Silk is a fascinating material, not just in fashion, but also in science and engineering, because the outstanding mechanical properties of these whisper-thin threads made by insects easily overshadow most man-made fibers.
German researchers have now taken inspiration from the lacewing, which lays its eggs on stalks made of silk with extremely high tensile strength. As they report in the journal Angewandte Chemie, they successfully produced synthetic egg stalks from biotechnologically generated proteins modeled on an egg-stalk protein.
Lacewings are light-green insects with transparent wings that are used by farmers to combat aphids. In order to protect their own offspring from predators, lacewings lay their eggs on very fine but extremely resilient silk stalks. To do this, the lacewing sticks a drop of silk dope from its abdomen to the underside of a leaf. It then presses an egg into the drop and pulls it downward. In this way, it pulls a thread that hardens within a few seconds in the air – the egg is now secured under the leaf. The threads are significantly finer than a human hair, but are so strong that they do not bend under the weight of the egg when the leaf is turned over.
The lacewing’s silk dope secretion contains several different proteins. One of the proteins contains a core domain with many repeated similar sequences. This area is flanked by small terminal domains that essentially control the properties of the silk proteins.
Thomas Scheibel and Felix Bauer at the University of Bayreuth wanted to produce an egg stalk with properties as similar as possible to the lacewing stalks. They thus developed a synthetic egg-stalk protein made of eight repeated building blocks consisting of 48 amino acids based on the repeating units of the natural silk protein. The end units were copied exactly from the original. The researchers synthesized a gene segment that codes for this artificial protein and introduced it into bacteria that then produce the protein.
Imitating silk stalk formation, the researchers dipped tweezers into a drop of protein solution, pulled out a filament, and attached the end of the stalk to a piece of aluminum foil. After drying, the stalks had similar tensile strength and elasticity to the natural version. At higher humidity, lacewing egg stalks are superior: they can be stretched out to up to six times their original length without tearing. The reason for this is the special accordion-like structure of other silk components. The researchers are confident that they will also be able to imitate this.
Possible applications for future synthetic silks range from the vehicle construction, for example in airbags, to medical applications, such as synthetic nerve conduits or drug delivery.About the Author
Angewandte Chemie International Edition, Permalink to the article: http://dx.doi.org/10.1002/anie.201200591
Climate Impact Research in Hannover: Small Plants against Large Waves
17.08.2018 | Leibniz Universität Hannover
First transcription atlas of all wheat genes expands prospects for research and cultivation
17.08.2018 | Leibniz-Institut für Pflanzengenetik und Kulturpflanzenforschung
New design tool automatically creates nanostructure 3D-print templates for user-given colors
Scientists present work at prestigious SIGGRAPH conference
Most of the objects we see are colored by pigments, but using pigments has disadvantages: such colors can fade, industrial pigments are often toxic, and...
Scientists at the University of California, Los Angeles present new research on a curious cosmic phenomenon known as "whistlers" -- very low frequency packets...
Scientists develop first tool to use machine learning methods to compute flow around interactively designable 3D objects. Tool will be presented at this year’s prestigious SIGGRAPH conference.
When engineers or designers want to test the aerodynamic properties of the newly designed shape of a car, airplane, or other object, they would normally model...
Researchers from TU Graz and their industry partners have unveiled a world first: the prototype of a robot-controlled, high-speed combined charging system (CCS) for electric vehicles that enables series charging of cars in various parking positions.
Global demand for electric vehicles is forecast to rise sharply: by 2025, the number of new vehicle registrations is expected to reach 25 million per year....
Proteins must be folded correctly to fulfill their molecular functions in cells. Molecular assistants called chaperones help proteins exploit their inbuilt folding potential and reach the correct three-dimensional structure. Researchers at the Max Planck Institute of Biochemistry (MPIB) have demonstrated that actin, the most abundant protein in higher developed cells, does not have the inbuilt potential to fold and instead requires special assistance to fold into its active state. The chaperone TRiC uses a previously undescribed mechanism to perform actin folding. The study was recently published in the journal Cell.
Actin is the most abundant protein in highly developed cells and has diverse functions in processes like cell stabilization, cell division and muscle...
17.08.2018 | Event News
08.08.2018 | Event News
27.07.2018 | Event News
17.08.2018 | Physics and Astronomy
17.08.2018 | Information Technology
17.08.2018 | Life Sciences