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The polymeric nanogels were prepared by the copolymerization of polyethylene glycol methyl acrylate (PEGMEM) and 3-acrylamide phenylboronic acid (AAPBA) using N, N-methylene bis acrylamide (BIS) as cross-linking agent. The as-prepared nanogels were characterized by 1H NMR, FT-IR, transmission electron microscopy (TEM), and dynamic light scattering (DLS). Due to the pH sensitivity and the glucose-sensitivity of as-prepared nanogels, the nanogels could be used to encapsulate insulin. The insulin release properties of nanogels under different pH and glucose concentrations were investigated. These results showed that the nanogels are one of effective candidate carriers for insulin release. [ABSTRACT FROM AUTHOR]

Background The majority of patients with acute myelogenous leukemia (AML) still die of their disease. In order to improve survival rates in AML patients, new strategies are necessary to discover biomarkers for the detection and targeted therapy of AML. One of the advantages of the aptamer-based technology is the unique cell-based selection process, which allows us to efficiently select for cell-specific aptamers without knowing which target molecules are present on the cell surface. Methods The NB4 AML cell line was used as the target cell population for selecting single stranded DNA aptamers. After determining the affinity of selected aptamers to leukocytes, the aptamers were used to phenotype human bone marrow leukocytes and AML cells in clinical specimens. Then a biotin-labelled aptamer was used to enrich and identify its target surface protein. Results Three new aptamers were characterized from the selected aptamer pools (JH6, JH19, and K19). All of them can selectively recognize myeloid cells with Kd in the low nanomole range (2.77 to 12.37 nM). The target of the biotin-labelled K19 aptamer probe was identified as Siglec-5, a surface membrane protein in low abundance whose expression can serve as a biomarker of granulocytic maturation and be used to phenotype AML. More importantly, Siglec-5 expression can be used to detect low concentrations of AML cells in human bone marrow specimens, and functions as a potential target for leukemic therapy. Conclusions We have demonstrated a pipeline approach for developing single stranded DNA aptamer probes, phenotyping AML cells in clinical specimens, and then identifying the aptamerrecognized target protein. The developed aptamer probes and identified Siglec-5 protein may potentially be used for leukemic cell detection and therapy in our future clinical practice. [ABSTRACT FROM AUTHOR]

Degradable materials based on poly(α-angelica lactone-co-ε-caprolactone) (PAL-co-PCL) copolymers were successfully synthesized via ring-opening polymerization (ROP) of α-angelica lactone (AL) and ε-caprolactone (CL). The chemical structures of the PAL-co-PCL were confirmed by ¹H NMR and FTIR measurements. The crystallization behaviour of copolymers was analyzed by XRD patterns, the thermal properties were investigated by DSC and TGA curves. The degradation rate of PAL-co-PCL could be controlled through adjusting the ratio of PAL to PCL in the copolymer as well as the pH values of media. [ABSTRACT FROM AUTHOR]

Multi-arm star amphiphilic hyperbranched copolymers with poly(2-(dimethylamino) ethyl methacrylate) (PDMAEMA) shell and hyperbranched poly(3-ethyl-3-(hydroxymethyl)oxetane) (HBPO) core were synthesized by reversible addition-fragmentation chain transfer method. The hyperbranched copolymers were further modified by succinic anhydride (SUC) to obtain the novel pH- and thermosensitive hyperbranched copolymer HBPO- star-PDMAEMAs-SUC. The composition and morphology of synthesized copolymers were investigated by H NMR, dynamic light scattering, and transmission electron microscopy. These copolymers exhibited phase transitions in response to pH and temperature. The pH-dependent release properties of the drug-loaded micelles were also investigated using indomethacin (IND) as a model drug. The IND-loaded micelles displayed a rapid drug release at an alkaline pH. [ABSTRACT FROM AUTHOR]

A multiarm star polymer, poly(3-ethyl-3-oxetanemethanol)-graft-poly(2-dimethyl aminoethyl methacrylate) (PEOM-g-PDMAEMA), with a three-dimensional structure was synthesized via cationic ring-opening polymerization and atom transfer radical polymerization (ATRP). The polymer, consisting of a hydrophobic hyperbranched polyether (PEOM) inner core and hydrophilic poly(2-dimethylaminoethyl methacrylate) (PDMAEMA) multiarm shell, was used as the host for molecular encapsulations, and water-soluble dye (Congo Red) was selected as the corresponding guest molecule. Due to the multiarm structure and inner polar core, the synthesized polymer could be used as carrier for encapsulation and release of the guest molecule. The skeleton of this polymer played an important role in the procedure of guest encapsulation. The influences of controlled pH on encapsulation performance and release behaviors were mainly investigated and examined in vitro in simulated synthetic body fluids. This polymer system could be an attractive candidate for drug-delivery systems in aqueous media and could provide the phase-transfer carriers between water and organic media. [ABSTRACT FROM AUTHOR]

