12 research outputs found
Patterned Ni–P Alloy Films Prepared by “Reducing–Discharging” Process and the Hydrophobic Property
Patterned hydrophobic Ni–P
alloy films consisting of orderly and regular micro-nanoscale particles
were fabricated through the synergistic effect of electrochemical
deposition and chemical deposition. Ni–P alloy films were deposited
for different times and characterized by scanning electron microscope
(SEM). It was confirmed that the addition of reducing agent induced
the formation of nanoscale particles, in contrast with pure Ni film
deposited by single electrochemical deposition. As “point-discharge
effect”, the current density was higher at the edge of the
nanoscale particles, and Ni ions would be deposited at the particles
through the “point-discharge effect”. Then the Ni–P
alloy films grew by “reducing–discharging” process.
The X-ray photoelectron spectroscopy (XPS) was used to detect the
composition and valence states of these alloy films. The existence
of oxidation state of element P in these films corresponding to that
in H<sub>2</sub>PO<sub>3</sub><sup>–</sup>, also gave direct
evidence for the occurrence of chemical deposition, during the electrochemical
deposition process. The prolongation of deposition time could provide
more time for the patterned morphology to grow up. The surface roughness,
evaluated by surface profilometer, increased as the deposition time
extension. And these films showed gradually increased hydrophobic
properties with the increase in deposition time
Visual Biopsy by Hydrogen Peroxide-Induced Signal Amplification
Visual biopsy has attracted special
interest by surgeons due to
its simplicity and practicality; however, the limited sensitivity
of the technology makes it difficult to achieve an early diagnosis.
To circumvent this problem, herein, we report a visual signal amplification
strategy for establishing a marker-recognizable biopsy that enables
early cancer diagnosis. In our proposed approach, hydrogen peroxide
(H<sub>2</sub>O<sub>2</sub>) was selected as a potential underlying
marker for its compact relationship in cancer progression. For selective
recognition of H<sub>2</sub>O<sub>2</sub> in the process of visual
biopsy, a benzylbenzeneboronic acid pinacol ester-decorated copolymer,
namely, PMPC–Bpe, was synthesized, affording the final formation
of the H<sub>2</sub>O<sub>2</sub>-responsive micelles in which amylose
was trapped. The presence of H<sub>2</sub>O<sub>2</sub> activates
the boronate ester recognition site and induces it releasing abundant
indicator amylose, leading to signal amplification. The indicator
came across the solution of KI/I<sub>2</sub> added to the sample,
and the formative amylose–KI/I<sub>2</sub> complex has a distinct
blue color at 574 nm for visual amplification detection. The feasibility
of the proposed method is demonstrated by visualizing the H<sub>2</sub>O<sub>2</sub> content of cancer at different stages and three kinds
of actual cancerous samples. As far as we know, this is the first
paradigm to rationally design a signaling amplification-based molecular
recognizable biopsy for visual and sensitive disease identification,
which will extend new possibilities for marker-recognition and signal
amplification-based biopsy in disease progressing
Poly β‑Cyclodextrin/TPdye Nanomicelle-based Two-Photon Nanoprobe for Caspase‑3 Activation Imaging in Live Cells and Tissues
Two-photon excitation (TPE) with
near-infrared (NIR) photons as
the excitation source has important advantages over conventional one-photon
excitation (OPE) in the field of biomedical imaging. β-cyclodextrin
polymer (βCDP)-based two-photon absorption (TPA) fluorescent
nanomicelle exhibits desirable two-photon-sensitized fluorescence
properties, high photostability, high cell-permeability and excellent
biocompatibility. By combination of the nanostructured two-photon
dye (TPdye)/βCDP nanomicelle with the TPE technique, herein
we have designed a TPdye/βCDP nanomicelle-based TPA fluorescent
nanoconjugate for enzymatic activity assay in biological fluids, live
cells and tissues. This sensing system is composed of a <i>trans</i>-4-[<i>p</i>-(<i>N</i>,<i>N</i>-diethylamino)Âstyryl]-<i>N</i>-methylpyridinium iodide (DEASPI)/βCDP nanomicelle
as TPA fluorophore and carrier vehicle for delivery of a specific
peptide sequence to live cell through fast endocytosis, and an adamantine
(Ad)-GRRRDEVDK-BHQ2 (black hole quencher 2) peptide (denoted as Ad-DEVD-BHQ2)
anchored on the DEASPI/βCDP nanomicelle’s surface to
form TPA DEASPI/βCDP@Ad-DEVD-BHQ2 nanoconjugate by the βCD/Ad
host–guest inclusion strategy. Successful in vitro and in vivo
enzymatic activities assay of caspase-3 was demonstrated with this
sensing strategy. Our results reveal that this DEASPI/βCDP@Ad-DEVD-BHQ2
nanoconjugate not only is a robust, sensitive and selective sensor
for quantitative assay of caspase-3 in the complex biological environment
