Synthesis, Characterization, and Electrospinning of a Functionalizable, Polycaprolactone-Based Polyurethane for Soft Tissue Engineering

Abstract

We synthesized a biodegradable, elastomeric, and functionalizable polyurethane (PU) that can be electrospun for use as a scaffold in soft tissue engineering. The PU was synthesized from polycaprolactone diol, hexamethylene diisocyanate, and dimethylolpropionic acid (DMPA) chain extender using two-step polymerization and designated as PU-DMPA. A control PU using 1,4-butanediol (1,4-BDO) as a chain extender was synthesized similarly and designated as PU-BDO. The chemical structure of the two PUs was verified by FT-IR and 1H-NMR. The PU-DMPA had a lower molecular weight than the PU-BDO (~16,700 Da vs. ~78,600 Da). The melting enthalpy of the PU-DMPA was greater than that of the PU-BDO. Both the PUs exhibited elastomeric behaviors with a comparable elongation at break (λ=L/L0= 13.2). The PU-DMPA had a higher initial modulus (19.8 MPa vs. 8.7 MPa) and a lower linear modulus (0.7 MPa vs. 1.2 MPa) and ultimate strength (9.5 MPa vs. 13.8 MPa) than the PU-BDO. The PU-DMPA had better hydrophilicity than the PU-BDO. Both the PUs displayed no cytotoxicity, although the adhesion of human umbilical artery smooth muscle cells on the PU-DMPA surface was better. Bead free electrospun PU-DMPA membranes with a narrow fiber diameter distribution were successfully fabricated. As a demonstration of its functionalizability, gelatin was conjugated to the electrospun PU-DMPA membrane using carbodiimide chemistry. Moreover, hyaluronic acid was immobilized on the amino-functionalized PU-DMPA. In conclusion, the PU-DMPA has the potential to be used as a scaffold material for soft tissue engineering.

Elastomeric Polyesters in Cardiovascular Tissue Engineering and Organs-on-a-Chip

“…Electrospinning is a process in which electrically charged streams of dissolved polymers are subjected to a high-voltage electric field, resulting in the production of elongated nanofibers as the solvents evaporate. Various polymers have been electrospun to create scaffolds with tunable mechanical properties and high porosity. − However, for soft tissue engineering, only a few candidates such as PGS, have been shown to be adaptable to the electrospinning process. ,− The fabrication of PGS via electrospinning is challenging due to its low molecular weight and limited number of organic solvents that can dissolve cured PGS . The addition of spinnable polymers such as PCL, , poly­(methyl methacrylate) (PMMA), polyvinyl chloride (PVA), , or PLLA have been explored to overcome these challenges (Figure a).…”

“…The addition of spinnable polymers such as PCL, , poly­(methyl methacrylate) (PMMA), polyvinyl chloride (PVA), , or PLLA have been explored to overcome these challenges (Figure a). Electrospinning of POC/PLCL or POC/PCL composites as well as soft polyester-urethane , have also shown a potential in the fabrication of soft scaffolds. Laser ablation involves using brief laser bursts in the ultraviolet spectrum to rupture polymer chains, creating photoablated cavities .…”

Advances in Electrostatic Spinning of Polymer Fibers Functionalized with Metal-Based Nanocrystals and Biomedical Applications

“…By virtue of the aforementioned advantages of electrospun nanofibers, such as nanoscale size, high porosity and large specific surface area, their potential applications have been widely studied in many fields [ 5 , 6 , 7 , 8 , 9 , 10 , 11 ]. Specifically, nontoxic electrospun nanofibers were regarded as promising candidates for biomedicines [ 23 , 24 , 25 , 26 , 27 , 28 ], with adjustable properties, such as drug release, wound dressing, tissue engineering and trauma repair.…”

“…Due to the aforementioned properties, electrospun fibers have promising applications in the field of biomedical materials, especially in the controlled release of compounds in drug delivery [ 23 , 24 ], scaffolds in tissue engineering [ 25 , 26 ] and wound dressings [ 27 , 28 ]. The number of publications on the bio-application of electrospinning technology also keeps increasing in the most recent 20 years, as shown in Figure 1 B.…”

Synthesis of Sucrose-HDI Cooligomers: New Polyols for Novel Polyurethane Networks

“…Such properties include, e.g., mechanical and thermomechanical properties as well as biocompatibility and biodegradability. Thus, PUs based on polyesters such as polycaprolactones have gained considerable interest as biodegradable polymers [3][4][5]. In addition, semi-crystalline polycaprolactones (PCL) provide good flexibility [6] and often act as switching components in shape memory polymers (SMPs).…”