For the first time, silkworms spin spider silk, providing a more
environmentally friendly option to synthetic fibers.
The research is the first to use silkworms to effectively synthesize
full-length spider silk proteins, and it was published in the journal Matter
on September 20. The results show how a method for producing a greener
substitute for commercial synthetic fibers like nylon may be used.
"With well-established rearing techniques, silkworm silk is currently the
only animal silk fiber commercialized on a large scale," stated Mi.
Consequently, low-cost, large-scale commercialisation is made possible by
using genetically engineered silkworms to generate spider silk fabric.
Spider silk has caught the attention of scientists as a very attractive and
environmentally friendly substitute for synthetic fibers, which are
frequently made from fossil fuels that emit greenhouse gases and have the
potential to discharge hazardous microplastics into the environment. But
there are drawbacks to looking to nature for solutions.
The application of a surface layer of glycoproteins and lipids to
artificial spider silk, which provides an anti-aging "skin layer" similar to
what spiders apply to their webs, has proven difficult in previous attempts
to spin the silk.
According to Mi, the issue may be resolved by using genetically modified
silkworms because they have a comparable protective covering on their own
fibers.
A Ph.D. candidate at Donghua University's College of Biological Science and
Medical Engineering, Junpeng Mi is the study's first author. "Spider silk
stands as a strategic resource in urgent need of exploration," Mi
stated.
"The fibers generated in this work have remarkably good mechanical
performance, which indicates great promise in this sector. This kind of
fiber may be used for surgical sutures, meeting a need that exceeds 300
million surgeries worldwide each year."
According to Mi, the spider silk strands may potentially find usage in
smart materials, biomedical engineering, aerospace technology, and the
military. They might also be utilized to make novel kinds of protective
vests and more comfortable clothing.
In order to create spider silk from silkworms, Mi and his colleagues used a
combination of CRISPR-Cas9 gene editing technology and hundreds of thousands
of microinjections into fertilized silkworm eggs to insert spider silk
protein genes into the DNA of the silkworms so that it would be produced in
their glands.
A indication that the gene editing had been effective, Mi noted that the
microinjections were "one of the most significant challenges" in the
project. Nevertheless, he was ecstatic to see the silkworms' red flashing
eyes under the fluorescence microscope.
In order to ensure that the fiber would be spun correctly, the researchers
also had to carry out "localization" alterations on the transgenic spider
silk proteins to enable optimal interaction with proteins in the silkworm
glands. The group created a "minimal basic structure model" of silkworm silk
to serve as a guide for the changes.
Mi states, "This thesis introduces a concept of 'localization,' along with
the proposed minimal structural model, which represents a significant
departure from previous research." "We have no doubt that widespread
commercialization will soon occur."
Mi intends to create genetically modified silkworms that generate spider
silk fibers from both natural and synthetic amino acids in the future. This
will allow her to take advantage of the knowledge about the strength and
toughness of spider silk fibers gained from the current work.
"There is endless potential for engineered spider silk fibers with the
introduction of over one hundred engineered amino acids," claims Mi.
