β-glucan-Induced Eu3+ Coordination Complex with Synergistic Luminescence: Multifunctional Fe2+/Fe3+ Sensing and Flexible Film Fabrication

β -glucan served as the raw material to fabricate β -glucan-Eu(tta) 2 (phen), effectively enhancing Eu 3+ luminescence by synergistic sensitization. • β -glucan-Eu(tta) 2 (phen) showed selective luminescence quenching for Fe 2+ /Fe 3+ by a static quenching mechanism. • β -glucan reduced Eu 3+ coordination complex cytotoxicity and conferred antibacterial activity against S. aureus and E. coli. • Flexible luminescent films retained sensing performance and facilitated visual Fe 3+ detection. This study presents a novel lanthanide luminescent material featuring a synergistic sensitization system composed of β -glucan, 4,4,4-trifluoro-1-(thiophen-2-yl) butane-1,3-dione (tta), and 1,10-phenanthroline (phen), which efficiently enhances and modulates the luminescence of Eu 3+ . The resulting β -glucan-induced Eu 3+ coordination complex exhibits specific luminescent responses toward Fe 3+ and Fe 2+ , with detection limits (LOD = 3 σ /K SV ) of 1.44 μmol·L -1 and 1.05 μmol·L -1 , respectively. The luminescence quenching mechanism was attributed to static quenching, accompanied by the inner filter effect. Notably, luminescence quenched by Fe 3+ is reversible upon the addition of EDTA, whereas no luminescence recovery is observed when EDTA is introduced subsequent to Fe 2+ -mediated quenching. Furthermore, the antibacterial activity and cytotoxicity of β -glucan-induced Eu 3+ coordination complex have been evaluated. The antibacterial zone experiments confirm that β -glucan-induced Eu 3+ coordination complex has good antibacterial effects on both Staphylococcus aureus ( S. aureus ) and Escherichia coli ( E. coli ). β -glucan exerts a pronounced effect on mitigating the toxicity of Eu 3+ coordination complex. β -glucan-induced Eu 3+ coordination complex can form flexible luminescent films with carrageenan (CRG) or D4 hydrogel (D4), while retaining excellent luminescent properties, thereby holding significant potential for application in the detection of metal ions in environmental water samples. Download: Download high-res image (253KB) Download: Download full-size image