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An important intestinal bacterial strain Akkermansia muciniphila contributes to improving carbohydrate and lipid metabolism, thus alleviating obesity symptoms. Here, we find that the Akk membrane protein Amuc_1100 regulates lipid metabolism in 3T3-L1 preadipocytes.

Nanoparticles with a strong absorption of incident radio frequency (rf) or microwave irradiation are desirable for remote hyperthermia treatments. While controversy has surrounded the absorption properties of spherical metallic nanoparticles, other geometries, such as prolate and oblate spheroids, have not received sufficient attention for application in hyperthermia therapies. Here, we use the electrostatic approximation to calculate the relative-absorption ratio of metallic nanoparticles in various biological tissues. We consider a broad parameter space, sweeping across frequencies from 1 MHz to 10 GHz, while also tuning the nanoparticle dimensions from spheres to high-aspect-ratio spheroids approximating nanowires and nanodisks. We find that, while spherical metallic nanoparticles do not offer differential heating in tissue, large absorption cross sections can be obtained from long prolate spheroids, while thin oblate spheroids offer minor potential for absorption. Our results suggest that metallic nanowires should be considered for rf- and microwave-based wireless hyperthermia treatments in many tissues going forward.

Many in vivo biological techniques, such as fluorescence imaging, photodynamic therapy, and optogenetics, require light delivery into biological tissues. The limited tissue penetration of visible light discourages the use of external light sources and calls for the development of light sources that can be delivered in vivo. A promising material for internal light delivery is persistent phosphors; however, there is a scarcity of materials with strong persistent luminescence of visible light in a stable colloid to facilitate systemic delivery in vivo. Here, we used a bioinspired demineralization (BID) strategy to synthesize stable colloidal solutions of solid-state phosphors in the range of 470 to 650 nm and diameters down to 20 nm. The exceptional brightness of BID-produced colloids enables their utility as multicolor luminescent tags in vivo with favorable biocompatibility. Because of their stable dispersion in water, BID-produced nanophosphors can be delivered systemically, acting as an intravascular colloidal light source to internally excite genetically encoded fluorescent reporters within the mouse brain.

Plasmonic nanoparticles show highly sensitive optical properties upon local dielectric environment changes. Hybridisation of plasmonic nanoparticles with active polymeric materials can allow stimuli-responsive and multiplex sensing over conventional monotonic sensing capacity. Such heterogeneous adlayers around the plasmonic core component, however, are likely to perturb the local refractive index in the nanometre regime and lead to uncertainty in its intrinsic sensitivity. Herein we prepare a series of polystyrene-grafted polyhedral gold nanoparticles, cubic and concave cubic cores, with different edge lengths and polymer thicknesses with precise synthesis control. Their localised surface plasmon resonance (LSPR) spectral changes are monitored to understand the effect of core morphological details in the interplay of nanoscale polymeric shells. Quantitative image analysis of changes in the core and shell shape contours and finite-difference time-domain simulations of the corresponding LSPR spectra and electric field distributions reveal that the magnitude of the LSPR spectral shift is closely dependent on the core morphology, polymer shell thickness and electric field intensity. We also demonstrate that the polystyrene-grafted gold concave cube displays higher sensitivity for nanoscale refractive index change in the polymer shell than the polystyrene-grafted gold cube at different temperatures. Our systematic investigation will help design polymer-composited plasmonic nanosensors for desirable applications.

Wet chemical etching has been one crucial method in the design strategy of functional materials, from microfabrication to nanoparticle synthesis. It has been suggested that shapes of building block...

Magnetic activated carbons were prepared from waste macroporous resin. The carbon materials were characterized by nitrogen adsorption–desorption isotherms, scanning and transmission electron microscopy, X-ray diffraction, and vibrating sample magnetometer. The results showed that Fenton’s reagent has a significant impact on the pore size and porosity distributions, crystal structures, and magnetic properties of the magnetic activated carbons. Fenton’s reagent as impregnation agent not only provides strong oxidant for degradation organic contaminants and cleaning bolcked pore of waste macroporous resin simultaneously, but also makes it easier for the iron ion (Fe2+/Fe3+) to penetrate into the pore of waste macroporous resin. The carbon/iron composite MAC-2 exhibited better pore structure, magnetic properties, and adsorption performance than that of controlled carbon materials AC-1 and MAC-1. A superparamagnetic property revealed that MAC-2 can be manipulated by an external magnetic field. Recycling of waste macroporous resin and preparation of magnetic activated carbons are economically feasible and high-efficiency.

