The application of tissue engineered constructs is a promising approach in regenerative therapies for damaged skeletal muscle tissue. It aims to deliver healthy and functional cells on a mechanically supporting matrix to the damaged area of the tissue. Moreover, aligned and patterned topographies can guide cell alignment and support the formation of aligned myotubes. Therefore, the development of highly aligned scaffolds based on polycaprolactone (PCL) has been studied extensively [1]. In this study, aligned polycaprolactone/collagen (PCL/Col) biocomposite nanofibers were fabricated via electrospinning using environmentally benign acetic acid as solvent. Acetic acid was used only once with the PCL/Col material combination, resulting in very inhomogeneous fibers and bead formation [2]. Therefore the solubility and spinnability of different PCL/Col ratios and different collagen batches were investigated. The most suitable solutions were spun at various spinning parameters and collected with different collector setups in order to determine ideal processing conditions for the fabrication of highly aligned nanofibers. Light microscopy and SEM were used to investigate the fiber morphology, yield and alignment. The results demonstrate that ultrasonic treatment helps to fully dissolve PCL and that it is possible to fabricate homogenous PCL/Col fibers. Nanoscale fiber diameters can be achieved, depending on the process parameters. Additionally, various parameter fields were investigated in order to determine the most stable and suitable parameters for nanofiber fabrication [3]. In the final step, various collagen batches were analyzed according to their viscosity and spinnability, to reveal how settings have to be adapted to the challenging batch-to-batch consistency of natural polymers. [1] Doergens, A.; Materials Letters, 2015, 140, 99. [2] Yogeshwar C., V.; Journal of Applied Polymer Science, 2012, 125, 3221. [3] Dippold, D.; Materials Science and Engineering C, 2017, 72.