Department of Biological Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032, India.
Langmuir. 2012 Jan 17;28(2):1460-9. doi: 10.1021/la203498j. Epub 2011 Dec 23.
In the presence of a small amount of a proteinous amino acid (arginine/tryptophan/histidine) or a nucleoside (adenosine/guanosine/cytidine), graphene oxide (GO) forms supramolecular stable hydrogels. These hydrogels have been characterized by field-emission scanning electron microscopy (FE-SEM), atomic force microscopy (AFM), X-ray diffraction (XRD) analysis, Raman spectroscopy, and rheology. The morphology of the hydrogel reveals the presence of nanofibers and nanosheets. This suggests the supramolecular aggregation of GO in the presence of an amino acid/nucleoside. Rheological studies of arginine containing a GO-based hydrogel show a very high G' value (6.058 × 10(4) Pa), indicating the rigid, solid-like behavior of this gel. One of these hydrogels (GO-tryptophan) has been successfully utilized for the in situ synthesis and stabilization of Au nanoparticles (Au NPs) within the hydrogel matrix without the presence of any other external reducing and stabilizing agents to make Au NPs containing the GO-based nanohybrid material. The Au NPs containing the hybrid hydrogel has been characterized by using UV/vis spectroscopy, X-ray diffraction (XRD), and transmission electron microscopy (TEM). In this study, gold salt (Au(3+)) has been bioreduced by the tryptophan within the hydrogel. This is a facile "green chemical" method of preparing the GO-based nanohybrid material within the hydrogel matrix. The significance of this method is the in situ reduction of gold salt within the gel phase, and this helps to decorate the nascently formed Au NPs almost homogeneously and uniformly on the surface of the GO nanosheets within the gel matrix.
在存在少量蛋白质氨基酸（精氨酸/色氨酸/组氨酸）或核苷（腺苷/鸟苷/胞苷）的情况下，氧化石墨烯（GO）会形成超分子稳定水凝胶。这些水凝胶已经通过场发射扫描电子显微镜（FE-SEM）、原子力显微镜（AFM）、X 射线衍射（XRD）分析、拉曼光谱和流变学进行了表征。水凝胶的形态揭示了纳米纤维和纳米片的存在。这表明在氨基酸/核苷存在的情况下，GO 发生了超分子聚集。含精氨酸的 GO 基水凝胶的流变学研究表明，其 G' 值（6.058×10(4) Pa）非常高，表明该凝胶具有刚性、固态的行为。其中一种水凝胶（GO-色氨酸）已成功用于在水凝胶基质中原位合成和稳定金纳米颗粒（Au NPs），而无需使用任何其他外部还原和稳定试剂来制备含有 GO 的纳米杂化材料。Au NPs 含有杂化水凝胶的特征在于使用紫外/可见光谱、X 射线衍射（XRD）和透射电子显微镜（TEM）。在这项研究中，金盐（Au(3+)）已被水凝胶中的色氨酸生物还原。这是一种在水凝胶基质中制备 GO 基纳米杂化材料的简便“绿色化学”方法。这种方法的意义在于在凝胶相中原位还原金盐，这有助于将新生的 Au NPs 均匀地装饰在凝胶基质中 GO 纳米片的表面上。
