3 research outputs found
Fluorescence Quenching of Carbon Nitride Nanosheet through Its Interaction with DNA for Versatile Fluorescence Sensing
This work investigates the interaction
of carbon nitride nanosheet (CNNS), a recently developed two-dimensional
nanomaterial, with DNA and its fluorescence quenching mechanism on
fluorophore labeled single-stranded DNA probes. The static quenching
through the photoinduced electron transfer (PET) from the excited
fluorophore to the conductive band of CNNS is identified. Utilizing
the affinity change of CNNS to DNA probes upon their recognition to
targets and the PET-based fluorescence quenching effect, a universal
sensing strategy is proposed for design of several homogeneous fluorescence
detection methods with short assay time and high sensitivity. This
strategy is versatile and can be combined with different amplification
tools for quick fluorescence sensing of DNA and extensive DNA related
analytes such as metal cations, small molecules, and proteins. As
examples, two simple fluorescence detection methods for DNA and Hg<sup>2+</sup>, one facile detection method coupled with Exo III-mediated
target recycling for sensitive DNA analysis, and a ratiometric fluorescence
protocol for DNA detection are proposed. This work provides an avenue
for understanding the interaction between two-dimensional nanomaterials
and biomolecules and designing novel sensing strategies for extending
the applications of nanomaterials in bioanalysis
Folate Receptor-Targeted and Cathepsin B‑Activatable Nanoprobe for <i>In Situ</i> Therapeutic Monitoring of Photosensitive Cell Death
The
integration of diagnostic and therapeutic functions in a single
system holds great promise to enhance the theranostic efficacy and
prevent the under- or overtreatment. Herein, a folate receptor-targeted
and cathepsin B-activatable nanoprobe is designed for background-free
cancer imaging and selective therapy. The nanoprobe is prepared by
noncovalently assembling phospholipid-polyÂ(ethylene oxide) modified
folate and photosensitizer-labeled peptide on the surface of graphene
oxide. After selective uptake of the nanoprobe into lysosome of cancer
cells via folate receptor-mediated endocytosis, the peptide can be
cleaved to release the photosensitizer in the presence of cancer-associated
cathepsin B, which leads to 18-fold fluorescence enhancement for cancer
discrimination and specific detection of intracellular cathepsin B.
Under irradiation, the released photosensitizer induces the formation
of cytotoxic singlet oxygen for triggering photosensitive lysosomal
cell death. After lysosomal destruction, the lighted photosensitizer
diffuses from lysosome into cytoplasm, which provides a visible method
for <i>in situ</i> monitoring of therapeutic efficacy. The
nanoprobe exhibits negligible dark toxicity and high phototoxicity
with the cell mortality rate of 0.06% and 72.1%, respectively, and
the latter is specific to folate receptor-positive cancer cells. Therefore,
this work provides a simple but powerful protocol with great potential
in precise cancer imaging, therapy, and therapeutic monitoring
Surface Decorated Porphyrinic Nanoscale Metal–Organic Framework for Photodynamic Therapy
Nanocrystallization
of organic molecular photosensitizers (PSs) by means of NMOF platforms
has been demonstrated to be a promising approach to build up highly
efficient PDT therapeutics. We report herein a new UiO-66 type of
NMOF-based PS (<b>UiO-66-TPP-SH</b>), which is generated from
UiO-66 NMOF and S-ethylthiol ester monosubstituted metal free porphyrin
(<b>TPP-SH</b>) via a facile postsynthetic approach under mild
conditions. The obtained NMOF (size less than 150 nm) with surface-decorated
porphyrinic PS can not only retain MOF crystallinity, structural feature,
and size, but also exhibit highly efficient singlet oxygen generation.
Compared to the interior-located porphyrinic NMOF, <b>UiO-66-TPP-SH</b> shows significantly higher photodynamic activity and more efficient
PDT tumor treatment