Electrochemical Impedimetric Platform Based on Con A@MIL-101 for Glycoprotein Detection.

An electrochemical impedimetric biosensing platform with lectin as a molecular recognition element has been established for the sensitive detection of glycoproteins, a class of important biomarkers in clinical diagnosis. One of the representative metal-organic framework materials, MIL-101(Cr)-NH2, was utilized as the supporting matrix, and its amino groups served as the anchors to immobilize the lectins of concanavalin A (Con A), constituting Con A@MIL-101(Cr)-NH2 for the determination of invertase (INV) as a model glycoprotein. The Con A concentration, immobilization time, and incubation time with INV were optimized. Under the optimal conditions, the degree of impedance increase was linearly proportional to the logarithm of INV concentration between 1.0 × 10-16 and 1.0 × 10-11 M, affording a limit of detection as low as 3.98 × 10-18 M. Good specificity, stability, reproducibility, and repeatability were demonstrated for the fabricated biosensing platform. Moreover, real mouse serum samples were spiked with different concentrations of INV. Excellent recoveries were obtained, which demonstrated the biosensing platform's capability of analyzing glycoproteins within a complex matrix.

Functional Interface for Glycoprotein Sensing: Focusing on Biosensors.

Glycosylated proteins or glycoproteins make up a large family of glycoconjugates, and they participate in a variety of fundamental biological events. Glycoproteins have become important biomarkers in the diagnosis and treatment of a number of tumors. Biosensors are quite suitable for glycoprotein detection. The design and fabrication of a functional sensing interface play a crucial role in the biosensor construction to target glycoproteins. The functional interface, particularly receptors, typically determines the key characteristics of a biosensor, such as selectivity and sensitivity. Antibody, peptide, aptamer, boronic acid derivative, lectin, and molecularly imprinted polymer are all capable receptors for glycoprotein recognition, and each of these will be discussed. Most glycoproteins exist in low abundance, thus rendering signal amplification techniques indispensable. Nucleic acid-mediated and nanomaterial-mediated signal amplification for the detection of glycoproteins will be focused on herein. This review aims to highlight these different functional interfaces for glycoprotein sensing.

Two-dimensional transmissive structural colors for high-security information encryption.

Structural colors produced from nanostructures have attracted much attention due to their promising advantages of long-term stability and high resolution. Many nanostructures like metasurfaces have been demonstrated to generate color information in the transmission or reflection mode. Here, a strategy of combining polarization-insensitive and polarization-sensitive transmissive structural color is proposed to realize convenient and diverse encrypted pattern designs. A two-dimensional metasurface, whose polarization characteristics are determined by the size of a nanobrick unit, is embedded inside an optical cavity to produce transmissive structural color. The polarization-insensitive transmissive structural color exhibits a wide color gamut and high excitation purity in all polarization states, while the polarization-sensitive transmissive structural color maintains the similar color appearance in x-direction polarization but appears nearly black in y-direction polarization. Combining these two transmissive structural colors can achieve diverse images designed at different polarizations instead of simply hiding the image in a specific polarization state. An image of "flower and flowerpot" using the generated colors is visually illustrated, which shows that the proposed transmissive structural colors would have great potential in the areas of security information encryption.

Superelastic oxide micropillars enabled by surface tension-modulated 90° domain switching with excellent fatigue resistance.

Superelastic materials capable of recovering large nonlinear strains are ideal for a variety of applications in morphing structures, reconfigurable systems, and robots. However, making oxide materials superelastic has been a long-standing challenge due to their intrinsic brittleness. Here, we fabricate ferroelectric BaTiO3 (BTO) micropillars that not only are superelastic but also possess excellent fatigue resistance, lasting over 1 million cycles without accumulating residual strains or noticeable variation in stress-strain curves. Phase field simulations reveal that the large recoverable strains of BTO micropillars arise from surface tension-modulated 90° domain switching and thus are size dependent, while the small energy barrier and ultralow energy dissipation are responsible for their unprecedented cyclic stability among superelastic materials. This work demonstrates a general strategy to realize superelastic and fatigue-resistant domain switching in ferroelectric oxides for many potential applications.

