Congenital heart disease affects approximately 40,000 newborns each year in the U.S. Valve and conduit replacements are needed for absent pulmonary valve, aortic stenosis (Konno procedure, Ross procedure), double outlet right ventricle (Rastelli operation), extracardiac conduit (Fontan operation), pulmonary valve replacement (Tetralogy of Fallot). Materials in current use include homograft blood vessels; glutaraldehyde treated bovine jugular veins (BJV, Contegra), polytetrafluorethylene (PTFE), and woven or knitted Dacron tubes. The limitations of these materials involve to varying degrees their thrombogenicity, durability, susceptibility to infection, and lack of growth potential. These materials also have varying degrees of stiffness and flexibility, which present technical challenges for surgeons, particularly in neonates and infants where size constraints and limited space in the mediastinum combine with the relatively thin immature native vascular tissues to create tissue-materials mechanical mismatches, which can compromise the ability to achieve a successful surgical repair. In Phase I STTR, we tested the feasibility of a prototype from decellularized and pentagalloyl glucose (PGG) stabilized novel BJV valved conduit device (TxGuard) to augment the already recognized qualities of BJV. All the preclinical testing shows that TxGuard valved conduit is viscoelastic, biocompatible, resists calcification, and thrombosis while allowing host cellular infiltration and the potential for remodeling and growth. To commercialize the TxGuard conduit, we need to obtain data under GMP and GLP conditions that can be submitted to the FDA for HDE application. Towards this goal, we propose the following specific aims for SBIR Phase II. Aim 1: Implement quality control SOPs documents for processing of the TxGuard conduit under GMP, Aim 2: Validate sterilization, packaging, and storage of the TxGuard conduits, Aim 3: Test hydrodynamic performance and fatigue resistance of TxGuard conduits, Aim 4: Perform long-term preclinical in-vivo testing for TxGuard conduits. The ovine model of TxGuard pulmonary valved conduit placement (n=6) will be conducted for 150 days in growing lambs and compared to the clinically available Contegra BJV conduits (n=3) under GLP conditions for FDA submission. The proposed Phase II SBIR project will spearhead the development of a novel BJV device (TxGuard) that would repopulate with host cells and slowly regenerate and grow with the patient without unwanted inflammation and degeneration in contrast to the existing devices.