Colorimetric photonic tongue for metal ions screening

Screening of metal ions in body fluid is vital for monitoring human health. Here, inspired by taste-sensing functions of human tongue, we reported a novel colorimetric photonic tongue for multiple metal ions screening by using spherical structural color hydrogel particles (SCHPs) as sensory units. As SCHPs are composed of acrylic acid (AA)-based skeleton, the sensory units could respond to metal ions with color variations like receptors in taste buds. Thus, through analyzing all units' sensory information, a colorimetric "fingerprint" for each metal ion could be obtained in a database. Based on this, we constructed a portable, reusable, and biocompatible device by integrating SCHP arrays into a test-strip microchip for real-time monitoring of metal ions. The target ions could be distinguished by multivariate data analysis for pattern recognition. These features indicated that the proposed photonic tongue is valuable for metal ions screening in biological samples and promising for clinical disease diagnosis.