Intrinsically reinforced silks obtained by incorporation of graphene quantum dots into silkworms

摄入石墨烯量子点的家蚕可直接吐出力学性能增强的蚕丝（英文）

Silkworm silks have been widely used in a variety of fields due to their sensuousness, luster and excellent mechanical properties. Researchers have paid special attention in improving the mechanical properties of silks. In this work,Bombyx mori larval silkworms are injected with graphene quantum dots(GQDs) through a vascular injection to enhance mechanical properties of the silkworm silks. The GQDs can be incorporated into the silkworm silk gland easily due to hemolymph circulation and influence the spinning process of silkworm. The breaking strength, elongation at break and toughness modulus of the silks increase by 2.74, 1.33 and 3.62 times, respectively, by injecting per individual with 0.6 μg GQDs. Wide-angle X-ray scattering indicates that the size ofβ-sheet nanocrystals in GQDs-silks is smaller than that in control-silks. Infrared spectra suggest that GQDs confine the conformation transition of silk fibroin to β-sheet from random coil/α-helix, and the change of the size and content of β-sheet may be the reason for the improvement of the mechanical properties. The toxicity and safety limit of GQDs incorporated into each silkworm is also evaluated, and the results show that the upmost dose of GQDs per silkworm is30.0 μg. The successful obtainment of reinforced silks by in vivo uptake of GQDs provides a promising route to produce high-strength silks.

家蚕蚕丝具有细腻、光鲜以及优良的力学特性,因而在诸多领域中都有广泛应用.许多科学家对提高家蚕蚕丝力学性能的研究非常感兴趣.本工作中,我们通过血管注射的方式给家蚕幼虫注入了石墨烯量子点(GQDs),并且得到了力学性能增强的蚕丝. GQDs可通过淋巴循环进入到家蚕的丝腺器官并影响家蚕的纺丝过程.研究发现,当家蚕的GQDs摄入量为0.6μg/头时,家蚕蚕丝的断裂强度、断裂伸长率以及韧性模量可分别增强到原来的2.74, 1.33和3.62倍.广角X射线散射(WAXS)结果表明GQDs-蚕丝中的β-折叠纳米晶体的尺寸比起空白蚕丝有所降低,红外光谱结果表明GQDs限制了丝素蛋白中无规则卷曲或者α-螺旋结构向β-折叠结构的构象转变.β-折叠结构的尺寸及含量的变化可能是引起蚕丝力学性能增强的原因所在.我们还对GQDs的毒性以及单头家蚕摄入GQDs的安全限进行了评估,结果发现家蚕摄入GQDs的上限为30.0μg/头.使家蚕直接摄入GQDs获得力学性能增强的蚕丝的方法为生产高强度蚕丝提供了一种有潜力的途径.