Au@BSA prepared under alkaline conditions as an electrochemical non-enzymatic glucose sensor interface

Au@BSA was prepared at pH 8, pH 9, pH 10, pH 11, pH 11.4, and pH 12 as the working electrode of the non-enzymatic glucose sensor by biological template method. The six kinds of gold-cluster film working electrodes sintered by Au@BSA show golden color, especially the golden films corresponding to pH 8 and pH 12 are obvious. The gold-cluster films at pH 8, pH 9, pH 10, and pH 11 showed mono-layer gold nanoparticles, while the gold-cluster film at pH 11.4 showed porous structure. The gold-cluster film prepared at pH 12 presents a multi-layer 3D structure composed of a large number of gold nanoparticles. The linear detection range of the non-enzymatic glucose sensor prepared at pH 8 is the widest among the six sensors, and its sensitivity is also better than the other four sensors except the sensor prepared at pH 12. The sensor with the gold-cluster film-modified working electrode prepared at pH 12 show the highest sensitivity (330.002 μA mM^?1 cm^?2), because multi-layer 3D structure can bring more electric catalytic active site for this sensor. The electrochemical impedance spectroscopy showed that the specific surface area of the sensor prepared at pH 12 was much larger than that of the other five sensors. We provide a pH cycling method for once shaping preparation that can be extended to other metal films or metal-oxide films electrochemical interfaces. The Au@BSA non-enzymatic glucose sensor prepared in this paper is stable and can resist the toxicity of excessive chloride ions without losing activity.