Biomineralized Nano-Assemblies of Poly(Ethylene Glycol) Derivative with Lanthanide Ions as Ratiometric Fluorescence Sensors for Detection of Water and Fe Ions.

An effective strategy was developed to fabricate novel lanthanide ions-pyromellitic acid-methoxy poly(ethylene glycol) (Ln-PMA-MPEG) nano-assemblies. The amphiphilic partially esterified derivative (PMA-MPEG) of pyromellitic acid with methoxy poly(ethylene glycol) was designed and synthesized via the coupling reaction. Ln-PMA-MPEG nano-assemblies were rapidly fabricated using PMA-MPEG as a polymer ligand with Eu ions or mixed Eu/Tb ions through biomimetic mineralization in neutral aqueous systems. The size of the as-prepared materials could be designed in the range 80-200 nm with a uniform distribution. The materials were readily dispersed in various solvents and displayed visible color variations and different photoluminescent properties for solvent recognition. The mixed Eu/Tb-PMA-MPEG nanomaterials were investigated as ratiometric sensors for the detection of trace water in DMF and Fe ions in aqueous solutions. The sensor materials can quantitatively detect trace water in DMF from 0% to 10% (/). The resultant materials also display a strong correlation between the double luminescence intensity ratios (/) and Fe concentration, with a good linear detection concentration in the range of 0-0.24 mM and a limit of detection of 0.46 μM, and other metal ions did not interfere with the sensing mechanism for Fe ions. The novel nano-assemblies have potential applications as ratiometric fluorescent nanosensors in the chemical industry as well as in biomedical fields.