A mini-review on the mechanical properties of spider silk and its potential future applications

*Corresponding author: Manav Shiven Polepalli. Copyright © 2025 Author(s) retain the copyright of this article. This article is published under the terms of the Creative Commons Attribution Liscense 4.0. A mini-review on the mechanical properties of spider silk and its potential future applications Manav Shiven Polepalli 1, * and Aditya Shukla 2 1 Grade 12, Delhi Public School (South), Bangalore, Karnataka, India. 2 Department of Microbiology, University of Calcutta, Kolkata, India. World Journal of Biology Pharmacy and Health Sciences, 2025, 24(01), 076-079 Publication history: Received on 27 August 2025; revised on 01 October 2025; accepted on 04 October 2025 Article DOI: https://doi.org/10.30574/wjbphs.2025.24.1.0877 Abstract Spider silk is renowned for its exceptional mechanical properties, including high tensile strength, elasticity, toughness, and biodegradability, surpassing many conventional synthetic fibers. These characteristics make it a promising candidate for sustainable applications across diverse sectors such as biomedicine, textiles, engineering, and architecture. However, large-scale harvesting from spiders is impractical due to their solitary and cannibalistic nature. Recent advances in bioengineering—including genetically modifying silkworms and microorganisms, and using microfluidic spinning—now allow the production of artificial spider silk with properties closely resembling its natural counterpart. This paper explores the fundamental mechanical attributes of spider silk, current artificial production techniques, scalability challenges, and potential future industrial applications. While high production costs remain a key limitation, continued developments in synthetic biology may enable spider silk to emerge as a sustainable nextgeneration material. Keywords: Spider silk; Mechanical properties; Artificial silk production; Genetically modified organisms; Microfluidic spinning; Industrial applications 1. Introduction Spider silk has garnered attention worldwide due to its outstanding mechanical properties. Efforts to replicate its structure and properties artificially include the use of microfluidic spinning (Chen et al., 2024) and genetic modification of silkworms (Xu et al., 2018). Spider silk is a protein-based polymer, initially secreted as a liquid by specialized glands in a spider’s abdomen. Spinnerets on the spider’s abdomen extrude the protein fluid through spigots, solidifying into silk threads (Singha et al., 2012). The mechanical superiority of spider silk—such as high tensile strength, elasticity (Bonino et al., 2003), toughness, and biodegradability—offers significant advantages over conventional synthetic fibers. These attributes make artificial spider silk a promising, sustainable alternative to materials like Kevlar and steel. This paper reviews the key mechanical properties of spider silk, current production techniques, scaling barriers, a comparison with industrial materials like steel, and its potential for future architectural and industrial applications. World Journal of Biology Pharmacy and Health Sciences, 2025, 24(01), 076-079 77 2. Mechanical Properties of Spider Silk 2.1. Tensile Strength Tensile strength refers to a material’s resistance to breaking under tension. According to Bonino (2003), spider silk exhibits a tensile strength of approximately 1.2 ± 0.22 GPa, making it a strong contender to replace traditional materials such as steel in applications demanding high tensile strength. 2.2. Elasticity Elasticity is the ability of a material to return to its original shape after deformation. Some spider silk types can stretch up to five times their original length. Elastic modulus values vary widely among species, ranging from 0.012 to 13.8 GPa (Osaki et al., 2002). The table below expresses the experimental values of stress, strain, and their ratios, which are then used to calculate the elasticity and tensile strength of spider silk. Table 1 Experimentally obtained values of the elasticity and tensile strength of spider silk Material Property Experimental Value Maximum Strain (%) 24.1±2 Young’s Modulus, Ei (GPa) 2.2±0.7 Final Modulus, Ef (GPa) 0.4±0.1 Tensile Strength (GPa) 1.2±0.2 Energy to Break (105 J/Kg) 1.4±0.3 (Source: Bonino, 2003) 2.3. Toughness Toughness is the ability of a material to absorb energy and deform plastically without fracturing. Spider silk’s combination of strength and extensibility enables it to absorb significantly more energy than materials like Kevlar and nylon (Römer & Scheibel, 2008). 2.4. Biodegradability Being protein-based, spider silk is biodegradable and can be broken down naturally by microorganisms. This ecofriendly trait gives it a sustainability edge over petroleum-based synthetic fibers. 3. Potential Applications of Spider Silk 3.1. Architecture Spider silk, due to its high tensile strength and elasticity, may serve as a potential alternative to steel in suspension cables, support beams, and flexible architectural frameworks. While still speculative, it holds promise for lighter and more environmentally friendly construction materials. 3.2. Machinery Spider silk’s tensile strength could make it suitable for load-bearing cables in machines such as elevators and cranes. Its superior load-to-weight ratio could enable lighter, more efficient machinery components. 3.3. Textiles Due to its toughness and biodegradability, spider silk can serve as an eco-friendly alternative to materials like Kevlar. It also has potential applications in fashion, sportswear, and even ballistic protection. World Journal of Biology Pharmacy and Health Sciences, 2025, 24(01), 076-079 78 4. Production Techniques 4.1. Natural Silk Formation Spiders synthesize silk as a liquid protein, which solidifies upon extrusion from spinnerets. However, the natural yield is too low for commercial use, and spiders’ solitary behavior prevents large-scale farming. 4.2. Microfluidic Spinning Researchers have mimicked spider silk formation using microfluidic wet-spinning (Peng et al., 2016). Despite successfully mimicking structural alignment, artificial fibers only reached a tensile strength of 510 MPa and an elongation of 15%, far below natural silk (Bonino, 2003). 4.3. Genetic Engineering Xu et al. (2018) demonstrated that genetically modified Bombyx mori silkworms can produce silk mimicking spider silk properties. This presents a scalable alternative, compatible with existing silk industry infrastructure. 5. Limitations The primary barrier to widespread adoption of spider silk is its high production cost. While steel costs about $802 per metric ton (FocusEconomics, 2025), synthetic silk via fermentation costs approximately $100/kg (~$100,000/ton) (Tullo, 2021). Although companies like Spiber are pioneering commercial-scale production using Brewed Protein, spider silk is not yet cost-competitive with metals or synthetic fibers. Additionally, mechanical consistency and process optimization remain technical hurdles. 5.1. Future Prospects Future commercial viability depends on reducing costs and improving yield. Genetic engineering of silkworms and microbial fermentation using yeast or bacteria hold the most promise. Optimizing spinning techniques and fermentation systems may allow mass production at a cost comparable to traditional fibers. With further development, spider silk could revolutionize industries from construction to medical devices. 6. Conclusion Spider silk boasts outstanding mechanical properties—strength, elasticity, toughness, and biodegradability. Artificial production methods, particularly genetic engineering and fermentation, show promise. Although commercial use is currently limited by high costs, future advances in synthetic biology and materials science could make spider silk a viable, sustainable alternative to conventional materials. Compliance with ethical standards Disclosure of conflict of interest No conflict of interest to be disclosed. References [1] Bonino, M. J. (2003). Material properties of spider silk (Doctoral dissertation, University of Rochester, Department of Materials Science Program). https://www.lle.rochester.edu/media/publications/documents/theses/Bonino.pdf [2] Chen, J., Tsuchida, A., Malay, A. D., Tsuchiya, K., Masunaga, H., Tsuji, Y., Kuzumoto, M., Urayama, K., Shintaku, H., & Numata, K. (2024). Replicating shear-mediated self-assembly of spider silk through microfluidics. 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