Liquid-phase transmission electron microscopy (TEM) has been recently applied to materials chemistry to gain fundamental understanding of various reaction and phase transition dynamics at nanometer resolution. However, quantitative extraction of physical and chemical parameters from the liquid-phase TEM videos remains bottlenecked by the lack of automated analysis methods compatible with the videos’ high noisiness and spatial heterogeneity. Here, we integrate, for the first time, liquid-phase TEM imaging with our customized analysis framework based on a machine learning model called U-Net neural network. This combination is made possible by our workflow to generate simulated TEM images as the training data with well-defined ground truth. We apply this framework to three typical systems of colloidal nanoparticles, concerning their diffusion and interaction, reaction kinetics, and assembly dynamics, all resolved in real-time and real-space by liquid-phase TEM. A diversity of properties for differently shaped anisotropic nanoparticles are mapped, including the anisotropic interaction landscape of nanoprisms, curvature-dependent and staged etching profiles of nanorods, and an unexpected kinetic law of first-order chaining assembly of concave nanocubes. These systems representing properties at the nanoscale are otherwise experimentally inaccessible. Compared to the prevalent image segmentation methods, U-Net shows a superior capability to predict the position and shape boundary of nanoparticles from highly noisy and fluctuating background—a challenge common and sometimes inevitable in liquid-phase TEM videos. We expect our framework to push the potency of liquid-phase TEM to its full quantitative level and to shed insights, in high-throughput and statistically significant fashion, on the nanoscale dynamics of synthetic and biological nanomaterials., Machine-learning-assisted extracting of nanoscale dynamics from liquid-phase TEM videos.

Fungi play key roles in various fields, including fermentation-based industries, medicine, and public health. The rapid and precise evaluation of fungal viability is critical for fungi-related fields. However, the methods currently applied have a series of limitations, such as time-consuming, laborious, and cumbersome. In this study, we designed and synthesized a water-dispersible fluorescent probe DPASI with typical aggregation-induced emission (AIE) characteristics for selectively lighting up dead Candida cells within 5 minutes. The rapid staining of the dead Candida cells could be ascribed to the efficient binding of DPASI with mitochondria, which was revealed by high-resolution fluorescence images taken by a structured illumination microscope (SIM) and colocalization images taken by a confocal laser scanning microscope (CLSM). Compared with traditional probes for the identification of dead Candida cells, the DPASI probe does not require tedious centrifugation and washing steps and has significant advantages in time-and-labor-saving. It thus provides a facile and promising tool for the rapid evaluation of antifungal susceptibility and screening of new antifungal drugs, which would greatly contribute to the fungal research.

Biological morphogenesis has inspired many efficient strategies to diversify material structure and functionality using a fixed set of components. However, implementation of morphogenesis concepts to design soft nanomaterials is underexplored. Here, we study nanomorphogenesis in the form of the three-dimensional (3D) crumpling of polyamide membranes used for commercial molecular separation, through an unprecedented integration of electron tomography, reaction-diffusion theory, machine learning (ML), and liquid-phase atomic force microscopy. 3D tomograms show that the spatial arrangement of crumples scales with monomer concentrations in a form quantitatively consistent with a Turing instability. Membrane microenvironments quantified from the nanomorphologies of crumples are combined with the Spiegler-Kedem model to accurately predict methanol permeance. ML classifies vastly heterogeneous crumples into just four morphology groups, exhibiting distinct mechanical properties. Our work forges quantitative links between synthesis and performance in polymer thin films, which can be applicable to diverse soft nanomaterials.

