Clarity of objectives and working principles enhances the success of biomimetic programs

Abstract

Biomimetics, the transfer of functional principles from living systems into product designs, is increasingly being utilized by engineers. Nevertheless, recurring problems must be overcome if it is to avoid becoming a short-lived fad. Here we assess the efficiency and suitability of methods typically employed by examining three flagship examples of biomimetic design approaches from different disciplines: (1) the creation of gecko-inspired adhesives; (2) the synthesis of spider silk, and (3) the derivation of computer algorithms from natural self-organizing systems. We find that identification of the elemental working principles is the most crucial step in the biomimetic design process. It bears the highest risk of failure (e.g. losing the target function) due to false assumptions about the working principle. Common problems that hamper successful implementation are: (i) a discrepancy between biological functions and the desired properties of the product, (ii) uncertainty about objectives and applications, (iii) inherent limits in methodologies, and (iv) false assumptions about the biology of the models. Projects that aim for multi-functional products are particularly challenging to accomplish. We suggest a simplification, modularisation and specification of objectives, and a critical assessment of the suitability of the model. Comparative analyses, experimental manipulation, and numerical simulations followed by tests of artificial models have led to the successful extraction of working principles. A searchable database of biological systems would optimize the choice of a model system in top-down approaches that start at an engineering problem. Only when biomimetic projects become more predictable will there be wider acceptance of biomimetics as an innovative problem-solving tool among engineers and industry.

Paradigms for biologically inspired design

“…While the main applications have focussed on static and semi-permanent adhesion (i.e. as a tape), the gecko uses the adhesion dynamically in a sequence of rapid attachments and detachments 33 .…”

“…However, the process of spinning occurring inside the spider, where the silk changes from a liquid phase in the glands and ducts to the solid phase extruded by the spinnerets via a complicated mechanical and chemical process is still not fully understood (step 3 not fully completed) 37 . Thus, while biomimetic applications including in protective clothes and crash helmets have been identified (step 4 and 5), and the biochemical structure is known and the liquid silk proteins can be produced by genetically modified bacteria, the biomimetic spinning process has not yet been mastered and artificial silk is therefore currently much inferior to natural silk 33 . However, while commercial products relying on spider silks' unique material properties are a long way off (step 6 and 7 not achieved), the biocompatibility and organic breakdown of artificial or reconstituted silk makes it potentially very useful as suture threads in surgery and for other biomedical applications 38 .…”

Ultrastructure of spider thread anchorages

“…Depending on the evolutionary history of the organism that produces the silk and the biological function the silk fulfils, its properties may vary enormously, and this variation modulates the ecology of silk use (Blackledge & Hayashi, ; Blamires, Blackledge, & Tso, ; Craig, ). Because silks are natural polymers that are tough, light weight, biodegradable and biocompatible, there is an increasing interest in unraveling the molecular basis that is responsible for these outstanding properties to develop new textile and biomedical applications (Altman et al, ; Altman et al, ; Arcidiacono et al, ; Blamires et al, ; Huemmerich, Slotta, & Scheibel, ; Osaki, ; Vollrath & Knight, ; Wolff, Wells, Reid, & Blamires, ). As with most biological materials, the properties of silks are based in a hierarchical structure, and from molecular to microscopic structure different effects are acting synergistically together (Cranford, ; Keten, Xu, Ihle, & Buehler, ; Wolff, Grawe, Wirth, Karstedt, & Gorb, ; Xu, Gong, Yang, & Liu, ).…”

“…Depending on the evolutionary history of the organism that produces the silk and the biological function the silk fulfils, its properties may vary enormously, and this variation modulates the ecology of silk use (Blackledge & Hayashi, 2006;Blamires, Blackledge, & Tso, 2017;Craig, 1997). Because silks are natural polymers that are tough, light weight, biodegradable and biocompatible, there is an increasing interest in unraveling the molecular basis that is responsible for these outstanding properties to develop new textile and biomedical applications (Altman et al, 2002;Altman et al, 2003;Arcidiacono et al, 2002;Blamires et al, 2017;Huemmerich, Slotta, & Scheibel, 2006;Osaki, 1996;Vollrath & Knight, 2001;Wolff, Wells, Reid, & Blamires, 2017).…”

Spider Silk Biomimetics Programs to Inform the Development of New Wearable Technologies

“…Despite great urgency being placed on the development of new environmentally benign materials, there have been few examples of the successful development of processes producing materials that mimic silks or other animal products (Wolff et al, 2017). Biomimetics, or the transfer of functional principles from living systems to engineering applications offer one way forward (Sanchez et al, 2005;Pawlyn, 2011;Wegst et al, 2015;Wolff et al, 2017).…”