Hydrothermal Effect on Mechanical Properties of Nephila pilipes Spidroin

Abstract

The superlative mechanical properties of spider silk and its conspicuous variations have instigated significant interest over the past few years. However, current attempts to synthetically spin spider silk fibers often yield an inferior physical performance, owing to the improper molecular interactions of silk proteins. Considering this, herein, a post-treatment process to reorganize molecular structures and improve the physical strength of spider silk is reported. The major ampullate dragline silk from Nephila pilipes with a high β-sheet content and an adequate tensile strength was utilized as the study material, while that from Cyrtophora moluccensis was regarded as a reference. Our results indicated that the hydrothermal post-treatment (50–70 °C) of natural spider silk could effectively induce the alternation of secondary structures (random coil to β-sheet) and increase the overall tensile strength of the silk. Such advantageous post-treatment strategy when applied to regenerated spider silk also leads to an increment in the strength by ~2.5–3.0 folds, recapitulating ~90% of the strength of native spider silk. Overall, this study provides a facile and effective post-spinning means for enhancing the molecular structures and mechanical properties of as-spun silk threads, both natural and regenerated.

Biofabricating a Silk Scaffold as a Functional Microbial Trap

“…A systematic deconvolution of FTIR spectra from Figure c (amide I region) was also conducted using PeakFIT 4.11 (Systat Software Inc.) to quantitatively compare the transition of secondary structures on the treated silk sponges. The major peak assignments were designated primarily by Cheng et al: β-sheet, ∼1625 cm –1 ; α-helix/random coil, ∼1643 and 1662 cm –1 ; β-turn, ∼1684 cm –1 . The contents of the secondary structures were normalized to a total of 100% basis and summarized in Table .…”

“…In comparison, a pronounced major signal was detected at 2θ ∼12° for the 80% ethanol group (SF3 + EtOH80; black curve) as opposed to the control silk sponge (SF3, red curve) . The peak signal with enhanced crystallinity of silk fibroin is believed to be associated with the formation of β-sheet secondary structures. − Subsequently, an ATR-FTIR analysis was also implemented to further profile the detailed alternation of secondary structures within the silk sponges. As shown in Figure c, the FTIR spectrum of the ethanol post-treatment group (black curve) indicated a major peak shift in the 1600–1700 cm –1 amide I region as compared to the control sample (red curve).…”

Progress in the application of spider silk protein in medicine

“…Further, the b-turn is partly involved in the formation of b-fold and is parallel to the fiber axis, b-turn, and a-helix. 3,4,14 According to research, the ion, 15 pH, 16,17 and temperature 18 are the factors that influence the conformation. As we know, the structure has a decisive influence on performance.…”