Polyurethanes are widely used in the development of medical devices due to their biocompatibility, degradability, non-toxicity and chemical versatility. Polyurethanes were obtained from polyols derived from castor oil, and isophorone diisocyanate, with the incorporation of polycaprolactone-diol (15% w/w) and chitosan (3% w/w). The objective of this research was to evaluate the effect of the type of polyol and the incorporation of polycaprolactone-diol and chitosan on the mechanical and biological properties of the polyurethanes to identify the optimal ones for applications such as wound dressings or tissue engineering. Polyurethanes were characterized by stress-strain, contact angle by sessile drop method, thermogravimetric analysis, differential scanning calorimetry, water uptake and in vitro degradation by enzymatic processes. In vitro biological properties were evaluated by a 24 h cytotoxicity test using the colorimetric assay MTT and the LIVE/DEAD kit with cell line L-929 (mouse embryonic fibroblasts). In vitro evaluation of the possible inflammatory effect of polyurethane-based materials was evaluated by means of the expression of anti-inflammatory and proinflammatory cytokines expressed in a cellular model such as THP-1 cells by means of the MILLIPLEX^® MAP kit. The modification of polyols derived from castor oil increases the mechanical properties of interest for a wide range of applications. The polyurethanes evaluated did not generate a cytotoxic effect on the evaluated cell line. The assessed polyurethanes are suggested as possible candidate biomaterials for wound dressings due to their improved mechanical properties and biocompatibility.

Diabetes mellitus, a chronic and non-transmissible disease, triggers a wide range of micro- and macrovascular complications. The differentiation of pancreatic β-like cells (PβLCs) from induced pluripotent stem cells (iPSCs) offers a promising avenue for regenerative medicine aimed at treating diabetes. Current differentiation protocols strive to emulate pancreatic embryonic development by utilizing cytokines and small molecules at specific doses to activate and inhibit distinct molecular signaling pathways, directing the differentiation of iPSCs into pancreatic β cells. Despite significant progress and improved protocols, the full spectrum of molecular signaling pathways governing pancreatic development and the physiological characteristics of the differentiated cells are not yet fully understood. Here, we report a specific combination of cofactors and small molecules that successfully differentiate iPSCs into PβLCs. Our protocol has shown to be effective, with the resulting cells exhibiting key functional properties of pancreatic β cells, including the expression of crucial molecular markers (pdx1, nkx6.1, ngn3) and the capability to secrete insulin in response to glucose. Furthermore, the addition of vitamin C and retinoic acid in the final stages of differentiation led to the overexpression of specific β cell genes.

Several polyurethane-formulated films with curcumin and/or chitosan additives for food packaging have been previously obtained. The study examines the effect of the additives on the film’s morphological, mechanical, barrier, and migration properties. Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), water contact angle, thermogravimetric and differential thermal analysis (TGA and DTGA), differential scanning calorimetry (DSC), dynamic mechanical thermal analysis (DMTA), oxygen transmission rate (OTR), water vapor transmission rate (WVTR), and the overall and specific migration tests were conducted. The results show that the presence of chitosan significantly increased the overall migration and mechanical properties, such as the elongation at break, tensile strength, and Young’s modulus of most polyurethane formulations, while curcumin had a minor influence on the mechanical performance. Based on the results, formulations with curcumin but without chitosan are suitable for food packaging.

Applications of polyurethanes (PUs) depend on several physicochemical factors due to the presence of varied monomers involving several ratios. The present study aimed to synthesize various chitosan/heparin-inserted PUs to examine the addition effect on the mechanical and biological properties of the PU-based polymeric material. The PUs were synthesized from unmodified castor oil and isophorone diisocyanate, including chitosan and heparin as fillers. The FTIR, thermal, and mechanical characterization of materials with and without fillers exhibited properties that can be considered within the accepted values. In addition, considering the non-cytotoxicity and antibacterial activity, these synthesized polymers can be exploited as biomaterials. The results also showed that these PUs offer a competitive advantage over other materials since the observed good mechanical and biological properties were found to be within the optimal range for the biomaterial design to myocardial or vascular tissue engineering. Graphical abstract

Cheese ripening is a time-consuming process that can lead to spoilage and product loss. The objective of this study was to evaluate the spoilage of Mozzarella-type cheese over 14 days at 4 °C, packaged with polyurethane-based films containing curcumin as an antioxidant agent. A series of physicochemical analyses were conducted, including lipid, crude fiber, and crude protein content, as well as color measurements, weight loss, moisture content, water activity, pH, titratable acidity, total and non-protein nitrogen, proteolysis index, and cheese oxidation (measured by thiobarbituric acid reactive substances—TBARS). Additionally, microbiological tests were performed to assess mesophilic bacteria, total coliforms, fungi, and yeasts. The results indicated that the polyurethane-based packaging helped maintain the Mozzarella-type cheese’s weight by significantly reducing water loss; after 14 days, the packaged cheese reached a weight loss of approximately 3%, compared to 27% of unpackaged cheese. However, that also increased moisture retention inside the package, which accelerated Mozzarella-type cheese spoilage compared to the negative control. The moisture content of packaged cheese was maintained at approximately 42%, compared to 22% of unpackaged cheese. Furthermore, the polyurethane-based films with curcumin did not exhibit any significant antioxidant effect on the cheese. It can be concluded that these polyurethane-based films are not suitable for foods with high moisture content.

Polyurethanes are versatile polymers that are frequently utilized in biomedical devices. To improve biocompatibility and antibacterial performance for the development of cardiovascular devices, we present in this study the novel synthesis of polyurethanes modified with chitosan grafted with gallic acid. Using castor oil and isophorone diisocyanate, the prepolymer method was used to create the polyurethanes. Heparin (0.05 and 0.1 weight percent) and chitosan-gallic acid conjugates (1, 2, and 3 weight percent) were also added. Tensile testing, DSC, and TGA were used to assess mechanical and thermal properties, While FTIR and SEM were used for structural and surface characterizations. The materials interacted favorably with l-929 fibroblast cells and demonstrated enhanced mechanical resistance and thermal stability. Furthermore, hemocompatibility tests and antibacterial assays against Escherichia coli and MRSA validated their potential for biomaterials. One promising method for creating next-generation polyurethanes with improved biological functionality for cardiovascular applications is functionalization using gallic acid-grafted chitosan. Graphical abstract