Abstract
Biological systems have long been a source of inspiration in the development of novel chemical processes, functional structures, advanced materials, and innovative devices. Nature demonstrates remarkable precision and efficiency across all scales, from individual molecules to complex organisms. For instance, spider silk exhibits exceptional tensile strength and toughness, insect resilin is renowned for its resilience, and the dermis of sea cucumbers display dynamic stiffness. These properties have motivated researchers to develop biomimetic materials that replicate such desirable characteristics. This dissertation focuses on the development and application of advanced biomimetic hydrogels derived from spidroins, the core proteins found in spider silk. Spidroins possess a unique combination of properties, including outstanding mechanical strength, extremely high toughness, biocompatibility, and adaptability, making them highly suitable for a wide range of applications. Herein, we presented seeks to leverage these attributes to engineer biomimetic hydrogels with potential applications in both biomedical and industrial fields.Firstly, we designed mutant recombinant spidroins that can form hydrogels at 37°C rapidly and controllably with visible light irradiation. In the mutant spidroins phenylalanine residues (F) are systematically substituted by tyrosine residues (Y) in repeat motifs of (GGX), which contributes to the self-assembly of β-sheet and further formation of amyloid-like nanofibrils. As expected, micellar/globular spidroins solution convert to spidroins hydrogel composed of nanofibrils network and subsequently further crosslinked by di-tyrosine. The conformation transformation process is verified by spectroscopy, Transmission Electron Microscopy (TEM) and molecular dynamics simulation.
Then we provided a comprehensive evaluation of the biocompatibility, toxicity, and functional performance of non-swelling spidroin-based scaffolds, as well as the micro- and nanofabrication of hydrogels for biomedical applications. Through a combination of theoretical modeling and experimental validation, the stability of spidroin hydrogels was attributed to the presence of β-sheet crystals, and the presence of tyrosine residues also rendered them suitable for 2PP 3D printing. In vivo, biochemical, and histological analyses confirmed the excellent biocompatibility of spidroin-based materials, with no evidence of systemic toxicity or adverse effects on internal organs.
Furthermore, we prepared spidroin-inspired nanogels with extraordinary processability, which can be spun into fibers via direct drawing and fabricated into thermal actuators easily after gelation. These soluble and spinnable nanogels are composed of a liquid metal (LM) core and a poly (acrylic acid) (PAA) shell and are entangled with each other. The fabricated nanogels and diluted dope solution could be stored for more than 1 month. The as-spun nanogel fibers with hierarchical structures achieved extraordinary mechanical properties (tensile stress of 575 MPa, toughness of 381 MJ m-3) and supercontraction at 60% RH. Besides, a photothermal actuator was prepared by coating the nanogels on a polyethylene (PE) substrate with a commercial shading ink, and the as-prepared actuator showed a rapid response to near-infrared (NIR) light as well as a fast recovery. Molecular dynamics simulation revealed a possible working mechanism of the actuator. This work provides a new strategy to prepare processable nanogels with broad application prospects for smart textiles and soft robotics.
In the end, we displayed the remarkable potential of spidroin-based biomimetic hydrogels across multiple applications, establishing their versatility in biomedical engineering and advanced manufacturing. The findings of this thesis demonstrate the significant potential of spidroin-based biomimetic hydrogels in various fields. The research advances our understanding of spidroin synthesis, processing, and application, paving the way for innovative solutions that leverage the remarkable properties of spider silk proteins.
| Date of Award | 11 Sept 2025 |
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| Original language | English |
| Awarding Institution |
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| Supervisor | Jinlian HU (Supervisor) |