This technology relates to a new class of gas sensors based on a 3D-printed architected scaffold that is converted into a conductive porous structure and functionalised for NO₂ sensing. The resulting device is designed to operate at room temperature. It avoids the complexity typically associated with conventional sensor manufacturing routes, such as thin-film coating, sintering, or heater-assisted operation. The multiscale architecture improves gas access to and interaction with the active material, supporting stable, repeatable sensing performance in a lightweight, potentially scalable format. The platform is particularly attractive for next-generation sensing systems, where low energy consumption, design flexibility, and integration with portable or distributed devices are important.