This article is from WeChat public account: Technology lit life (ID: kexuelife_com) , author: Akon, interview: ordinary sauce, Arkansas, title figure from: Sharklet official

Last night, the fat man with his own headline attributes hyped a concept that sounded delicious and amazing. At a press conference held at the Beijing University of Technology Olympic Stadium, Luo Yonghao announced a “new” technology that came out a few years ago-the shark pattern.

Swimming enthusiasts should be familiar with the concept of “shark skin bionic”. As early as 2000, the famous sports swimwear brand Speedo (速比 涛) launched its first sharkskin-inspired Fastskin bathing suit, which claims to imitate Rough furrows on the surface of sharkskin to reduce drag while advancing in the water. The most famous beneficiary of this new technology is the famous swimmer Phelps, known as “flying fish”.

Shark and real shark skin | Source Sharklet’s official website

#A delicious tip: In the Japanese food, shark skin will be used to grind wasabi … #

Fastskin swimwear is the first large-scale public appearance of shark skin bionic material. It is based on a research result: that sharks can travel at high speed in water, thanks to the special structure on the surface, which reduces the resistance of water. But over the past few decades, scientists have questioned whether the natural structure of this microgrooved tooth is really effective. Relevant research has been arguing on this issue for over thirty years, making the function of this very rough material an extraordinarily difficult topic (For this argument, you can refer to the nutshell article “What? Shark skin actually increases resistance?”) .

In spite of controversy in academia, in the eyes of athletes, sharkskin swimwear does improve the performance of the game. This technology even changed the rules of the game: In 2009, the FINA introduced a new rule called the “Dubai Charter”, which banned the use of swimsuits covering the whole body during the competition, and proposed more detailed information on material thickness and other aspects. specification.

In addition to resistance, another characteristic of shark skin has attracted the attention of another group of scientists: The skin surface of other large marine life is often settled by small organisms such as seaweed and barnacles, but it is rare on the surface of sharks. Phenomenon-therefore, the micro-groove structure of shark skin has also become a source of inspiration for resistance to microorganisms.

This is the story told by Luo Yonghao yesterday, shark bacteriostatic material.

Why is “Shark” antibacterial?

To discuss the bacteriostatic principle of the microgroove structure, we must first understand what the contact surface is when the liquid is in contact with the solid.

We know that when a drop of water drops on the glass, water will quickly spread on the glass, so glass is considered a “hydrophilic” material; if the glass is electroplated Or spray a special film, and then drop a drop of water at this time, the water can be aggregated into a small water droplet. We will call this film “hydrophobic” -hydrophobic and oleophobic The thin film coating is an important configuration to keep the mobile phone screen without fingerprints and keep it smooth.

In the research of interface science, such problems are called “wet” . The difference between hydrophilic and hydrophobic materials can be judged by “contact angle” .The droplets on the solid surface will form such an interface under the action of surface tension. At the triple point of gas, liquid and solid, the angle formed by the gas-liquid interface and the solid surface is liquid and solid “Contact angle”, and as the contact angle goes from large to small, the droplets will form different shapes on the solid surface as shown below.

Left: contact angle θc; right: droplet shape at different contact angles. Figure | wikipedia: Wetting

On an ideal plane, the contact angle between liquid and solid can be calculated according to Young’s equation:

γSG-γSL = γLGcos (θc)

Among them, γSG, γSL, and γLG are the surface tension coefficients of solid gas, solid-liquid, and gas-liquid, respectively. It is similar to the concept of surface free energy, but the description is different … remarks “label =” Remarks “> (Teacher: This question is beyond the outline, there is no need to take the exam) . Generally speaking, solid surfaces with lower surface free energy require a liquid with a lower tension coefficient to achieve wetting. For water, many surfaces are not wet.

Another important factor affecting contact angle is roughness. Under the rough surface, the non-wetting solid-liquid interface will form a larger contact angle. We often say that the lotus leaf is hydrophobic, part of which is the contribution from the rough surface. On the rough surface, it is different from whether the liquid fills the groove gap, and there are two different contact methods.

Source 丨

This is the first reason that sharks are used for bacteriostasis: On the surface of sharks, lower surface energy can reduce the contact area of ​​liquid stains with the surface, so it is difficult for stains to stay on the surface.

