Enzyme-Activatable Near-Infrared Photosensitizer with High Enrichment in Tumor Cells Based on a Multi-Effect Design

Enzyme-activatable near-infrared (NIR) fluorescent probes and photosensitizers (PSs) have emerged as promising tools for molecular imaging and photodynamic therapy (PDT). However, in living organisms selective retention or even enrichment of these reagents after enzymatic activation at or near sites of interest remains a challenging task. Herein, we integrate non-covalent and covalent retention approaches to introduce a novel “1-to-3” multi-effect strategy—one enzymatic stimulus leads to three types of effects—for the design of an enzyme-activatable NIR probe or PS. Using this strategy, we have constructed an alkaline phosphatase (ALP)-activatable NIR fluorogenic probe and a NIR PS, which proved to be selectively activated by ALP to switch on NIR fluorescence or photosensitizing ability, respectively. Additionally, these reagents showed significant enrichment (over 2000-fold) in ALP-overexpressed tumor cells compared to the culture medium, accompanied by massive depletion of intracellular thiols, the major antioxidants in cells. The investigation of this ALP-activatable NIR PS in an in vivo PDT model resulted in complete suppression of HeLa tumors and full recovery of all tested mice. Encouragingly, even a single administration of this NIR PS was sufficient to completely suppress tumors in mice, demonstrating the high potential of this strategy in biomedical applications.     

Large-scale Ni-MOF derived Ni_3S_2 nanocrystals embedded in N-doped porous carbon nanoparticles for high-rate Na~+ storage

Metal organic framework(MOF) has been confirmed as the promising precursor to develop the conve rsion-typed anode mate rials of sodium-ion batteries(SIBs) because of the tunable structure design and simple functional modification.Here,we prepare the ultrasmall Ni_3S_2 nanocrystals embedded into N-doped porous carbon nanoparticles using the scalable Ni-MOF as precursor(denoted as Ni_3S_2@NPC).The ultrasmall size of Ni_3S_2 can work for accelerated electro n/ion transfer to facilitate the electrochemical reaction kinetics.Moreover,the robust conductivity network originated from N-doped porous carbon nanoparticles can not only improve the electron conductivity,but also enhance the electrode integrity and stability of the electrode/electrolyte interface.In addition,the N heteroatoms provide extra Na storage sites.Accordingly,the electrode delivers the obviously competitive capacities and high-power output with respect to the currently reported Ni_3S_2/C composites.This study provides a scalable and universal strategy to develop the advanced transition metal sulfides for practically feasible SIBs.     

The effect of collector gap width on the extent of molecular orientation in polymer nanofibers

Electrospun poly(vinylidene fluoride) (PVDF) nanofibers were collected on aluminum foil across a gap with widths that varied in size from 2 to 10 mm. Scanning electron microscopy (SEM) images on fiber bundles showed that in all cases, fibers in the gap were macroscopically aligned across the gap. However, single fiber selected area electron diffraction (SAED) patterns and polarized Fourier Transform Infrared (FTIR) spectra demonstrated that fibers deposited across the gap were also highly aligned at the molecular level with the polymer backbones oriented along the fiber axis and that the extent of molecular orientation increased with the gap width. A possible explanation for this observation is based on the repulsion of similarly charged nanofibers and the simultaneous attraction of these fibers to the oppositely charged gap edges. This provides a plausible model for understanding the deposition kinetics and subsequent molecular orientation as a function of gap size when electrospinning using this method of fiber collection. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016 , 54, 617–623     

Electrochemical sensor based on chlorohemin modified molecularly imprinted microgel for determination of 2,4-dichlorophenol

A newly designed molecularly imprinted polymer (MIP) was synthesized and successfully utilized as a recognition element of an amperometric sensor for 2,4-dichlorophenol (2,4-DCP) detection. The MIP with a well-defined structure could imitate the dehalogenative function of the natural enzyme chloroperoxidase for 2,4-DCP. Imprinted sensor was fabricated in situ on a glassy carbon electrode surface by drop-coating the 2,4-DCP imprinted microgel suspension and chitosan/Nafion mixture. Under optimized conditions, the sensor showed a linear response in the range of 5.0–100 μmol L⁻¹ with a detection limit of 1.6 μmol L⁻¹. Additionally, the imprinted sensor demonstrated higher affinity to target 2,4-DCP over competitive chlorophenolic compounds than non-imprinted sensor. It also exhibited good stability and acceptable repeatability. The proposed sensor could be used for the determination of 2,4-DCP in water samples with the recoveries of 96.2–111.8%, showing a promising potential in practical application.     

EFFECT OF DISPERSED PHASE PARTICLES ON ELECTRICAL CONDUCTION OF PEO-NaSCN

Fast ionic conductors are one kind of solid state material with ionic conductivity as high as that of melten salts or liquid electrolytes.Ionic conductivity is one of the important parameters for characterizing a fast ionic conductor.For a long time materialists and chemists have made great efforts in search of new fast ionic conductors with high ionic conductivity.In view of structure,they have synthesised silver and copper fast ionic conductors with so called open structures.But it is not so successful for searching more applicable alkaline fast ionic conductors.Since polymer has flexibility for making thin film,it concentrates attention on the polymer-alkaline salt complex.Fenton et al.have first reported poly(ethylene oxide) (PEO)-alkaline salt complex.Later on Armard et al.have investigated the electrical property of PEO-NaSCN.     

