytokine/ALP assay and histopathology studies confirm a better biocompatibility of HBPU with MG than without MG. HBPU supports the proliferation of dermatocytes with no toxic effect in major organs, in addition the in vitro degraded products are non-toxic. Cell adherence and proliferation endorse the bio-based HBPU as a prospective scaffold material in the niche of tissue engineering.
Biomaterials, 2011
A degradable, polar/hydrophobic/ionic polyurethane (D-PHI) scaffold was optimized in in vitro studies to yield mechanical properties appropriate to replicate vascular graft tissue while eliciting a more woundhealing phenotype macrophage when compared to established materials. The objectives of this study were to characterize the biodegradation (in vitro and in vivo) and assess the in vivo biocompatibility of D-PHI, comparing it to a well-established, commercially-available scaffold biomaterial, polylactic glycolic acid (PLGA), recognized as being degradable, non-cytotoxic, and showing good biocompatibility. PLGA and D-PHI were formed into 6 mm diameter disk-shaped scaffolds (2 mm thick) of similar porosity (w82%) and implanted subcutaneously in rats. Both PLGA and D-PHI scaffolds were well-tolerated at the 7 d time point in vivo. In vitro D-PHI scaffolds degraded slowly (only 12 wt% in PBS in vitro after 120 d at 37 C). In vivo, D-PHI scaffolds degraded at a more controlled rate (7 wt% loss over the acute 7 d implant phase and subsequently a linear profile of degradation leading to a 21 wt% mass loss by 100 d (chronic period)) than PLGA scaffolds which showed an initial more rapid degradation (14 wt% over 7 d), followed by minimal change between 7 and 30 d, and then a very rapid breakdown of the scaffold over the next 60 d. Histological examination of D-PHI scaffolds showed tissue ingrowth into the pores increased with time whereas PLGA scaffolds excluded cells/tissue from its porous structure as it degraded. The results of this study suggest that D-PHI has promising qualities for use as an elastomeric scaffold material for soft TE applications yielding well integrated tissue within the scaffold and a controlled rate of degradation stabilizing the form and shape of the implant.