Effect of Urea and Thiourea on Generation of Xenogeneic Extracellular Matrix Scaffolds for Tissue Engineering

Effective solubilization of proteins by chaotropes in proteomic applications motivates their use in solubilization-based antigen removal/decellularization strategies. A high urea concentration has previously been reported to significantly reduce lipophilic antigen content of bovine pericardium (BP); however, structure and function of the resultant extracellular matrix (ECM) scaffold were compromised. It has been recently demonstrated that in vivo ECM scaffold fate is determined by two primary outcome measures as follows: (1) sufficient reduction in antigen content to avoid graft-specific adaptive immune responses and (2) maintenance of native ECM structural proteins to avoid graft-specific innate responses. In this work, we assessed residual antigenicity, ECM architecture, ECM content, thermal stability, and tensile properties of BP subjected to a gradient of urea concentrations to determine whether an intermediate concentration exists at which both antigenicity and structure-function primary outcome measures for successful in vivo scaffold outcome can simultaneously be achieved. Alteration in tissue structure-function properties at various urea concentrations with decreased effectiveness for antigen removal makes use of urea-mediated antigen removal unlikely to be suitable for functional scaffold generation.