It is well known that silk produced by spiders is considered the most robust material in the world. Thus, researchers seek a way to use such strong properties of spider silk in the chemistry field. Moreover, scientists tend to implement synthetic biology methods to advance the already superb characteristics of the material. As a result, they have recently managed to enhance the features of the most robust material on Earth, spider silk.
To begin with, the crucial component of spider silk is nanocrystals which are responsible for the material’‎s strength. However, when attempting to replicate the nanocrystals, scientists faced a problem: they could not produce the same or higher number of them (Berardo et al., 2021; Wang, 2021). As a result, the features of engineered spider silk were not on par with its natural counterpart (Wang, 2021). Consequently, scientists investigated the opportunity to create unique microorganisms that would be able to produce the silk with nanocrystals in the same amount as in natural spider silk (Berardo et al., 2021). In other words, new microorganisms were expected to create material of the same structure and similar properties to the natural alternative, spider silk (Berardo et al., 2021; Wang, 2021). Nevertheless, the need to alternate the production of nanocrystals was still evident and had to be fulfilled.
Thus, engineers at first focused on creating bacteria and only then on advancing nanocrystal production. For instance, engineers at Washington University in St. Louis (2021) have replicated unique proteins that further have been produced in bacteria. To be more precise, the amyloid silk hybrid proteins were initially made by bacteria engineered by professor Fuzhong Zhang in the Department of Energy, Environmental & Chemical Engineering (Washington University in St. Louis, 2021; Li et al., 2021). Zhang has already researched spider silk in his laboratory and, therefore, is familiar with its features (Washington University in St. Louis, 2021). For instance, in 2018, he designed a bacterium that could produce a material that, with its characteristics, is almost the same as spider silk (Washington University in St. Louis, 2021; Li et al., 2021). However, the professor also sought methods to advance the features of engineered material by alternating the structure of proteins.
Furthermore, to tackle the issue regarding nanocrystals, it was crucial to redesign the spider silks sequence. Fuzhong Zhangs team has developed unique flows of amyloid silk hybrid proteins to form nanocrystals as in natural counterparts (Washington University in St. Louis, 2021; Li et al., 2021). These proteins are different from the spider silk ones in the number of repetitive amino acid sequences: spider silk has a considerably higher amount (Washington University in St. Louis, 2021). However, precisely this feature is beneficial as it enables bacteria to produce them faster.
To sum up, the professors team has managed to create microorganisms that can develop a material similar in its features and properties to spider silk. Furthermore, scientists have successfully alternated the structure of proteins in the engineered material. It is now possible to produce the same or even a higher amount of nanocrystals that are crucial for silks strength. Consequently, it resulted in the less challenging and faster production of the spider silks alternative. This material is expected to be further enhanced by scientists to make it even more robust than its natural counterpart. In addition, such an invention in chemistry is beneficial to society for further technological advancement and in the manufacturing industry.
References
Berardo, A., Pantano, M. F., & Pugno, N. M. (2021). An insight into the toughness modulus enhancement of high-performance knotted microfibers through the correspondence analysis. Engineering Research Express, 3(2), 025010. doi:10.1088/2631-8695/abf748
Li, J., Zhu, Y., Yu, H., Dai, B., Jun, Y. S., & Zhang, F. (2021). Microbially synthesized polymeric amyloid fiber promotes the β-nanocrystal formation and displays gigapascal tensile strength. ACS Nano. doi:10.1021/acsnano.1c02944
Wang, A. (2021). Molecular mechanisms governing the mechanics of polymeric and protein-based materials (Publication No. 28497260) [Doctoral dissertation, Northwestern University]. ProQuest Dissertations Publishing.
Washington University in St. Louis. (2021). Microbially produced fibers: Stronger than steel, tougher than Kevlar. ScienceDaily.