Uniformly Dispersing and Anchoring Graphene on GaN Nanowire Substrate: Application to Electrochemical Detection of Glucose in Sweat

For deposition of two-dimensional materials (e.g., graphene) on a substrate, self-aggregation and poor anchor strength are still issues. Herein, the GaN nanowire (NW) substrate was employed for electrochemical deposition of reduced graphene oxide (rGO) with satisfying dispersion uniformity and anchor strength. The deposited rGO exhibited flake morphology without agglomeration. Moreover, PtAu and rGO can be simultaneously and uniformly deposited on the GaN NW substrate to realize a PtAu–rGO/GaN electrochemical sensor for glucose detection. In comparison with deposition of PtAu–rGO on a stainless steel (SS) substrate (i.e., PtAu–rGO/SS), PtAu–rGO/GaN demonstrated much higher sensitivity and long-term stability, owing to better dispersion and anchor strength on GaN NW. In addition, with decoration of glucose oxidase (GOx), the GOx/PtAu–rGO/GaN sensor can be used for detecting glucose in human sweat with a low limit of detection of 5 μM, a wide linear detection range of 5 μM–12 mM, and high long-term stability, which indicates that GOx/PtAu–rGO/GaN sensor is promising for noninvasive glucose detection.