Being able to produce artificial spider silk has long been a dream of many scientists, but all attempts have until now involved harsh chemicals and have resulted in fibers of limited use. Now, a team of researchers from the Swedish University of Agricultural Sciences and Karolinska Institutet has, step by step, developed a method that works.
Today they report that they can produce kilometer long threads that for the first time resemble real spider silk.Spider silk is an attractive material–it is well tolerated when implanted in tissues, it is light-weight but stronger than steel, and it is also biodegradable. However, spiders are difficult to keep in captivity and they spin small amounts of silk. Therefore, any large scale production must involve the use of artificial silk proteins and spinning processes. A biomimetic spinning process (that mimics nature) is probably the best way to manufacture fibers that resemble real spider silk. Until now, this has not been possible because of difficulties to obtain water soluble spider silk proteins from bacteria and other production systems, and therefore strong solvents has been used in previously described spinning processes.
Spider silk is made of proteins that are stored as an aqueous solution in the silk glands, before being spun into a fiber. Researcher Anna Rising and her colleagues Jan Johansson and Marlene Andersson at the Swedish University of Agricultural Sciences and at Karolinska Institutet have previously shown that there is an impressive pH gradient in the spider silk gland, and that this well-regulated pH gradient affects specific parts of the spider silk proteins and ensures that the fiber forms rapidly in a defined place of the silk production apparatus.
This knowledge has now been used to design an artificial spider silk protein that can be produced in large quantities in bacteria, which makes the production scalable and interesting from an industrial perspective.
“To our surprise, this artificial protein is as water soluble as the natural spider silk proteins, which means that it is possible to keep the proteins soluble at extreme concentrations”, says Anna Rising.
To mimic the spider silk gland, the research team constructed a simple but very efficient and biomimetic spinning apparatus in which they can spin kilometer-long fibers only by lowering the pH.
“This is the first successful example of biomimetic spider silk spinning. We have designed a process that recapitulates many of the complex molecular mechanisms of native silk spinning. In the future this may allow industrial production of artificial spider silk for biomaterial applications or for the manufacture of advanced textiles”, says Anna Rising.
Learn more: Spinning spider silk is now possible
It was founded in 1810 on Kungsholmen on the west side of Stockholm; the main campus was relocated decades later to Solna, just outside Stockholm. A second campus was established more recently in Flemingsberg, Huddinge, south of Stockholm.
Karolinska Institutet is Sweden’s third oldest medical school, after Uppsala University (founded in 1477) and Lund University (founded in 1666). According to the 2012 Times Higher Education World University Rankings, Karolinska Institutet is ranked 32nd worldwide, 6th in Europe, and 1st in the Nordic region and according to the 2011 Academic Ranking of World Universities, Karolinska Institute is ranked 11th in the world in the field of clinical medicine and pharmacology and 18th in life sciences.
Karolinska Institute research articles from Innovation Toronto
- Artifical neuron mimicks function of human cells – June 25, 2015
- Ion pump gives the body its own pain alleviation – May 12, 2015
- Two genes linked with violent crime – October 28, 2014
- Swedish team delivers cancer breakthrough that kills cancer cells but not normal cells – May 17, 2014
- Promising results for Swedish cancer drug candidate
- Steering stem cells with magnets
- Breath study brings roadside drug testing closer
- Trackable drug-filled nanoparticles: A potential weapon against cancer
- Stem Cell-Based Bioartificial Tissues and Organs
- Nanotechnology device aims to prevent malaria deaths through rapid diagnosis
- How the common ‘cat parasite’ gets into the brain
- A First: Organs Tailor-Made With Body’s Own Cells
- Alzheimer’s Vaccine Trial a Success
- Research Breakthrough for Drugs Via the Skin: Outermost Layer of Skin Described in Detail
- Helmets inspired by brain fluid to offer better impact protection
- New Drug Strategies for Alzheimer’s and Multiple Sclerosis
- Scientists claim that ‘self’ can be mentally transferred between bodies
- Drugs Tests Via Exhaled Breath
Scientists at Sweden’s Karolinska Institutet have managed to build a fully functional neuron by using organic bioelectronics. This artificial neuron contain no ‘living’ parts, but is capable of mimicking the function of a human nerve cell and communicate in the same way as our own neurons do.
Neurons are isolated from each other and communicate with the help of chemical signals, commonly called neurotransmitters or signal substances. Inside a neuron, these chemical signals are converted to an electrical action potential, which travels along the axon of the neuron until it reaches the end. Here at the synapse, the electrical signal is converted to the release of chemical signals, which via diffusion can relay the signal to the next nerve cell.
To date, the primary technique for neuronal stimulation in human cells is based on electrical stimulation. However, scientists at the Swedish Medical Nanoscience Centre (SMNC) at Karolinska Institutet in collaboration with collegues at Linköping University, have now created an organic bioelectronic device that is capable of receiving chemical signals, which it can then relay to human cells.
“Our artificial neuron is made of conductive polymers and it functions like a human neuron”, says lead investigator Agneta Richter-Dahlfors, professor of cellular microbiology. “The sensing component of the artificial neuron senses a change in chemical signals in one dish, and translates this into an electrical signal. This electrical signal is next translated into the release of the neurotransmitter acetylcholine in a second dish, whose effect on living human cells can be monitored.“
The research team hope that their innovation, presented in the journal Biosensors & Bioelectronics , will improve treatments for neurologial disorders which currently rely on traditional electrical stimulation. The new technique makes it possible to stimulate neurons based on specific chemical signals received from different parts of the body. In the future, this may help physicians to bypass damaged nerve cells and restore neural function.
“Next, we would like to miniaturize this device to enable implantation into the human body”, says Agneta Richer-Dahlfors. “We foresee that in the future, by adding the concept of wireless communication, the biosensor could be placed in one part of the body, and trigger release of neurotransmitters at distant locations. Using such auto-regulated sensing and delivery, or possibly a remote control, new and exciting opportunities for future research and treatment of neurological disorders can be envisaged.”