2 research outputs found
Self-Assembly of Folate onto Polyethyleneimine-Coated CdS/ZnS Quantum Dots for Targeted Turn-On Fluorescence Imaging of Folate Receptor Overexpressed Cancer Cells
No full textFolate receptor (FR) can be overexpressed by a number
of epithelial-derived
tumors, but minimally expressed in normal tissues. As folic acid (FA)
is a high-affinity ligand to FR, and not produced endogenously, development
of FA-conjugated probes for targeted imaging FR overexpressed cancer
cells is of significance for assessing cancer therapeutics and for
better understanding the expression profile of FR in cancer. Here
we report a novel turn-on fluorescence probe for imaging FR overexpressed
cancer cells. The probe was easily fabricated via electrostatic self-assembly
of FA and polyethyleneimine-coated CdS/ZnS quantum dots (PEI-CdS/ZnS
QDs). The primary fluorescence of PEI-CdS/ZnS QDs turned off first
upon the electrostatic adsorption of FA onto PEI-CdS/ZnS QDs based
on electron transfer to produce negligible fluorescence background.
The presence of FR expressed on the surface of cancer cells then made
FA desorb from PEI-CdS/ZnS QDs due to specific and high affinity of
FA to FR. As a result, the primary fluorescence of PEI-CdS/ZnS QDs
adhering to the cells turned on due to the inhibition of electron
transfer. The most important merits of the developed probe are its
simplicity and the effective avoidance of the false positive results
due to the simple electrostatic self-assembly of FA onto the surface
of PEI-CdS/ZnS QDs and the involved fluorescence “off-on”
mechanism. The probe was demonstrated to be sensitive and selective
for targeted imaging of FR overexpressed cancer cells in turn-on mode
Theoretical Study of Infrared Spectra of OCS‑(<i>p</i>H<sub>2</sub>)<sub>2</sub>, OCS‑(<i>o</i>D<sub>2</sub>)<sub>2</sub>, OCS-(HD)<sub>2</sub>, and Mixed OCS‑<i>p</i>H<sub>2</sub>‑He Trimers
No full textThe
calculated rovibrational energy levels and infrared spectra
for OCS-(<i>p</i>H<sub>2</sub>)<sub>2</sub>, OCS-(<i>o</i>D<sub>2</sub>)<sub>2</sub>, OCS-(HD)<sub>2</sub> and mixed
OCS-<i>p</i>H<sub>2</sub>-He trimers are obtained by performing
the exact basis-set calculations for the first time based on the newly
developed potential energy surfaces (<i>J. Chem. Phys.</i> <b>2017</b>, 147, 044313). The “adiabatic-hindered-rotor”
(AHR) method is used for reduced-dimension treatment of the hydrogen
rotation. The predicted band origin shifts and the infrared spectra
are in good agreement with the available experimental values: for
the band origin shifts and infrared transitions, the root-mean-squareÂ(rms)
deviations are smaller than 0.044 and 0.002 cm<sup>–1</sup>, respectively. We extend the assignments to the unrecorded infrared
transitions for OCS-(<i>p</i>H<sub>2</sub>)<sub>2</sub> and
OCS-(HD)<sub>2</sub> complexes and identify the infrared spectra for
OCS-(<i>o</i>D<sub>2</sub>)<sub>2</sub> and OCS-<i>p</i>H<sub>2</sub>-He for the first time. Three-dimensional
density distributions for the ground states of OCS-(<i>p</i>H<sub>2</sub>)<sub>2</sub>, OCS-<i>p</i>H<sub>2</sub>-He,
and OCS-(He)<sub>2</sub> show that the <i>p</i>H<sub>2</sub> molecules are localized in their corresponding global minimum regions,
while the pronounced locations of the He atoms are missing in OCS-<i>p</i>H<sub>2</sub>-He and OCS-(He)<sub>2</sub> with forming
incomplete circles around the OCS axis. A clear tunneling splitting
is observed for the torsional motion of the two hydrogen molecules
(<i>p</i>H<sub>2</sub>, HD, or <i>o</i>D<sub>2</sub>) on a ring about the OCS molecular axis, whereas no tunneling splitting
is found in OCS-<i>p</i>H<sub>2</sub>-He or OCS-(He)<sub>2</sub> due to a much lower torsional barrier
