Functionalization of Colored/Fluorescent Silkworm Silk Fibrous Materials - Soft Fibrillar Materials: Fabrication and Applications - page 214

adsorption. In 1992, Caorui Jie, from the Agricultural Sciences Institute of Anhui
Province, China, reported the preparation of miraculous dyes, which could be
mixed with the mulberry leaf to feed the silkworm. The silkworm then produced
colored silk. This was claimed to be the first time colored silk was produced by the
feeding method.
In 2011, Han et al . reported their results on an alternative method to produce
intrinsically luminescent silks directly from silkworms by the feeding method [50].
These intrinsically colored and luminescent silks were produced in vivo through
the direct uptake of dye molecules into domesticated silkworms through a dye-
modified diet (Figure 7.4) [50]. This method is environmentally friendly because it
eliminates the external dyeing process and post-treatments associated with it. These
fluorescent silk fibers were fabricated into silk scaffold and seeded with human

Control Rhodamine 101 Rhodamine 110 Rhodamine B

A

B

C

D

Figure 7.4 Intrinsically colored and lumi-
nescent silks produced through addition of
various fluorescent dyes including rhodamine
101, rhodamine 110, and rhodamine B into
silkworms' diet as compared to a control
cocoon produced by a silkworm with nor-
mal feed. (a) Photographs of colored co-
coons under room light. (b) Photographs of

luminescent cocoons under UV irradiation.
(c) Photographs of silk fibers under UV irra-
diation. (d) Confocal images of a small area
of the colored cocoons under 488-nm laser
irradiation. (Reprinted with permission from
Ref. [50]. © 2011 Wiley-VCH Verlag GmbH &
Co. KGaA, Weinheim.)