Due to their unique characteristics, dendrimers have attracted a great deal of attention over the past few years. The reason why they are of eminent interest in drug-delivery applications is that they have uniform size, water solubility, modifiable surface functionality and available internal cavities. Moreover, the high level of control over the dendritic architecture distinguishes them as ideal carriers. The bioactive agents may be encapsulated into the interior void spaces of the dendrimers or conjugated onto the dendrimer surface. Thus, they contribute to overcoming the challenge that quite a few drugs have low water solubility or cell membrane permeability and, therefore, never benefit patients. In this paper, we give a brief introduction of the synthesis of dendrimers, including divergent approach and convergent approach, and review two strategies used for drug-delivery applications and a vastly important function for gene transfection. [ABSTRACT FROM AUTHOR]

A multiarm star amphiphilic polymer with a three-dimensional structure was synthesized via melt polycondensation and atom transfer radical polymerization (ATRP). The polymer, consisting of a hydrophobic hyperbranched polyester (HPE) inner core and hydrophilic poly(2-dimethylaminoethyl methacrylate) (PDMAEMA) multiarm shell, was used as the host for molecular encapsulation, and water-soluble dye (Congo Red) was selected as the corresponding guest molecule. Due to the hyperbranched structure and inner polar core, the synthesized polymer was used as load carrier for encapsulation and release of Congo Red. The skeleton of these polymers played an important role in the procedure of guest-encapsulation. The influences of controlled pH on encapsulation and release behaviors were investigated and examined in vitro in simulated synthetic body fluid. This co-polymer system should be an attractive candidate for drug delivery in aqueous media and could provide the phase-transfer carriers between water and organic media. [ABSTRACT FROM AUTHOR]

A hyperbranched polymer (HBPO–PCL) consisting of a hyperbranched polyether (HBPO) inner core and biodegradable poly(ε-caprolactone) (PCL) shell was synthesized and used as the host for molecular encapsulation. A water-soluble dye (acid orange 7, AO 7) was selected as the corresponding guest molecule. Due to the hyperbranched structures and inner polar core, the hyperbranched polymer can be used as phase-transfer agent for reversible encapsulation and release of AO 7. The skeleton of these polymers played an important role in the procedure of guest-encapsulation. The effect of pH on phase-transfer performance and release behaviors were mainly investigated and examined in a in vitro simulated synthetic body fluids. Thus, this co-polymer system should be an attractive candidate for drug-delivery systems in aqueous media and could provide the phase-transfer carriers between water and organic media. [ABSTRACT FROM AUTHOR]

The present review deals with the design and preparation of environment-sensitive hyperbranched polymers, such as pH-, temperature-sensitive and salt-triggered polymers, in order to be employed as drug-delivery system. In particular, using known and well-characterized basic hyperbranched polymers as starting materials, this review discusses the kind of structural modifications that these polymers were subjected to for preparing nanocarriers of low toxicity, high encapsulating capacity, specificity to certain biological cells and transport ability under different environment conditions. Due to the great number of external groups of hyperbranched polymers either functionalization or multifunctionalization can occur, providing products that fulfill one or more of the requirements that an effective drug carrier should exhibit. Thus, hyperbranched polymers will play a significant role in the future development of new biomedical devices for the treatment of human diseases. [ABSTRACT FROM AUTHOR]

Calcineurin (CN), a Ca&sup2+; /calmodulin-dependent protein phosphatase, plays a critical role in T-cell activation by regulating the activity of NF-AT. CN is a heterodimer consisting of a catalytic subunit (CNA) and a Ca&sup2+; -binding regulatory subunit (CNB). CNB is composed of two global domains: the C-terminal domain (DC) and the N-terminal domain (DN), each containing two Ca&sup2+; binding sites. In this study, using purified DN and DC derived from constructed expression systems, we revealed that intact CNB and DC can stimulate the phosphatase activity of CNA, about 2.2 and 1.6 times the phosphatase activity of CNA alone, respectively, DN itself has little effect on the phosphatase activity of CNA. Fluorescence spectroscopy of an ANS-hydrophobic fluorescence probe shows that binding of Ca&sup2+; to CNB, DC or DN leads to expo-sure of the hydrophobic surface of the proteins and that the hydrophobicity of CNB is the greatest, that of DC is less, and that of DN is the least. The hydrophobic surface of CNB may be an important structural basis for stimulating CN phosphatase activity. [ABSTRACT FROM AUTHOR]

