The need for urinary tract reconstruction can result from a large variety of urologic disorders such as congenital hypospadias, neurogenic bladder, stricture disease, cancer and trauma that may affect the ureters, bladder or urethra

Our objective is to demonstrate an electrospun fibrinogen-PDO (polydioxanone) composite scaffold will retain the superior cellular interaction of fibrinogen while producing a product with the functional strength needed for direct implantation. Fibrinogen-PDO composite scaffolds were electrospun with PDO ratios of 0% (pure fibrinogen), 10%, 20%, 30%, 40%, 50% and 100% (pure PDO) and disinfected using standard methods. Scaffolds were seeded with human BSM (bladder smooth muscle cells) and incubated with twice weekly media changes. Samples were removed at 7, 14 and 21 days for evaluation by collagen assay, scanning electron microscopy and histology. Cell seeding and culture demonstrated human BSM readily migrate throughout and remodel electrospun fibrinogen-PDO composite scaffolds with deposition of native collagen. Cell migration and collagen deposition increased with increasing fibrinogen concentration while scaffold integrity increased with increasing PDO concentration. Electrospun fibrinogen-PDO composite structures promote rapid cellular in-growth by human BSM while maintaining structural integrity. The fibrinogen to PDO ratio can be adjusted to achieve the desired properties required for a specific tissue engineering application. Our ultimate objective is to utilize this innovative biomaterial technology to produce an acellular, bioresorbable product that enables in situ tissue regeneration. While there is still much work to be done, these initial findings indicate fibrinogen-PDO composite scaffolds deserve further investigation. INTRODUCTION The need for urinary tract reconstruction can result from a large variety of urologic disorders such as congenital hypospadias, stricture disease, cancer and trauma. These disorders may affect the ureters, bladder or urethra, decreasing the availability of adequate autologous tissue. Moreover, complications from inserting autologous tissue, such as enteric segments, into the urinary tract are well known and often manifests metabolic and histopathologic abnormalities. These sequelae have motivated investigators to search for tissue-engineered alternatives. Ideally, a tissue-engineered scaffold should mimic the structural and functional profile of the native extracellular matrix (ECM). To achieve this objective, the “ideal” scaffold has been described as having the following characteristics: 1) a three-dimensional structure with a surface chemistry that promotes cell attachment, proliferation and differentiation [1], 2) that does not induce adverse immune responses from the surrounding tissues [1], 3) mechanical properties to withstand organ-specific in vivo forces while being completely resorbable [2], and 4) a feasible production process that allows for various shapes and sizes [3]. Despite many recent advances, none of the scaffolds in use today meet all of the above mentioned criteria completely. Fibrinogen is a naturally occurring soluble blood protein that functions as a major structural element in the coagulation cascade, clot formation and wound healing [4, 5]. The reaction of fibrinogen with thrombin produces fibrin. This exposes regions of opposite charge leading to the assembly of fibrous clots and/or other fibrous structures. These fibrous structures function as nature’s provisional matrix, on which tissues rebuild and repair themselves, making this type of structure an attractive scaffold for tissue engineering and regeneration [6-8]. Fibrin and fibrinogen have a well established track record in tissue engineering, due to their innate ability to induce cellular interaction and subsequent scaffold remodeling. Fibrinogen based scaffolds have previously been developed in the form of fibrin gels [714] and wet extrusion fibronectin-fibrinogen cables [1517]. These studies demonstrated fibrinogen based scaffolds were easily degradable, nonimunogenic [9] and promoted increased cell migration [15, 17]. Journal of Engineered Fibers and Fabrics 12 http://www.jeffjournal.org Volume 3, Issue 2—2008 Electrospinning is a technology with the potential to fulfill the requirements of an ideal scaffold. Briefly, electrospinning is accomplished by inducing a large electric potential (15 to 30 kilovolts DC) in a polymer solution and separating that polymer from an oppositely charged target. This charge separation creates a static electric field. As the field strength grows, the charge separation overcomes the surface tension of the solution and a thin jet of entangled polymer chains is ejected from the polymer reservoir. As this jet travels toward the target, instabilities within the charged jet define its orientation in space (condition previously described as whipping). By the time the jet reaches the target, the solvent has evaporated and a dry fiber is collected in the form of a non-woven scaffold (Figure 1). FIGURE 1: Scanning electron micrographs of electrospun fibrinogenPDO composite scaffolds at 2000x magnification. 10% PDO composite (top) has a scale bar of 10 μm, while 40% PDO composite (bottom) has a scale bar of 5 μm.