A flexible composite electrode for effective real-time glucose monitoring via high-precision layer-by-layer inkjet...

Conventional techniques such as screen printing and hand-brushing, though scalable, often compromise on patterning resolution and material waste. In contrast, advanced inkjet printing offers a promising route for high-resolution and efficient manufacturing. In this study, a flexible electrode based on Ni-MOF material used high-precision scalable inkjet printing was developed for glucose sensing in human body fluids for wearable devices. Initially, Ni-MOF material with a high specific surface area and porous structure was synthesized via a hydrothermal method, and its potential for electrochemical detection was investigated. Experimental results demonstrated that the material exhibited high sensitivity and a broad detection range for glucose. Importantly, graphite and carbon nanotubes were incorporated to construct a Ni-MOF composite material with the composition ratio optimized to enhance conductivity and mechanical stability, for further application in flexible electrodes. Typically, a cost-effective, high-efficiency, and scalable fabrication process was achieved through high-precision inkjet printing technology, which enables 1200 dpi resolution while supporting ultra-large-scale printing up to 1200 × 1200 mm. Simutaneously, simulation-based optimization was conducted to determine the most effective electrode shape. As a result, the detection range of the inkjet-printed flexible electrode was extended to 0.005-2.63 mM, with an improved sensitivity of 12.2 μA·μM^-1·cm^-2. Moreover, excellent mechanical stability and long-term durability were achieved, enabling precise differentiation of glucose fluctuations in low-concentration simulated sweat. Finally, a microfluidic channel to provide environment for the reaction was designed, thereby establishing a fundamental foundation for applying the flexible electrode in wearable devices.