Development of Enzymatic-Resistant and Compliant Decellularized Extracellular Matrixes via Aliphatic Chain Modification for Bladder Tissue Engineering.

Here, we report the design and development of highly stretchable, compliant, and enzymatic-resistant transiently cross-linked decellularized extracellular matrixes (dECMs) (e.g., porcine small intestine submucosa/dSIS, urinary bladder matrix/dUBM, bovine pericardium/dBP, bovine dermis/dBD, and human dermis/dHD). Specifically, these dECMs were modified with long aliphatic chains (C9, C14, and C18). Upon modification, dECMs became significantly resistant to enzymatic degradation for extended periods, showed increased water contact angle (>20%-90%), and stretched >200% than their control counterparts. Modified dECMs are compliant, undergoing 100% elongation at only 0.3-0.5 MPa of applied tensile stress (∼10%-25% of their control counterparts), similar to the control bladder tissue. Furthermore, modified dECMs remain structurally stable at the physiological temperature with increased storage and loss modulus values but decreased tan δ values compared to their control counterparts. Although modification reduces cell adhesion, the gene expressions in polarized macrophages remain unchanged (e.g., TGFß, CD163, and CD86), except for the modified bovine pericardium (dBP) where a significant decrease in TNFα gene expression is observed. When implanted in the rat subcutaneous model, modified dECMs degraded relatively slowly and did not cause significant fibrotic tissue formation. The numbers of pro-regenerative macrophages increased to several folds in a later time point of evaluation. Modified dECM also supported the bladder wall regeneration with formations of the urothelium, lamina propria, blood vessels, and muscle bundles and reduced the occurrence of calculi formation by 50% in a rat bladder augmentation model. We anticipate that the enhanced stretchability, compliance, and physiological stability of dECMs indicate their suitability for urologic tissue regeneration.