In this study, selenium nanoparticles (SeNPs) were synthesized and stabilized by reducing sodium selenite using ascorbic acid in an aqueous solution of sodium carboxymethylcellulose (Na‐CMC) with a degree of substitution of 0.97 and a degree of polymerization of 810. IR‐Fourier spectroscopy revealed that coordination bonds between functional groups in Na‐CMC and SeNPs resulted in the development of polymer‐metal complexes. UV–Vis spectroscopy, scanning electron microscopy (SEM), atomic force microscopy (AFM), and dynamic light scattering (DLS) methods were used to determine the SeNP sizes in the structure of the nanocomposite film. Investigation of the stabilization and nonstabilization of SeNPs over several cycles has shown that the effect of the polymer matrix of Na‐CMC on the stabilization of nanoparticles was achieved for 672 h, which was confirmed by the unchanged size distribution and resistance to change of the SeNPs synthesized in Na‐CMC solutions. [ABSTRACT FROM AUTHOR]

In this article, the authors discuss various articles on new photocatalytic nanomaterials used for the degradation of organic pollutes published in this issue of the periodical.

Single-walled carbon nanotubes functionalized with generation (n) 0−2 dendritic poly(amidoamine) (denoted as SWNTs-Gn-NH2, n= 0, 1, or 2) were used as filler in thermosetting epoxy to prepare anisotropic microscale diameter fibers by reactive spinning. Dendritic poly(amidoamine) (PAMAM) was “grafted from” acid-modified and toluene 2,4-diisocyanate-activated SWNTs by repeating amidation of terminal ester groups via ethylenediamine (EDA) and Michael addition of methyl acrylate (MA) to amino groups. Fourier transform infrared (FTIR) and hydrogen nuclear magnetic resonance (1H NMR) spectroscopy and thermogravimetric analysis (TGA) confirmed the successful grafting and generation buildup. Optical and scanning electron microscope (SEM) observations revealed that PAMAM-functionalized SWNTs dispersed in epoxy much more uniformly than pristine nanotubes. The dispersibility improved with increasing generation number. Microsized fibers made of epoxy reinforced with aligned SWNTs-G2-NH2by reactive spinning show high tensile strength and Young’s modulus per unit weight fraction (dσ/dWNTand dE/dWNT). The respective measures are 7022 MPa and 118.0 GPa, which is a high reinforcement efficacy in comparison to other fillers. The nanotube alignment and grafting of dendritic PAMAM play a crucial role in the enhancement of the tensile strength of these reinforced composite fibers. [ABSTRACT FROM AUTHOR]

A series of crystalline/ionic complexed block copolymers (BCPs) with various compositions have been prepared by sequential reactions. The BCPs with different hydrophilic fractions can self-assemble into various morphologies, such as spindlelike, rodlike, and spherical micelles with different crystallinity of the core. Bis(2-ethylhexyl) sulfosuccinate sodium salt (AOT) is added as a surfactant to induce the morphological transition of BCPs in aqueous media. The introduced AOT can be tightly bound to the cationic units, and a water-insoluble unit in the corona forms, leading to a reduced tethering density. Consequently, morphological variety changing from rods to platelets to fibril to dendrite-like micelles can be observed. [ABSTRACT FROM AUTHOR]

For many applications such as tele-operational robots and interactions with virtual environments, it is better to have performance with force feedback than without. Haptic devices are force reflecting interfaces. They can also track human hand positions simultaneously. A new 6 DOF (degree-of-freedom) haptic device was designed and calibrated in this study. It mainly contains a double parallel linkage, a rhombus linkage, a rotating mechanical structure and a grasping interface. Benefited from the unique design, it is a hybrid structure device with a large workspace and high output capability. Therefore, it is capable of multi-finger interactions. Moreover, with an adjustable base, operators can change different postures without interrupting haptic tasks. To investigate the performance regarding position tracking accuracy and static output forces, we conducted experiments on a three-dimensional electric sliding platform and a digital force gauge, respectively. Displacement errors and force errors are calculated and analyzed. To identify the capability and potential of the device, four application examples were programmed. [ABSTRACT FROM AUTHOR]

