Miniaturized, portable gustation interfaces for VR/AR/MR.

Gustation is one of the five innate sensations for humans, distinguishing from vision, auditory, tactile, and olfaction, as which is a close and chemically induced sense. Despite the fact that a handful of gustation display technologies have been developed, the new technologies still pose significant challenges in miniaturization of the overall size for portability, enriching taste options within a limited working area, supporting natural human-device interaction, and achieving precisely controlled taste feedback. To address these issues, here, we report a set of intelligent and portable lollipop-shaped taste interfacing systems covering from 2 to 9 different taste options for establishing an adjustable taste platform in virtual reality (VR), augmented reality (AR), and mixed reality (MR) environments. Tasteful and food-grade chemicals embedded agarose hydrogels serve as taste sources based on iontophoresis operation principle, with an adjustable feedback intensity and independent operation time by tuning the voltage input. To achieve portability and user-friendly operation, the devices are miniaturized into a gustation interface with 9-channel taste generators in the dimension of 8 cm × 3 cm × 1 cm. To realize both gustation and olfaction feedbacks in Metaverse, an olfaction interface based on 7-channel odor generators is also introduced into the gustation interface system. As a result, the demonstrations of our gustation interface systems in intelligent medical gustation assessment, remote shopping, and mixed reality have proven their advances and great progress in various potential application areas, ranging from human-machine interfaces, to biomedical science, and to entertainment.