Search

Highlights • First 3-year large data emergency vaccination post-exposure prophylaxis study. • Varicella outbreaks in one-dose regime areas more likely in schools. • Emergency vaccinations effective within 3 days of exposure in prior vaccinated. • Emergency vaccinations control school outbreaks in one-dose varicella regime areas. Abstract Objectives To evaluate the effectiveness of post-exposure prophylaxis conducted during varicella outbreaks among students in Shanghai. Methods Surveillance data were collected from September 1, 2013 to December 31, 2016 involving 3524 susceptible students in 109 primary and middle school classes where emergency vaccinations (EVs) had been administered. Students were divided into two groups according to their prior vaccination (PV) varicella vaccine status. A secondary attack rate was used to compare EV and non-EV groups using a chi-squared test. Stratification analyses were performed, adjusting for the EV administration date, the vaccination coverage rate, and the number of cases prior to the EV. Results The effectiveness rate was 92.2% (95% confidence interval (CI): 37.1–99.0%) when EV was applied within 3 days following the outbreak onset date, and 95.2% (95% CI: 79.9–98.8%) when vaccination coverage was ≥80% among students with PV. When students with PV received an EV for varicella within 3 days, the effectiveness rate was 100%. Conclusions EV showed high protective effectiveness for varicella during outbreaks, especially if administered within 3 days of an outbreak and in conjunction with a high coverage rate. [ABSTRACT FROM AUTHOR]

Abstract: Lysosomal imaging represents a potent tool for investigating the organization of related cellular events and their modulation via diagnostic and therapeutic approaches. However, specific labeling of the lysosome in live cells is a significant challenge. Taking advantage of the inherent lysosomal entry of nanoparticles and unique digestive inclusions in the lysosome, we developed a nanoparticle-based, enzyme-switchable fluorescence OFF-ON strategy for specific labeling of the lysosome and further imaging of extracellular acidification-induced lysosome trafficking in living cells. The nanoprobe comprised a 16 nm spherical gold nanoparticle as the core and an enzyme-responsive oligomer of fluorescein-conjugated oligo(4-vinyl-phenyl phosphate) as the shell. Due to quenching of the core gold nanoparticle, the nanoprobe was non-fluorescent. After incubation with cancer cells, the nanoprobe was rapidly internalized via scavenger receptor-mediated endocytosis and significantly shuffled into the lysosome. The nanoprobe specifically lighted up the lysosome owing to lysosome-induced fluorescence enhancement. Specifically, digestive inclusions in the lysosome hydrolyzed and released gold-quenched fluorescein molecules, leading to significant augmentation of fluorescence. On account of specific lysosomal labeling, the nanoprobe effectively facilitated imaging of a 4–6 μm anterograde trafficking event of the lysosome from the perinuclear region to the cell surface when an acidic extracellular environment developed. Our findings collectively highlight the use of nanoprobes for lysosomal imaging. [Copyright &y& Elsevier]

Abstract: Aspects of the self-assembly of particles, which uses nanometer or micrometer sized building blocks to bridge the gap between microscopic and macroscopic scales, are reviewed. Particle self-assembly has been the focus of considerable research in recent years because it can lead to superstructures with a complexity inaccessible by molecular self-assembly, and functionalities entirely different from or superior to those of the primary particles. Examples in molecular self-assembly suggests that anisotropic interactions could be useful in promoting particle self-assembly, with the exception of colloidal crystallization, which requires particles of uniform size and shape. Anisotropic particles prepared by surface modification of precursor particles are often rigid and submicron or micron sized, and thus relatively strong isotropic van der Waals interactions tend to resist self-assembly into regular superstructures. In addition, the relatively large contact area between particles needed for a sufficient binding enthalpy to stabilize a superstructure is difficult for rigid spherical particles. In contrast, flexible anisotropic polymeric particles dispersed in solvents have been shown to self-assemble into various superstructures. The flexibility of primary anisotropic particles enables them to fuse and stabilize into a superstructure. Some flexible and multi-component particles that are isotropic in common solvents can undergo deformation and sufficient material redistribution to anisotropically self-assemble into regular superstructures in selective solvents. The self-assembly is also driven by anisotropic interactions, which is induced during self-assembly rather than in the particles as synthesized. This review focuses on recent achievements in soft particle self-assembly and describes briefly the advancements in rigid particle self-assembly. The presentation is divided into discussion of self-assembly by the colloidal crystallization of isotropic rigid particles, anisotropic rigid particles, anisotropic soft particles and isotropic soft particles, in that order. [Copyright &y& Elsevier]