Highly Flexible Freestanding BaTiO3 -CoFe2 O4 Heteroepitaxial Nanostructure Self-Assembled with Room-Temperature Multiferroicity.

Multiferroics with simultaneous electric and magnetic orderings are highly desirable for sensing, actuation, data storage, and bio-inspired systems, yet developing flexible materials with robust multiferroic properties at room temperature is a long-term challenge. Utilizing water-soluble Sr3 Al2 O6 as a sacrificial layer, the authors have successfully self-assembled a freestanding BaTiO3 -CoFe2 O4 heteroepitaxial nanostructure via pulse laser deposition, and confirmed its epitaxial growth in both out-of-plane and in-plane directions, with highly ordered CoFe2 O4 nanopillars embedded in a single crystalline BaTiO3 matrix free of substrate constraint. The freestanding nanostructure enjoys super flexibility and mechanical integrity, not only capable of spontaneously curving into a roll, but can also be bent with a radius as small as 4.23 µm. Moreover, piezoelectricity and ferromagnetism are demonstrated at both microscopic and macroscopic scales, confirming its robust multiferroicity at room temperature. This work establishes an effective route for flexible multiferroic materials, which have the potential for various practical applications.

Dynamics of Polar Skyrmion Bubbles under Electric Fields.

Room-temperature polar skyrmions, which have been recently discovered in oxide superlattice, have received considerable attention for their potential applications in nanoelectronics owing to their nanometer size, emergent chirality, and negative capacitance. For practical applications, their manipulation using external stimuli is a prerequisite. Herein, we study the dynamics of individual polar skyrmions at the nanoscale via in situ scanning transmission electron microscopy. By monitoring the electric-field-driven creation, annihilation, shrinkage, and expansion of topological structures in real space, we demonstrate the reversible transformation among skyrmion bubbles, elongated skyrmions, and monodomains. The underlying mechanism and interactions are discussed in conjunction with phase-field simulations. The electrical manipulation of nanoscale polar skyrmions allows the tuning of their dielectric permittivity at the atomic scale, and the detailed knowledge of their phase transition behaviors provides fundamentals for their applications in nanoelectronics.

Binary organic-inorganic nanocomposite of polyaniline-MnO2 for non-enzymatic electrochemical detection of environmental pollutant nitrite.

Due to wide usage as nitrogen fertilizer in agriculture and food additive in industry, nitrite, as one of inorganic environmental pollutants, could cause detrimental effects to the ecological environment. Therefore, accurate, sensitive and rapid detection of nitrite is necessary. In this work, binary hybrid polyaniline-MnO2 organic-inorganic nanocomposite is prepared chemically and characterized via X-ray diffraction spectroscopy, Fourier-transform infrared spectroscopy, scanning electron microscopy and energy-dispersive X-ray spectroscopy. Polyaniline-MnO2 organic-inorganic nanocomposite serves as excellent electrode modifier for electrochemical sensing of nitrite by two modes of cyclic voltammetry and chronoamperometry, achieving broad linear ranges and low limits of detection for both methods. Moreover, the organic-inorganic nanocomposite displays satisfactory sensing performance in real water sample analysis. Amine and imino groups of polyaniline contribute to the better adsorption behavior of nitrite onto the nanocomposite, which improves the nanocomposite's sensing performance. In summary, the synergistic effects between polyaniline and MnO2 is taken advantaged in the nanocomposite for effective electrochemical sensor development.

Thermal imprint of wide-angle viewing bi-stable cholesteric liquid crystal displays.

A thermal-imprint addressable and electrically erasable bi-stable cholesteric liquid crystal (CLC) display with a wide viewing angle is demonstrated. The proposed device with a multi-domain planar state is realized by filling a negative CLC in a vertical-alignment cell. The thermal-imprint method is introduced to restore the CLC from a reflective state (multi-domain planar state) to a translucent state (focal-conic state) to display images, and an electric field is used to erase the device back to totally reflective mode. This CLC display is bi-stable and does not require a complex driving circuit. Together with the features of a large viewing angle and less color shift, this device shows great potential for update-on-demand applications.

