In recent years, graphene-based enzyme biosensors have received considerable attention due to their excellent performance. Enormous efforts have been made to utilize graphene oxide and its derivatives as carriers of enzymes for biosensing. However, the performance of these sensors is limited by the drawbacks of graphene oxide such as slow electron transfer rate, low catalytic area and poor conductivity. Here, we report a new graphene-based enzyme carrier, i.e. a highly conductive 3D nitrogen-doped graphene structure (3D-NG) grown by chemical vapour deposition, for highly effective enzyme-based biosensors. Owing to the high conductivity, large porosity and tunable nitrogen-doping ratio, this kind of graphene framework shows outstanding electrical properties and a large surface area for enzyme loading and biocatalytic reactions. Using glucose oxidase (GOx) as a model enzyme and chitosan (CS) as an efficient molecular binder of the enzyme, our 3D-NG based biosensors show extremely high sensitivity for the sensing of glucose (226.24 μA mM⁻¹ m⁻²), which is almost an order of magnitude higher than those reported in most of the previous studies. The stable adsorption and outstanding direct electrochemical behaviour of the enzyme on the nanocomposite indicate the promising application of this 3D enzyme carrier in high-performance electrochemical biosensors or biofuel cells.

中文翻译：

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三维氮掺杂石墨烯结构：高效的生物传感器酶载体†

近年来，基于石墨烯的酶生物传感器由于其出色的性能而受到了广泛的关注。已经做出巨大努力来利用氧化石墨烯及其衍生物作为用于生物传感的酶的载体。但是，这些传感器的性能受限于氧化石墨烯的缺点，例如电子传输速度慢，催化面积低和导电性差。在这里，我们报告了一种新的基于石墨烯的酶载体，即通过化学气相沉积生长的高导电3D氮掺杂石墨烯结构（3D-NG），用于高效的基于酶的生物传感器。由于高电导率，大孔隙率和可调节的氮掺杂比，这种石墨烯骨架显示出出色的电性能，并具有较大的表面积，可用于酶负载和生物催化反应。我们使用基于3D-NG的生物传感器，使用葡萄糖氧化酶（GOx）作为模型酶，并使用壳聚糖（CS）作为该酶的有效分子结合剂，显示出对葡萄糖的极高灵敏度（226.24μAmM ^-1 m ^-2），几乎比以前的大多数研究报告的数量级高出一个数量级。该酶在纳米复合材料上的稳定吸附和出色的直接电化学行为表明该3D酶载体在高性能电化学生物传感器或生物燃料电池中的应用前景广阔。