Abstract: Complexation between poly(sodium acrylate) (PANa) and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide methiodide (ETC) in water, which leads to the formation of vesicle-like aggregates, was studied. Different from reported nano-aggregates of polymer complexes that may dissociate when being stimulated, the nano-aggregates of PANa/ETC complexes dissociate automatically in the aqueous solution at ambient environment, exhibiting a behavior similar to that of the nano-aggregates composed of degradable polymers. In the newly formed nano-aggregates, there are hydrophobic domains with a hydrophobicity close to that of hexane. Along with the dissociation, the hydrophobic domains vanish gradually. [Copyright &y& Elsevier]

In this study, we report a unique two-step approach to prepare pure and well-organized 10,12-pentacosadiynoic acid (DA)/melamine (MA) cocrystals, from which the topochemically polymerized product, poly(10,12-pentacosadiynoic acid) (PDA)/MA cocrystals, demonstrated reversible thermochromism (note that PDA in its pure crystalline form is thermochromically irreversible). In the first step, co-assembling DA and MA was achieve in a selective solvent for MA (i.e., water) using the non-covalently connected micelle method. In the second step, annealing the DA/MA co-assembly at a temperature higher than the melting point of pure DA crystals (62 °C) but below that of the cocrystals (87 °C) led to the formation of pure DA/MA cocrystals with a molar ratio of 2:1. The resultant lath-like DA/MA cocrystals were nano-sized and had an alternating DA/MA lamellar structure. Due to the strong intermolecular hydrogen-bonding and π-π stacking of MA molecules, the topochemically polymerized PDA/MA cocrystals were completely reversible in thermochromism. This is the first example that reversible thermochromism of PDA is realized through hydrogen-bonding assisted cocrystals with a small molecule. [ABSTRACT FROM AUTHOR]

In this study, preparation of nitrogen- and oxygen-codoped porous carbonaceous foam and its application as metal nanoparticles catalysts support for direct methanol fuel cell (DMFC) were presented. Tadpole-like single chain polymer nanoparticles stabilized water-in-acrylonitrile/divinyl benezene high internal phase emulsion (HIPE) was firstly prepared, and the formed HIPE was then converted into polymer of high internal phase emulsion (polyHIPE) through a radical polymerization reaction. Subsequently, the formed acrylonitrile/divinyl benezene based polyHIPE was hypercrosslinked via FeCl 3 catalyzed Friedel-Crafts reaction in 1,2-dichloroethane. After pyrolysis of the hypercrosslinked polyHIPE at elevated temperature under N 2 atmosphere, nitrogen- and oxygen-codoped porous carbonaceous foam exhibiting highly interconnected macroporous cells and a micro-/mesoporous carbon skeleton (carboHIPE) was obtained. The resultant carboHIPE was further applied as the support for Pt and Ru bimetal nanoparticles. Well-dispersed PtRu bimetal nanoparticles with a smaller size were perfectly dispersed on the surface of carboHIPE in the form of alloy phase. The PtRu alloy nanoparticles decorated carboHIPE (PtRu/carboHIPE) demonstrated superior electrocatalytic performances towards the methanol electrooxidation by comparison with Pt/carboHIPE and commercial PtRu/C with almost same Pt content, such as the higher current density, the better long term stability and the improved CO-resistance. [ABSTRACT FROM AUTHOR]

Nucleus-targeted drug delivery is a promising strategy for anticancer therapy, but in vivo nucleus-targeted drug delivery has been challenging. Limited by the channel size of the nucleopore, vehicles that enter the nucleus via the nucleopore actively should be small and decorated with nuclear localization signal (NLS). However, the small vehicle size may promote leakage of vehicles into normal tissues, and the positively-charged NLS can lead to strong non-specific interactions in vivo . In the present study, we demonstrate an in vivo nucleus-targeted drug delivery using large compound nanoparticles with detachable PEG shell. The nanoparticles are composed of PEG-benzoic imine-oligo- l -lysine/iridium(III) metallodrug complex and formed in a kinetically-controlled fashion. Under physiological conditions (pH 7.4), the nanoparticles are large (ca. 150 nm) and protected by an inert PEG shell. When internalized into intracellular acidic endo/lysosomes of cancer cells, the nanoparticles dissociate into smaller ones ( ca. 40 nm) and the PEG chains detach due to the cleavage of the benzoic imine bond at low pH. The small nanoparticles, with exposure of the oligo- l -lysine after the detachment of the PEG shield, then translocate into the nucleus via the nucleopore due to the small size and nuclear localization ability of the oligo- l -lysine. Importantly, the small particles could significantly release the contained drug into the nucleus, leading to ca. 20-fold higher cytotoxicity compared to the native drug in vitro . Further in vivo application of the nucleus-targeting nano-system in a nude-mice model showed significant tumor inhibition and remarkable life-span elongation. [ABSTRACT FROM AUTHOR]

