By Lin Li
Apr 13 2020
Most plants absorb nutrients from the soil through their roots. Carnivorous plants derive their nutrients from animals trapped inside their highly modified leaves. These unusual and sophisticated adaptations allow them to live in a wide range of habitats where nutrient concentrations are low. Carnivorous plants are not only fascinating for their ecology and intriguing forms, they are also inspirations for some of the brilliant inventions that make our technology better.
The tropical pitcher plant Nepenthes, or Monkey Cups, are native to Southeast Asia, Madagascar, and Australia. Like other carnivorous plants, Nepenthes grow in areas with poor soil conditions. The pitcher develops from tendrils at the leaf tip, which often contains water and other acidic viscoelastic fluids to form a deadly trap for small insects. The urn-shaped trap is initially covered with a brightly colored lid with nectar secreting glands; and when the trap is fully formed, the lid opens and the trap is ready! The prey that fell into the pitcher has almost no chance to escape due to the slippery inner surface of the trap. The key trapping feature is the upper pitcher rim (peristome), characterized by microstructured radial ridges of smooth epidermal cells.¹ The surface of the peristome is wetted by rain water and nectar secreted from the inner margin of the peristome. Only when wet, the surface becomes highly slippery, enough to repel oil, which leads the insects to slide off into the trap.
Researchers realized that the pitcher plant’s strategy can be applied to virtually everything. The cutting edge technology Slippery Liquid-Infused Porous Surfaces (SLIPS) is inspired by the peristome surface of Nepenthes. The SLIPS surface is fabricated out of nanofibers and coated with a lubricating film that is immiscible to a range of liquids.² This technology can provide coating solutions to multiple industries by creating customizable and highly repellent surfaces. Uses include self-cleaning agents for household appliances, graffiti and sticker resistant surfaces, and insect repelling products—a direct mimicry of the pitcher plants in nature. SLIPS also provides important medical uses for preventing blood clots and bacterial accumulation on sterile surfaces.³
Humans can learn so much by carefully observing nature. Many of our greatest inventions came from the sophisticated designs in nature. Nepenthes’ SLIPS technology is just one example of how incredibly advanced nature can be.