8 research outputs found
Correlating Molecular Character of NIR Imaging Agents with Tissue-Specific Uptake
Near-infrared
(NIR) fluorescent contrast agents are emerging in optical imaging
as sensitive, cost-effective, and nonharmful alternatives to current
agents that emit harmful ionizing radiation. Developing spectrally
distinct NIR fluorophores to visualize sensitive vital tissues to
selectively avoid them during surgical resection of diseased tissue
is of great significance. Herein, we report the synthetic variation
of pentamethine cyanine fluorophores with modifications of physicochemical
properties toward prompting tissue-specific uptake into sensitive
tissues (i.e., endocrine glands). Tissue-specific targeting and biodistribution
studies revealed localization of contrast agents in the adrenal and
pituitary glands, pancreas, and lymph nodes with dependence on molecular
characteristics. Incorporation of hydrophobic heterocyclic rings,
alkyl groups, and halogens allowed a fine-tuning capability to the
hydrophobic character and dipole moment for observing perturbation
in biological activity in response to minor structural alterations.
These NIR contrast agents have potential for clinical translation
for intraoperative imaging in the delineation of delicate glands
Tailored Near-Infrared Contrast Agents for Image Guided Surgery
The
success of near-infrared (NIR) fluorescence to be employed
for intraoperative imaging relies on the ability to develop a highly
stable, NIR fluorescent, nontoxic, biocompatible, and highly excreted
compound that retains a reactive functionality for conjugation to
a cancer-recognizing peptide. Herein, systematic modifications to
previously detailed fluorophore ZW800-1 are explored. Specific modifications,
including the isosteric replacement of the O atom of ZW800-1, include
nucleophilic amine and sulfur species attached to the heptamethine
core. These novel compounds have shown similar satisfactory results
in biodistribution and clearance while also expressing increased stability
in serum. Most importantly, all of the synthesized and evaluated compounds
display a reactive functionality (either a free amino group or carboxylic
acid moiety) for further bioconjugation. The results obtained from
the newly prepared derivatives demonstrate that the central substitution
with the studied linking agents retains the ultralow background in
vivo performance of the fluorophores regardless
of the total net charge
Bioimaging of Hyaluronate–Interferon α Conjugates Using a Non-Interfering Zwitterionic Fluorophore
We
conducted real-time bioimaging of the hyaluronate–interferon
α (HA–IFNα) conjugate using a biologically inert
zwitterionic fluorophore of ZW800-1 for the treatment of hepatitis
C virus (HCV) infection. ZW800-1 was labeled on the IFNα molecule
of the HA–IFNα
conjugate to investigate its biodistribution and clearance without
altering its physicochemical and targeting characteristics. Confocal
microscopy clearly visualized the effective <i>in vitro</i> cellular uptake of the HA–IFNα conjugate to HepG2 cells.
After verifying the biological activity in Daudi cells, we conducted
the pharmacokinetic analysis of the HA–IFNα conjugate,
which confirmed its target-specific delivery to the liver with a prolonged
residence time longer than that of PEGylated IFNα. <i>In
vivo</i> and <i>ex vivo</i> bioimaging of the ZW800-1-labeled
HA–IFNα conjugate directly showed real-time biodistribution
and clearance of the conjugate that are consistent with the biological
behaviors analyzed by an enzyme-linked immunosorbent assay. Furthermore,
the elevated level of OAS1 mRNA in the liver confirmed <i>in
vivo</i> antiviral activity of HA–IFNα conjugates.
