No one can compete with this plant when it comes to rock climbing

How does the ivy climb?

On the stem of the creeper, there are several small thin lines growing intermittently at the nodes of the stem, opposite to the leaves of the creeper, like the legs of the creeper. The foot of a creeper is actually something similar to a suction cup, and each suction cup is connected by a thin line to form its complete mobility. These thin lines stretch straight at first, and when the ivy needs to climb, the feet of the ivy will firmly stick to the surface of the wall, and the thin lines will become tendrils when they bend. Because the ivy has many tendrils, it can climb upwards with multiple legs, so its growth rate is extremely fast and it covers a wide area. Every time a tendril grows, the creeper will use it to climb up a little bit, clinging to the wall, waiting for the stem to elongate and new tendrils to grow again.

Why is the ivy so able to climb?

Don't underestimate those weak, very slender tendrils and suckers. If you don't use your fingers hard, it is still difficult to pull them off the wall. On this point, He Tianxian of the South China University of Technology agrees very much. The team found in 2012 that the average mass of a single sucker of a mature and dry creeper is about 0.0005 grams, and the average adhesive contact area with the substrate is only 1.22 square millimeters. But its adhesion force reaches 13.7 Newtons; a single sucker can bear 260 times its own weight during its growth and development, and the maximum pulling force it can carry is 2.8 million times its own weight. In other words, one foot of a creeper can support a bottle filled with 1.4 L of water.

The reason why the ivy can be firmly adsorbed on the surface of various objects is explained in detail from two aspects. The first is the unique structural characteristics of the sucker. Scientists used an electron microscope to scan the sucker of the creeper and found that: before touching the object, the tip of the tendril of the creeper is bulbous, composed of a large number of parenchyma cells, and a central area is a sucker. The surface is relatively smooth (Figure a, b).

Scanning electron microscope image of tendrils and immature suckers

When first touching an object, the micropores inside the suction cup secrete a large amount of viscous fluid, which gradually hardens over time (Fig. e).

Scanning electron microscope image of an immature sucker

At the same time, the sucker epidermal cells close to the contact point will elongate wildly, while other epidermal cells will maintain an anticline and separate so that the surface of the sucker will appear as if it is composed of a large number of balloon clusters brush morphology ( Figures d, e, f). These balloon clusters can be imitated according to the unevenness of the surface of the object, so as to further form the occlusion.

Scanning electron microscope image of a mature sucker

Early studies have shown that creeper tendrils contain high amounts of polyphenols and that the sticky substance secreted by fully-developed suckers is likely an acidic mucopolysaccharide. Later, with the development of compound analysis technology, scientists found that the mucus secreted by the ivy sucker was mainly a kind of debranched rhamnogalacturonan and some new compounds synthesized in a small amount.

Small plants, big uses

Professor Deng Wenli from the School of Materials Science and Engineering, South China University of Technology said,

the growth and development of ivy involve knowledge in many fields such as chemistry, biology, and machinery. The study of the microstructure and functionality of the ivy sucker will promote the development of biomimetic materials and bionic devices, which is of great scientific significance.

In 2015, someone designed a bionic dynamic exterior wall with a heat insulation function according to the meaning of a creeper climbing the wall, which effectively blocks the heat of sunlight outside the wall and has a dynamic decorative beautification effect.

Structural drawing of bionic dynamic exterior wall with thermal insulation function: 1-wall, 2-support rod, 3-blade

In 2019, the research group of Professor Xue Longjian from the School of Power and Mechanics of Wuhan University designed a bionic micro-pillar array adhesive pad based on the characteristics of creeper adhesion, which can achieve strong adhesion and controllable and reversible detachment on different rough surfaces.

SMP biomimetic micro-pillar arrays before and after adhesion

In the same year, in the journal Nature Communications, researchers from the Italian Institute of Technology (IIT) published a paper entitled "A Tendril-like Soft Robot with Variable Stiffness Driven by Dynamic Osmosis, showing us The world's first soft robot that imitates plant tendrils (not exactly like creepers), brings new ideas for the development of soft robots.

In 2021, the research group of Professor Wang Qigang from the School of Chemical Science and Engineering of Tongji University developed a new "crystal-like fiber-reinforced polymer gel" based on the polysaccharide mucus secreted in the micropores of the ivy sucker. This gel breaks through the limitations of different interfaces when objects are bonded, allowing more materials to adhere through a common interface.

Illustration of a crawling sucker whose microchannels release mucus to improve adhesion

In the same year, someone invented a creeper sucker-like bionic scaffold for periodontal tissue regeneration based on the creeper sucker structure, which can effectively promote the formation of the cementum-dentin interface. The unobtrusive creepers in life have occupied the high walls of the city by virtue of their unremitting climbing and gradually occupied a place in the field of scientific research. What reason do we have not to work hard?