47 research outputs found
To My Daughter
<p>Equal numbers of macaque CD34<sup>+</sup> cells were transduced in 3-d transduction cultures with either the HOXB4GFP or YFP vector and then cultured for an additional 9 d (T02266) or 6 d (K03290 and J02152) in the presence of SCF, TPO, Flt-3L, and G-CSF. All the transduced and expanded cells were infused into myeloablated animals. The percentage of HOXB4GFP<sup>+</sup> and YFP<sup>+</sup> granulocytes was assessed by flow cytometry. Shown is the engraftment of HOXB4GFP<sup>+</sup> and YFP<sup>+</sup> granulocytes after transplantation. (A) T02266, (B) K03290, and (C) J02152.
</p
Rational Design of NIR-II GāQuadruplex Fluorescent Probes for Accurate In Vivo Tumor Metastasis Imaging
Accurate in vivo imaging of G-quadruplexes (G4) is critical
for
understanding the emergence and progression of G4-associated diseases
like cancer. However, existing in vivo G4 fluorescent probes primarily
operate within the near-infrared region (NIR-I), which limits their
application accuracy due to the short emission wavelength. The transition
to second near-infrared (NIR-II) fluorescent imaging has been of significant
interest, as it offers reduced autofluorescence and deeper tissue
penetration, thereby facilitating more accurate in vivo imaging. Nonetheless,
the advancement of NIR-II G4 probes has been impeded by the absence
of effective probe design strategies. Herein, through a āstep-by-stepā
rational design approach, we have successfully developed NIRG-2, the
first small-molecule fluorescent probe with NIR-II emission tailored
for in vivo G4 detection. Molecular docking calculations reveal that
NIRG-2 forms stable hydrogen bonds and strong ĻāĻ
interactions with G4 structures, which effectively inhibit twisted
intramolecular charge transfer (TICT) and, thereby, selectively illuminate
G4 structures. Due to its NIR-II emission (940 nm), large Stokes shift
(90 nm), and high selectivity, NIRG-2 offers up to 47-fold fluorescence
enhancement and a tissue imaging depth of 5 mm for in vivo G4 detection,
significantly outperforming existing G4 probes. Utilizing NIRG-2,
we have, for the first time, achieved high-contrast visualization
of tumor metastasis through lymph nodes and precise tumor resection.
Furthermore, NIRG-2 proves to be highly effective and reliable in
evaluating surgical and drug treatment efficacy in cancer lymphatic
metastasis models. We are optimistic that this study not only provides
a crucial molecular tool for an in-depth understanding of G4-related
diseases in vivo but also marks a promising strategy for the development
of clinical NIR-II G4-activated probes
Evolving an Ultra-Sensitive Near-Infrared Ī²āGalactosidase Fluorescent Probe for Breast Cancer Imaging and Surgical Resection Navigation
Early diagnosis and therapy are clinically crucial in
decreasing
mortality from breast carcinoma. However, the existing probes have
difficulty in accurately identifying the margins and contours of breast
carcinoma due to poor sensitivity and specificity. There is an urgent
need to develop high-sensitive fluorescent probes for the diagnosis
of breast carcinoma and for differentiating tumors from normal tissues
during surgery. Ī²-Galactosidase is a significant biomarker,
whose overexpression is closely associated with the progression of
breast tumors. Herein, we have constructed a Ī²-galactosidase-activated
fluorescent probe NIR-Ī²gal-2 through rational design
and molecular docking engineering simulations. The probe displayed
superior sensitivity (detection limit = 2.0 Ć 10ā3 U/mL), great affinity (Km = 1.84 Ī¼M),
and catalytic efficiency (kcat/Km = 0.24 Ī¼Mā1 sā1) for Ī²-galactosidase. Leveraging this probe,
we demonstrated the differentiation of cancer cells overexpressing
Ī²-galactosidase from normal cells and then applied the probe
for intraoperative guided excision of breast tumors. Moreover, we
exhibited the application of NIR-Ī²gal-2 for the
successful resection of orthotopic breast tumors by āin situ
sprayingā and monitored a good prognostic recovery. This work
may promote the application of enzyme-activated near-infrared fluorescent
probes for the development of carcinoma diagnosis and image-guided
surgery
Efficient Two-Photon Fluorescent Probe for Nitroreductase Detection and Hypoxia Imaging in Tumor Cells and Tissues
Hypoxia plays an important role in
tumor progression, and the development
of efficient methods for monitoring hypoxic degree in living systems
is of great biomedical importance. In the solid tumors, the nitroreductase
level is directly corresponded with the hypoxic status. Many one-photon
excited fluorescent probes have been developed for hypoxia imaging
in tumor cells via the detection of nitroreductase level. However,
two-photon excited probes are more suitable for bioimaging. In this
work, a two-photon probe 1 for nitroreductase detection and hypoxic
status monitoring in living tumor cells and tissues was reported for
the first time. The detection is based on the fact that the nitro-group
of probe 1 could be selectively reduced to an amino-group by nitroreductase
in the presence of reduced NADH, following by a 1,6-rearrangement-elimination
to release the fluorophore, resulting in the enhancement of fluorescence.