Even if the stain stays, bacteria will easily fall into the gap between the textures and be isolated from other bacteria. When the individual bacteria are scattered and unable to form a bacterial group, the bacteria cannot supply nutrients to each other, it is difficult to reproduce, and they will die quickly. Therefore, without bacteria, there is no biofilm, and the surface can be kept clean for a long time.

Bacteria growth comparison between smooth surface and shark surface | Source:

Smooth surface on the left and shark-textured surface on the right. You can see that the smooth surface can stick more bacteria from the beginning. Over time, the bacteria on the smooth surface multiply faster and form larger bacteria. Community.

According to the results of the paper by Sharklet inventor, Sharklet’s CTO, University of Florida professor Anthony Brennan (Anthony Brennan) , Shark Can inhibit the biofilm formation of Staphylococcus aureus [2] , can reduce 81% of E. coli contact transmission and 76% of E. coli Reproduce [3] .

The design of this texture is also the result of continuous experimentation. Sharklet texture is more than twenty times smaller in size than the real sharkskin tooth structure, and its stripe width and gap are both 2 microns, which is close to the size of bacteria. Below are several textures that Dr. Brennan has tried. After constant experimentation and comparison, Brennan chose the optimal design.

Textures Brennan tried | Source: Schumacher et al. [4]

It looks great, but is it useful?

Articles that have been treated with a shark-stripe surface are not prone to sticking to dirt and bacteria. This means that as long as anything related to the word “clean”, it can be fun.

Imagine, If the antibacterial effect of the shark print achieves the desired effect, it will bring us a lot of convenience.

For people with cleanliness in their lives, the mobile phone will not be full of fingerprints and oil; the handlebars of shared bicycles will never be dirty; the refrigerator will never dispel the unpleasant odor.

For fitness enthusiasts, gym equipment and yoga mats no longer have “traces of others”.

For delicate pig girls and boys, the face wash machine will never hide dirt.

For doctors and patients, no drugs or disinfectants are needed, and infection prevention for medical devices and consumables can be an effective barrier, and the drug resistance caused by bacterial survival can be greatly reduced.

How wonderful.

From November 12th to November 20th, Luo Yonghao sent 14 Weibo posts in succession and asked if you knew some of the company’s management. heThe company mentioned covers mother and baby, sports, refrigerators (including his old friend Siemens) , travel mugs, bathrooms, toothbrushes, sex toys , Keyboard and mouse, medical silicone, dental care, leather goods, home improvement wallpaper, contact lenses, toys, tableware. He seems to be creating a department store empire.

Luo Yonghao began to frequently ask some product categories and corresponding companies on Weibo:

On November 20th, the frequency of questions reached its peak:

How was the shark pattern created?

Luo Yonghao intentionally used Sharklet to occupy your life, but the question is, to create a continuous, defect-free 2 micron wide fine structure on a large area of ​​different materials and different shapes, how does he plan to make it?

We asked the Sharklet team about this. The reply is-

The shark pattern manufacturing process is mainly divided into two types, injection molding process and lamination (release paper) process. For the injection molding process, Sharklet can provide shark-textured molds for production lines of various commodities, thereby reducing production costs.Marginal cost of production. The laminating process is provided by paper giant Sappi.

Both processes have excellent mass productivity.

Injection Process | Source: Gfycat

The two processes also have good material compatibility. They are suitable for plastics, PU, ​​silicone and other materials, but for the time being they are not suitable for glass and ceramics.

For the problem that the materials and molds may not have a sufficient degree of fit during the processing process, which leads to the problem of filling air bubbles, Dr. Xu Binjie of Sharklet said that it can be solved by adjusting the injection parameters. “Plastic” problem, the production line transformation of all mass-produced products will go through standard finished product testing and abrasion resistance testing processes to ensure product quality and safety.

Dr. Binjie Xu showed the surface of ordinary yoga mat and shark-printed yoga mat under the microscope. It can be seen that the surface of an ordinary yoga mat is irregular and has many holes, which are more likely to retain bacteria than a smooth surface. The surface of a shark yoga mat is very regular and smooth. Due to the same height of the microstructure, it is more detailed than traditional products. The smooth surface may bring better performance in mechanical properties.

Micro image of common yoga mat (top) and shark yoga (bottom) mat | Source: Sharklet

Last question: Bacteriostatic materials, what is the value?

The audience once again shouted to understand Viva, so … how do we understand Luo Yonghao’s “shark skin”?

