Highly Stable Upconverting Nanocrystal–Polydiacetylenes Nanoplates for Orthogonal Dual Signaling-Based Detection of Cyanide

Although the unique optical signaling properties of polydiacetylene (PDA) have been exploited in diverse bio-chemosensors, the practical application of most PDA sensor systems is limited by their instability in harsh environments and fluorescence signal weakness. Herein, a universal design principle for a highly stable PDA sensor system with a practical dual signaling capability is developed to detect cyanide (CN) ions, which are commonly found in drinking water. Effective metal intercalation and enhanced hydrophobic intermolecular interactions between PDA-metal supramolecules are used to construct highly stacked PDA-metal nanoplates that feature unusual optical stability upon exposure to strong acids, bases, organic solvents, and thermal/mechanical stresses, and can selectively detect CN anions, concomitantly undergoing a specific supramolecular structure change. To realize the practical dual signaling capability of the PDA sensor system, upconverting nanocrystals (UCNs) are incorporated into highly stacked PDA-metal nanoplates, and practical dual signaling (orthogonal changes in luminescence and visible color) is demonstrated using a portable detection system. The presented universal design principle is expected to be suitable for the development of other highly stable and selective PDA sensor systems with practical dual signaling capability.