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Oligonucleotide DNA aptamers represent an emergently important class of binding entities towards as different analytes as small molecules or even whole cells. Without the canonical isolation of individual aptamers following the SELEX process already the focused polyclonal libraries prepared by this in vitro evolution and selection can directly be used to label their dedicated analytes and to serve as binding molecules on surfaces. Here we report the first instance of a sensor able to discriminate between loaded and unloaded retinol binding protein 4 (RBP4), an important biomarker for the prediction of diabetes and kidney disease. The sensor relies purely on two aptamer libraries tuned such, that they discriminate between the protein isoforms, requiring no further sample labelling to detect RBP4 in both state. The evolution, binding properties of the libraries and the functionalization of graphene FET sensor chips are presented as well as the functionality of the resulting biosensor.

Based on their unique properties, oligonucleotide aptamers have been named a gift of biological chemistry to life science. We report the development of DNA aptamers as the first high-affinity binding molecules available for fast and rapid labeling of the human gut bacterium Akkermansia muciniphila with a certain impact on Alzheimer´s disease. Fast and reliable analyses of the composition of microbiomes is an emerging field in microbiology. We describe the molecular evolution and biochemical characterization of a specific aptamer library by a FluCell-SELEX and the characterization of specific molecules from the library by bioinformatics. The aptamer AKK13.1 exerted universal applicability in different analysis techniques in modern microbiology, including fluorimetry, confocal laser scanning microscopy and flow cytometry. It was also functional as a specific binding entity hybridized to anchor primers chemically coupled via acrydite-modification to the surface of a polyacrylamide-hydrogel, which can be prototypically used for the construction of affinity surfaces in sensor chips. Together, the performance and methodological flexibility of the aptamers presented here may open new routes not only to develop novel Akkermansia-specific assays for clinical microbiology and the analyses of human stool samples but may also be an excellent starting point for the construction of novel electronic biosensors., publishedVersion

© 2020 John Wiley & Sons, Ltd. The use of herbal medicines dates back a long way in history. Herbal medicines have been widely used all over the world since ancient times and have been recognized by physicians and patients for their good therapeutic value as they have fewer adverse effects than modern medicines. Recently, researchers have used gold nanoparticles synthesized by plants in the prevention, control, and treatment of infectious disorders and cutaneous wounds. The aims of this study were to synthesize gold nanoparticles from aqueous extract of Allium saralicum R.M. Fritsch (AuNPs) and assess their therapeutic capacities. The nanoparticles were characterized by UV–visible spectroscopy (UV–Vis), Fourier-transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). FT-IR results offered polysaccharides and protein in A. saralicum were the sources of reducing power, reducing gold ions to AuNPs. According to XRD analysis, the crystal size of the nanoparticles was 41.6 nm. TEM and FE-SEM images exhibited average diameters of 45 nm for the biosynthesized nanoparticles. The synthesized AuNPs had great cell viability on HUVECs line and showed this method was nontoxic. The 2,2-diphenyl-1-picrylhydrazyl free radical scavenging test indicated similar antioxidant potentials for A. saralicum, AuNPs, and butylated hydroxytoluene. To determine the antifungal and antibacterial properties of HAuCl4, A. saralicum, and AuNPs, agar diffusion tests were used. The aim of the application both HAuCl4 and A. saralicum in microbial tests was to investigate the synergism effects between them. The minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and minimum fungicidal concentration (MFC) were specified by macro-broth dilution assay. AuNPs exhibited higher antifungal and antibacterial effects than all standard antibiotics (p ≤ 0.01). The MIC and MBC of AuNPs against all bacteria were in the ranges 1–4 mg/ml and 2–8 mg/ml, respectively. The MIC and MFC of AuNPs against all fungi were in the ranges 1–4 mg/ml and 2–4 mg/ml, respectively. In vivo part, AuNPs ointment group raised significantly (p ≤ 0.01) the wound contracture, vessel, hydroxyl proline, hexuronic acid, fibrocyte, fibroblast, and fibrocytes/fibroblast rate and decreased significantly (p ≤ 0.01) the wound area, total cells, and lymphocyte compared to other groups in rats. The results of FT-IR, UV–Vis, XRD, TEM, and FE-SEM analyses confirm that the aqueous extract of A. saralicum leaves can be used to yield gold nanoparticles with a notable amount of remedial effects without any cytotoxicity against HUVECs.

Three-dimensional/two-dimensional (3D/2D) rare earth Ln3+ (Ln = Er or Eu)-doped BiOBr wrapped with reduced graphene oxide (Bi-Ln/rGO) was obtained via a two-step solvothermal–hydrothermal process. The doping of Ln3+ and the construction of heterojunction between 3D Ln3+-doped BiOBr microspheres and 2D rGO nanosheets were beneficial to the wide absorption of visible light and the efficient separation of photoinduced electrons and holes, further improving the photocatalytic activity of Bi-Ln/rGO composites for RhB photodegradation. The photocatalytic activity of Bi-Ln/rGO was higher than those of pure BiOBr, Ln3+-doped BiOBr, and BiOBr/rGO. The radical-trapping experiments on active species indicated that h+ and ·O2− were mainly responsible for the photodegradation of RhB. The mechanism of the enhanced photocatalytic performance was proposed on the basis of radical-trapping experiments on active species.

