Lanthanide luminescence from supramolecular hydrogels consisting of bio-conjugated picolinic-acid-based guanosine quadruplexes

The formation of bio-inspired healable lanthanide luminescent hydrogels is detailed. These materials are composed of K(I)-stabilized guanosine quadruplexes (G4) that were bio-conjugated to mannose-derived picolinic acid ligand 1 using boric acid chemistry (G4-1). The supramolecular self-assembly between G4-1 and europium (Eu(III)) was confirmed, including the use of time-gated luminescence spectroscopy. The most stable hydrogel was formed when the ratio between 1 and Eu(III) was 1:1, and this gel was found to retain a helical column. The obtained gel samples were further characterized using techniques, such as scanning electron microscopy (SEM), circular dichroism (CD), and luminescence spectroscopy. We demonstrate that a Eu(III)-centered circularly polarized luminescence (CPL) signal from guanosine hydrogels can be observed even via long-range interaction, whereas the rheology of these gels exhibits their healable properties.