Controlled cross-linking of porcine cholecyst extracellular matrix for preparing tissue engineering scaffold

Treatment with cross-linking agents for stabilizing biomolecules is an integral step during the preparation of many extracellular matrix-based tissue engineering scaffolds from mammalian organs. However, excess cross-linking may cause nonavailability of biomolecules and consequent deterioration of bioinductive properties of the scaffold. The present study considered controlling the extent of cross-linking in a porcine cholecyst extracellular matrix scaffold prepared by a nonenzymatic and nondetergent method, by ex situ incubation of the source organ in varying concentrations of neutral buffered formaldehyde (10, 4, 1 or 0%; v/v) for in situ cross-linking of biomolecules. Reduction of the formaldehyde concentration resulted in an increase in the extent of biodegradation and a decrease in the compactness of the mesh-like surface microarchitecture of the scaffold. Retention of collagen was maximum when treated with 10% neutral buffered formaldehyde without any variation in the content of elastin and sulphated glycosaminoglycans. Although there was a reduction in the quantity of growth factors following the cross-linking, fibroblasts remained viable on the scaffolds. The retention of major biomolecule was maximum and autodigestion was minimum in the scaffold prepared by the ex situ treatment of cholecyst in 10% neutral buffered formalin and found suitable for preparing the tissue engineering scaffold.