Rearranged Diels-Alder Adducts and Prenylated Flavonoids as Potential PTP1B Inhibitors from Morus nigra.

Two novel rearranged Diels-Alder adducts, morunigrines A (1) and B (2), and four new prenylated flavonoids, morunigrols A-D (3-6), were isolated from the twigs of Morus nigra, together with four known prenylated phenolic compounds, including two flavonoids (7 and 8) and two 2-arylbenzofurans (9 and 10). Morunigrines A (1) and B (2) are a novel class of Diels-Alder adducts with unprecedented carbon skeletons featuring a rearranged chalcone-stilbene/2-arylbenzofuran core decorated with a unique methylbiphenyl moiety. The structures of the new compounds were assigned by analysis of spectroscopic data. The absolute configuration of compound 6 was determined by the measurement of specific rotation. A plausible biogenetic pathway for 1 and 2 is also proposed. Compounds 1 and 2 exhibited more potent protein tyrosine phosphatase 1B inhibitory activity with IC50 values of 1.8 ± 0.2 and 1.3 ± 0.3 µM, respectively, than that of the positive control oleanolic acid (IC50, 2.5 ± 0.1 µM).

Glycosylated Conductive Polymer: A Multimodal Biointerface for Studying Carbohydrate-Protein Interactions.

Carbohydrate-protein interactions occur through glycoproteins, glycolipids, or polysaccharides displayed on the cell surface with lectins. However, studying these interactions is challenging because of the complexity and heterogeneity of the cell surface, the inherent structural complexity of carbohydrates, and the typically weak affinities of the binding reactions between the lectins and monovalent carbohydrates. The lack of chromophores and fluorophores in carbohydrate structures often drives such investigations toward fluorescence labeling techniques, which usually require tedious and complex synthetic work to conjugate fluorescent tags with additional risk of altering the reaction dynamics. Probing these interactions directly on the cell surface is even more difficult since cells could be too fragile for labeling or labile dynamics could be affected by the labeled molecules that may interfere with the cellular activities, resulting in unwanted cell responses. In contrast, label-free biosensors allow real-time monitoring of carbohydrate-protein interactions in their natural states. A prerequisite, though, for this strategy to work is to mimic the coding information on potential interactions of cell surfaces onto different biosensing platforms, while the complementary binding process can be transduced into a useful signal noninvasively. Through carbohydrate self-assembled monolayers and glycopolymer scaffolds, the multivalency of the naturally existing simple and complex carbohydrates can be mimicked and exploited with label-free readouts (e.g., optical, acoustic, mechanical, electrochemical, and electrical sensors), yet such inquiries reflect only limited aspects of complicated biointeraction processes due to the unimodal transduction. In this Account, we illustrate that functionalized glycosylated conductive polymer scaffolds are the ideal multimodal biointerfaces that not only simplify the immobilization process for surface fabrication via electrochemical polymerization but also enable the simultaneous analysis of the binding events with orthogonal electrical, optical, or mass sensing label-free readouts. We established this approach using polyaniline and polythiophene as examples. Two general methods were demonstrated for glycosylated polymer fabrications (i.e., electropolymerization of monomer bearing α-mannoside residues or click chemistry based mannose conjugation to electrochemically preformed quinone fused polymer with potential to introduce different carbohydrate moieties and construct glycan arrays in a similar manner). Their conjugated π system extending over a large number of recurrent monomer units renders them sensitive optoelectronic materials. The carbohydrate-protein interactions on the side chain could disrupt the electrostatic, H-bonding, steric, or van der Waals interactions within or between polymers, leading to a change of conductivity or optical absorption of the conductive polymers. This will allow concurrent interrogation of these interactions with adjoining biological processes and mechanisms in multimodal fashion. Furthermore, the functionalized glycosylated conductive polymers can be designed and synthesized with controlled oxidation states, desired ionic dopants, and the imperative density and orientation of the sugar ligands that enable the assessment of differential receptor binding profiles of carbohydrate-protein interactions with much more detailed information and high accuracy. Finally, the glycosylated biosensing interfaces were successfully validated for their applications in Gram-negative bacterial detection, antibiotic resistance studies, and antimicrobial susceptibility assays, all based on inferring carbohydrate-protein interactions directly on cell surfaces, thus illustrating their potential uses in infectious disease research, clinical diagnostics, and environmental monitoring of harmful pathogens.

