Researchers have achieved a significant milestone in biotechnology by genetically modifying silkworms to produce spider silk. Spider silk is renowned for its exceptional strength and durability, surpassing even the toughness of Kevlar. Justin Jones, a biologist specializing in engineered spider silks at Utah State University, described the material as “a truly high-performance fiber.” This breakthrough has the potential to revolutionize various industries. It could be employed in the production of lightweight yet incredibly strong structural components, thereby enhancing the fuel efficiency of planes and cars. Additionally, this innovation could lead to the development of wound dressings for faster healing and sutures for surgical procedures.
Silkworm cultivation has been practiced for thousands of years, providing raw material for textiles. However, their silks tend to be fragile. On the other hand, spiders face the opposite issue – their silks are remarkably strong and a greener alternative to synthetic fibers, which are produced by using fossil fuels. However, their silks are challenging to cultivate. Silkworms coexist peacefully, while spiders are territorial and tend to be aggressive when in close proximity.
Over the years, researchers have endeavored to genetically engineer silkworms to produce spider fibers, aiming to harness the desirable qualities of both organisms. The primary challenge has been the size of spider silk proteins, which are significantly larger. Inserting these large genes into the genomes of other animals has proven to be a complex task.
In a recent study, Junpeng Mi, a biotechnologist at Donghua University in Shanghai, China, opted to work with smaller spider silk proteins. Mi and his fellow scientists focused on MiSp, a protein found in Araneus ventricosus, an orb-weaving spider native to East Asia. They utilized CRISPR (clustered regularly interspaced short palindromic repeats), a gene editing tool, to replace the gene in silkworms responsible for their primary silk protein with MiSp. During this process, the scientists retained some silkworm sequences in their MiSp gene construct to ensure compatibility with the worm’s internal machinery.
The MiSp gene itself is 5440 base pairs in size and encodes 1766 amino acids. The protein features repetitive amino acid sequences, which contribute to the unique mechanical properties of spider silk. MiSp also possesses N and C terminal domains, which play specific roles in the assembly and characteristics of the silk protein. The protein exhibits a predominant beta-sheet structure, as opposed to an alpha-helix structure. Beta-sheets are a secondary structure in proteins, characterized by the arrangement of beta-strands connected by hydrogen bonds, resulting in a sheet-like structure.
The beta-sheet structure is a pivotal factor in the exceptional strength and toughness of spider silk. This structure facilitates the formation of crystalline regions within the silk fibers, providing both mechanical stability and properties that render spider silk one of the strongest natural materials known.
The genetically modified silkworms carrying the spider genes produced fibers with remarkable tensile strength and toughness. The resulting fibers were nearly as tough as the strongest natural spider silk and nearly six times stronger than Kevlar.
The flexibility of the MiSp-based fibers surprised the researchers. Typically, this protein produces strong but not stretchy fibers. “But it does make a flexible fiber when you put it in a silkworm,” says Jones.
Mi and his team aim to scale up the production of spider silk fibers for commercial use. This involves crossbreeding their specialized silkworms with commercially viable strains commonly used in large-scale silk farming. The resulting biodegradable fibers may initially find application in surgical sutures.
Jones raises concerns regarding safeguarding intellectual property rights during the commercialization process. This is likely to involve the distribution of transgenic silkworm eggs to numerous farmers. There is also uncertainty about whether the introduced genes will persist through subsequent generations of silkworm breeding.
The researchers plan to continue pushing the boundaries of spider silk engineering. They are currently exploring the possibility of modifying silkworms to produce spider silks with enhanced strength and elasticity. Mi and his team envision creating silk proteins that incorporate non-natural amino acids. This offers great potential for producing silks with unique properties. This could allow scientists to create silks that surpass the strength and toughness of materials like Kevlar.
When I first heard about CRISPR and the idea of genetically modifying living organisms, it raised many concerns for me. The notion of creating a material stronger than Kevlar in an organism smaller than my hand heightens my apprehensions. What if foreign countries exploit this technology for military purposes? What if it’s used as a biological weapon by enhancing the virulence or resistance of pathogens? What if terrorist organizations like Hamas employ this technology to further their destructive aims against the Israeli people?
Genetic modification prompts contemplation of numerous ethical concerns it may bring. If I were in a position of governance, I would impose stricter regulations, conduct more extensive long-term studies, and implement transparent labeling for genetically modified organisms. It is imperative to acknowledge that discussions about the ethics of genetic modification are ongoing and may evolve as the technology advances, along with society’s deepening understanding of genetics. Decisions in this realm should consider all potential applications that gene editing offers. Now, I ask you, what are your concerns with this technology? What problems do you think it brings? Personally, I am against this technology, and I believe there should be many legislative laws against it because of its potential impacts in the future.
Genetic modification is a powerful innovation with the potential to revolutionize and, potentially, disrupt our society. It is a tool that demands judicious use, taking into account its ethical and societal implications. Gene editing can be a catalyst for positive transformation in our world, cultivating a future that balances scientific progress with ethical responsibility. Spiders and silkworms represent just the beginning of this new frontier in scientific research.
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