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Wound healing is a biological process that requires a complex regulation to maintaining the function of skin. However, many factors can alter this process, resulting in non-healing wounds. An option for the treatment of this kind of wound is the use of stem cell secretome (S), since it has been shown that it promotes the tissue repair-regeneration processes. For this reason, this work focused on develop a polymeric matrix in hydrogel state, based on jellyfish collagen (CLG), polyurethane and S from mesenchymal stem cells (MSCs) from human amniotic membrane, and its in vitro evaluation in wound closure. Two types of polyurethane matrix were analyzed; the first one was crosslinking with polyurethane derived from hexamethylene diisocyanate (HDI), and the second one was crosslinking with polyurethane derived from isophorone diisocyanate (IPDI), giving rise to two different polymeric matrices, CLG-P(HDI)-S and CLG-P(IPDI)-S containing 0.5 wt.% of S for each matrix. The results suggest that the incorporation to S in the polymeric matrices generates interactions in the hydrogel state matrices, promoting amorphous surfaces, which seems to indicate that the S is encapsulated by physical or electrostatic interactions with polymeric chains. The CLG-P(HDI)-S showed a spherical structure, while the CLG-P(IPDI)-S exhibited a planar structure, which is related to the chemical structure of polyurethane crosslinker, these structural characteristics gave the polymeric matrices, suitable physicochemical, mechanical and biological properties for accelerating the wound healing process in an in vitro scratch assay, and thus could be a promising scaffold for wound management for non-healing wounds. Graphical abstract

The modification of collagen derived from jellyfish to generate hydrogels with high biocompatibility is in recent trend, since this type of collagen does not present allergenic effects or transmission of zoonosis in humans. Therefore, developing novel strategies that allow tailoring their properties for regenerative medicine and biomedical applications is a current research challenge. In this work, the generation of interpenetrating polymeric matrices (IPN) in the hydrogel state composed of jellyfish collagen ( C. andromeda ) and polyurethane is proposed; for this, dispersions of trifunctional polyurethane prepolymers (TPU) derived from glycerol ethoxylate and hexamethylene diisocyanate (P(HDI)) or isophorone diisocyanate (P(IPDI)) are used as interpenetrating agents for marine collagen chains. The evaluation of the structural modification produced by the chemical structure of the TPU on the properties and the in vitro biocompatibility of the matrices in the hydrogel state is addressed. The results indicate that IPN hydrogels based on P(HDI) show a structure based on microspheric agglomerates with interconnected porosity, while those generated from P(IPDI) exhibit a smooth structure with irregular porosity. The interpenetration of jellyfish collagen with P(HDI) produces an improvement in the storage modulus of 16,972%, enhancing the swelling in acidic, physiological and basic media; as well as delaying proteolytic degradation. Both novel matrices do not present cytotoxic effects for monocytes and fibroblasts, evaluated for up to 48 h of incubation, indicating that they have excellent in vitro biocompatibility, in addition they present enhanced hemocompatility and capacity to inhibit the growth of E. coli ; due to this, these matrices in hidrogel state can be applied in strategies for the design of dressings for regenerative medicine applications.

The preparation of hydrogels based on biopolymers like collagen and gum arabic gives a chance to provide novel options that can be used in biomedical field. Through a polymeric semi-interpenetration technique, collagen-based polymeric matrices can be associated with gum arabic while controlling its physicochemical and biological properties. To create novel hydrogels with their potential use in the treatment of wounds, the semi-interpenetration process, altering the concentration (0–40% by wt) of gum arabic in a collagen matrix is explored. The ability of gum arabic to create intermolecular hydrogen bonds in the collagen matrix enables the development of semi-interpenetrating polymeric networks (semi-IPN)-based hydrogels with a faster gelation time and higher crosslinking. Amorphous granular surfaces with linked porosity are present in matrices with 30% (by wt) of gum arabic, enhancing the storage modulus and thermal degradation resistance. The hydrogels swell to very high extent in hydrolytic and proteolytic environments, good hemocompatibility, and suppression of growth of pathogens like E. coli, and all it is enhanced by gum arabic included them, in addition to enabling the controlled release of ketorolac. The chemical composition of theses semi-IPN matrices have no deleterious effects on monocytes or fibroblasts, promoting their proliferation, and lowering alpha tumor necrosis factor (α-TNF) secretion in human monocytes. Graphical abstract

The contamination of water by Pb2+ ions is a problem that requires an imminent solution. Design of hydrogels based on polymers as well as inorganic phases is an innovative alternative for the generation of matrices with adapted properties. This work proposes the synthesis of a novel composite hydrogel based on collagen-polyurethane-chitosan reinforced with manganite; this inorganic phase increases the velocity of the adsorption process of the Pb2+ ions. The effect of the concentration of manganite on the properties of composite hydrogels is studied. The results indicate that the composite reinforced with manganite presents an amorphous structure, improved mechanical properties and resistance to the both acidic and proteolytic degradation. The hydrogel with 35 wt% of manganite show a removal rate of Pb2+ of 91 ± 6% at 24 h. These hydrogel composites could represent an efficient and sustainable alternative for the removal of Pb2+ ions from contaminated water.Graphic Abstract