Synthesis and Characterization of Biopolyol-Based Waterborne Polyurethane Modified through Complexation with Chitosan

Incorporation of Chitosan in Polyurethanes Based on Modified Castor Oil for Cardiovascular Applications

The increased demand for vascular grafts for the treatment of cardiovascular diseases has led to the search for novel biomaterials that can achieve the properties of the tissue. According to this, the investigation of polyurethanes has been a promising approach to overcome the present limitations. However, some biological properties remain to be overcome, such as thrombogenicity and hemocompatibility, among others. This paper aims to synthesize polyurethanes based on castor oil and castor oil transesterified with triethanolamine (TEA) and pentaerythritol (PE) and with the incorporation of 1% chitosan. Analysis of the wettability, enzymatic degradation, mechanical properties (tensile strength and elongation at break), and thermal stability was performed. Along with the evaluation of the cytotoxicity against mouse fibroblast (L929) and human dermal fibroblast (HDFa) cells, the hemolysis rate and platelet adhesion were determined. The castor-oil-based polyurethanes with and without 1% chitosan posed hydrophobic surfaces and water absorptions of less than 2% and enzymatic degradation below 0.5%. Also, they were thermally stable until 300 °C, with tensile strength like cardiovascular tissues. The synthesized castor oil/chitosan polyurethanes are non-cytotoxic (cell viabilities above 80%) to L929 and HDFa cells and non-thrombogenic and non-hemolytic (less than 2%); therefore, they are suitable for cardiovascular applications.

Combined use of novel chitosan-grafted N-hydroxyethyl acrylamide polyurethane and human dermal fibroblasts as a construct for in vitro-engineered skin

A rich plethora of information about grafted chitosan (CS) for medical use has been reported. The capability of CS-grafted poly(N-hydroxyethyl acrylamide) (CS-g-PHEAA) to support human dermal fibroblasts (HDFs) in vitro has been proven. However, CS-grafted copolymers lack good stiffness and the characteristic microstructure of a cellular matrix. In addition, whether CS-g-PHEAA can be used to prepare a scaffold with a suitable morphology and mechanical properties for skin tissue engineering (STE) is unclear. This study aimed to show for the first time that step-growth polymerizations can be used to obtain polyurethane (PU) platforms of CS-g-PHEAA, which can also have enhanced microhardness and be suitable for in vitro cell culture. The PU prepolymers were prepared from grafted CS, polyethylene glycol, and 1,6-hexamethylene diisocyanate. The results proved that a poly(saccharide-urethane) [(CS-g-PHEAA)-PU] could be successfully synthesized with a more suitable microarchitecture, thermal properties, and topology than CS-PU for the dynamic culturing of fibroblasts. Cytotoxicity, proliferation, histological and immunophenotype assessments revealed significantly higher biocompatibility and cell proliferation of the derivative concerning the controls. Cells cultured on (CS-g-PHEAA)-PU displayed a quiescent state compared to those cultured on CS-PU, which showed an activated phenotype. These findings may be critical factors in future studies establishing wound dressing models.