College of Polymer Science and Engineering, State Key Laboratory of Polymer Materials and Engineering, Sichuan University, Chengdu, Sichuan 610065, China.
Nanoscale. 2015 May 7;7(17):7992-8002. doi: 10.1039/c5nr01107h.
Graphene-nanoparticle (NP) composites have shown potential in applications ranging from batteries to, more recently, tissue engineering. Graphene and NPs should be integrated into uniform free-standing structures for best results. However, to date, this has been achieved only in few examples; in most cases, graphene/NP powders lacking three-dimensional (3D) structure were produced. Here we report a facile and universal method that can be used to synthesize such structures based on colloidal chemistry. We start from aqueous suspensions of both graphene oxide nanosheets and citrate-stabilized hydroxyapatite (HA) NPs. Hydrothermal treatment of the mixtures of both suspensions reduces graphene oxide to graphene, and entraps colloidal HA NPs into the 3D graphene network thanks to a self-assembled graphite-like shell formed around it. Dialysis through this shell causes uniform NP deposition onto the graphene walls. The resulting graphene-HA gels are highly porous, strong, electrically conductive and biocompatible, making them promising scaffolds for bone tissue engineering. This method can be applied to produce a variety of free-standing 3D graphene-based nanocomposites with unprecedented homogeneity.
石墨烯-纳米颗粒（NP）复合材料在从电池到组织工程等领域的应用中显示出了潜力。为了达到最佳效果，石墨烯和 NP 应该被整合到均匀的独立结构中。然而，迄今为止，这种情况只在少数几个例子中实现；在大多数情况下，所生产的石墨烯/NP 粉末缺乏三维（3D）结构。在这里，我们报告了一种基于胶体化学的简单且通用的方法，可以用来合成这种结构。我们从氧化石墨烯纳米片和柠檬酸稳定的羟基磷灰石（HA）NP 的水悬浮液开始。将两种悬浮液的混合物进行水热处理，可将氧化石墨烯还原为石墨烯，并通过在其周围形成自组装的类石墨壳，将胶体 HA NP 捕获到 3D 石墨烯网络中。通过这种壳进行透析会导致 NP 均匀地沉积到石墨烯壁上。由此得到的石墨烯-HA 凝胶具有高多孔性、高强度、导电性和生物相容性，使其成为骨组织工程有前途的支架。这种方法可以用来制备各种具有前所未有的均匀性的独立 3D 石墨烯基纳米复合材料。
