When light teaches materials to self-organize: Writing nature-like 3D nanowrinkles

Wrinkles are everywhere in nature. They shape the surface of leaves, insect wings, and even the tiny finger-like structures that line the human intestine. These patterns are not just decorative. They control how surfaces interact with light, liquids, and living cells. However, reproducing such intricate textures in the lab, especially in three dimensions and at the micro- and nanoscale, has long challenged scientists.

In the International Journal of Extreme Manufacturing, researchers from the Technical Institute of Physics and Chemistry at the Chinese Academy of Sciences now report a way to build such surfaces from the bottom up. By combining ultrafast laser writing with a natural pattern-forming process known as Turing self-organization, the researchers have developed a method to "program" 3D nanowrinkles inside soft materials. 

At the heart of the approach is femtosecond laser direct writing, which uses extremely short laser pulses to solidify materials with very high spatial precision. To this, the researchers added a reaction–diffusion mechanism first proposed by mathematician Alan Turing, in which simple chemical interactions spontaneously generate ordered patterns. When the laser-induced polymerization and the Turing process occur together, nanoscale wrinkles emerge naturally as the material is written.

"Instead of carving patterns into a surface, we let the material organize itself while we guide it with light," explains Prof. Mei-Ling Zheng, the corresponding author of the study. "This gives us both the freedom of self-organization and the accuracy of laser fabrication."

A key innovation is the use of laser polarization to control the outcome. By changing the polarization direction, the team can decide how the wrinkles grow. In some cases, the wrinkles lined up into ordered nanoscale ridges; in others, they grew into vertically arranged pillar-like patterns. The size, orientation, and spacing of these features could be well tuned by adjusting laser parameters.

To understand and predict when these patterns would appear, the scientists also developed an accessible theoretical model that links laser settings to wrinkle formation. Using a hydrogel based on methacrylated hyaluronic acid, a material commonly used in biomedical research, they showed how and when these patterns emerge, turning a once mysterious process into a controllable manufacturing tool.

With this level of precision, the team recreated several iconic natural surfaces. They produced moth-eye patterns known for reducing reflection, replicas of cicada wings with their distinctive textures, and structures resembling intestinal microvilli, which dramatically increase surface area in the human body. These examples highlight how the method can translate biological inspiration into engineered materials.

The team also demonstrated a practical application in chemical sensing. By coating the nanowrinkled surfaces with a thin layer of silver, they produced surface-enhanced Raman scattering substrates capable of detecting extremely small amounts of a test molecule. The sensors identified signals at concentrations as low as one part per billion.

"The ordered nanowrinkles do two jobs at once," Prof. Zheng explains. "They help capture molecules on the surface and, at the same time, enhance the optical signal. That combination is what leads to such high sensitivity."

So far, the method works best with soft materials that carry surface charges, such as hydrogels. Extending it to other organic and inorganic materials, and improving the mechanical strength of structures formed at low material concentrations, are important goals for future research.

By blending laser precision with nature's own pattern-forming rules, this research opens new possibilities for bio-inspired surfaces, ultra-sensitive sensors, and materials designed to interact intelligently with cells and light. It suggests a future where complex nanoscale structures can be written as easily as a pattern of light, yet carry the sophistication of the natural world.

International Journal of Extreme Manufacturing (IJEM, IF: 21.3) is dedicated to publishing the best research related to the science and technology of manufacturing functional devices and systems with extreme dimensions (extremely large or small) and/or extreme functionalities

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