Thioflavin-T-Enhanced Fluorescence in Cerium Adenosine
Triphosphate Coordination Polymer Nanoparticles for Selective and
Sensitive Copper(II) Detection in E‑Waste and Biological Samples
posted on 2024-01-01, 09:03authored bySachin
S. Kadlag, Madhusudan Ghosh, Prabhat K. Singh, Kallola K. Swain
Coordination
polymer nanoparticles (CPNs) are a unique class of
nanoparticles designed via the self-aggregation of a metal ion and
a polydentate ligand. Among them, lanthanide-based CPNs are considered
to be the most promising due to their intrinsic luminescent properties,
stability in different oxidation states, and high coordination flexibility.
In the present study, cerium-based coordination polymer nanoparticles
(Ce-CPNs) have been synthesized using adenosine triphosphate (ATP)
as a cross-linking ligand. A weakly emissive molecular-rotor-type
dye, Thioflavin-T (ThT), was incorporated into the porous polymeric
network of CPNs, which led to a drastic enhancement in the emission
intensity of ThT. The emission intensity of ThT-Ce(III)-ATP-Tris CPNs
is severely quenched in the presence of Cu(II) ions, which has been
utilized for the detection of Cu(II). The sensing mechanism was established
by using photophysical techniques such as absorbance, emission, excited-state
lifetime, and particle size measurements. The selectivity of this
methodology for Cu(II) ions was checked by studying the interference
of several metal ions, anions and biomolecules. The limit of detection
(LOD) obtained for Cu(II) in the present methodology was about 660
nM (42 ppb), which is far below the U.S. EPA prescribed limit (20
μM) in water. The present methodology was successfully demonstrated
to determine the Cu(II) concentration in e-waste leachate and also
in spiked human serum samples. The LOD of Cu(II) in diluted e-waste
leachate was found to be marginally higher (730 nM) compared to that
in the case of water, whereas the LOD in 10% (v/v) serum was to be
5 μM (320 ppb).