Man has always been inspired by his innovations from what God has placed in nature in terms of models, systems and elements in order to solve human problems, which has come to be called "biomimicry."
In this context, a group of Japanese researchers, from the National Institute for Materials Science, Hokkaido University of Education and Hamamatsu University School of Medicine, have created an adhesive structure inspired by nature.
We learn from flies
The results of the team’s study have been published in the journal Communications Biology, affiliated with the prestigious Nature Publishing Foundation.
According to the press release published on the Eurek Alert website on 28 August, the team has succeeded in developing an easy and inexpensive way to produce an adhesive structure capable of frequent attachment and detachment.
He explained that the design of the structure of this material was inspired by the adhesive bristles in the form of a spoon on the pads of the feet of flies, and the method of its production was inspired by the formation of the hair-like structures in pupae. These environmentally sound technologies can contribute to a more sustainable society.
As the press release indicates, many types of manufactured products are fortified with strong adhesives. However, the use of these adhesives hinders recycling processes, which conflicts with efforts to promote the circular economy. For this reason, adhesive technologies capable of repeated attachment and detachment have been designed and developed.
The biomimetic approach, which seeks to develop high-performance adhesive technologies, seeks to mimic the elaborate adhesive structures found in living organisms. However, this approach is often costly because it requires the use of fine electromechanical systems to create complex structures.
Foot pads for virgins
This research group focused on bio-adhesive structures (for example, insect foot pads) that are known to form in an energy-efficient way at room temperature. The group has developed adhesive structures and effective methods to create them by simulating biological processes.
In this research project, the group focused specifically on spoon-shaped adhesives, which grow on fly-foot pads as a model for developing adhesive structures that can be repeatedly attached to and separated from objects.
The research group observed the biological process by which hair-like structures are created in Drosophila melanogaster by staining the legs of flies for immunohistochemical analysis and labeling of cytoskeletal actin using fluorescent dyes.
As a result, the research group discovered that the adhesive footbed pad sets form in a simple two-step process:
(1) The component cells of the cytoskeleton elongate, the cytoskeletal actin filaments accumulate in the cells at the distal ends of the elongated cells, forming the spoon-like structures.
(2) Epidermal deposits form on the surfaces of the patches, causing them to harden.
Technology and applications
The research group succeeded in developing a similar simple two-step process to fabricate the spoon's adhesive frame at room temperature, by: stretching the nylon fibers to form the spoon's structure, and hardening it.
It was emphasized that the structure's adhesion strength and ease of detachment differ, depending on the direction in which it is being pulled away from the object to which it is attached, similar to the mechanisms that insects use to attach or separate themselves from objects.
The single-phase fibers are strong enough to suspend a silicon wafer weighing 52.8 g. Extrapolating from this, a beam of 756 fibers (9 cm2 in cross-sectional area) can be expected to support a person weighing 60 kg.
This adhesive structure, capable of repeated attachment and detachment, may provide a variety of new robotic applications. For example, it can be incorporated into industrial robot arms to enable it to better handle slippery objects, and it can be incorporated into outer robots' legs to allow them to climb vertical walls like insects.
The reusable adhesive structure, low cost and energy-saving production method, environmentally friendly technology can contribute to making society more sustainable.