The probe exhibited both one-photon and two-photon excited remarkable
fluorescence enhancement (ā¼70-fold) for nitroreductase, which
afforded a high sensitivity for nitroreductase, with a detection limit
of 20 ng/mL observed. Moreover, the applications of the probe for
fluorescent bioimaging of hypoxia in living cells and two-photon bioimaging
in tissues were carried out, with tissue-imaging depths of 70ā160
Ī¼m observed, which demonstrates its practical application in
complex biosystems
A Bioluminescent Probe for Imaging Endogenous Peroxynitrite in Living Cells and Mice
Peroxynitrite
(ONOO<sup>ā</sup>), an extremely reactive
nitrogen species (RNS), is implicated in diverse pathophysiological
conditions, including cancer, neurodegenerative diseases, and inflammation.
Sensing and imaging of ONOO<sup>ā</sup> in living systems remains
challenging due to the high autofluorescence and the limited light
penetration depth. In this work, we developed a bioluminescent probe <b>BP-PN</b>, based on luciferaseāluciferin pairs and the
ONOO<sup>ā</sup>-responded group Ī±-ketoamide, for highly
sensitive detection and imaging of endogenous ONOO<sup>ā</sup> in living cells and mice for the first time. Attributed to the BL
without external excitation, the probe <b>BP-PN</b> exhibits
a high signal-to-noise ratio with relatively low autofluorescence.
Furthermore, we examine the application of the probe <b>BP-PN</b> using the mice model of inflammation, and <b>BP-PN</b> shows
high sensitivity for imaging endogenous ONOO<sup>ā</sup> in
inflamed mice. This newly developed bioluminescent probe would be
a potentially useful tool for in vivo imaging of ONOO<sup>ā</sup> in wider physiological and pathological processes
Bifunctional Fluoroionphore-Ionic Liquid Hybrid for Toxic Heavy Metal Ions: Improving Its Performance via the Synergistic Extraction Strategy
Several heavy metal ions (HMIs), such as Cd<sup>2+</sup>, Pb<sup>2+</sup>, and Hg<sup>2+</sup>, are highly toxic even at
very low
concentrations. Although a large number of fluoroionphores have been
synthesized for HMIs, only a few of them show detection limits that
are below the maximum contamination levels in drinking water (usually
in the nM range), and few of them can simultaneously detect and remove
HMIs. In this work, we report a new fluoroionphore-ionic liquid hybrid-based
strategy to improve the performance of classic fluoroionphores via
a synergistic extraction effect and realize simultaneous instrument-free
detection and removal of HMIs. As a proof-of-concept, Hg<sup>2+</sup> was chosen as a model HMI, and a rhodamine thiospirolactam was chosen
as a model fluoroionphore to construct bifunctional fluoroionphore-ionic
liquid hybrid <b>1</b>. The new sensing system could provide
obviously improved sensitivity by simply increasing the aqueous-to-ionic
liquid phase volume ratio to 10:1, resulting in a detection limit
of 800 pM for Hg<sup>2+</sup>, and afford extraction efficiencies
larger than 99% for Hg<sup>2+</sup>. The novel strategy provides a
general platform for highly sensitive detection and removal of various
HMIs in aqueous samples and holds promise for environmental and biomedical
applications
A General Method To Increase Stokes Shift by Introducing Alternating Vibronic Structures
Fluorescent dyes
have enabled much progress in the broad range
of biomedical fields. However, many commercially available dyes suffer
from small Stokes shifts, resulting in poor signal-to-noise ratio
and self-quenching on current microscope configurations. In this work,
we have developed a general method to significantly increase the Stokes
shifts of common fluorophores. By simply appending a 1,4-diethyl-decahydro-quinoxaline
(DQ) moiety onto the conjugated structure, we introduced a vibronic
backbone that could facilely expand the Stokes shifts, emission wavelength,
and photostability of 11 different fluorophores by more than 3-fold.
This generalizable method could significantly improve the imaging
efficiency of commercial fluorophores. As a demonstration, we showed
that the DQ derivative of hemicyanine generated 5-fold signal in mouse
models over indocyanine green. Furthermore, the DQ-modified fluorophores
could pair with their parent molecules to conduct one-excitation,
multiple emission imaging, allowing us to study the cell behavior
more robustly. This approach shows promise in generating dyes suitable
for super-resolution microscopy and second window near-infrared imaging
Near Infrared Graphene Quantum Dots-Based Two-Photon Nanoprobe for Direct Bioimaging of Endogenous Ascorbic Acid in Living Cells
Ascorbic
acid (AA), as one of the most important vitamins, participates
in various physiological reactions in the human body and is implicated
with many diseases. Therefore, the development of effective methods
for monitoring the AA level in living systems is of great significance.
