Vanadium pentoxide flat-nanofiber networked thin layer-structure to initiate intercalated polymerization for rapidly...

Poly(3,4-ethylenedioxythiophene) (PEDOT)-based hydrogel has been studied extensively due to its low cost, good chemical/mechanical stability, printability and high biocompatibility, but still suffers from its relatively low conductivity and complex synthesis method. In this work, we use vanadium pentoxide (V₂O₅) flat-nanofiber networked thin layer-structure to boost EDOT-intercalation reaction for rapidly producing fiber-reinforced conductive gel (FCG), achieving superior conductivity of 10 S cm^-1 and extremely fast production time (10 s). The superior FCG formation mechanism is ascribed to the V₂O₅ flat-nanofiber networked thin layer-structure allowing EDOT rapidly penetrating to inter-layers and replacing inside water molecules for polymerization to high-conductive FCG. The FCG can be used to print various patterns and are further used to fabricate a flexible biomimetic hydrogen peroxide (H₂O₂) sensor, delivering a high sensitivity of 2100 µA mM^-1 cm^-2, ranking the best among all flexible enzyme-free H₂O₂ sensors. More importantly, this flexible biomimetic H₂O₂ sensor is successfully applied to real-time detect living cells-secreted H₂O₂, demonstrating its application for in situ monitoring of small biomolecules released from living cells. This work offers a universal approach to synthesize high-conductive printable hydrogels by designing precursors meriting from both physics and chemistry, while holding great promise for mass-manufacturing inexpensive hydrogels in applications of sensing or wearable devices.