title: Dual Thermosensitive Hydrogels Assembled from the Conserved C-Terminal Domain of Spider Dragline Silk.
abstract: Stimuli-responsive hydrogels have great potentials in biomedical and biotechnological applications. Due to the advantages of precise control over molecular weight and being biodegradable, protein-based hydrogels and their applications have been extensively studied. However, protein hydrogels with dual thermosensitive properties are rarely reported. Here we present the first report of dual thermosensitive hydrogels assembled from the conserved C-terminal domain of spider dragline silk. First, we found that recombinant C-terminal domain of major ampullate spidroin 1 (MaSp1) of the spider Nephila clavipes formed hydrogels when cooled to approximately 2 °C or heated to 65 °C. The conformational changes and self-assembly of the recombinant protein were studied to understand the mechanism of the gelation processes using multiple methods. It was proposed that the gelation in the low-temperature regime was dominated by hydrogen bonding and hydrophobic interaction between folded protein molecules, whereas the gelation in the high-temperature regime was due to cross-linking of the exposed hydrophobic patches resulting from partial unfolding of the protein upon heating. More interestingly, genetic fusion of the C-terminal domain to a short repetitive region of N. clavipes MaSp1 resulted in a chimeric protein that formed a hydrogel with significantly improved mechanical properties at low temperatures between 2 and 10 °C. Furthermore, the formation of similar hydrogels was observed for the recombinant C-terminal domains of dragline silk of different spider species, thus demonstrating the conserved ability to form dual thermosensitive hydrogels. These findings may be useful in the design and construction of novel protein hydrogels with tunable multiple thermosensitivity for applications in the future.
authors.affiliation: State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, and School of Life Sciences and Biotechnology, Shanghai Jiao Tong University , 800 Dongchuan Road, Shanghai 200240, P. R. China.
authors.forename: Zhi-Gang
authors.initials: ZG
authors.lastname: Qian
authors.affiliation: State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, and School of Life Sciences and Biotechnology, Shanghai Jiao Tong University , 800 Dongchuan Road, Shanghai 200240, P. R. China.
authors.forename: Ming-Liang
authors.initials: ML
authors.lastname: Zhou
authors.affiliation: State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, and School of Life Sciences and Biotechnology, Shanghai Jiao Tong University , 800 Dongchuan Road, Shanghai 200240, P. R. China.
authors.forename: Wen-Wen
authors.initials: WW
authors.lastname: Song
authors.affiliation: State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, and School of Life Sciences and Biotechnology, Shanghai Jiao Tong University , 800 Dongchuan Road, Shanghai 200240, P. R. China.
authors.forename: Xiao-Xia
authors.initials: XX
authors.lastname: Xia
mesh_terms: D000818:Animals; D002942:Circular Dichroism; D005349:Fibroins / Q000737:chemistry; D020100:Hydrogels / Q000737:chemistry*; D018625:Microscopy, Atomic Force; D008855:Microscopy, Electron, Scanning; D011487:Protein Conformation; D017510:Protein Folding; D011994:Recombinant Proteins / Q000737:chemistry; D047011:Silk / Q000737:chemistry*; D013050:Spectrometry, Fluorescence; D013112:Spiders
chemical_list: D020100:Hydrogels; D011994:Recombinant Proteins; D047011:Silk; C086087:spidroin 1; D005349:Fibroins