Metal–organic frameworks (MOFs) are materials with a large surface area and antimicrobial properties are advantageous properties for the controlled release of molecules for biomedical applications. However, their synthesis is expensive and harmful to the environment due to the use of organic ligands and solvents. Thus, this work proposes the synthesis of a new MOF by hydrothermal method using water as the solvent, aluminium nitrate as a metallic source, and bis(2-hydroxyethyl) terephthalate (BHET) as organic ligand, obtained via glycolysis of polyethylene terephthalate (PET); and its comparison with MIL53-Al MOF, synthesized from terephthalic acid (BDC) as organic ligand. Both MOFs were characterized by XRD, ATR-FTIR, N$_2$ physisorption, TGA, SEM and XPS; besides their in vitro biocompatibility was tested by porcine fibroblasts viability. The results indicate that aluminium ions are coordinated to both carbonyl and hydroxyl functional groups of the BDC and BHET organic ligands. The new BHET-Al MOF shows higher thermal stability than MIL53-Al, it also exhibits a macroporous structure in comparison with the microporosity of the MIL53-Al. BHET-Al MOF is not cytotoxic for porcine dermal fibroblasts growing on its surface for up to 48 h of culture, thus, this innovative MOF is a promising material for the controlled release of drugs.

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.