The crystallization of materials from a suspension determines the structure and function of the final product, and numerous pieces of evidence have pointed out that the classical crystallization pathway may not capture the whole picture of the crystallization pathways. However, visualizing the initial nucleation and further growth of a crystal at the nanoscale has been challenging due to the difficulties of imaging individual atoms or nanoparticles during the crystallization process in solution. Recent progress in nanoscale microscopy had tackled this problem by monitoring the dynamic structural evolution of crystallization in a liquid environment. In this review, we summarized several crystallization pathways captured by the liquid-phase transmission electron microscopy technique and compared the observations with computer simulation. Apart from the classical nucleation pathway, we highlight three nonclassical pathways that are both observed in experiments and computer simulations: formation of an amorphous cluster below the critical nucleus size, nucleation of the crystalline phase from an amorphous intermediate, and transition between multiple crystalline structures before achieving the final product. Among these pathways, we also highlight the similarities and differences between the experimental results of the crystallization of single nanocrystals from atoms and the assembly of a colloidal superlattice from a large number of colloidal nanoparticles. By comparing the experimental results with computer simulations, we point out the importance of theory and simulation in developing a mechanistic approach to facilitate the understanding of the crystallization pathway in experimental systems. We also discuss the challenges and future perspectives for investigating the crystallization pathways at the nanoscale with the development of in situ nanoscale imaging techniques and potential applications to the understanding of biomineralization and protein self-assembly.

We discuss recent research efforts towards understanding and implementing the physical rules needed to make materials—especially materials composed of nanoscale building blocks—that exhibit the defining characteristics of living systems: adaptive and evolving functional behavior. In particular, we highlight advancements in direct imaging and quantifying of kinetic pathways governing structural reconfiguration in model systems of colloidal nanoparticles as well as emerging opportunities brought by frontier efforts in synthesizing shape-shifting colloids and flexible electronics. Direct observation of kinetic “crossroads” in nanoparticle self-assembly and reconfiguration will offer insight into how these steps can be manipulated to design dynamic, potentially novel materials and devices. Moreover, these principles will not be limited to nanoparticles; when extended to building blocks like soft micelles and proteins, they have the potential to have a similar impact throughout the broader field of soft matter physics.

Nanoparticles with strong absorption of incident radio frequency (RF) or microwave irradiation are desirable for remote hyperthermia treatments. While controversy has surrounded the absorption properties of spherical metallic nanoparticles, other geometries such as prolate and oblate spheroids have not received sufficient attention for application in hyperthermia therapies. Here, we use the electrostatic approximation to calculate the relative absorption ratio of metallic nanoparticles in various biological tissues. We consider a broad parameter space, sweeping across frequencies from 1 MHz to 10 GHz, while also tuning the nanoparticle dimensions from spheres to high-aspect-ratio spheroids approximating nanowires and nanodiscs. We find that while spherical metallic nanoparticles do not offer differential heating in tissue, large absorption cross sections can be obtained from long prolate spheroids, while thin oblate spheroids offer minor potential for absorption. Our results suggest that metallic nanowires should be considered for RF- and microwave-based wireless hyperthermia treatments in many tissues going forward.

Radio frequency ablation and microwave hyperthermia are powerful tools for destroying dysfunctional biological tissues. However, wireless application of these techniques is hindered by their inability to focus the electromagnetic energy to small targets. The use of locally injected radio frequency- or microwave-absorbing nanomaterials can help to overcome this challenge by confining heat production to the injected region. Previous theoretical work suggests that high-aspect-ratio conducting nanomaterials, such as carbon nanotubes, offer powerful radio frequency and microwave absorption. While carbon nanotubes have been demonstrated as radiothermal agents, common solubilization methods may reduce their absorption efficiency, yielding undesirable nonspecific heating in the biological tissue background. In this manuscript, we hypothesize that pristine carbon nanotubes can act as efficient absorbers at radio frequencies, thus providing differential heating over the tissue background. Specifically, we use a sonication-free preparation technique to preserve both the high aspect ratio and local concentration of pristine carbon nanotubes. We validate the differential heating of these samples by 4.5-fold at 2 GHz compared to the heating of saline at a physiological concentration using infrared thermography. In addition, we successfully achieved local heating of pristine carbon nanotubes within a three-dimensional biological tissue phantom. Numerical simulations further aid in producing a temperature map within the phantom and confirming localized heating. Due to their significant differential and local heating, we believe that pristine carbon nanotubes may facilitate region-specific radio frequency ablation and microwave hyperthermia while keeping nonspecific heating to a low level in the normal tissue background.