With the data taken
together, we could confirm the feasibility of ZW800-1 as a biologically
inert fluorophore and target-specific HA–IFNα
conjugate for the treatment of HCV infection
Image_2_Real-Time Tracking of Ex Vivo-Expanded Natural Killer Cells Toward Human Triple-Negative Breast Cancers.jpg
Introduction<p>Ex vivo-expanded natural killer (NK) cells are a potential candidate for cancer immunotherapy based on high cytotoxicity against malignant tumor cells. However, a limited understanding of the migration of activated NK cells toward solid tumors is a critical dilemma in the development of effective and adoptive NK cell-based immunotherapy.</p>Methods<p>Ex vivo-expanded NK cells from healthy donors were stained with near-infrared fluorophores at different concentrations. NK cell proliferation and cytotoxicity were assessed using a WST-8 assay, while the expression levels of surface molecules were analyzed by flow cytometry. To investigate the biodistribution of NK cells in both normal and tumor-bearing NSG mice, NK cells labeled with ESNF13 were subjected to NIR fluorescence imaging using the Mini-FLARE imaging system. Finally, mice were sacrificed and histopathological tests were performed in resected organs.</p>Results<p>The signal intensity of ESNF-stained NK cells was long-lasting at 72 h using concentrations as low as 0.04 µM. At a low dose range, ESNF13 did not affect NK cell purity, expression levels of surface receptors, or cytotoxic functions against MDA-MB-231 cancer cells. Ex vivo-expanded NK cells labeled with ESNF13 had a 4-h biodistribution in non-tumor-bearing NSG mice that mainly localized to the lungs immediately after injection and then fully migrated to the kidney after 4 h. In an MDA-MB-231 tumor-bearing NSG mice with extensive metastasis in both lungs, the fluorescence signal was dominant in both lungs and steady at 1, 2, and 4 h post-injection. In a early phase of tumor progression, administered NK cell migrated to the lungs and tumor sites within 30 min post-injection, the signal dominated the tumor site after 1 h, and remained steady at 4 h.</p>Conclusion<p>Optical imaging with NIR fluorophore ESNF13 is a highly sensitive, applicable, and inexpensive method for the real-time tracking of ex vivo-expanded NK cells both in vitro and in vivo. Administered NK cells had different patterns of NK cell distribution and accumulation to the tumor site according to tumor progression in triple-negative breast cancer xenograft models.</p
Image_3_Real-Time Tracking of Ex Vivo-Expanded Natural Killer Cells Toward Human Triple-Negative Breast Cancers.jpeg
Introduction<p>Ex vivo-expanded natural killer (NK) cells are a potential candidate for cancer immunotherapy based on high cytotoxicity against malignant tumor cells. However, a limited understanding of the migration of activated NK cells toward solid tumors is a critical dilemma in the development of effective and adoptive NK cell-based immunotherapy.</p>Methods<p>Ex vivo-expanded NK cells from healthy donors were stained with near-infrared fluorophores at different concentrations. NK cell proliferation and cytotoxicity were assessed using a WST-8 assay, while the expression levels of surface molecules were analyzed by flow cytometry. To investigate the biodistribution of NK cells in both normal and tumor-bearing NSG mice, NK cells labeled with ESNF13 were subjected to NIR fluorescence imaging using the Mini-FLARE imaging system. Finally, mice were sacrificed and histopathological tests were performed in resected organs.</p>Results<p>The signal intensity of ESNF-stained NK cells was long-lasting at 72 h using concentrations as low as 0.04 µM. At a low dose range, ESNF13 did not affect NK cell purity, expression levels of surface receptors, or cytotoxic functions against MDA-MB-231 cancer cells. Ex vivo-expanded NK cells labeled with ESNF13 had a 4-h biodistribution in non-tumor-bearing NSG mice that mainly localized to the lungs immediately after injection and then fully migrated to the kidney after 4 h. In an MDA-MB-231 tumor-bearing NSG mice with extensive metastasis in both lungs, the fluorescence signal was dominant in both lungs and steady at 1, 2, and 4 h post-injection. In a early phase of tumor progression, administered NK cell migrated to the lungs and tumor sites within 30 min post-injection, the signal dominated the tumor site after 1 h, and remained steady at 4 h.</p>Conclusion<p>Optical imaging with NIR fluorophore ESNF13 is a highly sensitive, applicable, and inexpensive method for the real-time tracking of ex vivo-expanded NK cells both in vitro and in vivo. Administered NK cells had different patterns of NK cell distribution and accumulation to the tumor site according to tumor progression in triple-negative breast cancer xenograft models.</p
