Nanocrystalline cellulose-based mixed ionic–electronic conductor for bioelectronics†

Mixed ionic–electronic conductors (MIEC) are pivotal in advancing medical diagnostics, therapeutic devices, and health monitoring solutions due to their unique properties that enable more effective interfaces between electronic devices and biological systems. Cellulose, a natural and abundant polymer, is a promising material in the development of MIECs for bioelectronics. Combining cellulose with conductive polymer components can leverage the biocompatibility, sustainability, and mechanical properties of composite materials. In this study, we highlight the sulfated cellulose nanocrystals (S-CNCs) as a template for the facile green synthesis of conductive polymer PEDOT (poly(3,4-ethylenedioxythiophene)). The PEDOT:S-CNCs nanocomposite possesses good conductivity and high dispersibility in water. The electronic conductivity is recorded up to 5 S cm⁻¹. A comprehensive investigation for material characterization is associated with the changes in their micro- and nanostructure surface morphology. The biocomposite is deposited as a channel material in organic electrochemical transistors (OECTs) to analyze ion-to-electron transduction. The maximum transconductance values are obtained up to 13.6 mS and 44.3 mS for single-channel and interdigitated OECTs, respectively, without applying photolithography techniques. The high transconductance values reveal the great potential of PEDOT:S-CNCs composite for bioelectronics.