but also can be efficiently delivered into live cells as well as tissues
and act as a “signal-on” fluorescent biosensor for specific,
high-contrast imaging of enzymatic activities. This DEASPI/βCDP@Ad-DEVD-BHQ2
nanoconjugate provides a new opportunity to screen enzyme inhibitors
and evaluate the apoptosis-associated disease progression. Moreover,
our design also provides a methodology model scheme for development
of future TPdye/βCDP nanomicelle-based two-photon fluorescent
probes for in vitro or in vivo determination of biological or biologically
relevant species
Self-Assembly of Graphene Oxide with a Silyl-Appended Spiropyran Dye for Rapid and Sensitive Colorimetric Detection of Fluoride Ions
Fluoride
ion (F<sup>–</sup>), the smallest anion, exhibits
considerable significance in a wide range of environmental and biochemical
processes. To address the two fundamental and unsolved issues of current
F<sup>–</sup> sensors based on the specific chemical reaction
(i.e., the long response time and low sensitivity) and as a part of
our ongoing interest in the spiropyran sensor design, we reported
here a new F<sup>–</sup> sensing approach that, via assembly
of a F<sup>–</sup>-specific silyl-appended spiropyran dye with
graphene oxide (GO), allows rapid and sensitive detection of F<sup>–</sup> in aqueous solution. 6-(<i>tert</i>-Butyldimethylsilyloxy)-1′,3′,3′-trimethylspiro
[chromene- 2,2′-indoline] (SPS), a spiropyran-based silylated
dye with a unique reaction activity for F<sup>–</sup>, was
designed and synthesized. The nucleophilic substitution reaction between
SPS and F<sup>–</sup> triggers cleavage of the Si–O
bond to promote the closed spiropyran to convert to its opened merocyanine
form, leading to the color changing from colorless to orange-yellow
with good selectivity over other anions. With the aid of GO, the response
time of SPS for F<sup>–</sup> was shortened from 180 to 30
min, and the detection limit was lowered more than 1 order of magnitude
compared to the free SPS. Furthermore, due to the protective effect
of nanomaterials, the SPS/GO nanocomposite can function in a complex
biological environment. The SPS/GO nanocomposite was characterized
by XPS and AFM, etc., and the mechanism for sensing F<sup>–</sup> was studied by <sup>1</sup>H NMR and ESI-MS. Finally, this SPS/GO
nanocomposite was successfully applied to monitoring F<sup>–</sup> in the serum
Target-Activated Modulation of Dual-Color and Two-Photon Fluorescence of Graphene Quantum Dots for in Vivo Imaging of Hydrogen Peroxide
The development of nanoprobes suitable
for two-photon microscopy
techniques is highly desirable for mapping biological species in living
systems. However, at the current stage, the nanoprobes are restricted
to single-color fluorescence changes, making it unsuitable for quantitative
detection. To circumvent this problem, we report here a rational design
of a dual-emission and two-photon (TP) graphene quantum dot (GQD<sup>420</sup>) probe for imaging of hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>). For specific recognition of H<sub>2</sub>O<sub>2</sub> and
lighting the fluorescence of TPGQD<sup>420</sup>, a boronate ester-functionalized
merocyanine (BMC) fluorophore was used as both target-activated trigger
and the dual-emission fluorescence modulator. Upon two-photon excitation
at 740 nm, TPGQD<sup>420</sup>–BMC displays a green-to-blue
resolved emission band in response to H<sub>2</sub>O<sub>2</sub> with
an emission shift of 110 nm, and the H<sub>2</sub>O<sub>2</sub> can
be determined from 0.2 to 40 ÎĽM with a detection limit of 0.05
μM. Moreover, the fluorescence response of the TPGQD<sup>420</sup>–BMC toward H<sub>2</sub>O<sub>2</sub> is rapid and extremely
specific. The feasibility of the proposed method is demonstrated by
two-photon ratiometrically mapping the production of endogenous H<sub>2</sub>O<sub>2</sub> in living cells as well as in deep tissues of
murine mode at 0–600 μm. To the best of our knowledge,
this is the first paradigm to rationally design a dual-emission and
two-photon nanoprobe via fluorescence modulation of GQDs with switchable
molecules, which will extend new possibility to design powerful molecular
tools for in vivo bioimaging applications
Application of Cu<sub>3</sub>InSnSe<sub>5</sub> Heteronanostructures as Counter Electrodes for Dye-Sensitized Solar Cells
In this research,
we reported the synthesis of quaternary Cu<sub>3</sub>InSnSe<sub>5</sub> nanoparticles with uniform size distribution and morphology for
the first time through delicate controls over the chemical reaction
kinetics. On the basis of the preparation strategy of Cu<sub>3</sub>InSnSe<sub>5</sub> nanoparticles, Pt–Cu<sub>3</sub>InSnSe<sub>5</sub> and Au–Cu<sub>3</sub>InSnSe<sub>5</sub> heteronanostructures
were designed and yielded using a simple and efficient seed growth
method. These two heteronanostructures remained monodispersed without
presence of any Cu<sub>3</sub>InSnSe<sub>5</sub> nanocrystal impurities.
