Abstract
Although the physical and biological functions of the skin layer of spider dragline have been studied and partially clarified, the morphology and elemental contents of the skin layer of silk fibers have not been investigated in detail to date. Here, the surface of Nephila clavata spider dragline was evaluated by field emission scanning electron microscopy (FE-SEM) and X-ray photoelectron spectroscopy (XPS) to obtain clear surface morphological and molecular information. The FE-SEM images of the spider dragline indicate that the spider dragline forms a bundle of microfibrils. This hierarchical structure might induce faint fibrilar and network-like patterns on the surface of the dragline. XPS analysis revealed the presence of Na, P, and S, which are reasonably explained by considering the biological components of the major ampullate gland of spiders. The results obtained here are preliminary but will be important to consider the molecular transition of silk proteins to form excellent hierarchical structures during the spider dragline spinning process.
Highlights
Silk fibers are well known as tough biomaterials, especially spider dragline silk, which possesses excellent toughness due to a combination of great tensile strength and ductility (Blackledge, 2012; Holland et al, 2018)
We found with field emission scanning electron microscopy (FE-SEM) that the surface of the Nephila spider dragline has fibril and network-like patterns (Figure 1b)
The silk fibers were not pretreated for FE-SEM imaging, and the surface morphologies should not be induced by the sample treatment
Summary
Silk fibers are well known as tough biomaterials, especially spider dragline silk, which possesses excellent toughness due to a combination of great tensile strength and ductility (Blackledge, 2012; Holland et al, 2018). Surface Analysis of Spider Dragline forming an approximately 100 nm skin layer based on scanning transmission X-ray diffraction measurements (Rousseau et al, 2007; Riekel et al, 2017). The mechanical and physical properties of spider dragline and silkworm silk fibers are known to depend on the humidity; namely, the amorphous and crystalline regions are influenced by water molecules (Fu et al, 2009; Yazawa et al, 2016; Malay et al, 2017). The physical and biological functions of the skin layer of spider dragline have been studied and partially clarified, the morphological and elemental characterizations of the skin layer of silk fibers have not been investigated in detail to date. Fitting protocol used the Gaussian-Lorentzian function, but the best fit results were obtained with Gaussian 100%
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call