Collagen-ß-cyclodextrin hydrogels for advanced wound dressings: super-swelling, antibacterial action, inflammation modulation, and controlled drug release.

A key strategy in enhancing the efficacy of collagen-based hydrogels involves incorporating polysaccharides, which have shown great promise for wound healing. In this study, semi-interpenetrating polymeric network (semi-IPN) hydrogels comprised of collagen (Col) with the macrocyclic oligosaccharide ß-cyclodextrin (ß-CD) (20-80 wt.%) were synthesised. Fourier-transform infrared (FTIR) spectroscopy confirmed the successful fabrication of these Col/ß-CD hydrogels, evidenced by the presence of characteristic absorption bands, including the urea bond band at ∼1740 cm-1, related with collagen crosslinking. Higher ß-CD content was associated with increased crosslinking, higher swelling, and faster gelation. The ß-CD content directly influenced the morphology and semi-crystallinity. All Col/ß-CD hydrogels displayed superabsorbent properties, enhanced thermal stability, and exhibited slow degradation rates. Mechanical properties were significantly improved with contents higher than ß-CD 40 wt.%. These hydrogels inhibited the growth of Escherichia coli bacteria and facilitated the controlled release of agents, such as malachite green, methylene blue, and ketorolac. The chemical composition of the Col/ß-CD hydrogels did not induce cytotoxic effects on monocytes and fibroblast cells. Instead, they actively promoted cellular metabolic activity, encouraging cell growth and proliferation. Moreover, cell signalling modulation was observed, leading to changes in the expression of TNF-α and IL-10 cytokines. In summary, the results of this research indicate that these novel hydrogels possess multifunctional characteristics, including biocompatibility, super-swelling capacity, good thermal, hydrolytic, and enzymatic degradation resistance, antibacterial activity, inflammation modulation, and the ability to be used for controlled delivery of therapeutic agents, indicating high potential for application in advanced wound dressings.

Semi-IPN hydrogels of collagen and gum arabic with antibacterial capacity and controlled release of drugs for potential application in wound healing.

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.

Highly absorbent hydrogels comprised from interpenetrated networks of alginate-polyurethane for biomedical applications.

Developing new approaches to improve the swelling, degradation rate, and mechanical properties of alginate hydrogels without compromising their biocompatibility for biomedical applications represents a potential area of research. In this work, the generation of interpenetrated networks (IPN) comprised from alginate-polyurethane in an aqueous medium is proposed to design hydrogels with tailored properties for biomedical applications. Aqueous polyurethane (PU) dispersions can crosslink and interpenetrate alginate chains, forming amide bonds that allow the structure and water absorption capacity of these novel hydrogels to be regulated. In this sense, this work focuses on studying the relation of the PU concentration on the properties of these hydrogels. The results indicate that the crosslinking of the alginate with PU generates IPN hydrogels with a crystalline structure characterized by a homogeneous smooth surface with high capacity to absorb water, tailoring the degradation rate, thermal decomposition, and storage module, not altering the native biocompatibility of alginate, providing character to inhibit the growth of E. coli and increasing also its hemocompatibility. The IPN hydrogels that include 20 wt.% of PU exhibit a reticulation index of 46 ± 4%, swelling capacity of 545 ± 13% at 7 days of incubation at physiological pH, resistance to both acidic and neutral hydrolytic degradation, mechanical improvement of 91 ± 1%, and no cytotoxicity for monocytes and fibroblasts growing for up to 72 h of incubation. These results indicate that these novel hydrogels can be used for successful biomedical applications in the design of wound healing dressings.

Study of the polyacrylate interpenetration in a collagen-polyurethane matrix to prepare novel hydrogels for biomedical applications.

Currently, the control of the properties of collagen based hydrogels represents a promising area of research to develop novel materials for biomedical applications. The crosslinking of the collagen with trifunctional polyurethane (PU) allows a hybrid matrix to be formed by improving the coupling with exogenous polymeric chains to generate innovative semi-interpenetrated network (semi-IPN) hydrogels. The incorporation of polyacrylate (PA) within a hybrid matrix of collagen-PU allows to regulate the structure and physicochemical properties such as polymerization rate, physicochemical crosslinking, thermal stability, storage module and swelling/degradation behavior of the 3D matrices in the hydrogel state, also exhibiting modulation of their in vitro biocompatibility properties. This work contemplates the study of the effect of PA concentration on the physicochemical properties and the in vitro biological response of these novel semi-IPN hydrogels based on collagen-PU-PA. The results indicate that semi-IPN hydrogels that include 20 wt% of PA exhibit improved swelling with respect to the collagen-PU hydrogel, controlling the degradation rate in acidic, alkaline and proteolytic media; showing E. coli inhibition capacity, high hemocompatibility and not altering the metabolism of monocytes and fibroblasts growing on them. Therefore, these novel hydrogels represent biomaterials with potential application in biomedical strategies such as wound healing dressings.