10 research outputs found
Transient Behavior of Ni@NiO<sub><i>x</i></sub> Functionalized SrTiO<sub>3</sub> in Overall Water Splitting
Transients in the
composition of Ni@NiO<sub><i>x</i></sub> core–shell
co-catalysts deposited on SrTiO<sub>3</sub> are
discussed on the basis of state-of-the-art continuous analysis of
photocatalytic water splitting, and post-XPS and TEM analyses. The
formation of excessive hydrogen (H<sub>2</sub>:O<sub>2</sub> ≫
2) in the initial stages of illumination demonstrates oxidation of
NiÂ(OH)<sub>2</sub> to NiOOH (nickel oxyhydroxide), with the latter
catalyzing water oxidation. A disproportionation reaction of Ni and
NiOOH, yielding NiÂ(OH)<sub>2</sub> with residual embedded Ni, occurs
when illumination is discontinued, which explains repetitive transients
in (excess) hydrogen and oxygen formation when illumination is reinitiated
Ratiometric Biosensor for Aggregation-Induced Emission-Guided Precise Photodynamic Therapy
Photodynamic therapy faces the barrier of choosing the appropriate irradiation region and time. In this paper, a matrix metalloproteinase-2 (MMP-2) responsive ratiometric biosensor was designed and synthesized for aggregation-induced emission (AIE)-guided precise photodynamic therapy. It was found that the biosensor presented the MMP-2 responsive AIE behavior. Most importantly, it could accurately differentiate the tumor cells from the healthy cells by the fluorescence ratio between freed tetraphenylethylene and protoporphyrin IX (PpIX, internal reference). <i>In vivo</i> study demonstrated that the biosensor could preferentially accumulate in the tumor tissue with a relative long blood retention time. Note that the intrinsic fluorescence of PpIX and MMP-2-triggered AIE fluorescence provided a real-time feedback which guided precise photodynamic therapy <i>in vivo</i> efficiently. This strategy demonstrated here opens a window in the precise medicine, especially for phototherapy
Additional file 1 of Boltzmann- and Non-Boltzmann-Based Thermometers in the First, Second and Third Biological Windows for the SrF2:Yb3+, Ho3+ Nanocrystals Under 980, 940 and 915Â nm Excitations
Additional file 1: Fig. S1. Variation of upconversion emission intensity as a function of Yb3+ dopant concentration when fixed the concentration of Ho3+ (0.1 mol%). Fig. S2. The UV–vis–NIR absorption spectra of SrF2:Yb3+/Ho3+ (12/0.1 mol%) NCs. Fig. S3. The dependence of luminescence intensity at (a) 1012 nm and (c) 2020 nm of SrF2:Yb3+/Ho3+ NCs on the temperature under 980 nm excitation. Arrhenius equation is used to fit the luminescence intensity dependent on temperature at (b) 1012 nm and (d) 2020 nm
Tumor-Triggered Geometrical Shape Switch of Chimeric Peptide for Enhanced <i>in Vivo</i> Tumor Internalization and Photodynamic Therapy
Geometrical
shape of nanoparticles plays an important role in cellular
internalization. However, the applicability in tumor selective therapeutics
is still scarcely reported. In this article, we designed a tumor extracellular
acidity-responsive chimeric peptide with geometrical shape switch
for enhanced tumor internalization and photodynamic therapy. This
chimeric peptide could self-assemble into spherical nanoparticles
at physiological condition. While at tumor extracellular acidic microenvironment,
chimeric peptide underwent detachment of acidity-sensitive 2,3-dimethylmaleic
anhydride groups. The subsequent recovery of ionic complementarity
between chimeric peptides resulted in formation of rod-like nanoparticles.
Both <i>in vitro</i> and <i>in vivo</i> studies
demonstrated that this acidity-triggered geometrical shape switch
endowed chimeric peptide with accelerated internalization in tumor
cells, prolonged accumulation in tumor tissue, enhanced photodynamic
therapy, and minimal side effects. Our results suggested that fusing
tumor microenvironment with geometrical shape switch should be a promising
strategy for targeted drug delivery
Improving CT-image universal lesion detection with comprehensive data and feature enhancements
As a crucial task in Computer Vision, object detection has substantially improved in recent years, with the aid of deep learning and increasingly abundant datasets. However, compared with natural image detection, medical CT images require more precision due to the obvious clinical implications. Detecting multiple lesions or clusters with relatively few training samples and indistinctive feature representation is extremely problematic. In this paper, we propose comprehensive improvements to the original YOLOv3, such as data augmentation, feature attention enhancement and feature complementarity enhancement to increase general lesion area detection performance. Ablation studies use the open DeepLesion dataset to validate these improvements and confirm the effectiveness of each amendment. Comparisons between state-of-the-art counterparts demonstrated that the proposed lesion object detector has enhanced salient accuracy (under two commonly used metrics) and an exceptional speed-accuracy trade-off. The proposed model achieved 57.5% mAP and 85.07% sensitivity at 4 false positives (FPs) per image, while running at reliable 35.6 frames per second (FPS). These findings indicate that the proposed detector is more practicable than other currently available computer aided diagnostics (CAD)
Mitochondria-Targeted Chimeric Peptide for Trinitarian Overcoming of Drug Resistance
In
this report, an amphiphilic mitochondria-targeted chimeric peptide-based
drug delivery system (DDS) was designed to overcome drug resistance.
