38. Artificial Biospinning of Silkworm Silks

To obtain fibers with better properties, an artificial method of biospinning silk fiber matrices was adopted, and the fibers and matrices were used as substrates for tissue engineering. Wild silk worms (Antheraea mylitta) in their fifth instar were collected, and fibers were manually (forcefully) drawn from the silkworm onto glass slides as shown in Fig. 38.1a. Fibers obtained were aligned in various fashions to develop matrices for tissue engineering. Alternatively, the silk worms were allowed to naturally spin silk onto Teflon-coated glass plates, and the matrices formed (Fig. 38.1b) were collected. Fibers and matrices were degummed and later characterized for their properties, and the potential of using the fibers as substrates for tissue engineering was studied [10Man]. Fibers obtained by forceful extrusion and drawing were circular and had diameters of 12–15 μm compared to 30–35 μm for naturally extruded silk. Similarly, the biospun fibers had tensile strength of 4.1 ± 1.4 g/den, much higher than that of Bombyx mori or the natural fibers obtained from A. mylitta. The fibers and matrices developed had enhanced stability to degradation by proteases and found to have good compatibility and supported the attachment and proliferation of fibroblasts [10Man].