Rare Earth Ion-Induced Functionalized Fluorescent MOF Hydrogel Patches for Monitoring Lysozyme in Tears

A multiemission metal organic framework hydrogel (Eu-Dy MOF gels) fluorescence probe was designed and prepared as a noninvasive wearable fluorescent sensor, for visual detection of lysozyme (LZ) in human tears. Eu-Dy MOF gels were synthesized by the coordination polymerization of Eu³⁺ and Dy³⁺ with 5-boronobenzene-1,3-dicarboxylic acid. Under an excitation of 275 nm, the Eu-Dy MOF displayed blue fluorescence under ultraviolet light. The sensing region on the eye patch realized the selective detection of LZ in tears by modifying with an Eu-Dy MOF, and the detection limit (LOD) of the probe was 1.5 nM. The application of the eye patch fluorescence sensor was expanded by capturing the color signals with the smartphone's camera and analyzed using a color recognition application (APP), through a smartphone in contact with the sensing region on the eye patch under UV light. The recovery of tear fluid samples ranged from 94% to 110%. Eu-Dy MOF gel-based fluorescence sensors for eye patches enable noninvasive visual monitoring of the LZ in tears, highlighting the promise of functionalized MOF fluorescence sensors in health monitoring.