Robust and washable silk fiber-based electrochemical biosensor for high-performance sensing of hydrogen peroxide

Wearable electronics, especially fiber-based biosensors, show promise in large-scale production and reusability compared with conventional wafer-based electronics. However, it is challenging to use wearable electronics, with less intensity and non-wash ability, to produce fiber-based biosensors for textiles. Here, a robust and washable Prussian blue (PB)-functionalized silk fiber (PB-SF) flexible electrode is reported. Modified cyanotype is successfully employed to immobilize PB nanoparticles (∼18.32 nm) onto silk fibers for hydrogen peroxide (H₂O₂) detection. The intrinsic mechanical properties of silk fibers are well maintained with slight increases in stress (∼10 %) and strain (∼16 %). Furthermore, the PB-SF electrode displays good electrochemical H₂O₂ sensing performance with a sensitivity of 716.54 μA/mM·cm², a linear range of 0.01–0.6 mM and a low detection limit of 10 μM (S/N = 3). Notably, the hybrid PB-SF electrode adapts to mechanical deformations with a series of angles and the electrical signals are not compromised obviously even after 100 home laundry washing cycles. PB modified silk fibers is simple, easy-operating and cost-effective electrode that is suitable for large-scale production as it can be integrated into e-textiles through typical textile processing methods.