A Mixed-Crystal Lanthanide Zeolite-like Metal–Organic Framework as a Fluorescent Indicator for Lysophosphatidic Acid, a Cancer Biomarker

Two
lanthanide zeolite-like metal–organic frameworks (Ln-ZMOFs)
with rho topology, Tb-ZMOF and Eu-ZMOF, were constructed by self-assembly of a 4-connected lanthanide molecular
building block and a bipyridine-dicarboxylate ligand. Varying the
Tb3+ and Eu3+ ratio during synthesis afforded
three mixed-crystal isostructural MZ­MOFs with variable
Eu:Tb stoichiometry. Fluorescence studies revealed that a methanol
suspension of one of these mixed crystals, MZ­MOF-3, exhibits selective detection of lyso­phospha­tidic acid
(LPA), a biomarker for ovarian cancer and other gynecologic cancers.
Linear correlation between the integrated fluor­escence intensity
and the concentration of LPA was observed, enabling quantitative analysis
of LPA in physiologically relevant ranges (1.4–43.3 μM). MZ­MOF-3 therefore has the potential to act as a self-referencing
and self-calibrating fluor­escent indicator for LPA.