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Blends of arabinoxylan ferulate (AXF) and gelatin (GEL) at 1:1, 2:1 and 4:1 mass ratios were electrospun into composite fibrous mats as a wound-healing drug delivery platform. The composite...

Arabinoxylan ferulate (AXF) foams were fabricated via enzymatic peroxidase/hydrogen peroxide crosslinking reaction followed by freeze-drying and studied as a potential wound dressing material. The AXF foam's rheological, morphological, porous, and swelling properties were examined. AXF foams were found to be a viscoelastic material that proved to be highly porous and water absorbent. AXF foams possessed low endotoxin levels and were cytocompatible with fibroblasts. Silver was successfully integrated into AXF foams and slowly released over 48 h. AXF foams impregnated with silver demonstrated efficacy inhibiting bacterial growth according to a modified Kirby-Bauer disk diffusion susceptibility test. Overall, AXF foams possess appropriate material properties and the silver-loaded AXF foams showed antimicrobial activity necessary to be a candidate material in wound dressing development. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 2456-2465, 2016.

Despite considerable recent progress in defining neutrophil functions and behaviors in tissue repair, much remains to be determined with regards to its overall role in the tissue integration of biomaterials. This article provides an overview of the neutrophil's numerous, important roles in both inflammation and resolution, and subsequently, their role in biomaterial integration. Neutrophils function in three primary capacities: generation of oxidative bursts, release of granules and formation of neutrophil extracellular traps (NETs); these combined functions enable neutrophil involvement in inflammation, macrophage recruitment, M2 macrophage differentiation, resolution of inflammation, angiogenesis, tumor formation and immune system activation. Neutrophils exhibit great flexibility to adjust to the prevalent microenvironmental conditions in the tissue; thus, the biomaterial composition and fabrication will potentially influence neutrophil behavior following confrontation. This review serves to highlight the neutrophil's plasticity, reiterating that neutrophils are not just simple suicidal killers, but the true maestros of resolution and regeneration.

Although electrospun templates are effective at mimicking the extracellular matrix (ECM) of native tissue due to the tailorability of parameters such as fiber diameter, polymer composition, and drug loading, these templates are often limited with regards to cell infiltration and the tailorability of the microenvironments within the structures. Thus, there remains a need for a flexible threedimensional template system which could be combined with cell suspensions to promote three-dimensional tissue regeneration, and ultimately allow cells to freely reorganize and modify their microenvironment. In this study, a mincing process was designed and optimized to create mixtures of electrospun fibers/branched-clusters for use as fundamental tissue engineering building units. These fiber/branched-cluster elements were characterized with regards to fiber and branch lengths, and a method was optimized to combine them with normal human dermal fibroblasts (nHDFs) in culture to create interconnected template constructs. Sectioning and imaging of these constructs revealed cell/fiber integration as well as even cell distribution throughout the construct interior. These fiber/branched-cluster elements represent an innovative flexible tissue regeneration template system.

Electrospun fibrous meshes are promising vehicles for sustained, localized delivery of therapeutic agents to specific target tissues. Their large surface area to volume ratio facilitates a high loading efficiency, and the versatility of methods for drug attachment and/or encapsulation allows for loading with many types of drug molecules. Additionally, varying polymer type and fiber morphology and the use of additional drug-encapsulating particles allow the release profile, mechanical properties, and degradation rate to be tailored to each application. Studies have demonstrated the efficacy of these systems in antibiotic delivery, establishing hemostasis, eliciting tissue growth and remodeling, and treating various types of cancer. These results indicate promising avenues for commercialization, which have yet to be fully realized.

Electrospinning, a fabrication technique used to create non-woven, porous templates from natural and synthetic polymers, is commonly used in tissue engineering because it is highly tailorable. However, traditional electrospinning creates restrictive pore sizes that limit the required cell migration. Therefore, tissue engineering groups have sought to enhance and regulate porosity of tissue engineering templates. Air-impedance electrospinning generates templates with tailorable, patterned areas of low and high density fiber deposition. Here we demonstrate an improved air-impedance electrospinning system, consisting of a newly designed funnel equipped to hold changeable porous deposition plates and administer air flow in a confined and focused manner, with parameters that maintain template integrity. In this preliminary study, we quantify the increase in porosity of polydioxanone templates with use of traditional fiber and pore analysis as well as with mercury porosimetry. Additionally, we validate the system’s significance in fabricating enhanced porosity templates that maintain their mechanical properties (i.e. elastic modulus, tensile strength, and suture retention strength) despite the deliberate increase in porosity. This is of exceptional value to the template’s integrity and efficacy as these parameters can be further optimized to induce the desired template porosity, strength, and texture for a given application.