2 research outputs found
Highly Chemiluminescent Magnetic Beads for Label-Free Sensing of 2,4,6-Trinitrotoluene
Until now, despite
the great success acquired in scientific research
and commercial applications, magnetic beads (MBs) have been used for
nothing more than a carrier in most cases in bioassays. In this work,
highly chemiluminescent magnetic beads containing <i>N</i>-(4-aminobutyl)-<i>N</i>-ethyl isoluminol (ABEI) and Co<sup>2+</sup> (Co<sup>2+</sup>/ABEI/MBs) were first synthesized via a
facile strategy. ABEI and Co<sup>2+</sup> were grafted onto the surface
of carboxylated MBs by virtue of a carboxyl group and electrostatic
interaction. The as-prepared Co<sup>2+</sup>/ABEI/MBs exhibited good
paramagnetic properties, satisfactory stability, and intense chemiluminescence
(CL) emission when reacted with H<sub>2</sub>O<sub>2</sub>, which
was more than 150 times that of ABEI functionalized MBs. Furthermore,
it was found that 2,4,6-trinitrotoluene (TNT) aptamer could attach
to the surface of Co<sup>2+</sup>/ABEI/MBs via electrostatic interaction
and coordination interaction between TNT aptamer and Co<sup>2+</sup>, leading to a decrease in CL intensity due to the catalytic site
Co<sup>2+</sup> being blocked by the aptamer. In the presence of TNT,
TNT would bind strongly with TNT aptamer and detach from the surface
of Co<sup>2+</sup>/ABEI/MBs, resulting in partial restoration of the
CL signal. Accordingly, label-free aptasensor was developed for the
determination of TNT in the range of 0.05–25 ng/mL with a detection
limit of 17 pg/mL. This work demonstrates that Co<sup>2+</sup>/ABEI/MBs
are easily connected with recognition biomolecules, which are not
only magnetic carriers but also direct sensing interfaces with excellent
CL activity. It provides a novel CL interface with a magnetic property
which easily separates analytes from the sample matrix to construct
label-free bioassays
Systematic Study and Imaging Application of Aggregation-Induced Emission of Ester-Isophorone Derivatives
The dicyanoisophorone derivatives
show obvious AIE behaviors in
our previous work. To study the bioimaging application of these chromophores
with AIE/AIEE properties, the ester groups substituted for one cyan
to form a new family based on isophorone (<b>2a</b>–<b>2e</b>). <b>2a</b>–<b>2d</b> exhibit obvious
AIE/AIEE phenomena, while <b>2e</b> shows fluorescence quenching
in the aggregate state. The morphology and size of aggregates with
different water contents were investigated using SEM and DLS, indicating
that a large number of smaller globular or quadrate nanoparticles
with average diameters in the range 78.79–392.7 nm in mixed
solutions are related to these AIE/AIEE or ACQ behaviors. We also
made comparative analyses of their optical properties in different
states. The crystal data of <b>2a</b>–<b>2d</b> reveal that the multiple intra- and intermolecular interactions
leads to the molecular conformation being more stable, increases the
planarity of compounds, restricts the intramolecular motions, and
promotes the formation of <i>J</i>-type aggregate, enabling
chromophores <b>2a</b>–<b>2d</b> to emit intensely
in the solid state. In addition, the frontier molecular orbital energy
and band gap calculated by density functional theory are quite consistent
with the experimental results. Finally, these AIE/AIEE-active compounds
could be used in bioimaging applications, which immensely provide
a new strategy to the application of some AIE/AIEE systems