**5. Conclusions**

The method of BiSA was presented in detail and applied to a first case study. The integration of bio-inspiration into sustainability and sustainability assessment proved to lead to new insights and a better connection to actual development processes. Furthermore, the connection of system properties derived from biology showed to provide improved access to the overall sustainability performance for practitioners. The results are depicted in a reduced approach, providing a single value for each aspect, including burdens and functions. However, several main points stay unresolved due to the limited amount of conducted studies so far. Since the project in which the evaluation was developed will be continued, an ongoing application of the assessment model is expected. Thereby, several key points will be investigated:


Furthermore, a comprehensive investigation on the interaction of multifunctionality (both simultaneously and temporally separated) and resource demand will be performed. This will include the assessment of functionality as multidimensional set of functions and underlying properties enabling self-maintenance of living organisms making use of resources under environmental stress. The concept of bio-inspired sustainability provides a consistent framework including a sustainability model and a thereupon developed assessment system including all three dimensions of sustainability for both intended functions and unintended burdens. Its assessment is performed based on a consistent model on the basis of life cycle thinking and aims to reintegrate the principles of nonhuman biological systems into product development to purposefully develop sustainable solutions. While providing a first implementation, the model will be further developed towards a tool with a higher degree of automation and adapted in conventional, bio-inspired and biobased practical application.

**Acknowledgments:** The authors especially thank the German Research Foundation DFG for funding the CRC-Transregio 141 "Biological Design and Integrative Structures—Analysis, Simulation and Implementation in Architecture", in which the bio-inspired sustainability assessment has been developed. The co-author, H. Dahy developer of Bio-flexi, would like to thank the University of Stuttgart for the funded technology transfer project (HDF flexible BIO-Faserplatte), for the further development of the product and the Agency of Renewable Resources (FNR) under the German Ministry for Consumer Protection, Food and Agriculture (BMEL) for funding the project PLUS-funding number FKZ: 22008413 in which among others, upgrading systems for mass-production of NFRP have been developed. In addition, the authors thank the project partner companies Naftex GmbH—Germany where the extrusion took place, think-blue company—Germany for providing the extrusion tool and K. Westermann GmbH + Co. KG Company—Germany for assisting in the veneering finishing of the Bio-flexi.

**Author Contributions:** Rafael Horn has developed the bio-inspired sustainability assessment and performed the assessment of the case study; Rafael Horn, Johannes Gantner and Philip Leistner have written and harmonized the assessment related chapters, Hanaa Dahy provided the information on Bio-flexi and wrote the technology-related application chapters, Olga Speck wrote the biology-related chapters and supported the assessment development with biological expertise.

**Conflicts of Interest:** The authors declare no conflict of interest.