To explore their application potentials for dye-sensitized solar cells,
counter electrodes consisting of individual Cu<sub>3</sub>InSnSe<sub>5</sub>, Pt–Cu<sub>3</sub>InSnSe<sub>5</sub>, or Au–Cu<sub>3</sub>InSnSe<sub>5</sub> constituents were fabricated. Current density–voltage
(<i>J</i>–<i>V</i>) characteristics evaluation
reveals that Cu<sub>3</sub>InSnSe<sub>5</sub> nanoparticles, Pt–Cu<sub>3</sub>InSnSe<sub>5</sub> and Au–Cu<sub>3</sub>InSnSe<sub>5</sub> heterostructured nanoparticles display a comparative power
conversion efficiency (PCE) of 5.8%, 7.6%, and 6.5% to that of a Pt-based
counter electrode (7.9%), respectively. As such, we believe that the
reported preparation strategy could provide new insights to the design
and manufacture of counter electrode materials with controlled structure,
morphology, and optimized power conversion efficiency for dye-sensitized
solar cells
Three-Dimensional Nitrogen-Doped Multiwall Carbon Nanotube Sponges with Tunable Properties
A three-dimensional (3D) nitrogen-doped
multiwall carbon nanotube (N-MWCNT) sponge possessing junctions induced
by both nitrogen and sulfur was synthesized by chemical vapor deposition
(CVD). The formation of “elbow” junctions as well as
“welded” junctions, which are attributed to the synergistic
effect of the nitrogen dopant and the sulfur promoter, plays a critically
important role in the formation of 3D nanotube sponges. To the best
of our knowledge, this is the first report showing the synthesis of
macroscale 3D N-MWCNT sponges. Most importantly, the diameter of N-MWCNT
can be simply controlled by varying the concentration of sulfur, which
in turn controls both the sponge’s mechanical and its electrical
properties. It was experimentally shown that, with increasing diameter
of N-MWCNT, the elastic modulus of the sponge increased while the
electrical conductivity decreased. The mechanical behaviors of the
sponges have also been quantitatively analyzed by employing strain
energy function modeling
Transfer of IgG derived from peptide-immunized mice does not induce impairment of tear and salivary secretion in healthy animals.
<p>The production of saliva (A, C) and tears (B, D) of the mice injected 400 ÎĽg IgG isolated from mice immunized with OVA-2ndEL (A, B) (n = 9) or OVA-c2ndEL (C, D) (n = 13) or 400 ÎĽg IgG from mice immunized with OVA peptide (A, B; n = 9 and B, C; n = 16; respectively).</p
Summary of the autoantibodies against the linear or cyclic peptides of the second extracellular loop of M3R in healthy control and pSS patients.
<p>Summary of the autoantibodies against the linear or cyclic peptides of the second extracellular loop of M3R in healthy control and pSS patients.</p
Autoantibodies directed against peptides of the second extracellular loop of the M3R in pSS patients and healthy controls.
<p>Sera derived from pSS patients and healthy controls were collected and diluted 1:200 before use. The ELISA was performed for three linear peptides 2ndEL (A), OVA-2ndEL(C) and biotin-2ndEL(E), and three cyclic peptides c2ndEL(B), OVA-c2ndEL(D) and biotin-c2ndEL(F) of the second extracellular loop of M3R. The amount bound antibodies was expressed as arbitrary units (AU). G. Receiver operating characteristics curves for the six peptides were made using SPSS 17 software to determine sensitivity and specificity of the tested peptides. The <i>P</i> value was calculated using the Mann-Whitney U-test.</p