Abstract: Metal ion detection using commercially available ionochromic polydiacetylenes has not been selective. In this work, we report selective detection of metal ions in small organic compound (SOC)-stabilized poly(10,12-pentacosadiynoic acid) (PDA) nanocrystals suspended in an aqueous solution. These PDA nanocrystals were topochemically polymerized using a 254-nm UV light from the corresponding SOC-stabilized DA nanocrystals prepared by a solvent/nonsolvent micellization method. In this detection, the stabilizing SOC could selectively regulate the intercalation of specific metal ions into the galleries of PDA nanocrystals. Whenever the specific metal ions were intercalated, a fast (<1 min) ionochromic transition was observed. In addition, different metal ion selectivity could be achieved by utilization of different SOCs. For example, selective detections of Pb2+ and Ag+ with different detection sensitivities were achieved for a PDA/glycine (Gly) nanocrystal suspension and selective detection of Zn2+ was found for a PDA/boric acid nanocrystal suspension. X-ray diffraction and Fourier transform infrared studies revealed that Pb2+ and Ag+ intercalated into the galleries of PDA nanocrystals and deprotonated most –COOH groups in the side chains of PDA, forming a strong ionic interaction. This strong ionic interaction effectively reduced the conjugation length in the PDA main chain, and therefore selectively induced a blue-to-red ionochromic transition. [Copyright &y& Elsevier]

Abstract: Transporting drug-containing nanoparticles into the nucleus of cancer cells through nucleopores and then releasing the drug intranuclearly provide an efficient strategy to overcome the drug resistance mechanisms evolved by cancer cells. However, limited by the diameter of nucleopores, nanoparticles capable of going through nucleopores should be small enough, whereas the nanoparticles with the small size may have short circulation time in blood and low accumulation in solid tumors. We solved this dilemma successfully by preparing kinetically frozen large compound nanoparticles (sized 128 nm) of complex of oligolysine/iridium(III) compound (a potential anticancer drug) that can dissociate into small ones in lysosome environment. The small nanoparticles retain their small size in cytosol after escaping from the lysosomes, so that they can enter the nucleus actively through nucleaopores, with the help of oligolysine segments on the surfaces of nanoparticles acting as the nuclear targeting moieties. It is significant that the nanoparticles can release the contained Ir compound within the nucleus. Further study reveals that the release is triggered by DNA interaction with the nanoparticles, which is responsible for the observation that the release occurs only in the nucleus. We believe that the present study, representing the first example of DNA triggered intranuclear release from nanoparticles, will provide a promising pathway for chemotherapy. [Copyright &y& Elsevier]

Abstract: A diiron hexacarbonyl complex possessing an alkynyl group as a model complex of the diiron sub-unit of [FeFe]-hydrogenase was polymerized under the catalysis of WCl6-SnPh4. The polymer (Poly-{Fe2}) functionalized with {Fe2(CO)6} units which is dominated by cis-form was fully characterised using FTIR, NMR, SEM, TEM, and TGA techniques. Through modifying the monomer, the properties, for example, solubility, of the resultant polymer could be tuned and much larger molecule weight, which was estimated as 7.93 × 105 g mol−1 using static light scattering technique was achieved without compromising its solubility. Spin-coating the functionalized polymer onto the surface of vitreous carbon electrode with or without multi-wall carbon nanotubes (MWCNTs) produced film electrodes which show electrochemical responses. Adding MWCNTs into the film enhances significantly the electrochemical response probably via not only improving the conductivity of the film, but also the increase in its effective surface area after being doped with MWCNTs. [Copyright &y& Elsevier]

Abstract: Using fluorescence spectrometry, it was found pyrene begins to partition into the core of poly(ε-caprolactone)/poly(N-isopropylacrylamide) (PCL/PNIPAM) core–shell nanoparticles at a low nanoparticle concentration (0.001mg/mL). The partition coefficient for pyrene partitioning between water and the nanoparticles is around 104. The rate for pyrene partitioning into PCL core is very quick, depending on the relative PCL core weight. And the distinct on–off property of the nanoparticle with temperature was revealed: pyrene molecules enter into PCL core freely when temperature is less than 34°C; while it becomes difficult when temperature rises to 37°C. In addition, a new procedure to accurately determine the loading capacity of nanoparticle core for hydrophobic compound using UV–vis spectrometry was developed. [Copyright &y& Elsevier]