6 research outputs found
FRET Imaging Approaches for <i>in Vitro</i> and <i>in Vivo</i> Characterization of Synthetic Lipid Nanoparticles
DiI
and DiD, two fluorophores able to interact by FRET (Förster
resonance energy transfer), were coencapsulated in the core of lipid
nanocapsules (LNCs) and nanoemulsions (LNEs), lipophilic reservoirs
for the delivery of drugs. The ability of FRET imaging to provide
information on the kinetics of dissociation of the nanoparticles in
the presence of bovine serum albumin (BSA) or whole serum, or after
incubation with cancer cells, and after systemic administration in
tumor-bearing mice, was studied. Both microscopic and macroscopic
imaging was performed to determine the behavior of the nanostructures
in a biological environment. When 2 mg/mL FRET LNEs or LNCs were dispersed
in buffer, in the presence of unloaded nanoparticles, BSA, or in whole
serum, the presence of serum was the most active in destroying the
particles. This occurred immediately with a diminution of 20% of FRET,
then slowly, ending up with still 30% intact nanoparticles at 24 h.
LNCs were internalized rapidly in cultured cells with the FRET signal
decreasing within the first minutes of incubation, and then a plateau
was reached and LNCs remained intact during 3 h. In contrast, LNEs
were poorly internalized and were rapidly dissociated after internalization.
Following their iv injection, LNCs appeared very stable in subcutaneous
tumors implanted in mice. Intact particles were found using microscopic
FRET determination on tumor sections 24 h after injection, that correlated
well with the 8% calculated noninvasively on live animals. FRET investigations
showed the potential to determine valid and reliable information about <i>in vitro</i> and <i>in vivo</i> behavior of nanoparticles
Comparison of the In Vitro and In Vivo Behavior of a Series of NIR-II-Emitting Aza-BODIPYs Containing Different Water-Solubilizing Groups and Their Trastuzumab Antibody Conjugates
The development of new fluorescent organic probes effective
in
the NIR-II region is currently a fast-growing field and represents
a challenge in the domain of medical imaging. In this study, we have
designed and synthesized an innovative series of aza-boron dipyrromethenes
emitting in the NIR-II region. We have investigated the effect of
different water-solubilizing groups not only on the photophysical
properties of the compounds but also on their in vitro and in vivo
performance after bioconjugation to the antibody trastuzumab. Remarkably,
we discovered that the most lipophilic compound unexpectedly displayed
the most favorable in vivo properties after bioconjugation. This underlines
the profound influence that the fluorophore functionalization approach
can have on the efficiency of the resulting imaging agent
Comparison of the In Vitro and In Vivo Behavior of a Series of NIR-II-Emitting Aza-BODIPYs Containing Different Water-Solubilizing Groups and Their Trastuzumab Antibody Conjugates
The development of new fluorescent organic probes effective
in
the NIR-II region is currently a fast-growing field and represents
a challenge in the domain of medical imaging. In this study, we have
designed and synthesized an innovative series of aza-boron dipyrromethenes
emitting in the NIR-II region. We have investigated the effect of
different water-solubilizing groups not only on the photophysical
properties of the compounds but also on their in vitro and in vivo
performance after bioconjugation to the antibody trastuzumab. Remarkably,
we discovered that the most lipophilic compound unexpectedly displayed
the most favorable in vivo properties after bioconjugation. This underlines
the profound influence that the fluorophore functionalization approach
can have on the efficiency of the resulting imaging agent
Nanoparticle Mediated Tumor Vascular Disruption: A Novel Strategy in Radiation Therapy
More than 50% of all cancer patients
receive radiation therapy. The clinical delivery of curative radiation
dose is strictly restricted by the proximal healthy tissues. We propose
a dual-targeting strategy using <i>vessel</i>-<i>targeted</i>-radiosensitizing gold nanoparticles and <i>conformal</i>-image guided radiation therapy to specifically amplify damage in
the tumor neoendothelium. The resulting tumor vascular disruption
substantially improved the therapeutic outcome and subsidized the
radiation/nanoparticle toxicity, extending its utility to intransigent
or nonresectable tumors that barely respond to standard therapies
The Natural Cell-Penetrating Peptide Crotamine Targets Tumor Tissue <i>in Vivo</i> and Triggers a Lethal Calcium-Dependent Pathway in Cultured Cells
Our goal was to demonstrate the <i>in vivo</i> tumor specific accumulation of crotamine, a natural peptide from
the venom of the South American rattlesnake <i>Crotalus durissus
terrificus</i>, which has been characterized by our group as
a cell penetrating peptide with a high specificity for actively proliferating
cells and with a concentration-dependent cytotoxic effect. Crotamine
cytotoxicity has been shown to be dependent on the disruption of lysosomes
and subsequent activation of intracellular proteases. In this work,
we show that the cytotoxic effect of crotamine also involves rapid
intracellular calcium release and loss of mitochondrial membrane potential
as observed in real time by confocal microscopy. The intracellular
calcium overload induced by crotamine was almost completely blocked
by thapsigargin. Microfluorimetry assays confirmed the importance
of internal organelles, such as lysosomes and the endoplasmic reticulum,
as contributors for the intracellular calcium increase, as well as
the extracellular medium. Finally, we demonstrate here that crotamine
injected intraperitoneally can efficiently target remote subcutaneous
tumors engrafted in nude mice, as demonstrated by a noninvasive optical
imaging procedure that permits <i>in vivo</i> real-time
monitoring of crotamine uptake into tumor tissue. Taken together,
our data indicate that the cytotoxic peptide crotamine can be used
potentially for a dual purpose: to target and detect growing tumor
tissues and to selectively trigger tumor cell death
Functionalization of Small Rigid Platforms with Cyclic RGD Peptides for Targeting Tumors Overexpressing α<sub>v</sub>β<sub>3</sub>‑Integrins
Gadolinium based Small Rigid Plaforms
(SRPs) have previously demonstrated
their efficiency for multimodal imaging and radiosensitization. Since
the RGD sequence is well-known to be highly selective for α<sub>v</sub>β<sub>3</sub> integrins, a cyclic pentapeptide containing
the RGD motif (cRGDfK) has been grafted onto the SRP surface. An appropriate
protocol led to the grafting of two targeting ligands per nano-object.
The resulting nanoparticles have demonstrated a strong association
with α<sub>v</sub>β<sub>3</sub> integrins in comparison
with cRADfK grafted SRPs as negative control. Flow cytometry and fluorescence
microscopy have also been used to highlight the ability of the nanoparticles
to target efficiently HEK293(β3) and U87MG cells. Finally the
grafted radiosensitizing nanoparticles were intravenously injected
into <i>Nude</i> mice bearing subcutaneous U87MG tumors
and the signal observed by optical imaging was twice as high for SRP-cRGDfK
compared to their negative analogue