Image_1_Real-Time Tracking of Ex Vivo-Expanded Natural Killer Cells Toward Human Triple-Negative Breast Cancers.jpg
Introduction<p>Ex vivo-expanded natural killer (NK) cells are a potential candidate for cancer immunotherapy based on high cytotoxicity against malignant tumor cells. However, a limited understanding of the migration of activated NK cells toward solid tumors is a critical dilemma in the development of effective and adoptive NK cell-based immunotherapy.</p>Methods<p>Ex vivo-expanded NK cells from healthy donors were stained with near-infrared fluorophores at different concentrations. NK cell proliferation and cytotoxicity were assessed using a WST-8 assay, while the expression levels of surface molecules were analyzed by flow cytometry. To investigate the biodistribution of NK cells in both normal and tumor-bearing NSG mice, NK cells labeled with ESNF13 were subjected to NIR fluorescence imaging using the Mini-FLARE imaging system. Finally, mice were sacrificed and histopathological tests were performed in resected organs.</p>Results<p>The signal intensity of ESNF-stained NK cells was long-lasting at 72 h using concentrations as low as 0.04 µM. At a low dose range, ESNF13 did not affect NK cell purity, expression levels of surface receptors, or cytotoxic functions against MDA-MB-231 cancer cells. Ex vivo-expanded NK cells labeled with ESNF13 had a 4-h biodistribution in non-tumor-bearing NSG mice that mainly localized to the lungs immediately after injection and then fully migrated to the kidney after 4 h. In an MDA-MB-231 tumor-bearing NSG mice with extensive metastasis in both lungs, the fluorescence signal was dominant in both lungs and steady at 1, 2, and 4 h post-injection. In a early phase of tumor progression, administered NK cell migrated to the lungs and tumor sites within 30 min post-injection, the signal dominated the tumor site after 1 h, and remained steady at 4 h.</p>Conclusion<p>Optical imaging with NIR fluorophore ESNF13 is a highly sensitive, applicable, and inexpensive method for the real-time tracking of ex vivo-expanded NK cells both in vitro and in vivo. Administered NK cells had different patterns of NK cell distribution and accumulation to the tumor site according to tumor progression in triple-negative breast cancer xenograft models.</p
High-Throughput Screening of Small Molecule Ligands Targeted to Live Bacteria Surface
The
discovery of small molecule ligands targeted to the surface of live
pathogenic bacteria would enable an entirely new class of antibiotics.
We report the development and validation of a microarray-based high-throughput
screening platform for bacteria that exploits 300 μm diameter
chemical spots in a 1 in. × 3 in. nanolayered glass slide format.
Using 24 model compounds and 4 different bacterial strains, we optimized
the screening technology, including fluorophore-based optical deconvolution
for automated scoring of affinity and cyan–magenta–yellow–key
(CMYK) color-coding for scoring of both affinity and specificity.
The latter provides a lossless, one-dimensional view of multidimensional
data. By linking in silico analysis with cell binding affinity and
specificity, we could also begin to identify the physicochemical factors
that affect ligand performance. The technology we describe could form
the foundation for developing new classes of antibiotics
Near-Infrared Illumination of Native Tissues for Image-Guided Surgery
Our
initial efforts to prepare tissue-specific near-infrared (NIR)
fluorescent compounds generated successful correlation between physicochemical
properties and global uptake in major organs after systemic circulation
and biodistribution. Herein, we focus on the effects on biodistribution
based on modulating electronic influencing moieties from donating
to withdrawing moieties at both the heterocyclic site and through <i>meso</i>-substitution of pentamethine cyanine fluorophores.
These selected modifications harnessed innate biodistribution pathways
through the structure-inherent targeting, resulting in effective imaging
of the adrenal glands, pituitary gland, lymph nodes, pancreas, and
thyroid and salivary glands. These native-tissue contrast agents will
arm surgeons with a powerful and versatile arsenal for intraoperative
NIR imaging in real time