PROJECT SUMMARY This is an initial submission of a K08 application by Dr. Renea Sturm, an Assistant Professor of Pediatric Urology at the University of California, Los Angeles (UCLA). Candidate: Dr. Sturm’s primary training objectives in this proposal are to: 1. Fill existing knowledge gaps in the interaction between materials science and modeling 2. Learn scientific methodologies in material fabrication and evaluation 3. Develop study design and scientific communication skills 4. Develop management and leadership skills for a career as an independent investigator. Dr. Sturm will accomplish these activities through mentorship, focused coursework, and participation in select workshops/conferences. This will be supported by her primary mentors Song Li, PhD, Chair of Bioengineering at UCLA and an expert in cellular-materials interactions and co-mentor Nasim Annabi, PhD, an expert in modifiable elastic hydrogels. She will be further supported by mentor Isla Garraway, MD, PhD, an independent urologic surgeon-scientist. Her external advisory committee will include focused materials science and tissue engineering expertise through Ali Khademhosseini, PhD with expert knowledge of tissue engineering for the lower urinary tract provided by Arun Sharma, PhD. Research: Urethral defects requiring urethroplasty occur in children and adults secondary to congenital, traumatic, infectious, and malignant conditions. Current tissue sources for urethral replacement are limited by donor site morbidity and lack of optimal tissue characteristics to support lifelong voiding and penile erections. A subsequent high risk of short- and long-term urethroplasty complications highlights the need for an improved tissue alternative with a bioinspired design. The goal of this proposal is to establish an independent surgeon- scientist with focused materials expertise and a track record of creating and evaluating a highly elastic, biomimetic urethral scaffold with optimized biomechanical properties by layer to support cellularization followed by extracellular matrix (ECM) deposition. The research plan addresses key design requirements: 1) optimized mechanical properties, 2) reproducible synthesis methods, and 3) wound healing and vascularization. Our overall hypothesis is that a novel scaffold with the proposed combination of a hydrogel and elastin-like peptide designed to meet targeted mechanical and structural parameters will improve suturability, early urinary tract function, and local tissue recapitulation as compared to preputial or unseeded scaffold urethroplasties. In Aim 1, composite electrospun scaffolds will be engineered with mechanical and structural properties that mimic native urethral tissue. In Aim 2, an in vitro evaluation will elucidate the role of the mechanical niche in cellular behavior and ECM deposition. In Aim 3, an ex vivo evaluation of functional and anatomic findings following application of seeded and unseeded grafts will occur versus standard of care pr...