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Our aim was to develop a biodegradable fibrous dressing to act as a tissue guide for in situ wound repair while releasing Ibuprofen to reduce inflammation in wounds and reduce pain for patients on dressing changes. Dissolving the acid form of Ibuprofen (from 1% to 10% by weight) in the same solvent as 75% polylactide, 25% polyglycolide (PLGA) polymers gave uniformly loaded electrospun fibers which gave rapid release of drug within the first 8 h and then slower release over several days. Scaffolds with 10% Ibuprofen degraded within 6 days. The Ibuprofen released from these scaffolds significantly reduced the response of fibroblasts to major pro-inflammatory stimulators. Fibroblast attachment and proliferation on scaffolds was unaffected by the addition of 1-5% Ibuprofen. Scaffolds loaded with 10% Ibuprofen initially showed reduced cell attachment but this was restored by soaking scaffolds in media for 24 h. In summary, addition of Ibuprofen to electrospun biodegradable scaffolds can give acute protection of adjacent cells to inflammation while the scaffolds provide an open 3D fibrous network to which cells can attach and migrate. By 6 days, such scaffolds will have completely dissolved into the wound bed obviating any need for dressing removal.

There remains a substantial shortfall in the treatment of severe skeletal injuries. The current gold standard of autologous bone grafting from the same patient has many undesirable side effects associated such as donor site morbidity. Tissue engineering seeks to offer a solution to this problem. The primary requirements for tissue-engineered scaffolds have already been well established, and many materials, such as polyesters, present themselves as potential candidates for bone defects; they have comparable structural features, but they often lack the required osteoconductivity to promote adequate bone regeneration. By combining these materials with biological growth factors, which promote the infiltration of cells into the scaffold as well as the differentiation into the specific cell and tissue type, it is possible to increase the formation of new bone. However due to the cost and potential complications associated with growth factors, controlling the rate of release is an important design consideration when developing new bone tissue engineering strategies. This paper will cover recent research in the area of encapsulation and release of growth factors within a variety of different polymeric scaffolds.

What’s known on the subject? and What does the study add? The use of tissue engineered buccal mucosa in substitution urethroplasty removes some of the potential drawbacks of harvesting buccal mucosa however it introduces the risk of using donor tissue (allodermis) in its creation. Biocompatible biodegradable non‐woven fabrics created by electrospinning can be used as entirely synthetic matrices for seeding with autologous cells, creating tissues for implantation. This would both remove the donor tissue disease transmission risk and reduce the potential risks of harvesting buccal mucosa. While removing the risks of donor tissue, we showed that we can indeed make a replacement tissue which has similar biomechanical properties to buccal mucosa. We also found that each processing step in the creation of such a tissue is critical, for example the initial sterilisation can have a profound effect on the tissue created. OBJECTIVE To develop a synthetic biodegradable alternative to using human allodermis for the production of tissue‐engineered buccal mucosa for substitution urethroplasty, looking specifically at issues of sterilization and cell‐seeding protocols and, comparing the results to native buccal mucosa. MATERIAL AND METHODS Three methods of sterilization, peracetic acid (PAA), γ‐irradiation and ethanol, were evaluated for their effects on a biodegradable electrospun scaffold of polylactide‐co‐glycolide (PLGA, 85 : 15), to identify a sterilization method with minimal adverse effects on the scaffolds. Two protocols for seeding oral cells on the scaffold were compared, co‐culture of fibroblasts and keratinocytes on the scaffolds for 14 days, and seeding fibroblasts for 5 days then adding keratinocytes for a further 10 days. Cell viability and proliferation on the scaffolds, scaffold contraction and mechanical properties of the scaffolds with and without cells were examined. RESULTS γ‐irradiation and PAA sterilized scaffolds remained sterile for >3 months when incubated in antibiotic‐free culture medium, while ethanol sterilized and unsterilized samples became infected within 2–14 days. All scaffolds showed extensive contraction (up to 50% over 14 days) irrespective of the method of sterilization or the presence of cells. All methods of sterilization, particularly ethanol, reduced the tensile strength of the scaffolds. The addition of cells tended to further reduce mechanical properties but increased elasticity. The cell‐seeding protocol of adding fibroblasts for 5 days followed by keratinocytes for 10 days was the most promising, achieving a mean (sem) ultimate tensile stress of 1.20 (0.24) × 105 N/m2 compared to 3.77 (1.05) × 105 N/m2 for native buccal mucosa, and a Young’s modulus of 2.40 (0.25) MPa, compared to 0.73 (0.09) MPa for the native buccal mucosa. CONCLUSION This study adds to our understanding of how sterilization and cell seeding affect the physical properties of scaffolds. Both PAA and γ‐irradiation appear to be suitable methods for sterilizing PLGA scaffolds, although both reduce the tensile prope...

Direct writing melt electrospinning is an additive manufacturing technique capable of the layer-by-layer fabrication of highly ordered 3d tissue engineering scaffolds from micron-diameter fibers. The utility of these scaffolds, however, is limited by the maximum achievable height of controlled fiber deposition, beyond which the structure becomes increasingly disordered. A source of this disorder is charge build-up on the deposited polymer producing unwanted coulombic forces. In this study, the authors introduce a novel melt electrospinning platform with dual voltage power supplies to reduce undesirable charge effects and improve fiber deposition control. The authors produced and characterized several 90° cross-hatched fiber scaffolds using a range of needle/collector plate voltages. Fiber thickness was found to be sensitive only to overall potential and invariant to specific tip/collector voltage. The authors also produced ordered scaffolds up to 200 layers thick (fiber spacing 1 mm and diameter 40 μm) and characterized structure in terms of three distinct zones: ordered, semiordered, and disordered. Our in vitro analysis indicates successful cell attachment and distribution throughout the scaffolds, with little evidence of cell death after seven days. This study demonstrates the importance of electrostatic control for reducing destabilizing polymer charge effects and enabling the fabrication of morphologically suitable scaffolds for tissue engineering.