Background Hypoxia adaptation is developed in many fish species, which helped them to habitat most of water bodies. However, fishes living under high oxygen concentration may lose this feature. Rapid flows provide high level and stable dissolved oxygen, which facilitate organism’s oxygen supply and energy production. Previous studies showed that fish species from rapid-flow habitats exhibited lower hypoxia tolerance compared with fish from intermediate- and slow-flow habitats. Mitochondrial genomes code 13 key components in oxidative phosphorylation pathway; these genes may be under relaxed selection in rapid-flow species. Objectives The primary objectives of this study is to investigate the evolutionary patterns of the 13 mitochondrial OXPHOS genes among nine cyprinids from different water bodies and to test the hypotheses that mitochondrial OXPHOS genes may experience relaxed selection in rapid-flow habitats. Methods We classified nine cyprinid fish species into three groups based on their habitats: rapid-flow, intermediate-flow and slow-flow. To detect relaxed selections, we investigated the 13 protein-coding genes with codon evolution programs RELAX; to estimate evolutionary rates among the cyprinids, free-ratio model in Codeml program was applied; Branch-site models were applied to detect positive selection sites. The polymorphisms of homologous sites were evaluated with PROVEAN program and projected to 3D structure prediction of the proteins using SWISS-MODEL. Results We found that nine out of the 13 genes are under relaxed selection in rapid-flow species. Furthermore, dN, dS and dN/dS are relatively increased when compared with those of intermediate-flow species. More amino acid polymorphic sites are presented in rapid-flow species than in intermediate- and slow-flow species. Furthermore, rapid-flow species had more deleterious substitutions than other groups. 3D structure prediction of these proteins and projection of the polymorphic sites indicated that these sites were randomly distributed, suggesting relaxed functional constraints of these proteins in rapid-flow species. Conclusion Our results suggest that mitochondrial genes are under relaxed selection in rapid-flow cyprinids.

Platelet-derived growth factors (PDGFs) are important biochemical mediators regulating many physiological and pathophysiological processes, including promotion of the chemotactic recruitment and proliferation of cells involved in wound repair. Previously, homodimers of rhPDGF-AA protein were purified from Escherichia coli. However, eukaryotic proteins often contain posttranslational modifications, such as glycosylation, that are required for biological functions. In this study, an efficient method was established to purify a glycosylated rhPDGF-AA dimer from P. pastoris culture media by one step CM Sepharose ion exchange chromatography yielding about 20mg/L of over 95% highly purified rhPDGF-AA. Mass spectrometry analysis of the purified rhPDGF-AA displayed a molecular weight (MW) of 27,825.513Da, composed of a subunit with MW of 15,042.945Da and a subunit with MW of 12,904.374Da. The size difference is accounted for by differential glycosylation of the monomers. Biological activity of the rhPDGF-AA was confirmed by its ability to induce NIH/3T3 cells proliferation. The experimental procedure we have developed facilitates production of an active glycosylated rhPDGF-AA in large amounts for further research and drug development.

In this communication, the morphology of double branched anodic aluminum oxide (AAO) templates from linear down or step down function of anodizing voltage is discussed. The interconnected AAO film is obtained when the thin pore wall at the final branched channels is dissolved by chemical etching. The three-dimensional interconnected porous carbons are fabricated by carbonization of polyimide film which is negative replicated from the layered interconnected AAO template. Keywords: Anodic aluminum oxide, Branch, Interconnected, Carbon

In this letter, we demonstrated the growth of different morphologies of silver submicrostructures influenced by o-phenylenediamine (oPD) concentrations and pH values. The results indicated that concentration ratios of the oPD to Ag+ colloids in the solution determine the final morphology of the products. oPD is found to act as a stabilizer as well as reduction agent. Particle shape ranges from sheets to spheres, increasing with molar ratio. Meanwhile, morphologies of structures and the time consumption to form particles both depend on pH values. We could obtain plates, polyhedrons, spheres, and dendrites through adjusting pH from 1.3 to 12.3. A mechanism is proposed to interpret the controlled synthesis of silver submicrostructures.

A biocatalytic route for the synthesis of a water soluble and conducting complex of polyaniline (PANI)/sodium dodecylsulfate (SDS) is presented. Hemoglobin is used in SDS anion surfactant. The polymerization proceeded quickly to result in a homogeneous emeraldine-colored dispersion of PANI. Absorption spectra of PANI/SDS in the aqueous dispersions at various pH values confirms that the reversibility of dedoping and redoping process of PANI/SDS and shows that the transition from emeraldine salt to emeraldine base form occurred at about pH 10.0–11.0 in this anionic micellar system. PANI/SDS in the organic solutions dedoped initially and redoped after 24 h.

