Scalable Wheat Bran‐Algae Composites for Edible Electronics with Spray‐Coated Food‐Grade Conductive Inks

ABSTRACT The growing challenge of electronic waste drives demand for sustainable, biocompatible technologies and accelerates interest in edible electronics, systems that are safe for ingestion, biodegradable, and environmentally benign. Yet, the absence of mechanically reliable, healthy, and fully edible substrates compatible with scalable fabrication remains a major bottleneck. Here, we present a mechanically stable, fully edible substrate fabricated from wheat bran and algae via compression moulding, whose surface is further modified with chitosan spray coating to enhance water resistance and provide a uniform, coating‐compatible interface for subsequent deposition of functional inks. The substrate exhibits an ultimate tensile strength of ∼2.44 MPa, providing a stable platform for device integration. Subsequently, we develop a food‐grade conductive ink based on activated carbon and gummy bear binder, enabling uniform spray‐coated films with sheet resistance (7.6 kΩ/sq at 10 layers ∼67 µm) and linear Ohmic I–V characteristics. Moreover, electrochemical impedance spectroscopy reveals near‐ideal capacitive behaviour, with phase angle measurements across the 10 3 –10 6 Hz frequency range and Nyquist plots confirming the suitability of the system for energy storage applications. This scalable approach establishes a versatile route toward fully edible electronic platforms, opening opportunities for safe, low‐cost devices in diagnostics, smart packaging, and sustainable IoT applications.