Apr 9, 2025
1:45pm - 2:15pm
Summit, Level 3, Room 326
Emiliano Bilotti1,Qichen Zhou1
Imperial College London1
Silk, a naturally occurring proteinaceous biopolymer fibre primarily synthesised by specific arthropods, such as silkworms and spiders [1], is a marvel of nature. These fibres exhibit outstanding mechanical properties [2], biocompatibility [3], and (bio)degradability [4]. The origin of silk's physical properties is still a topic of debate but is hypothesised to be a result of its chemical composition as well as its unique hierarchical structure, which has undergone natural evolutionary refinement over hundreds of millions of years [5]. Owing to these inherent advantages, silk has been a textile material of choice for millennia, tracing its origins back to ancient China.
Over the past few decades, there has been a resurgence of interest in silk, and as a result, silk has been transformed into a variety of different formats, such as films and hydrogels [6]. This transformation has supported exploration in various fields, including biomedical engineering [6], nanogenerators [7], food preservation [8] and sensors [9]. The majority of these activities rely on regenerating silk solutions, a process that involves dissolving silk fibres into an aqueous solution, followed by casting into moulds to form new regenerated silk materials.
This canonical solution-derived processing method has broadened the scope of silk applications but at the expense of a high economic and environmental footprint.
The fabrication process of converting silk into silk-based bulk materials typically involves large amounts of water, chemicals and time (days to weeks) [10], and, most importantly, disrupts the inherent hierarchical structure of silk, compromising its original physical properties [11].
In this work, we report a simple method to convert silk fibres, of different origins, directly into high-performance transparent bulk materials of record-high mechanical properties (>20 GPa Young’s Modulus). These findings offer significant potential for biomedical and sustainable structural applications alongside the recycling and reuse of waste silk. Moreover, it offers a unique platform to develop for semi-structural biodegradable components with integrated multifunctionalities, including (triboelectric) energy harvesting, sensing and actuation.
References:
1. F. Vollrath, D. P. Knight, Liquid crystalline spinning of spider silk. Nature 410, 541-548 (2001).
2. Z. Shao, F. Vollrath, Surprising strength of silkworm silk. Nature 418, 741-741 (2002).
3. G. H. Altman, et al., Silk-based biomaterials. Biomaterials 24, 401-416 (2003).
4. C. Guo, et al., Enzymatic degradation of Bombyx mori silk materials: a review. Biomacromolecules 21, 1678-1686 (2020)
5. M. A. Meyers, et al., Structural biological materials: critical mechanics-materials connections. Science 339, 773-779 (2013)
6. Y. Wang, et al., Silk-protein-based gradient hydrogels with multimode reprogrammable shape changes for biointegrated devices. PNAS 120, e2305704120 (2023).
7. I. C. Candido, et al., PVA-silk fibroin bio-based triboelectric nanogenerator. Nano Energy 105, 108035 (2023).
8. Y. Han, et al., Design of biodegradable, climate-specific packaging materials that sense food spoilage and extend shelf life. ACS Nano 17, 8333-8344 (2023).
9. H. Wang, et al., Inter Shell Sliding in Individual Few Walled Carbon Nanotubes for Flexible Electronics. Adv. Mater. 35, 2306144 (2023)
10. D. N. Rockwood, et al., Materials fabrication from Bombyx mori silk fibroin. Nat. Protoc. 6, 1612-1631 (2011).
11. L.-D. Koh, et al., Structures, mechanical properties and applications of silk fibroin materials. Prog. Polym. Sci. 46, 86-110 (2015).