Biomimetic Polyurethane 3D Scaffolds Based on Polytetrahydrofuran Glycol and Polyethylene Glycol for Soft Tissue Engineering

Abstract

In this study, a novel polyurethane porous 3D scaffold based on polyethylene glycol (PEG) and polytetrahydrofuran glycol (PTMG) was developed by in situ polymerization and freeze drying. Aliphatic hexamethylene diisocyanate (HDI) as a nontoxic and safe agent was adopted to produce the rigid segment in polyurethane polymerization. The chemical structure, macrostructure, and morphology—as well as mechanical strength of the scaffolds—were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscope (SEM), and tensile tests. The results show that the HDI can react mildly with hydroxyl (–OH) groups of PEG and PTMG, while gas foaming action caused by the release of CO2 occurred simultaneously in the reactive process, resulting in a uniform porous structure of PU scaffold. Moreover, the scaffolds were soaked in water and freeze dried to obtain higher porosity and more interconnective microstructures. The scaffolds have a porosity of over 70% and pore size from 100 to 800 μm. The mechanical properties increased with increasing PEG content, while the hydrophilicity increased as well. After immersion in simulated body fluid (SBF), the scaffolds presented a stable surface structure. The gas foaming/freezing drying process is an excellent method to prepare skin tissue engineering scaffold from PTMG/PEG materials with high porosity and good inter connectivity.

Thermally stable poly(urethane‐imide)s with enhanced hydrophilicity for waterproof‐breathable textile coatings

“…All the PUIs exhibit broad halos at 2θ ~ 6° and 2θ ~ 20–21°, however, the width of these diffraction peaks is narrower as compared to PU, which is indicative of a slightly higher degree of order. The presence of a small peak at 2θ ~ 23° in the diffraction pattern of PUI46 indicates partial crystallization of soft segments associated with PEG 43,44 . This crystallization of the PEG‐based soft segment is also evidenced as a distinct melting peak at 20 °C in the DSC trace of PUI46 (Figure 7).…”

“…The presence of a small peak at 2θ ~23 in the diffraction pattern of PUI46 indicates partial crystallization of soft segments associated with PEG. 43,44 This crystallization of the PEG-based soft segment is also evidenced as a distinct melting peak at 20 C in the DSC trace of PUI46 (Figure 7).…”

Three-Dimensional Printing Strategies for Irregularly Shaped Cartilage Tissue Engineering: Current State and Challenges

“…In addition, PU is thermally sensitive and exhibits a sol-gel transition at 37°C ( Hsieh and Hsu., 2015 ). As a result, it has been used to fabricate scaffolds in some soft tissue engineering experiments ( Luo K. et al, 2020 ; Farzan et al, 2020 ). PU is widely used in various fields of 3D printing by way of fused fiber fabrication (FFF), bio-plotting, SLA ( Griffin et al, 2020 ), and FDM ( Xiao and Gao., 2017 ).…”

Engineering bioactive synthetic polymers for biomedical applications: a review with emphasis on tissue engineering and controlled release

“…One frequently used strategy to produce open cell foams from polyurethane is to use CO 2 as a blowing agent. 128 CO 2 can be generated during the polymerization of urethane by adding water to the reaction mix in the presence of isocyanates.…”