Inspired by octopuses: active nanophotonics enables photonic skin
Drawing inspiration from octopods’ ability to adapt, a team of researchers from Stanford University (USA) and Paderborn University have developed a thin film-like platform that is able to dynamically change not only its colour, but also its surface structure. In the future, this technology could be used for intelligent camouflage systems, flexible displays, robotic systems, or even bioengineering applications such as targeted cell manipulation. The findings have now been published in the renowned journal ‘Nature’.
This concept is built on a relatively widespread composite polymer film that contains the material polystyrene sulfonate, which swells when exposed to moisture and forms delicate nanoscale structures. Junior Professor Nicholas Güsken, Department of Physics at Paderborn University, explained: ‘Electron beam lithography, which is employed in semiconductor manufacturing, can be used to precisely pretreat the film so that certain areas swell by varying amounts. This creates controlled surface patterns that appear when exposed to moisture and change from glossy to matt depending on the water content.’
The surface structure affects light diffusion and creates a realistic visual result. In addition, Fabry-Pérot resonators were used to generate colours, in a process where the metallic layers in the polymer film alter the wavelength of the reflected light depending on the thickness of the film. This enables a single-colour film to transform into a complex, colourful pattern once moisture is introduced. The structures are reversible: controlling the water content in the surrounding area causes the surface to either revert to its original flat state or display specific new patterns. This allows the photonic skin to match a background, just as an octopus is able to do. „We are still far from achieving the full complexity of cephalopod physiology, with its intricate muscular control and real-time adjustment. This work brings us a step closer to one of their key capabilities, which is simulating not just the colour but also the texture of a surface in a lifelike manner", noted lead author Siddharth Doshi, a former PhD student at Stanford University who is now a postdoctoral fellow at Caltech.
Combining multiple layers allowed colour and texture to be controlled independently, something that had never previously been achieved. ‘Actively controlling light-matter interactions on a micrometre and nanometre level offers a wide range of opportunities for fundamental science, as well as for technological applications’, Junior Professor Güsken explained. Future developments will be seeking to integrate artificial intelligence (AI) and its subfield of computer vision, so that adapting to different backgrounds can take place automatically and in real time. In addition, the material technology will also be explored from an artistic perspective.
Junior Professor Güsken, who was previously part of the research group at Stanford, spent several months developing his own research group at Paderborn University. He was involved in designing and manufacturing the thin film layer under the project headed by Dr. Doshi.
View the paper: https://www.nature.com/articles/s41586-025-09948-2
Watch the Video: https://www.nature.com/articles/d41586-026-00101-1
