Photoprotection by Silk Cocoons

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• 作者：Jasjeet Kaur ; Rangam Rajkhowa ; Takuya Tsuzuki ; Keith Millington ; Jin Zhang ; Xungai Wang
• 刊名：Biomacromolecules
• 出版年：2013
• 出版时间：October 14, 2013
• 年：2013
• 卷：14
• 期：10
• 页码：3660-3667
• 全文大小：466K
• 年卷期：v.14,no.10(October 14, 2013)
• ISSN：1526-4602

文摘

A silk cocoon protects a silkworm during its pupal stage from various threats. We systematically investigated the role of fiber, sericin, and embedded crystals in the UV protection of a silk cocoon. Diffuse reflectance and UV absorbance were measured and free radicals generated during exposure to UV radiation were quantified using photoinduced chemiluminescence (PICL). We identified the response to both UV-A and UV-B radiations by silk materials and found that sericin was primarily responsible for UV-A absorption. When sericin was removed, the photoinduced chemiluminescence intensity increased significantly, indicating higher UV-A-induced reactions of cocoons in the absence of sericin. There is progressively higher sericin content toward the outer part of the cocoon shell that allows an effective shield to pupae from UV radiation and resists photodegradation of silk fibers. The study will inspire development of advanced organic photoprotective materials and designing silk-based, free-radical-scavenging antioxidants.