An Aggregation-Induced Emission Active Peptide-Based Fluorescent Probe for Highly Selective and Sensitive Detection...

In this study, a novel aggregation-induced emission (AIE) active peptide-based fluorescent probe (L) was rationally designed and successfully synthesized with a tetraphenylethene (TPE) derivative modified tetrapeptide (Pro-Gly-Asp-His-NH₂). L has many advantages of good water solubility, a large Stokes shift, and a high fluorescence quantum yield. According to the design, L was utilized to selectively recognize Hg²⁺ against other competitive metal ions in the HEPES buffer solution (pH = 7.4, 10.0 mM, containing 5% DMSO), and the limit of detection (LOD) for Hg²⁺ was obtained to be as low as 25.4 nM. In addition, L not only was successfully applied to monitor Hg²⁺ in living cells and zebrafish larvae, but also was used to measure Hg²⁺ in three different real water samples. Moreover, the test strips were successfully made using L solution, and qualitatively identified Hg²⁺ through using the naked eye under UV light at 365 nm. Furthermore, the reversible switching characteristics of L were used to mimic the INHIBIT molecular logic gate. More interestingly, the integrated smartphone color recognition App converts the color of L solution into digital values through the RGB channel and was successfully applied to the semiquantitative detection of Hg²⁺ without relying on expensive instruments.