Up to date, various technologies have been developed for the detection
of AA. However, few methods can realize the direct detection of endogenous
AA in living cells. In this work, we for the first time reported that
near-infrared (NIR) graphene quantum dots (GQD) possessed good two-photon
fluorescence properties with a NIR emission at 660 nm upon exciting
with 810 nm femtosecond pulses and a two-photon (TP) excitation action
cross-section (Ī“Ī¦) of 25.12 GM. They were then employed
to construct a TP nanoprobe for detection and bioimaging of endogenous
AA in living cells. In this nanosystem, NIR GQDs (NGs), which exhibited
lower fluorescence background in living system to afford improved
fluorescence imaging resolution, were acted as fluorescence reporters.
Also CoOOH nanoflakes were chosen as fluorescence quenchers by forming
on the surface of NGs. Once AA was introduced, CoOOH was reduced to
Co<sup>2+</sup>, which resulted in a āturn-onā fluorescence
signal of NGs. The proposed nanoprobe demonstrated high sensitivity
toward AA, with the observed LOD of 270 nM. It also showed high selectivity
to AA with excellent photostability. Moreover, the nanoprobe was successfully
used for TP imaging of endogenous AA in living cells as well as deep
tissue imaging
Development of Dual-Responsive Fluorescent Probe for Drug Screening of Diabetes Cardiomyopathy
For specific drug research and development,
a drug-screening strategy
(DSS) plays an indispensable role in the biomedical field. Unfortunately,
traditional strategies are complicated and insufficiently accurate
due to the widely used single-target screening method. Herein, a simple
dual-target-based drug-screening strategy (dt-DSS) is proposed to
screen highly effective drugs by fluorescence imaging. As a proof
of concept, we utilized a dual-responsive fluorescence probe to screen
drugs for diabetic cardiomyopathy (DCM). We first developed and took
advantage of a dual-response probe HDB to detect reactive oxygen species
(ROS) and mitophagy levels in cellular starvation and high glucose
models. Based on this, HDB was utilized to study the effects of different
drugs in the mitophagy process caused by the high-glucose cell model
for DCM. Combined with Western blotting assays, we found that Drp-1
inhibitors could fundamentally reduce mitophagy caused by the high-glucose
cells model. Compared with commercial single-target antioxidant drugs,
the drugs with simultaneous antioxidant capacity and Drp-1 inhibition
screened by dt-DSS, such as resveratrol and icariin, could treat DCM
better. Therefore, HDB as an effective tool could accurately and quickly
screen high-potency drugs for DCM. We believe that this work provides
an attractive strategy to explore the pathogenesis of diabetic cardiomyopathy
and precisely screen for highly effective drugs
Two-Photon DNAzymeāGold Nanoparticle Probe for Imaging Intracellular Metal Ions
RNA-cleaving
DNAzymes have been demonstrated as a promising platform
for sensing metal ions. However, the poor biological imaging performance
of RNA-cleaving DNAzyme-based fluorescent probes has limited their
intracellular applications. Compared with traditional one-photon fluorescence
imaging, two-photon (TP) fluorescent probes have shown advantages
such as increased penetration depth, lower tissue autofluorescence,
and reduced photodamage. Herein, for the first time, we developed
an RNA-cleaving DNAzyme-based TP imaging probe (TP-8ā17ESāAuNP)
for Zn<sup>2+</sup> detection in living cells by modifying a Zn<sup>2+</sup>-specific DNAzyme (8ā17) with a TP fluorophore (TP-8ā17ES)
and using gold nanoparticles (AuNPs) for intracellular delivery. The
modified TP-8ā17ES exhibits good two-photon properties and
excellent photostability. For the TP-8ā17ESāAuNP, in
the absence of Zn<sup>2+</sup>, the TP fluorophore is quenched by
both AuNPs and the molecular quencher. Only in the presence of Zn<sup>2+</sup> does the DNAzyme cleave the TP fluorophore-labeled substrate
strand, resulting in fluorescence enhancement and TP imaging. Such
probe shows remarkable selectivity of Zn<sup>2+</sup> over other metal
ions existing in the biological environment. Benefiting from the labeled
TP fluorophore, the near-infrared (NIR) excited probe has the capability
of TP imaging of Zn<sup>2+</sup> in living cells and tissue with a
deep tissue penetration up to 160 Ī¼m. This method can be generally
applied to detect other metal ions in biological systems under TP
imaging with higher tissue penetration ability and lower phototoxicity