Monodispersed SWNTs Assembled Coating Layer as an Alterna-tive to Graphene with Enhanced Alkali-ion Storage Performance

Graphene coating is commonly used to improve the performance of electrode materials,while its steric hindrance effect hampers fast ion transport with compromised rate capability.Herein,a unique single-walled carbon nanotubes(SWNTs)coating layer,as an alternative to graphene,has been developed to improve the battery behavior of iron-based anodes.Benefiting from the structure merits of mesoporous SWNTs layer for fast electron/ion transport and hollow Fe₃O₄ for volume accommodation,as-prepared Fe₃O₄@SWNTs exhibited excellent lithium storage performance.It delivers a high capacity,excellent rate capability,and long lifespan with capacities of 582 mA·h·g^-1 at 5 A·g^-1 and 408 mA·h·g^-1 at 8 A·g^-1 remained after 1000 cycles.Such performance is better than graphene-coated Fe₃O₄ and other SWNT-Fe₃O₄ architectures.Besides,SWNTs coating is also used to improve the sodium and potassium storage performance of FeSe₂.The kinetics analysis and ex-situ experiment further reveal the effect of SWNTs coating for fast electron/ion transfer kinetics and good structure stability,thus leading to the superior performance of SWNTs-coated composites.     

关于广义Stirling数偶的同余性

本文证明了广义Ｓｔｉｒｌｉｎｇ数偶的一些同余性质，从而回答了文［５］中的一个猜测．这些结果做为特例推广了已知的关于两类Ｓｔｉｒｌｉｎｇ数的同余性质．     

Rheological Properties and Morphology of PC/AES Blends

Blends of polycarbonate (PC) and acrylonitrile–EPDM (ethylene/propylene/diene elastomer)–styrene terpolymer (AES) were prepared at 20%, 30%, 40%, 50%, and 80% by weight of AES. The rheological properties and morphology of the PC, AES, and their blends were studied systematically. The strain sweep results show that the linear viscoelastic region of the AES is far less than that of PC. With the addition of AES, the linear viscoelastic regions become shorter gradually. The dynamic frequency sweep measurements indicate that the dependences of the complex viscosity on frequency for PC and AES are very different. With the increase of AES content, the complex viscosities of blends exhibit a more significant shear thinning behavior. All the samples, except PC, display a distinct nonterminal behavior at low frequencies. The level of the plateau depends on the volume fraction of the rubber phase. PC, AES, and PC/AES blends obey the Cox–Merz rule generally. The blends, which have similar morphology, show similar rheological properties.     

Synthesis, characterization and application of a novel sorbent, glucamine-modified MCM-41, for the removal/preconcentration of boron from waters

A novel sorbent was prepared by the functionalization of an inorganic support material, MCM-41, with N-methylglucamine for the uptake of boron from aqueous solutions prior to its determination by inductively coupled plasma optical emission spectrometry (ICP-OES). Characterization of the newly synthesized material was performed using BET, XRD, TEM, SEM and DRIFTS techniques, in addition to its C and N elemental content. Sorption behavior of the novel sorbent for boron was also investigated and found to obey Freundlich and Dubinin-Radushkevich (D-R) isotherm models. The maximum amount of B (as H₃BO₃) that can be sorbed by the sorbent was calculated from the D-R isotherm and was found to be 0.8 mmol B g⁻¹ of sorbent. The applicability of the new sorbent for the removal/preconcentration of boron from aqueous samples was examined by batch method. It was found that the sorbent can take up 85% of boron in 5 min whereas quantitative sorption is obtained in 30 min. Any pH greater than 6 can be used for sorption. Desorption from the sorbent was carried out using 1.0 M HNO₃. The sorption efficiency of the new sorbent was also compared to that of Amberlite IRA 743, a commercial resin with N-methylglucamine functional groups. Within the experimental conditions employed, the new sorbent was found to have higher sorption efficiency than the commercial resin. For method validation, spike recovery tests were performed at various concentration levels in different water types and were found to be between 83-95 and 75-92% for ultra pure water and geothermal water, respectively.     

Derivatives of the 21-tungsto-9-antimonate heteropolyanion. Part 1. Inclusion of lanthanide cations

Nine new heteropolytungstates, (NH₄)₁₆[LnSb₉W₂₁O₈₆]-xH₂O, (Ln=La, Ce, Pr, Nd, Sm, Eu, Gd, Dy or Yb) have been prepared from [NaSb₉W₂₁O₈₆]¹⁸⁻, and characterized by elemental analysis, i.r., u.v., emission spectra, magnetic susceptibility, and electrochemistry. Based on¹⁸³W-n.m.r. spectroscopy of the lanthanum complex, the lanthanide cations occupy the central site in the structure previously demonstrated for the sodium derivative.