Duct measurements

Mean length, mean internal diameter and mean thickness of the cuticle of a typical cribellar silk extrusion duct were measured in Photoshop CS2

VideoS1

For the assessment of the hackling speed of Uloborus plumipes, the spider was recorded with a Canon 5D Mark III in full HD (1920 x 1080) using LED-lamps (Dedolight Ledzilla)

Thermally Induced Changes in Dynamic Mechanical Properties of Native Silks

Dynamic mechanical thermal analysis (DMTA) on individual native silk fibers demonstrates changes in the dynamic mechanical properties of storage modulus and loss tangent as a function of temperature and temperature history ranging from −100 to 250 °C. These property changes are linked quantitatively to two main types of change in the silk structure. First, the evaporation of water with increasing temperature up to 100 °C increases the storage modulus and removes two characteristic loss tangent peaks at −60 and +60 °C. Second, various discrete loss tangent peaks in the range 150–220 °C are associated with specific disordered silk structures that are removed or converted to a limiting high-temperature relaxed structure by the combination of increasing temperature and static load in the DMTA tests. The results identify important origins of silk filament quality based on the analysis of measurements that can be traced back to differences in production and processing history

Forced Reeling of <i>Bombyx mori</i> Silk: Separating Behavior and Processing Conditions

Controlled reeling is a powerful tool to investigate the details of silk processing. However, consistent forced reeling of silkworms is hindered by the significant degree of behaviorally induced variation caused by the animal. This paper proposes silkworm paralysis as a novel method to control the animal and thus in vivo spinning conditions. Using these methods, we achieve low and consistent reeling forces during the collection of over 500 m of individual silk fiber while monitoring filament variability, morphology, and properties. Novel techniques to measure the irregular silk cross-sectional areas lead to the more accurate calculation of the true engineering values and mechanical property variation of individual silk fibers. Combining controlled reeling and accurate thread measurement techniques allows us to present the relative contributions of processing and behavior in the performance envelope of <i>Bombyx mori</i> silk

Micrographs of ducts testing positively for chitin.

<p>(A) <i>Nephila edulis</i>, showing outer cuticle of spinneret and duct, scale bar 500 µm. (B) <i>Bombyx mori</i>, showing spigot, silk press then both ducts stained. Scale bar 500 µm.</p

Example of FTIR spectra peak deconvolution for the Amide I region of silks. from Analysing the structure and glass transition behaviour of silks for archaeology and conservation

Fig. S1 An example of FTIR spectrum peak deconvolution for the Zhejiang Raw silk. The figure shows the five main peaks deconvoluted from the Amide I region of the spectrum. Below shows the peak deconvolution results including peak amplitude and centre position etc

XRD profiles of various silks. from Analysing the structure and glass transition behaviour of silks for archaeology and conservation

Fig. S2 (a) XRD profiles of glass slide as sample base (i) and various types of silk fabrics: library gauze silk (ii); commercial fine silk (iii); UV-aged fine silk (iv); starch-coated fine silk (v) and UV-aged starch-coated fine silk (vi); (b) Overlay of the three curves (ii), (iii) and (iv) in the grey rectangle from (a)

Original length of spider duct and portion testing positive for chitin plotted against cephalothorax width.

<p>Original length of duct (black squares), portion testing positive for chitin (red circles). Error bars show standard deviations of length measurements.</p

Spectroscopic data with normalised absorbance.

<p>(A) Spider proximal and distal ducts, (B) spider duct average, spigot, cuticle and midgut, (C) silkworm duct, spigot, head plate and untreated ducts, (D) spider, silkworm and commercial chitin showing great similarity between results of chitin containing parts of both animals.</p

Spider Silk: Mother Nature’s Bio-Superlens

It was recently discovered that transparent microspheres and cylinders can function as a super-resolution lens (i.e., superlens) to focus light beyond the diffraction limit. A number of high-resolution applications based on these lenses have been successfully demonstrated and span nanoscopy, imaging, and spectroscopy. Fabrication of these superlenses, however, is often complex and requires sophisticated engineering processes. Clearly an easier model candidate, such as a naturally occurring superlens, is highly desirable. Here, we report for the first time a biological superlens provided by nature: the minor ampullate spider silk spun from the <i>Nephila</i> spider. This natural biosuperlens can distinctly resolve 100 nm features under a conventional white-light microscope with peak wavelength at 600 nm, attaining a resolution of λ/6 that is well beyond the classical limit. Thus, our work opens a new door to develop biology-based optical systems that may provide a new solution to integrating optics in biological systems