School of Materials Science & Engineering, Beijing Institute of Technology, Beijing 100081, PR China.
Small. 2013 Jul 8;9(13):2331-40. doi: 10.1002/smll.201202923. Epub 2013 Feb 19.
Highly porous hosting materials with conducting (favorable to electron transfer) and magnetic (favorable to product separation) bicontinuous networks should possess great potentials for immobilization of various enzymes in the field of biocatalytic engineering, but the synthesis of such materials is still a great challenge. Herein, bifunctional graphene/γ-Fe2 O3 hybrid aerogels with quite low density (30-65 mg cm(-3) ), large specific surface area (270-414 m(2) g(-1) ), high electrical conductivity (0.5-5 × 10(-2) S m(-1) ), and superior saturation magnetization (23-54 emu g(-1) ) are fabricated. Single networks of either graphene aerogels or γ-Fe2 O3 aerogels are obtained by etching of the hybrid aerogels with acid solution or calcining of the hybrid aerogels in air, indicative of the double networks of the as-synthesized graphene/γ-Fe2 O3 hybrid aerogels for the first time. The resulting bifunctional aerogels are used to immobilize β-glucuronidase for biocatalytic transformation of glycyrrhizin into glycyrrhetinic acid monoglucuronide or glycyrrhetinic acid, with high biocatalytic activity and definite repeatability.
具有导电网络（有利于电子转移）和磁网（有利于产物分离）双连续网络的高多孔主体材料在固定化各种酶的生物催化工程领域具有巨大的潜力，但此类材料的合成仍然是一个巨大的挑战。在此，制备了具有低密度（30-65 mg cm(-3)）、大比表面积（270-414 m(2) g(-1)）、高电导率（0.5-5 × 10(-2) S m(-1)）和超饱和磁化强度（23-54 emu g(-1)）的双功能石墨烯/γ-Fe2 O3 杂化气凝胶。通过酸溶液刻蚀杂化气凝胶或在空气中煅烧杂化气凝胶，可以得到单网络的石墨烯气凝胶或 γ-Fe2 O3 气凝胶，这首次表明所合成的石墨烯/γ-Fe2 O3 杂化气凝胶具有双网络结构。所得的双功能气凝胶用于固定β-葡萄糖醛酸酶，以生物催化转化甘草酸成单葡萄糖醛酸甘草酸或甘草次酸，具有较高的生物催化活性和一定的可重复性。
