ADVANCED MATERIALS & PROCESSES | APRIL 2025 12 SURFACE ENGINEERING LASER SURFACE TEXTURING KEEPS BACTERIA AT BAY Researchers from the Hopkirk Research Institute, New Zealand Food Safety Science & Research Centre, and Applied Technologies Group in New Zealand are developing a new approach to keep work surfaces free of bacteria in meat processing facilities. Instead of trying to prevent bacteria buildup, they created surfaces that stop bacteria from attaching in the first place. This is essential because bacteria from meat can attach, grow, and build into a biofilm that is difficult to remove, even on stainless steel surfaces. It can also aggregate, clumping together into an invisible mass stronger than its individual cells, which makes it harder to kill with antibacterial surface cleaners. Using lasers to etch the metal surface, researchers were able to create micro or nanoscale textures that make it difficult for microbial cells to attach. This laser-induced surface texturing also changes the metal’s water-repellent properties, another key to halting bacterial growth. “These nanoscale and microscale surface textures mimic natural antimicrobial surfaces, such as those found on cicada wings and shark skin,” says researcher Sebastiampillai Raymond. His team found the lasertexturing technique to be highly effective for carefully controlling and tuning textures on metal. Scientists are also working on developing machine learning models that could help manufacturers optimize and automate laser surface texturing. www.nzfssrc.org.nz. ART MEETS SCIENCE IN COLOR-SHIFTING COATINGS Researchers at Cornell University, Ithaca, N.Y., along with the KoreanAmerican artist Kimsooja are working to recreate the natural iridescence of things like peacock feathers and butterfly wings in synthetic materials. Unlike traditional pigments that absorb specific wavelengths of light, these natural materials use microscopic structures to split light into different colors. This structural color approach creates vibrant hues that do not fade over time and require no toxic pigments. The challenge lies in creating and maintaining precise structures that are just hundreds of nanometers thick across surfaces many meters wide. The Cornell team developed a new method for creating large-scale iridescent coatings, demonstrated through a 46-ft-tall installation titled, “A Needle Woman: Galaxy was a Memory, Earth is a Souvenir.” Initially exhibited at Cornell, the piece now resides at Yorkshire Sculpture Park in Wakefield, U.K., where it has maintained its optical properties for over a decade. The scientific breakthrough relies on custom-designed plastic molecules that automatically arrange themselves into regular patterns. These molecules consist of two different types of plastic chemically bonded together— polystyrene and poly(tert-butyl methacrylate). When properly designed, thousands of these dual-component molecules spontaneously stack into alternating layers, creating a natural grating that splits light into different colors. cornell.edu. Inspired by the antimicrobial surface of shark skin, micro and nanoscale textures at the scale of bacterial cells resist bacteria attachment. Courtesy of Sebastiampillai Raymond. This installation of “A Needle Woman” features window panels coated with iridescent self-assembled lamellar block copolymer film. Courtesy of Wiley-VCH Verlag. Researchers at Nagaoka University of Technology, Japan, developed a method for synthesizing surfacemodified apatite nanoparticles that results in improved cell adhesion, offering new possibilities for the next generation of biocompatible medical implants. www.nagaokaut.ac.jp. BRIEF
RkJQdWJsaXNoZXIy MTYyMzk3NQ==