Investigation into the ring-substituted polyanilines and their application for the detection and adsorption of sulfur dioxide.

It has been demonstrated in this study that the substituents on the monomer aniline benzene ring are able to introduce the significant differences to the resulting polyaniline's collective properties. We systematically evaluated the structural perturbation effects of two substituents (methyl and methoxy) of aniline monomer through the electrochemical method. Our results showed that the methoxy group induces the less structural perturbation than the methyl counterpart, because of its partial double bond restriction. The morphologies are different for the polyaniline and the ring-substituted polyanilines, in which substituted polyanilines feature the larger porosities with the addition of these side groups. The influential effects of the methoxy side group have been further illustrated and amplified by its superior sensing performance towards the environmentally-significant sulfur dioxide gas, evaluated through the construction of the quartz crystal microbalance (QCM)-based gas sensor with these polyaniline materials. The as-constructed gas sensor's sensitivity, selectivity and stability in terms of its SO2 responses have been evaluated in details. The methoxy-substituted polyaniline was tested to show the unique gas sensing properties for the sulfur dioxide at the low concentrations (50-250 ppm) and function as the adsorbing material at the high concentrations (500-1250 ppm). Thus it can be used both as sensing material as well as a novel filter and/or storage reservoir for the removal of sulfur dioxide pollutant from the environments.

Extracting the time domain Green's function from ocean ambient noise using acoustic vector sensors.

A function that closely resembles the two-point time-domain Green's function (TDGF) representing the time delays associated with multipath between the two sensors can be recovered by correlating the noise field measured by two sensors. Here, a technique for extracting the TDGF from ambient ocean noise using acoustic vector sensors is presented. Experimental results suggest that the averaging time to extract TDGF is greatly reduced if sound pressure sensors (hydrophones) are replaced by acoustic vector sensors. The direct arrival and bottom bounce arrival were extracted successfully with only 1 min of vertical velocity data, while the bottom bounce arrival was not extracted with even 10 min of sound pressure data.

Simultaneous Detection of Static and Dynamic Signals by a Flexible Sensor Based on 3D Graphene.

A flexible acoustic pressure sensor was developed based on the change in electrical resistance of three-dimensional (3D) graphene change under the acoustic waves action. The sensor was constructed by 3D graphene foam (GF) wrapped in flexible polydimethylsiloxane (PDMS). Tuning forks and human physiological tests indicated that the acoustic pressure sensor can sensitively detect the deformation and the acoustic pressure in real time. The results are of significance to the development of graphene-based applications in the field of health monitoring, in vitro diagnostics, advanced therapies, and transient pressure detection.

In-line polarization rotator based on the quantum-optical analogy.

An in-line polarization rotator (PR) is proposed based on the quantum-optical analogy (QOA). The proposed PR possesses an auxiliary E7 liquid crystal (LC) waveguide in the vicinity of the single-mode fiber (SMF) core. Because of the matched core size, the PR demonstrates good compatibility with the established backbone networks which are composed of conventional SMFs. With optimized parameters for the auxiliary waveguide, the PR offers a near 100% polarization conversion efficiency at the 1550 nm band with a bandwidth of ∼30 nm, a length of ∼4625.9 µm with a large tolerance of ∼550 µm, and a tolerance of the input light polarization angle and rotation angle of the E7 LC of ∼π/30 and ∼π/36 rad, respectively. The performance was verified by the full-vector finite-element method. The proposed PR can be easily fabricated based on the existing photonics crystal fiber manufacturing process, making it a potentially inexpensive device for applications in modern communication systems. Moreover, the QOA, compared with the previous supermode-theory design method, allows a designer to consider several waveguides separately. Therefore, various unique characteristics can be met simultaneously which is consistent with the trend of modern fiber design.

Nanoscale characterization of 1D Sn-3.5Ag nanosolders and their application into nanowelding at the nanoscale.

