Wood‐Based Bioelectronics: Lignosulfonate‐Based Conductive Biocomposites for Paper Organic Electrochemical Transistors

ABSTRACT The growing demand for sustainable diagnostic devices has shifted attention toward biodegradable choices in both material and substrate design. Recent advances in wood‐ and lignin‐derived materials have enabled a growing class of sustainable electronic and bioelectronic systems, often referred to as ‘wood‐based bioelectronics’. Within this context, the present work contributes a distinct materials and device strategy by integrating PEDOT:Lignosulfonate as an active mixed ionic–electronic channel material in organic electrochemical transistors (OECTs) fabricated on biodegradable paper substrates. The PEDOT:LigS biocomposite was synthesized via chemical oxidative polymerization using various oxidants. The thin films of the resulting biocomposites exhibited good electrical conductivity of up to 1.1 S cm ^{− 1} , along with biocompatibility confirmed for L929 cells by following ISO 10993 standard protocol conditions. Conventional OECTs fabricated with PEDOT:LigS showed transconductance values of up to 12.9 mS. Replacing glass substrates with photographic paper enabled the fabrication of degradable OECT devices, revealing a material weight loss of 85% after 43 days in soil. These results highlight the potential of bio‐based materials for more sustainable wood‐based bioelectronics.