Experimental and theoretical studies on Gallic acid assisted EDC/NHS initiated crosslinked collagen scaffolds

The effect of Gallic acid (GA) in the presence of 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide (EDC)/N-hydroxysuccinimide (NHS) on collagen scaffold is investigated. The thermal mechanical analyzer (TMA), differential scanning calorimetric (DSC), and thermogravimetric analysis (TGA) including tensile strength (TS, 180 ± 3 MPa), denaturation temperature (Td, 80.03°C), % elongation (% E, 180 ± 9) and weight loss (31.76%), indicate that the modification improves the structural integrity and stability of the collagen scaffold. The GA-EDC/NHS treatment inhibits the action of collagenase against collagen degradation compared to GA and EDC/NHS. It is concluded from docking studies that GA binds with collagen like peptide (CLP) and collagenase through multiple H-bonds and hydrophobic interactions leading to low binding energy -5.1 and -5.3 Kcal/mol, respectively. The hydrophobic core of the GA molecules, probably incorporates itself into the hydrophobic areas of the collagen groups, whereas OH and COOH moieties of GA establish multiple H-bonds with neighboring collagen molecules and carboxamide bond, thereby improving the swelling and water uptake properties, biocompatibility and cell adhesion properties. This results in improving stability of the scaffold, which prevents the free access of the collagenase to reactive sites in the triple helical collagen chains.