The expansion of low heat Portland slag cement with slight expansion (LSE cement) was studied by XRD, SEM and test methods for strength and expansion. Results indicated that under the condition of 4.5–5.0% MgO in clinker and 2.8–3.4% SO 3 in cement, ettringite expansion and brucite expansion produced by periclase hydration in the paste had continuity, entirety and stability. Periclase hydration in the paste started at about 60 days and was completed up to 2000 days and ettringite was stable from 3 to 2000 days. At the ages of 28, 90, 365, 730 and 2000 days the expansion of the paste reached 0.08–0.13%, 0.09–0.14%, 0.12–0.17%, 0.13–0.18% and 0.15–0.21%, respectively. At the ages of 2, 28 and 180 days the autogenous volume deformation of mass concrete made out of LSE cement was positive and was 0.0042%, 0.0050% and 0.0066%, respectively and the prestress of the concrete with 2.0% steel bar content was 0.069, 0.060 and 0.082 MPa, respectively. The results suggest that using this cement in mass concrete may compensate for a part of its thermal shrinkage and autogenous shrinkage.

Pure and Ti-doped WO3 thin films prepared by RF (radio-frequency) magnetron at room temperature were determined by XRD, Raman and SEM to analyze the micro-structure and the morphology of the films. In addition, electrochemical workstation and UN-Vis-NIR spectrophotometer were used to measure their cycling stability and optical property. Research results showed that Ti doping had little interference with the surface morphology and optical constants, but the film crystallization temperature could be increased by Ti doping. Electrochemical test results showed that Ti doping could improve reversibility of ion injection and extraction, and improve cycling performance of films. Meanwhile, the switching speed and optical modulation performance of films were enhanced. In detail, the switching time of colored and bleached states were shortened from 9.8 s and 3.5 s to 8.4 s and 2.7 s, respectively. Therefore, Ti doped WO3 thin films has better electrochromic properties.

Novel anodic aluminium oxide (AAO) films and hollow nanostructures were synthesized via a simple electrochemical and chemical etching route; fluctuating nanotube growth inside AAO film fabricated under ultra-high voltage was considered to be the main reason for the formation of such new structures.

The intrinsic mechanisms of aluminium anodization processes have been investigated in detail by analyzing the anodization current density (ia). The characteristics and general chemical reactions of mild anodization (MA) and hard anodization (HA) have been discussed, and the avalanche of the electronic current is considered to be the main reason to trigger the HA process. Moreover, the formation mechanisms of the maximum anodization voltage (Umax) in different electrolytes have been studied in detail, and it is found that the electrolyte dissociation constant can have a direct impact on the avalanche electronic current density (ie) and Umax. Based on the above arguments, the electrolyte modifying process has been investigated. In addition, the representative microstructural morphologies of anodic aluminium oxides (AAO) together with their intrinsic formation mechanisms have also been studied.

Nanoporous anodic aluminium oxide (AAO) films with a large-range tunable interpore distance (Dint) and unique microstructures have been fabricated by high voltage anodization (140–400 V) in 0.3 M oxalic acid electrolyte. The influences of anodization conditions (e.g., anodization voltage (Ua) and current density (ia)) on the microstructures of AAO films have been investigated in detail. Experimental results show that there is a linear relationship between Ua and Dint under relatively low Ua. With the increase of Ua, the influences of ia and dehydration of aluminium hydroxide on the Dint may not be ignored, thus resulting in a nonlinear relationship between Ua and Dint. When the anodization is performed at an excessively high Ua of 400 V, an interesting competitive growth of nanochannels inside the AAO film tends to occur, thus forming an AAO film with unique nano/micro morphology at the barrier layer side.

By adjusting the anodization voltage periodically in the process of electrochemical oxidation of aluminum and subsequent chemical etching, anodic aluminum oxide membranes with a dual periodic layer-by-layer structure are prepared. Optical transmission spectra analyses prove that the dip position is dependent on the thickness of the layer and can be easily adjusted by the anodization voltage according to the Bragg–Snell formula. This result implies that the position and width of the stop band and the pass band in the visible and near infrared wavelength region can be designed and prepared arbitrarily. It is expected that these kinds of anodic aluminum oxide membranes may find applications in the fabrication of various optical devices.

A novel model, which indicates that the growth of branched channels in anodic alumina oxide membranes is different from what has been reported before, has been established in this communication.

The amorphous carbon nitride films were prepared by dc magnetron sputtering first and then were heat－treated at high temperature.DTA XRD Auger spectroscopy wer e used to study the difference of composition structure before and after heat－t reatment.The results showed that crystallization occurred at 1186℃.Heat－treatm ent can induce the crystallization of carbon nitride and the diffraction peaks a ppeared in the XRD pattern.The results of Auger spectroscopy also showed that th ere existed SiCN－riched area and the content of N decreased.