Influence of hydrophilic/hydrophobic diols on the properties of polyurethane hydrogels: A solvent-free one-pot synthesis

Abstract

We report here on the design and synthesis of bio-degradable porous polyurethane hydrogels developed by a green, solvent-free technique that is capable of withstanding physiological mechanical loads which can aid in tissue regeneration. The hydrophilic/hydrophobic nature of hydrogel was tuned using diols such as polycaprolactone diol (PCL), polycarbonate diol (PCD), in combination with polyethylene glycol (PEG, MW ≈ 4000 g/mol), and 4,4’- methylene bis(cyclohexyl isocyanate) (H12MDI) and hexanetriol (HT) which served as the crosslinking agent. The structural characterizations of hydrogels were performed using FT-IR and 1H, 13C HR-MAS spectroscopy. The utilization of various diols in the synthesis of hydrogels enabled precise control over crystallinity, pore sizes, and the customization of mechanical and degradation properties. These hydrogels exhibited the tensile strength in the range of 0.22-2.82 MPa, while the compressive strength varied between 0.92 to 29.3 MPa. In vitro degradation profiles in the presence and absence of the enzyme Amino Lipase PS, revealed that the degradation process is contingent upon the specific diol present in the hydrogel. Furthermore, preliminary in vitro biological experiments confirmed the biocompatibility of the gels, indicating their potential as suitable substrates for drug delivery applications. This diverse library of gels can also be shaped into specific forms, highlighting their promising applications as scaffolds and implants in both drug delivery systems and tissue engineering.