sepharose and genipin

The generation of biomimetic and biocompatible artificial tissues is the basic research objective for tissue engineering (TE). In this sense, the biofabrication of scaffolds that resemble the tissues' extracellular matrix is an essential aim in this field. Uncompressed and nanostructured fibrin-agarose hydrogels (FAH and NFAH, respectively) have emerged as promising scaffolds in TE, but their structure and biomechanical properties must be improved in order to broaden their TE applications. Here, we generated and characterized novel membrane-like models with increased structural and biomechanical properties based on the chemical cross-linking of FAH and NFAH with genipin (GP at 0.1%, 0.25%, 0.5% and 0.75%). Furthermore, the scaffolds were subjected to rheological (G, G', G″ modulus), ultrastructural and ex vivo biocompatibility analyses. Results showed that all GP concentrations increased the stiffness (G) and especially the elasticity (G') of FAH and NFAH. Ultrastructural analyses demonstrated that GP and nanostructuration of FAH allowed us to control the porosity of FAH. In addition, biological studies revealed that higher concentration of GP (0.75%) started to compromise the cell function and viability. Finally, this study demonstrated the possibility to generate natural and biocompatible FAH and NFAH with improved structural and biomechanical properties by using 0.1%-0.5% of GP. However, further in vivo studies are needed in order to demonstrate the biocompatibility, biodegradability and regeneration capability of these cross-linked scaffolds.

Topics: Biocompatible Materials; Biomechanical Phenomena; Colorimetry; Elasticity; Extracellular Matrix; Fibrin; Fibroblasts; Humans; Hydrogels; Iridoids; Materials Testing; Microscopy, Electron, Scanning; Porosity; Rheology; Sepharose; Stress, Mechanical; Tissue Engineering; Tissue Scaffolds; Viscosity

A facile 6-aminoagarose (AA) mediated synthesis of new fluorogenic amides of agarose with nicotinic (AA-NA) and picolinic acids (AA-PA) employing carbodiimide chemistry have been described. 6-Amino agarose (AA) was synthesized in a facile Mitsunobu-inspired microwave mediated method involving the reaction of agarose with phthalimide in presence of diisopropyl azodicarboxylate and triphenylphosphene (DIAD/TPP) followed by hydrazinolysis. All compounds were characterized by GPC, UV spectrophotometry, fluorescence spectroscopy, FT-IR, (1)H and (13)C NMR spectra. The fluorescence emissions (λmax 430 and 412 nm) of 1 × 10(-3)M solutions of AA-NA and AA-PA in water were significantly higher (ca. 82% and ca. 90%) than those of the molar equivalents (0.2mg) of NA and PA present in the 1 × 10(-3)M solutions of the amides, respectively. These fluorogenic pyridine carboxylic acid amides of agarose may find applications as sensors in biomedical and pharmaceutical industries.

Topics: Amides; Amino Sugars; Azo Compounds; Carbohydrate Conformation; Carboxylic Acids; Cross-Linking Reagents; Fluorescent Dyes; Hydrogels; Iridoids; Microwaves; Niacin; Nuclear Magnetic Resonance, Biomolecular; Organophosphorus Compounds; Phthalimides; Picolinic Acids; Pyridines; Sepharose; Solutions; Spectrophotometry; Spectroscopy, Fourier Transform Infrared