Biofibers Made from Green Lacewing Silk
High-Grade Rigid Fiber for Lightweight Plastics
In order to protect their offspring from being eaten by predators near the ground, green lacewings deposit their eggs on the underside of leaves – on the ends of stable silk threads. These so-called egg stalks are only around 15 micrometers thick and can easily hold the weight of the eggs. In order to produce these impressive fibers, the green lacewing excretes a protein secretion onto the leaf. The egg is then laid in the droplet and perpendicularly pulled out from the leaf. The resulting silk thread then hardens in the air.
In a joint project with the company AMSilk GmbH, researchers from the Fraunhofer Institute for Applied Polymer Research IAP, are working on manufacturing large amounts of green lacewing silk protein with the aid of bacteria using a biotech process. The aim is to use the material in the future as a high-grade rigid fiber, for example, in lightweight plastics in transportation technology. It can also be conceivably used in medical technology, for example, as a biocompatible silk coating on implants.
A team led by Professor Thomas Scheibel from the Chair of Biomaterials at the University of Bayreuth conducted the preliminary molecular-biological work. They constructed a special gene sequence which enables bacteria to produce the silk protein. Martin Schmidt, biotechnologist at the Fraunhofer IAP in Potsdam-Golm, Germany, is now optimizing the manufacturing process at the Fraunhofer IAP so that the silk protein can be produced inexpensively on an industrial scale. After this step it will be possible to develop the material.
AMSilk GmbH, Martinsried, Germany, supports the project by conducting molecular biological work and by contributing its wide-ranging expertise in the field of silk analysis and production. The company has been successfully developing silk-based biopolymers for various applications for years. “We have been able to establish our silk technology and our first products are already available on the market. While the Biosteel fiber we use is modelled after spider silk and is more soft and flexible, green lacewing silk is very rigid. This special property makes it interesting for medical technology and as a reinforcement fiber in lightweight engineering, for example in cars, airplanes or ships,“ explains Dr. Lin Römer, scientific director of AMSilk. The project is being funded by the Agency for Renewable Resources (FNR), a project management organization of the Federal Ministry of Food and Agriculture.