Redefining Electronics Through Sustainable Biopolymers

Recent advancements in materials science and manufacturing have expanded the capabilities of electronic devices beyond traditional uses, incorporating features like flexibility, stretchability, biocompatibility, and biodegradability. These innovations are crucial for developing smart devices that adapt to 3D surfaces, dissolve in specific environments, and interact with biological systems, benefiting areas such as environmental monitoring, wearable technology, medical implants, and sustainable agriculture. Biopolymers, being renewable and eco-friendly, offer a promising platform for these technologies while addressing concerns about electronic waste and sustainable production.
Among biopolymers, nanocellulose (CNC) and chitin nanocrystals (ChNC) stand out for their biodegradability and eco-friendly synthesis. In particular, CNC provides high mechanical strength and optical transparency, along with excellent dielectric properties and oxygen barrier protection. Chitin-derived chitosan is also a promising material due to its abundance, biodegradability, and biocompatibility, offering anti-bacterial, bio-adhesive, and non-toxic properties. We demonstrate flexible resistive temperature detectors (RTDs) and thermistors on chitosan substrates, using 100 nm thick Molybdenum for RTDs and 50 nm Indium-Gallium-Zinc-Oxide for thermistors. These biodegradable temperature sensors could be used to monitor body fluids, environmental pollutants, and plant health, providing a sustainable pathway for bio-interfacing electronics.
Biopolymer electrolytes show significant promise for use in solid-state organic electrochemical transistors (OECTs). These transistors rely on electrolytes to conduct and transport ions within an organic mixed ionic-electronic conductor (OMIEC). Compared to traditional electrolytes, biopolymer-based versions are biodegradable and derived from renewable resources, reducing environmental impact. Our research features OECTs using printed chitosan- and agar-based electrolytes with high on-off ratios. The use of biopolymer electrolytes in OECTs enables applications in biosensing, wearable technology, and neuromorphic circuits that mimic neural processes.
Beyond electronics, biopolymers can also act as scaffolds for cell growth and plant support in biohybrid systems. Polyethylene oxide (PEO)-based and alginate-based hydrogels used in 3D bioprinting offer excellent biocompatibility, supporting cell growth and providing tunable mechanical properties. Integrating these biopolymer-based scaffolds with electronics can create bioelectronic platforms that monitor cellular activities or deliver electrical stimuli to influence cell behavior and enhance tissue regeneration. In agriculture, superabsorbent biopolymer scaffolds aid plant growth by retaining water (swelling up to 7000% in various media) and supporting nutrient delivery. Their biodegradable nature ensures minimal environmental impact, while embedded sensors enable precision agriculture by monitoring plant health and soil conditions in real time.
The intersection of biopolymer materials, electronics, and living systems highlights their potential to drive the development of sustainable next-generation electronic devices, fostering applications that harmonize technology with nature. Biopolymers serve as versatile and eco-friendly foundations for unconventional electronics, ranging from sensor substrates to electrolytes for OECTs and scaffolds for biohybrid systems. Their unique properties, coupled with environmental benefits, make them crucial for addressing challenges in electronics, healthcare, and agriculture. By leveraging biopolymers, future electronic devices can align with sustainability goals, contribute to a circular economy, and reduce the ecological footprint of technology.