3 research outputs found
PEG-Phospholipids Coated Quantum Rods as Amplifiers of the Photosensitization Process by FRET
Singlet oxygen (<sup>1</sup>O<sub>2</sub>) generated upon photostimulation of photosensitizer molecules
is a highly reactive specie which is utilized in photodynamic therapy.
Recent studies have shown that semiconductor nanoparticles can be
used as donors in fluorescence resonance energy transfer (FRET) process
to excite attached photosensitizer molecules. In these studies, their
unique properties, such as low nanoscale size, long-term photostability,
wide broad absorbance band, large absorption cross section, and narrow
and tunable emission bands were used to provide advantages over the
traditional methods to produce singlet oxygen. Previous studies that
achieved this goal, however, showed some limitations, such as low
FRET efficiency, poor colloidal stability, nonspecific interactions,
and/or complex preparation procedure. In this work, we developed and
characterized a novel system of semiconductor quantum rods (QRs) and
the photosensitizer meso-tetraÂ(hydroxyphenyl) chlorin (<i>m</i>THPC), as a model system that produces singlet oxygen without these
limitations. A simple two-step preparation method is shown; Hydrophobic
CdSe/CdS QRs are solubilized in aqueous solutions by encapsulation
with lecithin and PEGylated phospholipid (PEG–PL) of two lipid
lengths: PEG<sub>350</sub> or PEG<sub>2000</sub>. Then, the hydrophobic
photosensitizer <i>m</i>THPC, was intercalated into the
new amphiphilic PEG–PL coating of the QR, providing a strong
attachment to the nanoparticle without covalent linkage. These PEGylated
QR (eQR)–<i>m</i>THPC nanocomposites show efficient
FRET processes upon light stimulation of the QR component which results
in efficient production of singlet oxygen. The results demonstrate
the potential for future use of this concept in photodynamic therapy
schemes