Glucose Biosensors Based on Pinecone-Shaped Au and Ni Nanoparticle Composite Microelectrodes

Glucose concentration in the body is a very important index for health evaluation. Nonenzymatic glucose biosensors attract persistent interest and research. The acupuncture technique has been developed for treating the disease for thousands of years. Here, a stainless-steel acupuncture needle (AN) was first used to sense glucose after functionalizing with bimetal of gold nanoparticles (AuNPs) and nickel nanoparticles (NiNPs). AuNPs were electrodeposited as particle clusters, and the NiNPs could be further electrodeposited around AuNPs to form a nano-pinecone shape with a size of about 600 nm. Au/AN exhibited the best electroconductivity compared to the weakest Ni/AN and medium Ni/Au/AN interfaces. Three nanotechnically processed interfaces showed obvious electrochemical response behavior for glucose compared with the bare AN. Surprisingly, the matrix of AuNPs could drastically boost the electrochemical response of NiNPs for glucose, which might be due to the abundance of active sites in the bimetallic hierarchy. The Ni/Au/AN electrode possessed an additive signal compared with Au/AN and Ni/AN. Under the optimized conditions, the prepared nonenzymatic biosensor exhibited two linear relationships in the wide concentration range of 0.5 μM to 1.5 mM and 1.5–5 mM with sensitivities of 766.02 and 368.77 (μA/mM/cm2), and the limit of detection was 0.14 μM. Moreover, the Ni/Au/AN showed superior performance over reported electrodes with great selectivity, stability, and reproducibility. The apparent Km of 0.161 mM was lower than that of glucose oxidase, implying that the Ni/Au-modified AN exhibited a strong affinity for glucose. The fabricated biosensor can be successfully used for the detection of glucose concentration in human serum, which provided a leading direction and potential for clinical point-of-care monitoring.