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 H₂PO₃^–, 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 (H₂O₂) was selected as a potential underlying marker for its compact relationship in cancer progression. For selective recognition of H₂O₂ in the process of visual biopsy, a benzylbenzeneboronic acid pinacol ester-decorated copolymer, namely, PMPC–Bpe, was synthesized, affording the final formation of the H₂O₂-responsive micelles in which amylose was trapped. The presence of H₂O₂ 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/I₂ added to the sample, and the formative amylose–KI/I₂ complex has a distinct blue color at 574 nm for visual amplification detection. The feasibility of the proposed method is demonstrated by visualizing the H₂O₂ 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)­styryl]-<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^–), 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^– 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^– sensing approach that, via assembly of a F^–-specific silyl-appended spiropyran dye with graphene oxide (GO), allows rapid and sensitive detection of F^– 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^–, was designed and synthesized. The nucleophilic substitution reaction between SPS and F^– 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^– 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^– was studied by ¹H NMR and ESI-MS. Finally, this SPS/GO nanocomposite was successfully applied to monitoring F^– 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 (GQD⁴²⁰) probe for imaging of hydrogen peroxide (H₂O₂). For specific recognition of H₂O₂ and lighting the fluorescence of TPGQD⁴²⁰, 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, TPGQD⁴²⁰–BMC displays a green-to-blue resolved emission band in response to H₂O₂ with an emission shift of 110 nm, and the H₂O₂ can be determined from 0.2 to 40 μM with a detection limit of 0.05 μM. Moreover, the fluorescence response of the TPGQD⁴²⁰–BMC toward H₂O₂ is rapid and extremely specific. The feasibility of the proposed method is demonstrated by two-photon ratiometrically mapping the production of endogenous H₂O₂ 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 Cu₃InSnSe₅ Heteronanostructures as Counter Electrodes for Dye-Sensitized Solar Cells

In this research, we reported the synthesis of quaternary Cu₃InSnSe₅ 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 Cu₃InSnSe₅ nanoparticles, Pt–Cu₃InSnSe₅ and Au–Cu₃InSnSe₅ heteronanostructures were designed and yielded using a simple and efficient seed growth method. These two heteronanostructures remained monodispersed without presence of any Cu₃InSnSe₅ nanocrystal impurities. To explore their application potentials for dye-sensitized solar cells, counter electrodes consisting of individual Cu₃InSnSe₅, Pt–Cu₃InSnSe₅, or Au–Cu₃InSnSe₅ constituents were fabricated. Current density–voltage (<i>J</i>–<i>V</i>) characteristics evaluation reveals that Cu₃InSnSe₅ nanoparticles, Pt–Cu₃InSnSe₅ and Au–Cu₃InSnSe₅ 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 μg IgG isolated from mice immunized with OVA-2ndEL (A, B) (n = 9) or OVA-c2ndEL (C, D) (n = 13) or 400 μg 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