Spider silks spinning

Fig. 6. Structural stability of major ampullate silk protein in constrained Nephila edulis. The graph shows a time series of circular dichroism spectra of major ampullate (MA) protein at 1% w/v in distilled water. The spiders prior to dissection were prevented from spinning, but fed and watered for at least 2 weeks. With time, the secondary structure of silk protein is becoming more and more disordered. The arrow indicates increasing time (days). Note that the amino acid composition of the silk protein was similar to that of a native N. edulis spider. Interestingly, silk protein extracted from the constrained spider did not respond to denaturing conditions (detergents, alcohols, pH, and salts Dicko et al, 2004a, 2005).

Although spider and insect spinning silks are different and their silk types and functions diverse (Craig, 2003 Foelix, 1996), it is strongly... 

Knight, D. P., Knight, M. M., and Vollrath, F. (2000). Beta transition and stress-induced phase separation in the spinning of spider dragline silk. Int. J. Biol. Macromol. 27, 205-210. 

Super-contraction, the chaperonage of the special structure of spidroin, is indeed an obstacle to the use of native spider dragline silk, especially in bioapplication (usually wet condition). Recently, it was found that the intrinsic properties of silk fibroin are much better than the data listed in Table 2. The inferior properties are generated by the spinning habit of... 

As to fibers, it was reported that the inferior mechanical properties of silk from cocoons compared to spider silk result from the silkworm spinning process. If silkworm silk is processed at a constant pulling speed rather than constant force pulling, it possesses excellent properties, approaching the spider dragline silk (Shao and Vollrath, 2002). This suggests that the silkworm silk has the potential to produce better fibers, and the regenerated fibroin, which is easy to harvest, has the possibility to be fabricated into a reconstituted super-fiber. 

Kummerlen, J., vanBeek, J.D., Vollrath, F., and Meier, B.H. "Local structure in spider dragline silk investigated by two-dimensional spin-diffusion nuclear magnetic resonance". Macromolecules 29(8), 2920-2928 (1996). 

There are all sorts of silk that are found in nature. The stuff that is usually found in textiles comes from silkworms (Bombyx mori). They are not really worms, but the larvae of moths. They emerge from very small eggs with an incredible lust for mulberry leaves, which they consume until they are ready to. pupate and weave a cocoon around themselves. Unlike spiders, which spin silk from their rear end, silkworm silk is actually hardened saliva, which comes out of the mouth. The larva has a small spinneret on its lip, through which the silk emerges. The cocoon is formed from a single strand of silk that... 

Other types of spider webs include tangle webs and sheet webs sptm by different species. Many other insects spin silk fibers for cocoons, shelter, egg sacs, egg stalks, and tunnels. For example, tarantulas use silk to spin tunnel-shaped shelters, and spin fibers from their feet as support lines. Caddisfiy larvae spin underwater tubes and nets, and the aquatic midge spins underwater silk tubes. Honeybee larvae spin silk to inCTease the mechanical strength and thermal stability of the beehive. These silks are subject to inaeasing amounts of research, as reviewed in Reference 11. 

In the fibers produced from lyotropic spinning dopes, there still appear to be limitations on the ultimate physical properties due to higher-order morphological defects (the periodic director-orientation distortions alluded to earlier) [115]. In this context, much experimental and theoretical work remains to be done to delineate those parameters that control disclination textures and director patterns created by complex shear fields encountered in processing LCPs. As is typically the case, there are natural systems wherein these difficulties appear to have been optimally minimized spiders spin nearly defect-free fibers from a mesomorphic form of silk [116]. Consequently, efforts to analyze the spinning process - the spinner draw-down geometry and its associated shear field - used by arachnids are under way. 

In contrast to current fossil fuel-based synthetic materials, spiders spin the ultra-strong and totally recyclable fibers at ambient temperatures, low pressures, and using water as the solvent [5, 6]. There are accordingly many advantages to copying the spider silk and silk production capabilities. 

Silk is a protein fiber spun by silkworm, which is the caterpillar or larva of the domesticated silkmoth, Bombyx mori. In addition to silkworm, many other insects or non-insects (eg., spider) can spin silk fibers. However, the silk of Bombyx mori is the mainstay of commercial silk production and consumption. This section will only discuss the formation of silk fiber by silkworm. 

The feeling of a spider web may be unsettling, but a similar natural material has been used for centuries to make silk fabric that is prized for its smooth texture. Silkworms produce the silk fibers used to make clothing. They feast on mulberry leaves and convert the molecules from these leaves into silk, from which they spin cocoons. 

Synthetic Spider Silk Fibers Natural i/s Artificial Spinning Strategies... 

Raw silk was dissolved in hexafluoro-iso-propanol (HFIP) [17, 33]. A typical working concentration for spinning was 2.5% (w/v) silk fibroin in HFIP. The spinning solution was pressed through a small needle (0 80-250 pm) into a precipitation bath (methanol for Bombyx mori silk proteins and acetone for Nephila clavipes silk proteins) and the silk solution immediately precipitated as a fiber. The best performing fibers approached the maximum strength measured for native fibers of Bombyx mori, but did not achieve the mechanical properties of natural spider silk. 

The spinning of silk monofilaments from a concentrated aqueous solution (>20% protein) of recombinant spider silk protein might be the best way to generate stress-... 

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