Nature is an incredibly useful source of inspiration. Whenever you have a problem that is difficult to solve, try to find where nature has already solved a similar problem, and adapt the solution to yours. Previous examples on SynTAROTis can be found in Natural inspiration, Natural inspiration 2, Natural inspiration 3, Natural inspiration 4, Natural inspiration 5, Natural inspiration 6, and Natural inspiration 7. Here are three more examples:
Spider glue
The problem: In wet or highly humid conditions, glue and the surface it is supposed to stick to, become … unglued. For example, paint peels away from walls as a slippery layer of water forms between the surface and the glue. Another example is bandages separating from the skin in the bath or swimming pool.
This layer of water—known as interfacial water—is a significant problem for the developers of commercial, synthetic glues.
The solution: spider glue.
The sticky glue that coats the silk threads of spider webs is one of the strongest materials found in nature. The glue is a hydrogel, meaning it is full of water. One would think spiders would find it difficult to catch prey, especially in humid conditions. However, this glue is one of the most effective biological adhesives in nature.
The glue consists of three elements: two specialized glycoproteins (a collection of low molecular mass organic and inorganic compounds, or LMMCs), and water.
The LMMCs are hygroscopic (water attracting), acting as primary binding agents to the surface. The LMMCs move water away from the boundary between the glue and the surface, keeping the glue soft and tacky enough to stick to the surface.
Glycoprotein-based glues have been identified in several other biological types of glue, for example in fungi, algae, diatoms, sea stars, sticklebacks, and English ivy.
The research is being done at the University of Akron’s Biomimicry Research Innovation Center, which specializes in emulating biological forms, processes, patterns and systems to solve technical challenges.
Sources
Singla, S., Amarpuri, G., Dhopatkar, N. Blackledge, T.A., and Dhinojwala, A. (2018). Hygroscopic compounds in spider aggregate glue remove interfacial water to maintain adhesion in humid conditions. Nature Communications, 9(1). DOI: 10.1038/s41467-018-04263-z
University of Akron. (2018, June 5). Spider glue research resolves sticky problem: The way spider glues function in humid conditions provides clues for better commercial adhesives. ScienceDaily. Retrieved October 8, 2018 from www.sciencedaily.com/releases/2018/06/180605120816.htm
Spider silk
The problem: Metal plates are often inserted to repair broken load-bearing bones, such as those in the leg. The problem is that some metals leach ions into the surrounding tissue, causing inflammation and irritation. Metals are also very stiff: if a metal plate bears too much load in the leg, the new bone may grow back weaker and be vulnerable to fracture.
The solution: spider silk.
Silk fibroin is a protein found in the silk fibres spun by spiders and moths. It is known for its toughness and tensile strength. It is also biodegradable.
Researchers at the University of Connecticut have succeeded in making a dense, biodegradable composite of silk fibres that is strong and stiff, yet not so much so that it would inhibit dense bone growth. It is flexible, which will allow patients to retain their natural range of motion and mobility while the bone heals.
This composite starts to degrade after a year, with no surgery required to remove it.
Silk fibroin is already used in medical sutures and tissue engineering because of its strength and biodegradability.
Sources
Heimbach, B., Tonyali, B., Zhang, D., and Wei, M. (2018). High performance resorbable composites for load-bearing bone fixation devices. Journal of the Mechanical Behavior of Biomedical Materials, 81:(1). DOI: 10.1016/j.jmbbm.2018.01.031
University of Connecticut. (2018, April 19). Spider silk key to new bone-fixing composite. ScienceDaily. Retrieved October 8, 2018 from www.sciencedaily.com/releases/2018/04/180419130915.htm
Octopus skin
The problem: Controlling soft material to form a particular shape.
The solution: octopus skin.
Researchers at Cornell University have developed a material with a stretchable surface and a programmable 3D texture. Like octopus skin, on which the material is modelled, these properties allow the material to "camouflage" itself by changing its colour, shape, and texture.
The material initially has a flat surface, but can be morphed into three-dimensional ones on demand. This quality can be compared to inflating a balloon to, for example, a box shape.
A cephalopod changes its shape to blend into its surroundings. It does this by activating its papillae--protuberances that are controlled by erector muscles under the skin. The new material mimics this property by combining two materials: a fibre mesh, embedded in a silicone elastomer.
This method is known as Circumferentially Constrained and Radially Stretched Elastomer (CCOARSE). A patent is in the works, and the scientists say it a simple process that could fit a range of applications. MIlitary camouflage is one example. In robotics, a part of the robot could be inflated to carry out a particular task. The material can also be transported in a flat state, and inflated into the desired shape on arrival.
Wikipedia has a video showing an octopus moving and changing its colour, shape and texture, at https://upload.wikimedia.org/wikipedia/commons/1/14/Octopus.ogv.
Sources
Fleischman, T. (2017, 12 October 2017). Octopus inspired 3-D texture morphing project. Cornell University. Retrieved 8 October from https://news.cornell.edu/stories/2017/10/octopus-inspires-3-d-texture-morphing-project
O'Callaghan, J. (2017, 13 October). This weird shape-shifting 3D material is inspired by octopus skin. IFLScience. Retrieved 8 October 2018 from https://www.iflscience.com/technology/this-weird-shapeshifting-3d-material-is-inspired-by-octopus-skin/