The research field of glucose biosensing has shown remarkable growth and development since the first reported enzyme electrode in 1962. Extensive research on various immobilization methods and the improvement of electron transfer efficiency between the enzyme and the electrode have led to the development of various sensing platforms that have been constantly evolving with the invention of advanced nanostructures and their nano-composites. Examples of such nanomaterials or composites include gold nanoparticles, carbon nanotubes, carbon/graphene quantum dots and chitosan hydrogel composites, all of which have been exploited due to their contributions as components of a biosensor either for improving the immobilization process or for their electrocatalytic activity towards glucose. This review aims to summarize the evolution of the biosensing aspect of these glucose sensors in terms of the various generations and recent trends based on the use of applied nanostructures for glucose detection in the presence and absence of the enzyme. We describe the history of these biosensors based on commercialized systems, improvements in the understanding of the surface science for enhanced electron transfer, the various sensing platforms developed in the presence of the nanomaterials and their performances.

We demonstrate the successful electrodeposition of Cu nanodendrite foams onto a series of lithographically formed gold band electrodes at negative overpotentials (-5V and -6V) in an acidic environment. The nanodendrite foams were deposited onto two different integrated microelectrode arrays fabricated using standard lithographic techniques. Each electrode consisted of 17 gold band electrodes deposited onto a silicon wafer substrate, labelled BA5 (with a width of 5 µm and a length of 250 µm) and BA10 (with a width of 10 µm and a length of 500 µm). Prior to Cu deposition the gold electrodes were characterized by scanning electron microscopy (SEM) in order to evaluate the morphology of each design and by cyclic voltammetry (CV) in order to investigate their diffusion profiles. After Cu deposition the resulting 3D foam structures were studied using SEM, XPS and EDX. The Cu foam/Au microelectrodes were then used for the electrocatalytic detection of glucose via oxidation at a potential of +0.45 V vs. Ag/AgCl in an alkaline medium. It was found that both types of electrode arrays used showed excellent analytical performance in terms of sensitivity, reproducibility and stability in comparison with the best performances reported in the literature. In particular, the BA5-CuFoam electrode exhibited an outstanding sensitivity of 10,630 µA mM -1 cm -2 towards glucose with a wide linear range up to 22.55 mM. The performance of this new type of electrochemical sensor is attributed to a combination of the use of the very high surface area Cu nanodendrite foam and the enhanced radial distribution profile associated with the use of the smaller band microfabricated electrodes. Additionally, both biosensors also showed a strong resistance to the poisoning effects of chlorine ions and excellent stability over a period of three months.

We report the development of a dual-enzyme electrochemical biosensor based on microfabricated gold band array electrodes which were first modified by gold foam (Au-foam) in order to dramatically increase the active surface area.

BACKGROUND Carbon‐based nanostructures have been attracting major interest in many research fields, including chemical and biological sensing, because of their unique structural dimensions and excellent physical, chemical and mechanical properties. A recently developed laser scribing approach allows design and fabrication of flexible, graphitic carbon‐based substrates for (bio‐)electrochemical applications, as it provides highly robust and low‐cost sensing platforms. RESULTS Here we demonstrate the fabrication of a highly reproducible laser‐scribed graphitic electrode (LSE) on a polyimide (Kapton) film using a simple, do‐it‐yourself laser engraving system equipped with a 405 nm wavelength laser. Copper nanostructures were deposited onto an electrode surface via the electrodeposition process. The developed three‐dimensional graphitic electrodes modified by nano copper/copper oxide species (LSE‐Cu) were used for the detection of dopamine and glucose. Electrochemical studies of LSE‐Cu showed that in the presence of nano‐copper there is an apparent shift of the oxidation peaks of dopamine and ascorbic acid, allowing determination of dopamine without an interference effect, with an excellent sensitivity of 1321.54 μA L mmol−1 cm−2. Furthermore, the LSE‐Cu sensor exhibited highly satisfying analytical performance towards glucose electro‐oxidation, with a reproducibility of 5.47% (RSD %). CONCLUSION We have demonstrated a simple design, fabrication and passivation route for the preparation of LSEs performing as biosensors. Such a cost‐effective and design‐flexible system is highly suitable for developing a biosensing platform towards various target analytes and further miniaturization of the electrode. © 2020 Society of Chemical Industry