Strictly speaking, this time Luo Yonghao released a slightly “virtual” technology, because apart from the yoga mat, you do n’t have a single standardized product that you can actually hold in your hand. A sample of the “texture” technology is shown (only yoga mats were sent to the media) . Lao Luo also said at the press conference that an advanced technology that wants to be commercialized after being invented will go through a very difficult process.

For example, Sharklet and COOK made a shark-patterned catheter for 5 years, and a shark-patterned catheter is 10 times the price of an ordinary catheter.

“A lot of companies are doing it and there is no later … and then there is no money.” Lao Luo said with a mockery, “like some companies.”

Because it was too difficult, Sharklet was awarded by Hangzhou company Peaceful Uni in 2017on acquisition. The latter found a leather factory and made a mass-produced shark-printed PU (Artificial leather) products (In fact, it is a yoga mat) . In addition, there are products such as pacifiers, which can also be mass produced.

Luo Yonghao said that at the beginning, he helped Peng Jinzhou solve the problem of the mouthpiece of Ono electronic cigarette. As a result, he accidentally became Shakerlet’s global partner and chief flicker officer.

Luo Yonghao at the end of 2019 does not care about Luo Yonghao in 2012.

Luo Yonghao himself said that the conference was essentially a business invitation conference. Our site perception is: the essence is still through the consumer (to C) Forcing the brand merchant (to B) . Consumers will ask, “This technology is so good, why haven’t you used it?” This forces brands to adopt this technology.

Peaceful Union meets a mysterious Party A who cooperates with you. “That’s me.” Luo Yonghao said that at the beginning, he helped Peng Jinzhou solve the problem of the mouthpiece of Ono electronic cigarette. As a result, he accidentally became Sharklet’s global partner and chief flicker officer.

It may not be appropriate for the Chief Huyou Officer to ridicule or talk about feelings now. Whether it is crazy to tweet “help” before the press conference, or on-site or even commercialization authorization, the commercialization of high-tech technology is the issue that everyone cares about most.

First is the medical field. Sharks are purely physical microstructures and nothing more. Can “harass and torture bacteria without killing them.” Lao Luo said that the shark pattern technology is useful for any “super bacteria” (such as methicillin-resistant Staphylococcus aureus) .

Luo Yonghao said that currently the cost of urinary catheters can be greatly reduced, and there are good resources and contacts in the manufacturing industry.

Second? “Everything you can use can be used.” For example, next spring, you may buy high-end antibacterial chopsticks with shark pattern technology.

Others such as sporting goods (including sports shoes) , refrigerator freezer, watch strap, and even sex toys, but Lao Luo is very stable “Violation of relevant laws and regulations”, so coded.

Lao Luo in Shangyan said to the 143 brands at the scene: “The costs are completely controllable. People in related industries are welcome to contact us.”

Lao Luo started to talk about Sharklet’s market advantages, but the classmates in front of us are hungry.

First, I wish Luo Yonghao to be able to turn over the shark.


[1] Boomsma, A., & Sotiropoulos, F. (2016). Direct numerical simulation of sharkskin denticles in turbulent channel flow Physics of Fluids, 28 (3), 035106. doi: 10.1063 / 1.4942474

[2] Chung, KK, Schumacher, JF, Sampson, EM, Burne, RA, Antonelli, PJ, & Brennan, AB (2007).Impact of engineered surface microtopography on biofilm formation of Staphylococcus aureus. Biointerphases, 2 (2), 89–94. Doi: 10.1116 / 1.2751405

[3] Reddy, ST, Chung, KK, McDaniel, CJ, Darouiche, RO, Landman, J., & Brennan, AB (2011). Micropatterned Surfaces for Reducing the Risk of Catheter-Associated Urinary Tract Infection: An In Vitro Study on the Effect of Sharklet Micropatterned Surfaces to Inhibit Bacterial Colonization and Migration of Uropathogenic Escherichia coli. Journal of Endourology, 25 (9), 1547–1552. Doi: 10.1089 / end.2010.0611

[4] Schumacher, JF, Long, CJ, Callow, ME, Finlay, JA, Callow, JA, & Brennan, AB (2008). Engineered Nanoforce Gradients for Inhibition of Settlement (Attachment) of Swimming Algal Spores. Langmuir, 24 (9), 4931–4937. Doi: 10.1021 / la703421v

This article is from the WeChat public account: Technology Lights Life (ID: kexuelife_com) , author: Akon, interview: ordinary sauce, Akon