Carbon nanotubes are a promising sensing material for bio-transduction devices, due to their unique electrical properties, nanosize, bio-compatibility, and their simple low-cost processability. In this contribution, we present two classes of devices (i.e., electrolyte-gated field-effect transistorbased sensors and gas sensors) fabricated by facile and scalable spray deposition of water-based carbon nanotube inks. The developed sensing platforms have been employed for the detection of several analytes for different applications, including food quality assessment, physical activity monitoring, environmental monitoring, and detection of gaseous species.