Tailoring properties of extracellular matrix hydrogels by crosslinking with water-soluble oligourethanes and dispersion of silica particles

摘要

Introduction: Biomedical composite hydrogels are an alternative in the design of templates that regulate the cell behavior via the constituents and properties, and consequently the regenerative outcomes. Water-soluble oligourethanes have proven to be excellent crosslinking agents controlling the properties in scaffolds based on extracellular matrix varying pH, temperature and concentration.Silica incorporated into tissue mammalian-derived meshes has shown a stimulating effect on macrophages to secrete signaling molecules that participate in the angiogenesis and fibrillogenesis. In this work, we explore the processing aspects that improve the hydrogels properties as result of the combination of ECM-derived hydrolysates (hECM) with silica precursor-coupled and blocked oligourethanes. The 3D structure and mechanics of hybrid hydrogels, as well swelling, in vitro biodegradation, blocked collagen amines, cylocompatibility and drug incorporation/release were checked on novel composite hydrogels. Materials and Methods: hECM were obtained from decellularized rats tendon, bovine tendon, pericardial and submucosal intestinal tissues (HCI, pepsin, pH 2, RT). Water-soluble oligourethanes (PUP) were synthetized from polyethoxy diol or triol (1000 g mol-1) and hexamethylene, isophorone and lysine diisocyanates and were coupled with orthosilicate (TEOS, 5 and 15 %). The gel was obtained by the combination of hECM and PUP (37°C, pH 7.4), in some case penicillin, gentamicin or dexamethasone were incorporated before gelation. The structure and mechanics were investigated by turbidimetry, scanning electronic microscopy and by oscillatory rheology. Degradation and swelling of hydrogels were evaluated in the presence of collagenaseand saline solution, respectively. RAW264.7 macrophages and dermal fibroblasts were seeded on hydrogels and cell viability and TGF-β secretion were quantified by I tetrazolium salt reduction and immunoassays. Drug delivery was followed by UV-vis spectroscopy. Results: The collagen fibrillogenesis and the crosslinking between pendant hECM-amines and end PUP-isocyanates, both in response to changes in temperature and ionic strength (pH 7.0,37°C), drive the gel formation. In addition, oligourethane drives the orthosilicate polycondensation resulting in silica particles dispersed onto hydrogels. The chemical structure of the starting aliphatic diisocyanates influences the crosslinking capacity of the oligourethanes and, along with the silica'5', reinforces the tailored properties of the composite matrices such as gelation rate, surface morphology, rate degradation, swelling capacity, storage modulus, drug incorporation/release, and in vitro cells viability. Discussion: The tunable composite hydrogels are excellent candidates to generate templates for encapsulation and controlled releasing of therapeutics and signaling molecules. In addition, the encapsulating capacity of the silica favors the drug incorporation/release. Conclusions: The oligourethane concentration determines the crosslinking densities of hECM gels obtained in a simultaneous process of collagen polymerization and chemical crosslinking. The variation in the crosslinking density controls the physicochemical and viscoelastic properties of hybrid gels as well as their capacity to support cell proliferation. Therefore, this novel composite hydrogel have potential applications as effective delivery systems for therapeutic factors that induce soft tissue repair.