One-dimensional Sn-3.5Ag alloy nanosolders have been successfully fabricated by a dc electrodeposition technique into nanoporous templates, and their soldering quality has been demonstrated in nanoscale electrical welding for the first time, which indicates that they can easily form remarkably reliable conductive joints. The electrical measurement shows that individual 1D Sn-3.5Ag nanosolders have a resistivity of 28.9 µΩ·cm. The morphology, crystal structure and chemistry of these nanosolders have been characterized at the nanoscale. It is found that individual 1D Sn-3.5Ag alloy nanosolders have a continuous morphology and smooth surface. XPS confirms the presence of tin and silver with a mass ratio of 96.54:3.46, and EDX elemental mappings clearly reveal that the Sn and Ag elements have a uniform distribution. Coveragent beam electron diffractions verify that the crystal phases of individual 1D Sn-3.5Ag alloy nanosolders consist of matrix ß-Sn and the intermetallic compound Ag3Sn. The reflow experiments reveal that the eutectic composition of the 1D Sn-Ag alloy nanowire is shifted to the Sn rich corner. This work may contribute one of the most important tin-based alloy nanosolders for future nanoscale welding techniques, which are believed to have broad applications in nanotechnology and the future nano-industry.

Ultrahigh Energy Storage Performance of BiFeO3-BaTiO3 Flexible Film Capacitor with High-Temperature Stability via Defect Design.

Nanoengineering polar oxide films have attracted great attention in energy storage due to their high energy density. However, most of them are deposited on thick and rigid substrates, which is not conducive to the integration of capacitors and applications in flexible electronics. Here, an alternative strategy using van der Waals epitaxial oxide dielectrics on ultra-thin flexible mica substrates is developed and increased the disorder within the system through high laser flux. The introduction of defects can efficiently weaken or destroy the long-range ferroelectric ordering, ultimately leading to the emergence of a large numbers of weak-coupling regions. Such polarization configuration ensures fast polarization response and significantly improves energy storage characteristics. A flexible BiFeO3-BaTiO3 (BF-BT) capacitor exhibits a total energy density of 43.5 J cm-3 and an efficiency of 66.7% and maintains good energy storage performance over a wide temperature range (20-200 °C) and under large bending deformation (bending radii ≈ 2 mm). This study provides a feasible approach to improve the energy storage characteristics of dielectric oxide films and paves the way for their practical application in high-energy density capacitors.

Antibiotic prophylaxis for surgical wound infections in clean and clean-contaminated surgery: an updated systematic review and meta-analysis.

BACKGROUND: The efficacy and necessity of prophylactic antibiotics in clean and clean-contaminated surgery remains controversial. METHODS: The studies were screened and extracted using databases including PubMed, Embase, Cochrane Library, Web of Science, and Clinical Trials.gov according to predefined eligibility criteria. Randomized controlled trials (RCTs) comparing the effect of preoperative and postoperative prophylactic antibiotic use on the incidence of surgical site infections (SSIs) in patients undergoing any clean or clean-contaminated surgery. RESULTS: A total of 16,189 participants in 48 RCTs were included in the primary meta-analysis following the eligibility criteria. The pooled odds ratio (OR) for SSI with antibiotic prophylaxis versus placebo was 0.60 (95% CI: 0.53-0.68). The pooled OR among gastrointestinal, oncology, orthopedics, neurosurgery, oral, and urology surgery was 3.06 (95% CI: 1.05-8.91), 1.16 (95% CI: 0.89-1.50), 2.04 (95% CI: 1.09-3.81), 3.05 (95% CI: 1.25-7.47), 3.55 (95% CI: 1.78-7.06), and 2.26 (95% CI: 1.12-4.55), respectively. Furthermore, the summary mean difference (MD) for patients' length of hospitalization was -0.91 (95% CI: -1.61, -0.16). The results of sensitivity analyses for all combined effect sizes showed good stability. CONCLUSION: Antibiotics are both effective, safe, and necessary in preventing surgical wound infections in clean and clean-contaminated procedures, attributed to their reduction in the incidence of surgical site infections as well as the length of patient hospitalization.

Spatial evolution of the proton-coupled Mott transition in correlated oxides for neuromorphic computing.

