CHEMICAL COMPOSITION, STRUCTURE, AND PROPERTIES OF NATURAL SILK: A COMPREHENSIVE REVIEW

Natural silk is a high-performance biopolymer fiber produced by Bombyx mori silkworms and various spider species. It is composed primarily of two proteins—fibroin and sericin—which endow silk with its unique combination of mechanical strength, biocompatibility, and biodegradability. This article reviews the chemical composition, molecular architecture, and physicochemical properties of silk, with emphasis on the crystalline beta-sheet domains of fibroin, the role of sericin as a protective coating, and the hydrogen-bonding network that governs fiber performance. Thermal stability, solubility behavior, and response to chemical treatments are discussed in detail. The article also surveys current chemical modification strategies, including degumming, fibroin dissolution, and regeneration protocols. Understanding silk chemistry at the molecular level is critical for expanding its applications in biomedicine, textile engineering, and functional materials. This review synthesizes findings from eight primary research sources to provide a rigorous chemical perspective on this remarkable natural polymer.天然丝是由桑蚕（Bombyx mori）与多种蜘蛛分泌的高性能生物聚合物纤维。其主要由丝素蛋白（fibroin）与丝胶蛋白（sericin）两种蛋白质构成，赋予了天然丝兼具机械强度、生物相容性与可降解性的独特综合性能。本文综述了天然丝的化学组成、分子结构与物理化学性质，重点探讨了丝素蛋白的结晶态β-折叠（beta-sheet）结构域、丝胶蛋白作为保护性涂层的作用，以及调控纤维性能的氢键网络。本文还详细讨论了天然丝的热稳定性、溶解行为及其对化学处理的响应特性。此外，本文梳理了当前主流的化学改性策略，包括脱胶、丝素蛋白溶解与再生工艺。从分子层面解析天然丝的化学特性，对拓展其在生物医学、纺织工程与功能材料领域的应用至关重要。本综述整合了8项核心研究成果，为这种优异的天然聚合物提供了严谨的化学视角。