An integrated dual-signal self-powered flexible sensor based on ferrocene-mediated biofuel cell for glucose detection†

Continuous glucose level monitoring is essential for the effective treatment of diabetes and overall metabolic health, requiring advanced sensing technologies that provide precise, reliable, and sustained performance in physiological situations. This study presents an integrated enzymatic dual-signal self-powered flexible sensor based on ferrocene-mediated glucose biofuel cells (BFCs), allowing rapid glucose detection through dual signal transduction of current and electrochromic response. The anode (flexible Au/CNT–rGO paper films), functionalized with glucose oxidase/ferrocene (GOD/Fc), catalyzes glucose oxidation to gluconate and generates electrons and outputs the current signal, where Fc facilitates electron transport to mitigate oxygen dependency. The cathode (ITO/PET) provides a visual signal with chitosan@prussian (CS@PB) nano-composite integrated as an electrochromic region. The sensor exhibits a low detection limit of 0.018 mM and a linear detection range from 0.1 to 80 mM, with excellent selectivity and stability. In addition, clinical serum glucose and urine testing experiments validated the sensor's efficacy, demonstrating its potential for biomedical research and clinical applications. The sensor's self-power generation and dual-signal readout provide a promising platform for the development of point-of-care (POC) devices tailored for personalized metabolic health assessment.