Pyrene-bridged covalent immobilization of aminoferrocene on laser-induced graphene: toward high-performance sweat glucose sensors

Continuous non-invasive glucose monitoring remains challenging due to the lack of robust sensing interfaces that simultaneously ensure mediator stability, high sensitivity, and resistance to complex biofluid matrices. To address this, we develop a wearable electrochemical biosensor leveraging laser-induced graphene (LIG) functionalized via a π–π stacking-assisted covalent conjugation strategy. Unlike conventional approaches requiring corrosive electrode activation, our method exploits 1-pyrenebutyric acid N-hydroxysuccinimide ester (PBASE) as a molecular bridge to anchor aminoferrocene (AFc) mediators on pristine LIG through non-destructive π–π stacking followed by stable amide bonding. Glucose oxidase (GOx) is encapsulated in a chitosan matrix, forming a biocompatible sensing interface.The fabricated sensor exhibited a high electrochemically active surface area and fast electron transfer kinetics. Under optimized conditions, the sensor demonstrated a optimally wide linear range (0–1.0 mM), high sensitivity (32.1 μA mM −1  cm −2 ), and a low detection limit (13 μM). The device showed excellent selectivity against common sweat interferents, good reproducibility (RSD = 2.85 %), and long-term stability. Standard addition recovery tests in artificial sweat yielded recoveries between 93.7 % and 105.3 %, confirming its practical applicability. This work resolves the long-standing trade-off between stable mediator immobilization and electrode integrity, providing a scalable platform for reliable diabetes management.