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Electrospinning is used for producing nonwovens for medical polymer-based implants, such as prosthetic valves or covered scaffolds. In this study, nonwovens for prosthetic venous valves are investigated regarding their morphology and mechanics in physiological medium. Spinning molds were developed based on previous venous valve leaflet designs, 3D printed in different sizes and covered with electrospun nonwovens. Samples were stored in a physiological 0.9% saline at 37°C to investigate the influence of fiber rearrangement and swelling in medium for several weeks. Two different nonwovens of thermoplastic silicone-based polycarbonaturethane (TSPCU) were compared. Tensile test results show that storage in medium has a relevant influence on the mechanical properties. SEM images of TSPCU show substantially increased fiber diameters after 8 days stored in medium. After detaching the valve leaflet nonwovens from the molds, shrinkage of the material of approximately 12% was detected. A suitable valve size could be identified for joining with the stent structure into an interventional prosthetic venous valve. The results demonstrate the influence of storage conditions on the morphological and mechanical properties of electrospun TSPCU nonwovens. For development and dimensioning of venous valve leaflets, this change in mechanical behavior and possible shrinkage of the material has to be considered.

Electrospun fiber nonwoven materials of different polymer classes provide promising perspectives in almost all fields of application, including medical science. In this paper we present the fiber generation of selected biostable polymers (PBT, TPC-ET, PA 6.12 and PVDF) by direct electrospinning, as an extremely powerful tool for manufacturing of new superfiber implant materials. This initial study includes the variation of some relevant process parameters, such as polymer concentrations or electrode spacing. The influence on fiber morphology, tensile strength and biocompatibility is shown. The results presented indicate that the choice and combination of materials is crucial for the application on load-bearing implants, independent of the processing technology and thus of the fiber bonding, delamination or fiber strength.

Electrospinning is a method for producing fibrous polymer scaffolds that can be applied in drug delivery systems as well as for polymer-based implants. Biodegradable polymers for the purpose of cardiac tissue engineering are often applied as fibrous scaffolds for morphological mimikry of natural matrices but also drugeluting approaches are very promising. Hydrolytic degradation is one of the key parameters for successful application. The focus of our investigations is on monitoring accelerated in vitro degradation of electrospun nonwoven scaffolds. In the presented study degradation of poly(Llactide) is accelerated by alkaline hydrolysis. The process is characterized by weight loss, loss of molecular mass, surface morphology and thermal behavior of nonwoven samples, showing a fast degradation of the fibrous material within two weeks.

Electrospun poly(L-lactide) (PLLA) nonwoven represent potential options for biodegradable medical implants. They can be manufactured with high reproducibility and do offer the potential for chemical modification to alter matrix properties. In our study, we investigate the mechanical, thermal and morphological properties of PLLA fiber matrices. Fibrous nonwovens were fabricated from polymer solution by needle electrospinning. The polymer solutions were loaded with Triton X-100 (TX- 100), formic acid and tetraethyl ammonium chloride (TEAC) with respect to polymer weight. Morphology of the PLLA nonwoven scaffolds was examined with SEM. We performed uniaxial tensile tests and differential scanning calorimetry (DSC). Different concentrations of the additives TEAC, formic acid and Triton X-100 lead to strong changes regarding mechanical and thermal properties of the electrospun PLLA fiber matrices. In comparison with mechanical properties of established biological tissue materials, the results indicate the suitability for medical applications.

The usage of synthetic scaffolds is a promising approach in development of implant materials. In this study we fabricated nanofibrous nonwovens of polyamide 6 (PA-6) by means of electrospinning and performed a systematic characterization with regard to the mechanical and biological performance of scaffold materials. Mechanical strength was assessed by uniaxial tensile testing and biological performance was evaluated by measuring cell viability and qualitative analysis of cellular morphology when human umbilical vein endothelial cells (EA.hy926) or human fibroblasts (HT-1080) were grown on polymeric substrates. While all polymeric materials exhibited an excellent biocompatibility with respect to cell viability, their surface topography promoted the adhesion of endothelial but not fibroblast cells. A better understanding of the physicochemical and morphological material properties with a selective impact on cell adhesion will help to further improve biocompatibility of nonwovens for biomedical applications.

The generation of electrospun nonwovens from polyimide (PI) is challenging as the fibers are prone to distinct delamination. In consequence, the resulting nonwoven material has particularly low structural integrity and loose fibre interlocking, demanding for a follow-up treatment, such as high temperature thermal treatment. In this work, a facile method for a post-processed treatment of PI nonwoven is presented in order to obtain a mechanically stable material while maintaining the characteristics of the electrospun nonwoven. The procedure was performed using a solution of EDA in methanol at 37 °C and ambient pressure to achieve a modified fiber interaction. Overall, the developed protocol opens new possibilities in the processing of PI into delamination-free nonwovens. Potential adverse effects of a high temperature thermal treatment are being avoided, and new applications in the field of medical devices may become accessible.

Electrospinning (ES) is a suitable and cost effective method to mimic the chemical composition, morphology, and functional surface of natural tissues, for example of the nervous, dermal, vascular, and musculoskeletal systems. This technique is a versatile tool to obtain tailored fibrous scaffolds from various polymer materials. By varying the diameter, porosity, orientation, layering, surface structuring, mechanical properties and biodegradability of the fibers the properties can be adapted for specific applications ranging from implantable medical devices to wound repair and protective clothing. Especially the combination of different polymer types offers a high potential. In this study electrospun two-component nonwoven structures of thermoplastic copolyester elastomer (TPC-ET) and bioresorbable polylactide (PLLA) were fabricated, using different ES setups. A comparative evaluation in terms of porosity, thermal and mechanical properties as well as required fabrication effort, was performed. Nonwovens made from polymer blends and coaxial spun core-sheath fibers showed similar tensile strength, which was higher than dual electrospun fabrics. Porosity was found to be in the range of 80 - 90%. By modifying the polymer solution and process parameters multicomponent nonwoven structures with tailored properties and drug release profiles can be manufactured. [ABSTRACT FROM AUTHOR]