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14Prosthetic cardiac valves implantation is a common procedure used to treat heart 15 valve diseases. Although there are different prosthesis already available in the market 16 (either mechanical or bioprosthetic), their use presents several problems, specifically 17 concerning thrombogenicity and structural failure. Recently, some progresses have 18 been achieved in developing heart valves based on synthetic materials with special 19 emphasis in polymers. Among them, polyurethanes are one of the most commonly 20 used for the production of these devices. 21Herein, Elastollan ® 1180A50, a thermoplastic polyurethane (TPU), was used to 22 formulate films whose surfaces were modified by grafting 2-23 hydroxyethylmethacrylate (HEMA) either by Ultra-violet (UV) or by plasma 24 treatment. All films were analyzed before and after grafting. X-ray photoelectron 25 spectroscopy (XPS) measurements were used to evaluate TPU surfaces 26 functionalization. HEMA grafting was confirmed by the increase of the hydroxyl 27 (OH) groups' concentration at the surface of the films. Atomic force microscopy 28 (AFM) analysis was done to evaluate the surface topography of the biomaterials. 29Results showed that the roughness of the surface decreased when HEMA was grafted, 30 especially for plasma treated samples. 31After grafting the films' hydrophilicity was improved, as well as the polar component 32 of the surface energy, by 15 to 30%. Hydrophobic recovery studies using milli Q 33 water or PBS were also performed to characterize the stability of the modified 34 surface, showing that the films maintained their surface properties along time. 35Furthermore, blood-contact tests were performed to evaluate haemolytic and 36 thrombogenic potential. The results obtained for HEMA grafted surfaces, using 37 plasma treatment, confirmed biomaterials biocompatibility and low thrombogenicity. 38

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Embedded bio-printing has fostered significant advances toward the fabrication of soft complex tissue-like constructs, by providing a physical support that allows the freeform shape maintenance within the prescribed spatial arrangement, even under gravity force. Current supporting materials still present major drawbacks for up-scaling embedded 3D bio-printing technology towards tissue-like constructs with clinically relevant dimensions. Herein, we report a a cost-effective and widely available supporting material for embedded bio-printing consisting on a continuous pseudo-plastic matrix of xanthan-gum (XG). This natural polisaccharide exhibits peculiar rheological properties that have enabled the rapid generation of complex volumetric 3D constructs with out-of-plane features. The freedom of design within the three orthogonal axes through the independent and controlled bio-printing process opens new opportunities to produce on demand large arbitrary shapes for personalized medicine. Additionally, we have demonstrated the versatile functionality of XG as a photocurable gel reservoir to engineer perfused cell-laden hydrogel constructs, addressing other practical biomedical applications such as in vitro models and organ-on-chip platforms.

Bioinspired and adhesive multilayer membranes are produced using the layer-by-layer (LbL) assembly of chitosan (CHT), alginate (ALG) and hyaluronic acid modified with dopamine (HA-DN). Freestanding multilayer membranes without DN are also produced as a control. The success of the synthesis of HA-DN was confirmed using UV-visible spectroscopy. Scanning electron microscopy images indicate that the surface of the DN-containing membranes is more porous than the control ones; they also present a higher average thickness value for the same number of CHT/ALG/CHT/HA(-DN) tetralayers (n = 100). Also, water uptake, mechanical strength and adhesion are enhanced with the introduction of DN moieties along the nano-layers. Besides, human dermal fibroblast viability, enhanced adhesion and proliferation were confirmed by immunofluorescence assays and by measuring both the metabolic activity and DNA content. Moreover, in vivo assays with such kinds of DN-containing multilayer membranes were performed; the application of these membranes in the treatment of dermal wounds induced in Wistar rats results in the highest decrease of inflammation of rat skin, compared with the control conditions. Overall, this investigation suggests that these mussel-inspired freestanding multilayer membranes may enhance either their mechanical performance or cellular adhesion and proliferation, leading to an improved wound healing process, being a promising material to restore the structural and functional properties of wounded skin.