Highly stable bioelectronics based on wrapped SWCNT monolayers via dual click chemistry

Reliable single-walled carbon nanotubes (SWCNTs)-based bioelectronics have been hindered by the inability to form SWCNT films that simultaneously provide strong substrate adhesion, high areal density, and uniform electrical characteristics. Conventional deposition or linker-mediated functionalization often results in multilayered or weakly adhered networks that suffer from device-to-device variability, hysteresis, and instability in aqueous or gas environments. Building on our previously established monolayer, high-density, and highly uniform SWCNT platform created via click-chemistry-driven covalent immobilization, this work advances the material into a fully functional bioelectronic interface through a dual-click chemistry strategy. The approach integrates CuAAC-mediated covalent anchoring of polymer-wrapped SWCNTs with a subsequent copper-free click reaction for biomolecular conjugation, enabling a chemically robust monolayer that maintains structural integrity under harsh solvent sonication, repeated gate-voltage cycling, and long-term sensing operation. Devices fabricated on this dual-click SWCNT monolayer exhibit hysteresis-free electrical characteristics, excellent reproducibility across substrates, and ultrasensitive detection of both gas-phase cadaverine (LOD: 27.02 ppb) and liquid-phase cortisol (LOD: 5 pM). This study demonstrates, for the first time, that a covalently immobilized, monolayer, and high-density SWCNT network can serve as a scalable, stable, and versatile platform for molecular sensing in diverse chemical environments, establishing a unified materials-to-device framework for next-generation SWCNT bioelectronics.