The increasing popularity of wearable electronic devices has led to the rapid development of flexible energy conversion systems. Flexible rechargeable zinc-air batteries (ZABs) with high theoretical energy densities demonstrate significant potential as next-generation flexible energy devices that can be applied in wearable electronic products. The design of highly efficient and air-stable cathodes that can electrochemically catalyze both the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are highly desirable but challenging. Flexible carbon-based catalysts for ORR/OER catalysis can be broadly categorized into two types: (i) self-supporting catalysts based on the in situ modification of flexible substrates; (ii) non-self-supporting catalysts based on surface coatings of flexible substrates. Methods used to optimize the catalytic performance include doping with atoms and regulation of the electronic structure and coordination environment. This review summarizes the most recently proposed strategies for the synthesis of designer carbon-based electrocatalysts and the optimization of their electrocatalytic performances in air electrodes. And we significantly focus on the analysis of the inherent active sites and their electrocatalytic mechanisms when applied as flexible ZABs catalysts. The findings of this review can assist in the design of more valuable carbon-based air electrodes and their corresponding flexible ZABs for application in wearable electronic devices.

Highlights • Heating-activation at 56 °C for 30 min does not impair the antibodies of SARS-CoV-2. • Heating-activation would not decrease the diagnostic efficacy of SARS-CoV-2 IgM or IgG antibodies (ELISA-immunoassay). • Sera inactivated by heating should be recommended to minimize the risk of virus contamination of laboratory staff., Background To establish a safe and accurate method for detecting SARS-CoV-2 IgM and IgG, we assessed the impact of sera after heat-inactivation on the SARS-CoV-2 IgM and IgG levels measured by ELISA-immunoassay. Methods The serum samples of 62 patients with COVID-19 and 18 healthy controls were collected in Hankou’s Hospital of Wuhan from February 27 to March 6, 2020. Before and after the samples were inactivated, the levels of IgM and IgG antibodies were measured. Results The indexes of antibodies after inactivated were significantly higher than those in fresh sera, while the positive rates in all participants or in patients with COVID-19 did not change. The positive coincidence rate, negative coincidence rate and total coincidence rate of IgM antibodies before and after inactivation were 100.00% (55/55), 96.00% (24/25) and 98.75% (79/80), respectively (κ = 0.971, P

Objective Alzheimer’s disease (AD) is a global health problem without effective methods to alleviate the disease progression. Amyloid β-protein (Aβ) is widely accepted as a key biomarker for AD. Metabolic syndromes, including obesity and insulin resistance, are key high risk factors for AD. Akkermansia muciniphila (Akk), the only representative human gut microbe in the genus Verrucomicrobia, can prevent the weight gain caused by a high-fat diet, repair the damaged integrity of the intestinal epithelium barrier, reduce endotoxin levels in blood and improve insulin resistance. The aim of this study is to explore the impact of Akk administration in AD model mice in different diets. Methods APP/PS1 mice were fed either a normal chow diet or a high-fat diet and were treated with Akk by gavage each day for 6 months. The impacts of Akk on glucose metabolism, intestinal barrier and lipid metabolism in the mouse model of AD were determined. Changes in brain pathology and neuroethology were also analyzed. Results Akk effectively reduced the fasting blood glucose and serum diamine oxidase levels, and alleviated the reduction of colonic mucus cells in APP/PS1 mice. After treatment with Akk, the APP/PS1 mice showed obviously reduced blood lipid levels, improved hepatic steatosis and scapular brown fat whitening. Moreover, Akk promoted the reduction of Aβ 40–42 levels in the cerebral cortex of APP/PS1 mice, shortened the study time and improved the completion rate in Y-maze tests. Conclusion Akk effectively improved glucose tolerance, intestine barrier dysfunction and dyslipidemia in AD model mice. Our study results suggested that Akk could delay the pathological changes in the brain and relieve impairment of spatial learning and memory in AD model mice, which provides a new strategy for prevention and treatment of AD., APP/PS1 mice display alterations in physiological processes after treated with Akk. It is showed that the damaged integrity of the intestinal epithelium barrier is repaired, leading to obviously reduced blood glucose and lipid levels, improved hepatic steatosis, insulin resistance and scapular brown fat whitening, which are beneficial to reduce Aβ 40–42 levels in the brain of APP/PS1 mice.

