Scaffolds for cardiac patch application must meet stringent requirements such as biocompatibility, biodegradability, and facilitate vascularization in the engineered tissue. Here, a bioactive, biocompatible, and biodegradable electrospun scaffold of poly(glycerol sebacate)-poly(ε-caprolactone) (PGS-PCL) is proposed as a potential scaffold for cardiac patch application. The fibers are smooth bead free with average diameter = 0.8 ± 0.3 μm, mean pore size = 2.2 ± 1.2 μm, porosity = 62 ± 4%, and permeability higher than that of control biological tissue. For the first time, bioactive PGS-PCL fibers functionalized with vascular endothelial growth factor (VEGF) are developed, the approach used being chemical modification of the PGS-PCL fibers followed by subsequent binding of VEGF via amide bonding. The approach results in uniform immobilization of VEGF on the fibers; the concentrations are 1.0 μg cm(-2) for the PGS-PCL (H) and 0.60 μg cm(-2) for the PGS-PCL (L) samples. The bioactive scaffold supports the attachment and growth of seeded myogenic and vasculogenic cell lines. In fact, rat aortic endothelial cells also display angiogenic features indicating potential for the formation of vascular tree in the scaffold. These results therefore demonstrate the prospects of VEGF-functionalized PGS-PCL fibrous scaffold as promising matrix for cardiac patch application.

The present article investigates the use of a novel electrospun fibrous blend of poly(glycerol sebacate) (PGS) and poly(butylene succinate-butylene dilinoleate) (PBS-DLA) as a candidate for cardiac tissue engineering. Random electrospun fibers with various PGS/PBS-DLA compositions (70/30, 60/40, 50/50, and 0/100) were fabricated. To examine the suitability of these fiber blends for heart patches, their morphology, as well as their physical, chemical, and mechanical properties were measured before examining their biocompatibility through cell adhesion. The fabricated fibers were bead-free and exhibited a relatively narrow diameter distribution. The addition of PBS-DLA to PGS resulted in an increase of the average fiber diameter, whereas increasing the amount of PBS-DLA decreased the hydrophilicity and the water uptake of the nanofibrous scaffolds to values that approached those of neat PBS-DLA nanofibers. Moreover, the addition of PBS-DLA significantly increased the elastic modulus. Initial toxicity studies with C2C12 myoblast cells up to 72 h confirmed nontoxic behavior of the blends. Immunofluorescence analyses and scanning electron microscopy analyses confirmed that C2C12 cells showed better cell attachment and proliferation on electrospun mats with higher PBS-DLA content. However, immunofluorescence analyses of the 3-day-old rat cardiomyocytes cultured for 2 and 5 days demonstrated better attachment on the 70/30 fibers containing well-aligned sarcomeres and expressing high amounts of connexin 43 in cellular junctions indicating efficient cell-to-cell communication. It can be concluded, therefore, that fibrous PGS/PBS-DLA scaffolds exhibit promising characteristics as a biomaterial for cardiac patch applications.

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Port spaces, functions, and interests have shaped the growth and development of many cities around the world. At times, different stakeholders—private and public, local, regional, national and global—have collaborated to assure the continuity of port functions in old and new locations and, if the port relocates or if that effort fails, to redevelop former port spaces. Through the lens of port- and city-related urban developments in London, Hamburg, and Philadelphia, this article explores the multiple conditions that are part of port city resilience. It uses historical institutionalism as a theoretical framework for understanding these long-term changes, particularly in institutional and governance dynamics. It shows that the development paths of port and city spaces and the actors who shape them are not always aligned. Through the case of London, it shows a development path that is led by private investment building and relocating a world-class port and administrating it from the city center, while local and national institutions only intervene to balance spatial or social short-comings of the private actors. The case of the city-state Hamburg illustrates the development of shared port-city paths under long-term public leadership that has provided direction for the expanding port as well as for the growing city. In the case of Philadelphia, national interests, the Navy, and private investments played an important role in the creation of port infrastructure and, later, in the largely failed transformation of former port areas into public waterfronts. As shipping elites left the city and new land-based employers emerged, such as the University of Pennsylvania, the port-city path was partly discontinued. The article concludes by pointing to the expected capacity of each of these cities to address future challenges. Awareness of historical practices can help readers understand where current conditions may stand in the way of innovative solutions.