Spider silk produced by genetically modified silkworms is 6x stronger than Kevlar

Scientists have successfully synthesized spider silk using genetically modified silkworms, creating fibers with a toughness six times superior to that of Kevlar, a material prominently used in bulletproof vests.

This revolutionary work is the first to fabricate full-length spider silk proteins through silkworms, presenting a methodology that might give rise to an eco-friendly substitute to prevalent synthetic commercial fibers such as nylon.

Tackling synthetic fiber issues

Synthetic fibers like nylon have been widely used, but they pose environmental concerns due to their ability to release detrimental microplastics and their production from fossil fuels leading to greenhouse gas emissions.

Scientists, therefore, have been exploring spider silk as a sustainable alternative, given its exceptional mechanical properties and potential applications in various fields like medical sutures, textiles, military, aerospace technology, and biomedical engineering.

Innovating spider silk production

Silkworm silk is the only large-scale commercialized animal silk fiber, with proven rearing techniques. Junpeng Mi, a PhD candidate at the College of Biological Science and Medical Engineering at Donghua University, reveals that utilizing genetically modified silkworms opens avenues for the low-cost, mass commercialization of spider silk fibers.

This alternative is not just innovative but solves persistent issues in spider silk synthesis, such as applying a protective “skin layer” to the silk, allowing it to endure humidity and exposure to sunlight. Genetically modified silkworms, by virtue of having a similar protective layer on their fibers, overcome this problem, making them the ideal conduit for spider silk production.

Evolutionary step in silk synthesis

To achieve the synthesis, Mi and his team integrated spider silk protein genes into the silkworm’s DNA, ensuring the expression in their glands. This intricate process involved CRISPR-Cas9 gene editing technology and countless microinjections into fertilized silkworm eggs, a step Mi described as one of the most significant challenges of the study.

Observing the red glow in the silkworms’ eyes under a fluorescence microscope indicated the success of gene editing, a moment of triumph and excitement for the team. Further, “localization” modifications were crucial to align the transgenic spider silk proteins with proteins in the silkworm glands, ensuring the proper spinning of the fiber.

The team also proposed a “minimal basic structure model” of silkworm silk to guide these modifications, a concept that Mi emphasizes as a crucial shift from previous research.

Future with engineered spider silk

Junpeng Mi foresees the application of insights gained from this study to further enhance the toughness and strength of spider silk fibers by developing genetically modified silkworms capable of producing spider silk fibers from both natural and engineered amino acids.

This introduces the possibility of over one hundred engineered amino acids, unveiling immense potential for the development of engineered spider silk fibers.

Mi is confident about the potential for large-scale commercialization of this innovation, promising a sustainable and versatile material that could revolutionize industries, offering solutions ranging from more comfortable clothing and advanced bulletproof vests to medical sutures catering to global demand exceeding 300 million procedures annually.

In summary, this pioneering research marks a significant leap towards environmentally friendly and sustainable material production, confronting the ecological drawbacks of synthetic fibers. It paves the way for extensive applications, impacting numerous domains, reinforcing the potential of bioengineered products in addressing modern-day challenges.

As scientists venture deeper into the realms of spider silk synthesis, the anticipation of more discoveries and innovations in this domain holds promise for a future where sustainability and technology converge.

More about spider silk

The complete study is available in the journal Matter.

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