In vitro studies revealed that chimeric peptide could encapsulate
doxorubicin (DOX) with high efficacy and target tumor mitochondria,
realizing controlled release of DOX and in situ photodynamic therapy
(PDT) in mitochondria. Importantly, reactive oxygen species (ROS)
during PDT significantly disrupted mitochondria, leading to a dramatic
decrease of intracellular adenosine 5′-triphophate (ATP). As
a result, ATP-dependent efflux of DOX was remarkably inhibited. Trinitarian
therapeutic strategy was developed to ablation of drug-resistant cells,
that is, (1) enhanced cellular uptake of hydrophobic DOX via encapsulation
in DDS, (2) combined chemo-/photodynamic therapies, and (3) suppressed
generation of intracellular ATP as well as drug efflux via in situ
PDT in mitochondria. This trinitarian strategy may open a new window
in the fabrication of subcellular organelle destructive DDS in overcoming
drug resistance
Self-Powered Electrostatic Filter with Enhanced Photocatalytic Degradation of Formaldehyde Based on Built-in Triboelectric Nanogenerators
Recently,
atmospheric pollution caused by particulate matter or
volatile organic compounds (VOCs) has become a serious issue to threaten
human health. Consequently, it is highly desirable to develop an efficient
purifying technique with simple structure and low cost. In this study,
by combining a triboelectric nanogenerator (TENG) and a photocatalysis
technique, we demonstrated a concept of a self-powered filtering method
for removing pollutants from indoor atmosphere. The photocatalyst
P25 or Pt/P25 was embedded on the surface of polymer-coated stainless
steel wires, and such steel wires were woven into a filtering network.
A strong electric field can be induced on this filtering network by
TENG, while both electrostatic adsorption effect and TENG-enhanced
photocatalytic effect can be achieved. Rhodamine B (RhB) steam was
selected as the pollutant for demonstration. The absorbed RhB on the
filter network with TENG in 1 min was almost the same amount of absorption
achieved in 15 min without using TENG. Meanwhile, the degradation
of RhB was increased over 50% under the drive of TENG. Furthermore,
such a device was applied for the degradation of formaldehyde, where
degradation efficiency was doubled under the drive of TENG. This work
extended the application for the TENG in self-powered electrochemistry,
design and concept of which can be possibly applied in the field of
haze governance, indoor air cleaning, and photocatalytic pollution
removal for environmental protection
Acidity-Triggered Tumor Retention/Internalization of Chimeric Peptide for Enhanced Photodynamic Therapy and Real-Time Monitoring of Therapeutic Effects
Photodynamic
therapy (PDT) holds great promise in tumor treatment. Nevertheless,
it remains highly desirable to develop easy-to-fabricated PDT systems
with improved tumor accumulation/internalization and timely therapeutic
feedback. Here, we report a tumor-acidity-responsive chimeric peptide
for enhanced PDT and noninvasive real-time apoptosis imaging. Both
in vitro and in vivo studies revealed that a tumor mildly acidic microenvironment
could trigger rapid protonation of carboxylate anions in chimeric
peptide, which led to increased ζ potential, improved hydrophobicity,
controlled size enlargement, and precise morphology switching from
sphere to spherocylinder shape of the chimeric peptide. All of these
factors realized superfast accumulation and prolonged retention in
the tumor region, selective cellular internalization, and enhanced
PDT against the tumor. Meanwhile, this chimeric peptide could further
generate reactive oxygen species and initiate cell apoptosis during
PDT. The subsequent formation of caspase-3 enzyme hydrolyzed the chimeric
peptide, achieving a high signal/noise ratio and timely fluorescence
feedback. Importantly, direct utilization of the acidity responsiveness
of a biofunctional Asp–Glu–Val–Asp–Gly
(DEVDG, caspase-3 enzyme substrate) peptide sequence dramatically
simplified the preparation and increased the performance of the chimeric
peptide furthest
Activable Cell-Penetrating Peptide Conjugated Prodrug for Tumor Targeted Drug Delivery
In
this paper, an activable cell-penetrating peptide (CR<sub>8</sub>G<sub>3</sub>PK<sub>6</sub>, ACPP) with a shielding group of 2,3-dimethylmaleic
anhydride (DMA) was conjugated with antitumor drug doxorubicin (DOX)
to construct a novel prodrug (DOX-ACPP-DMA) for tumor targeted drug
delivery. The shielding group of DMA linked to the primary amines
of K<sub>6</sub> through the amide bond was used to block the cell-penetrating
function of the polycationic CPP (R<sub>8</sub>) through intramolecular
electrostatic attraction at physiological pH 7.4. At tumor extracellular
pH 6.8, the hydrolysis of DMA led to charge reversal, activating the
pristine function of CPP for improved cellular uptake by tumor cells.
Confocal laser scanning microscopy (CLSM) and flow cytometry studies
revealed that the cellular uptake of DOX-ACPP-DMA was significantly
enhanced after acid-triggered activation in both HeLa and COS7 cells.
After cell internalization, the overexpressed intracellular proteases
would further trigger drug release in cells. Both in vitro and in
vivo investigations showed that the peptidic prodrug exhibited significant
tumor growth inhibition and demonstrated great potential for tumor
therapy