Sabine Illner*, Jonathan Ortelt, Daniela Arbeiter, Valeria Khaimov, Katharina Wulf, Stefan Oschatz, Thomas Reske, Volkmar Senz, Klaus-Peter Schmitz and Niels Grabow Adaptable Superfibers as Implant Material Opening new paths to tailored polymer properties with optional drug incorporation Abstract: 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. Keywords: electrospinning, nanofiber, polybutylene terephthalate, polyamide, polyester elastomer, polyvinylidene fluoride. https://doi.org/10.1515/cdbme-2020-3120 1 Introduction Electrospun polymeric nanofibers with tailor-made, flexible three-dimensional porous structures and a high surface-to-volume ratio offer new solutions in various fields of application such as filtration, desalination, catalysis, tissue replacement, nutrient or drug supply and textile industry already today [1,2]. New biomimetic surface structures in the sub micrometer to nanometer range, both with or without local drug release, are also debated intensively and explored in the field of medical engineering [3]. Especially in the cardiovascular field, many implant surfaces could benefit from innovative fibrous structures, but are also subject to various restrictions and regulatory barriers. The vision of creating adaptive, implant-specific and drug-loaded surfaces that are anti-infective, flexible or expandable, chemically modifiable and cell-sensitive can be achieved relatively straightforward by using modern electrospinning or 3D-printing technologies. However, identification of chemically inert, long-term stable and yet processable materials which are clear for regulatory approval appears as an almost unresolvable challenge and has become an important topic of research worldwide. This is the background for our endeavors to iteratively introduce extraordinary materials and systematically expand the material portfolio. In this study we present first mechanical, morphological and biological investigations of promising polymers for implant coating or covering. The processing procedures have been established and optimized for a thermoplastic copolyester elastomer (TPC-ET), poly- vinylidene fluoride (PVDF), polyamide (PA 6.12) and polybutylene terephthalate (PBT). Furthermore, biocompa- tibility studies and mechanical tests in medium at 37°C were carried out. Each of the selected polymer classes has unique properties, such as high mechanical strength, thermal stability and excellent chemical resistance of PA 6.12 or the rubber- like and extremely elastic properties of TPC-ET. Being extremely versatile, PBT combines stiffness and toughness, superior electrical insulation properties and exceptional surface finish [4,5]. Even though all materials have exceptional chemical and physical properties, decisive factors for their use as implant material are often missing, be it long-term stability, availability or fatigue strength. In addition, the mechanical properties of the individual polymers are often insufficient to mimic biological materials. Therefore, the combination or layered structures with tunable local and controllable drug depots are indispensable for potential applications in biomedical engineering. ______ *Corresponding author: Sabine Illner: Institute for Biomedical Engineering, University Medical Center Rostock, Friedrich- Barnewitz-Str. 4, D-18119 Rostock, Germany, sabine.illner@uni- rostock.de Jonathan Ortelt, Daniela Arbeiter, Valeria Khaimov, Katharina Wulf, Stefan Oschatz, Thomas Reske, Volkmar Senz, Klaus- Peter Schmitz, Niels Grabow: Institute for Biomedical Engineering, University Medical Center Rostock, Rostock, Germany DE GRUYTER Current Directions in Biomedical Engineering 2020;6(3): 20203120 Open Access. © 2020 Sabine Illner et al., published by De Gruyter. This work is licensed under the Creative Commons Attribution 4.0 License.