Laser‐Engraved Boron‐Doped Diamond for Copper Catalyzed Non‐Enzymatic Glucose Sensing

Abstract

oxidase has opened up the horizon for continuous glucose monitoring. However, enzymatic glucose sensors showcase slow response, low sensitivity, complex immobilization process, and they are susceptible to temperature, humidity, and pH variations. [5][6][7] Therefore, the development of fabrication methods for high-performance nonenzymatic glucose sensors needs to be explored.In nonenzymatic glucose sensors, catalytic sensing is performed using transition metals immobilized on conductive substrates. [8,9] The role of transition metals is demonstrated in the recently established d-band model, in which the d-band center of the transition metal serves as an electronic descriptor to evaluate the binding strength of the reaction intermediate on the metal. [10,11] When the adsorbate molecule approaches the metal surface, its energy levels are shifted by the metal electrons. Although the wide s-band of the metal only shifts and broadens the electronic state of the molecule, [12] the narrow d-band with large density of states (DOS) splits the electronic state of the molecule into bonding and antibonding states, which determine the chemisorption and desorption processes. As a result, the d-band center can be adopted as a descriptor to evaluate catalytic performance. [13,14] Among all transition metals, Cu is one of the most widely utilized transition metal catalysts, offering great potential as an ideal electrocatalyst for glucose oxidation. [9,15] The sensing capability of an electrocatalyst is affected by its support material. [16,17] In comparison with conductive carbonbased materials such as graphene [18] and carbon nanotubes, [16] boron-doped diamond (BDD) has a wide semiconductor bandgap (E g = 5.47 eV), wide electrochemical window, and excellent stability. Thus, it serves as an ideal electrode material for sensing applications that demand low background currents and high signal-to-noise (S/N) ratios. [19,20] For instance, Pinar et al. [21] achieved the simultaneous detection of epinephrine and lidocaine using a BDD electrode by taking advantage of its wide electrochemical window. The high S/N ratio of BDD electrodes enables electrophysiological recording, dopamine sensing, [22] and real-time drug tracking. [23] However, because BDD is electrochemically inert and has poor glucose sensitivity, decorating BDD electrodes with transition metals may offer a unique opportunity for the development of glucose sensors with ultrahigh sensitivity and improved stability. Robust and high-performance electrochemical electrodes for non-enzymatic glucose sensing are in constant demand. Herein, a hierarchical nonenzymatic glucose sensing electrode on boron-doped diamond (BDD) is fabricated using high-speed laser engraving and pulsed electrodeposition of Cu nanostructures. The obtained electrode contains a densely packed Cu nanoflake (CuNF) array periodically decorated on the laser-engraved BDD. The hierarchical nanoarchitecture combines the d-band catalytic activity of the CuNFs with the low capacitive background current of the engra...

Laser Micro/Nano‐Structuring Pushes Forward Smart Sensing: Opportunities and Challenges

“…Reproduced with permission. [199] Copyright 2022, Wiley-VCH. g) Mass-producible laser-engraved graphene arrays for a disposable and flexible graphene sensor, presenting a selective response to NP, S1-IgG, and S1-IgM isotypes, and CRP sensors against different non-target circulating analytes.…”

“…To achieve robust and high-performance electrochemical sensing electrodes, Gao et al combined high-speed laser-engraving and pulsed electrodeposition of Cu nanostructures to fabricate a hierarchical nonenzymatic glucose sensing electrode on BDD. [199] Owing to the d-band catalytic activity of the Cu nanoflake with the low capacitive background current of the engraved BDD substrate, the hierarchical nanostructured electrode enabled fast, precise, and high signal-to-noise ratio detection of trace glucose, showing a high sensitivity, ultrafast response time, and low LOD (Figure 10f). Besides, excellent cyclicality and anti-interference ability made the sensor to be great stability for practical usage.…”

“…f) Schematic diagram of high-speed laser-engraved BDD and deposited Cu nanoflake as electrodes for copper-catalyzed non-enzymatic glucose sensing, showing a good response to continuously dripping glucose and interfering substances. Reproduced with permission [199]. Copyright 2022, Wiley-VCH.…”