Vanadium pentoxide flat-nanofiber networked thin layer-structure to initiate intercalated polymerization for rapidly producing superior conductive hydrogel and its biomimetic hydrogen peroxide sensing application.

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 (VO) 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 and extremely fast production time (10 s). The superior FCG formation mechanism is ascribed to the VO 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 (HO) sensor, delivering a high sensitivity of 2100 µA mM cm, ranking the best among all flexible enzyme-free HO sensors. More importantly, this flexible biomimetic HO sensor is successfully applied to real-time detect living cells-secreted HO, 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.