The proton-electron coupling effect induces rich spectrums of electronic states in correlated oxides, opening tempting opportunities for exploring novel devices with multifunctions. Here, via modest Pt-aided hydrogen spillover at room temperature, amounts of protons are introduced into SmNiO3-based devices. In situ structural characterizations together with first-principles calculation reveal that the local Mott transition is reversibly driven by migration and redistribution of the predoped protons. The accompanying giant resistance change results in excellent memristive behaviors under ultralow electric fields. Hierarchical tree-like memory states, an instinct displayed in bio-synapses, are further realized in the devices by spatially varying the proton concentration with electric pulses, showing great promise in artificial neural networks for solving intricate problems. Our research demonstrates the direct and effective control of proton evolution using extremely low electric field, offering an alternative pathway for modifying the functionalities of correlated oxides and constructing low-power consumption intelligent devices and neural network circuits.

[Epidemiological status and risk factors of hyperuricemia in rural area of the Three Gorges].

OBJECTIVE: To explore the epidemiological status and risk factors of hyperuricemia in rural area of the Three Gorges. METHODS: A cross-sectional survey was carried out in rural area of Yiling District, Yichang City, which was located north-west bank of Xiling Gorge in 2007. A standard structure questionnaire was used to collect demographic data, social-economic status and life-style features. Fasting venous blood was collected and serum uric acid (SUA) was determined. Hyperuricemia was defined as SUA levels ≥ 417 µ mol/L (70 mg/L) in men and ≥ 357 µmol/L (60 mg/L) in women. Multiple logistic regression analysis was used to analysed the risk factors of hyperuricemia. RESULTS: A total of 9354 participants aged 35 and above were included, 19.9% (1866/9354) participants were the Three Gorges migrants. Serum uric acid level in men was significantly higher than that in women [(285.1 ± 80.2) µmol/L vs. (210.3 ± 65.0) µmol/L,P < 0.01].Serum uric acid level increased significantly in both genders in proportion to increase of age, and was higher in men than in women in all age groups (all P < 0.01). The age-adjusted prevalence was significantly higher in men than in women (5.6% vs. 3.3%, P < 0.01), and was also higher in men aged 35-44 and aged 45-54 than in women (both P < 0.01). There was no significance in prevalence of hyperuricemia in both men and women aged 55-64 and aged ≥ 65. After adjusting age, gender, educational level, migration and occupation, the multiple logistic regression analysis showed that the prevalence of hyperuricemia was higher in alcohol drinking participants than that of non-alcohol drinking participants (OR = 2.06, 95%CI:1.59-2.67, P < 0.01), and in participants used to consume less green vegetables and fruits than in participants consuming more green vegetables and fruits (OR = 1.77, 95% CI:1.27-2.47, P < 0.01). CONCLUSIONS: The prevalence of hyperuricemia is relatively low in rural area of the Three Gorges.Alcohol drinking and low intake of green vegetables and fruits are the risk factors of hyperuricemia in this population.

Bis-enzyme cascade CRISPR-Cas12a platform for miRNA detection.

MicroRNA (miRNA) play a vital role in the pathological development of many diseases. It is considered to be the diagnosis and potential biomarkers of prognosis. Herein, we proposed Bis-enzyme cascade Platform by combining T7 RNA polymerase and CRISPR-Cas12a (BPTC) for a miRNA detection. In the proposed BPTC, the RNA to DNA conversion ability of phi29 amplification and trans-cleavage of CRISPR-Cas12a are combined. The target miRNA can be amplified after binding to the recognizer ssDNA, and then transcribed the CRISPR-derived RNA (crRNA) by T7 RNA polymerase. The produced crRNA can thereby be assembled by CRISPR-Cas12a and recognized with its target dsDNA, thus triggered its trans-cleavage towards surrounding fluorescent reporters, labeled with a fluorophore and a corresponding quenching group. Based on the bis-enzyme cascade system, the biosensor shows highly sensitivity and excellent specificity. Moreover, this study provided a novel all-in-one detect strategy for miRNA and may open a new idea for the design of CRISR-Cas-based miRNA biosensing platforms.