Ionophore-Based Ion-Selective Nanospheres Based on Monomer-Dimer Conversion in the Near-Infrared Region.

Affiliation

Deng L(1), Zhai J(2), Du X(1), Xie X(1).
Author information:
(1)Department of Chemistry, Southern University of Science and Technology, Shenzhen 518055, China.
(2)Academy for Advanced Interdisciplinary Studies, Southern University of Science and Technology, Shenzhen 518055, China.

Abstract

Here, we report ion-selective nanospheres with readout in the near-infrared (NIR) region in both fluorescence and absorbance modes. The nanospheres rely on an ionophore-mediated monomer-dimer conversion of an NIR transducer, DTTC. The DTTC monomer in the nanospheres emits fluorescence around 820 nm, while the dimer in the aqueous environment generates strong blue-shifted emission around 660 nm. With a lead ionophore, an unprecedented lower detection limit of 3 pM for Pb2+ was achieved, allowing us to determine Pb2+ levels in river water without diluting the sample. Also, the Cu2+-selective nanospheres showed a detection limit of 5 nM. Taking advantage of the biologically desired NIR window, blood potassium concentrations were also determined without a complicated sample pretreatment. The sensing process was explained with a theoretical model. The detection range was found finely adjustable by the amount of nanospheres used. Therefore, the nanospheres formed a highly selective, sensitive, versatile, and rapid analytical platform for metal-ion sensing.