Department of Physics and Astronomy, Rowan University, Glassboro, NJ 08028, USA; Center of Analysis and Testing, Nanjing Normal University, Nanjing 210023, China.
Department of Physics and Astronomy, Rowan University, Glassboro, NJ 08028, USA; Department of Chemistry and Biochemistry, Rowan University, Glassboro, NJ 08028, USA.
Mater Sci Eng C Mater Biol Appl. 2017 Oct 1;79:728-739. doi: 10.1016/j.msec.2017.05.120. Epub 2017 May 17.
Green graphene materials prepared by photoreduction of graphite oxide were first time blended with aqueous-based silk fibroin proteins to improve the mechanical and thermal properties of silk biomaterials, and their nanocomposite interaction mechanism was illustrated. Powder X-ray diffraction (XRD) analysis confirmed the complete exfoliation of graphite oxide to graphene in presence of focused pulses of solar radiation. By varying the concentration of graphene (0.1wt% to 10wt%), a series of free standing graphene-silk films were prepared and were systematically characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and nanoindentation measurements. The homogeneity of graphene in silk as well as the thermal stability of the composite films was demonstrated by thermal gravimetric analysis (TGA) and temperature-modulated differential scanning calorimetry (TMDSC). Surprisingly, silk composite film containing only 0.5wt% of graphene gives the highest Young's modulus of 1.65GPa (about 5.8 times higher than the pure silk's modulus), indicating a nano-composite to micro-composite transition of silk-graphene structure occurred around this mixing ratio. This finding provided an easy approach to improve the elastic modulus and other physical properties of silk materials by adding a tiny amount of graphene sheets. Fibroblast cells studies also proved that these graphene-silk materials can significantly improve cell adhesion, growth and proliferation. This protein nanocomposite study provided a useful model to understand how to manipulate the hydrophobic-hydrophobic and polar-polar interactions between high-surface-area inorganic nanomaterials and amphiphilic protein materials, which has many emerging applications in the material science and engineering, such as bio-device fabrication, drug storage and release, and tissue regeneration.
首次将通过石墨氧化物光还原制备的绿色石墨烯材料与基于水的丝素蛋白混合，以改善丝生物材料的机械和热性能，并阐明了它们的纳米复合材料相互作用机制。粉末 X 射线衍射（XRD）分析证实了在聚焦的太阳辐射脉冲存在下，石墨氧化物完全剥离成石墨烯。通过改变石墨烯的浓度（0.1wt%至 10wt%），制备了一系列独立的石墨烯-丝素薄膜，并通过傅里叶变换红外光谱（FTIR）、扫描电子显微镜（SEM）和纳米压痕测量对其进行了系统表征。通过热重分析（TGA）和温度调制差示扫描量热法（TMDSC）证明了石墨烯在丝中的均匀性以及复合膜的热稳定性。令人惊讶的是，仅含 0.5wt%石墨烯的丝复合膜给出了 1.65GPa 的最高杨氏模量（比纯丝的模量高约 5.8 倍），表明在该混合比周围发生了丝-石墨烯结构的纳米复合材料到微复合材料的转变。这一发现为通过添加少量石墨烯片来提高丝材料的弹性模量和其他物理性能提供了一种简单的方法。成纤维细胞研究也证明了这些石墨烯-丝材料可以显著改善细胞的黏附、生长和增殖。这项蛋白质纳米复合材料研究提供了一个有用的模型，以了解如何操纵高表面积无机纳米材料和两亲性蛋白质材料之间的疏水性-疏水性和极性-极性相互作用，这在材料科学和工程中具有许多新兴应用，如生物器件制造、药物储存和释放以及组织再生。