The Singapore grouper iridovirus (SGIV), a member of the genus Ranavirus, is a major viral pathogen that has caused heavy economic losses to the grouper aquaculture industry in China and Southeast Asia. No efficient method of controlling SGIV outbreaks is currently available. Systematic evolution of ligands by exponential enrichment (SELEX) is now widely used for the in vitro selection of artificial ssDNA or RNA ligands, known as aptamers, which bind to targets through their stable three-dimensional structures. In our current study, we generated ssDNA aptamers against the SGIV, and evaluated their ability to block SGIV infection in cultured fish cells and cultured fish in vivo. The anti-SGIV DNA aptamers, LMB-761, LMB-764, LMB-748, LMB-439, LMB-755, and LMB-767, were selected from a pool of oligonucleotides randomly generated using a SELEX iterative method. The analysis of the secondary structure of the aptamers revealed that they all formed similar stem-loop structures. Electrophoretic mobility shift assays showed that the aptamers bound SGIV specifically, as evidenced by a lack cross-reactivity with the soft shell turtle iridovirus. The aptamers produced no cytotoxic effects in cultured grouper spleen cells (GS). Assessment of cytopathic effects (CPE) and viral titer assays showed that LMB-761, LMB-764, LMB-748, LMB-755, and LMB-767 significantly inhibited SGIV infection in GS cells. The in vivo experiments showed that LMB-761 and LMB-764 reduced SGIV-related mortality, and no negative effects were observed in orange-spotted grouper, Epinephelus coioides, indicating that these DNA aptamers may be suitable antiviral candidates for controlling SGIV infections in fish reared in marine aquaculture facilities. [ABSTRACT FROM AUTHOR]

A simple sol-gel method was used to prepare magnetic Fe3O4/SiO2/TiO2 composites with core-shell structure. Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and transmission electron microscopy (TEM) have been applied to investigate the structure and morphology of the resultant composites. The obtained composites showed excellent magnetism and higher photodegradation ability than pure TiO2. The photocatalytic mechanism was also discussed. The magnetic composites should be extended to various potential applications, such as photodegradation, catalysis, separation, and purification processes. [ABSTRACT FROM AUTHOR]

Endocrinological action is generally thought to be a way for animals to respond to stress at low temperatures. To learn the role of hormones in ectotherms inhabiting alpine environments, we studied the effects of acute low temperature exposure on the endocrinological reactions of Qinghai toad-headed lizards in the Qinghai-Tibetan Plateau. We monitored plasma corticosterone and insulin concentration of the lizards under five low temperature treatments. We found no significant difference in plasma corticosterone or insulin in lizards among our five different treatments. For males and females the correlation between plasma corticosterone and insulin concentrations was not significant. In contrast to other studies on reptiles at low altitude, we suggest that due to the alpine environment (low temperature and low oxygen concentration) they inhabit, Qinghai toad-headed lizards respond to experimental cold stress slightly to mobilize energy and live their vivid life. In addition, corticosterone and insulin of Qinghai toad-headed lizards are secreted independently along with low temperature treatments. [ABSTRACT FROM AUTHOR]

Silver nanowires were prepared by polyol process and doped to the system containing conventional micro-scaled sphere or flake silver particles. It is found that the conductance of doped system is much better than the undoped system with the same quantity silver. A plausible mechanism is described as that these nanowires are favor to act as bridges to establish perfect linkage among particles, and the chance of contact and contact area become more than the cases without wires. This development will be meaningful for the preparation of advanced electrically conductive adhesive (ECA) with high conductivity and good adhesive strength. [ABSTRACT FROM AUTHOR]

In this paper, we synthesized epoxy resin/CaCO 3 nanocomposites through in-situ and inclusion polymerization, and the nanoparticles were well dispersed in the resin matrix observed by SEM. The effects of the nanoparticles on the properties of epoxy resin are discussed. [ABSTRACT FROM AUTHOR]

A novel polymer of poly(diglycidyl maleate-co-stearyl methacrylate) (P(DGMA-co-SMA)) was synthesized by reaction between poly(maleic anhydride-co-stearyl methacrylate) (P(MA-co-SMA)) and epichlorohydrin. The self-assembly behavior of the resultant copolymer was investigated. It was found that the spheral aggregates could converse to nanorods after being aged for 2.5 days and nanolines composed of the nanorods were obtained after being aged for an additional 5.5 days. The mechanism of their self-assembly behavior and morphology conversion of self-assembly systems is discussed. [ABSTRACT FROM AUTHOR]