Enhanced biocompatibility and bactericidal properties of hydrogels based on collagen–polyurethane–aluminium MOFs for biomedical applications

Composite materials in hydrogels state based on collagen and metal-organic frameworks (MOFs) have recently gained attention in tissue engineering due to the enhancement of their mechanical and bactericidal properties. In this work, composite hydrogels based on collagen crosslinked with polyurethane (derived from HDI or IPDI) and MOFs with aluminium as metallic center (MIL53-Al and BHET-Al MOFs) were synthesized by the microemulsion method. The physicochemical properties of these materials were characterized by WAXS, ATR-FTIR, TGA, reticulation by ninhydrin assay, degradation profiles varying pH and using a proteolytic medium, scanning electron microscopy and elemental mapping. At the same time, their in-vitro biocompatibility was tested by the hemolysis test, metabolic activity of fibroblasts by MTT assay, and the inhibition growth of pathogens like E. coli. It was found that the entanglement of collagen, polyurethane and MOFs was made by hydrogen and coordination bonds promoted by the chemical structure of the MOF, leading to a semi-crystalline rough surface with interconnected porosity and aggregates of round-shape, enhancing the mechanical, resistance to thermal degradation and biocompatibility. Interestingly, the better dispersion of MIL53-Al in the collagenic matrix with crosslinker based on HDI leads to a hemolytic capacity of 1.2%, a fibroblast viability of 169.4%, and an E. coli inhibition growth of 96.7%, a potential biomaterial to be used as a wound dressing for chronic wounds in the skin.