The detection of serum antibodies to the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is emerging as a new tool for the coronavirus disease-2019 (COVID-19) diagnosis. Since many coronaviruses are sensitive to heat, heating inactivation of samples at 56 °C prior to testing is considered a possible method to reduce the risk of transmission, but the effect of heating on the measurement of SARS-CoV-2 antibodies is still unclear. By comparing the levels of SARS-CoV-2 antibodies before and after heat inactivation of serum at 56 °C for 30 minutes using a quantitative fluorescence immunochromatographic assay, we shown that heat inactivation significantly interferes with the levels of antibodies to SARS-CoV-2. The IgM levels of all the 34 serum samples (100%) from COVID-19 patients decreased by an average level of 53.56%. The IgG levels were decreased in 22 of 34 samples (64.71%) by an average level of 49.54%. Similar changes can also be observed in the non-COVID-19 diseases group (n=9). Of note, 44.12% of the detected IgM levels were dropped below the cut-off value after heating, suggesting heat inactivation can lead to false-negative results of these samples. Our results indicate that heat inactivation of serum at 56 °C for 30 minutes interferes with the immunoanalysis of antibodies to SARS-CoV-2. Heat inactivation prior to immunoanalysis is not recommended and the possibility of false-negative results should be considered if the sample was pre-inactivated by heating.

Phascolarctobacterium can produce short-chain fatty acids, including acetate and propionate, and can be associated with the metabolic state and mood of the host. The present study investigated the colonization characteristics of Phascolarctobacterium faecium in healthy individuals 1 year old). The permillage of Phascolarctobacterium faecium in total bacteria ranged between 0.004–1.479. There was presence of Phascolarctobacterium faecium-like bacteria in younger individuals with a gradual increase in the number of bacteria maintained at a high level with increasing ages (between 1 and 60 years old), but with a decrease in elderly individuals (>60 years old). The results of the present study demonstrated that Phascolarctobacterium faecium is abundantly colonized in the human gastrointestinal tract.

Background The study aimed to investigate the differences of different Akkermansia muciniphila (A.muciniphila) genotypes on metabolic protective effects in mice with high-fat diet and explore possible mechanisms. Methods Male C57BL/6 mice were randomly divided into 6 groups, including high-fat diet (HFD)+ A.muciniphila I/II/PBS group, normal chow diet (NCD)+A.muciniphila I/ II /PBS group, respectively. Dietary intervention and A.muciniphila gavage were performed simultaneously. Blood glucose and lipid metabolism, brown adipose morphology and activities, and intestinal barrier function were examined after the mice were sacrificed. Results A.muciniphila gavage improved the impaired glucose tolerance, hyperlipidemia and liver steatosis in HFD mice, and that A.muciniphila II was not as effective as A.muciniphila I. This phenomenon might be because A.muciniphila I intervention significantly inhibited brown adipose tissue whitening and inflammation induced by HFD, by repairing the intestinal barrier and relieving endotoxemia. A.muciniphila II did not display the same results as A.muciniphila I in HFD mice, but had stronger effects in the NCD mice. Conclusions This study mainly reveals the distinct functions of different A.muciniphila genotypes on diet-induced obesity, suggesting that different A.muciniphila genotypes may play inequitable roles in pathological conditions through distinct action pathways.

3D coil structures through 2D processing, combined with ferrofluid core, achieve unprecedented high magnetic flux density., Monolithic strong magnetic induction at the mtesla to tesla level provides essential functionalities to physical, chemical, and medical systems. Current design options are constrained by existing capabilities in three-dimensional (3D) structure construction, current handling, and magnetic material integration. We report here geometric transformation of large-area and relatively thick (~100 to 250 nm) 2D nanomembranes into multiturn 3D air-core microtubes by a vapor-phase self-rolled-up membrane (S-RuM) nanotechnology, combined with postrolling integration of ferrofluid magnetic materials by capillary force. Hundreds of S-RuM power inductors on sapphire are designed and tested, with maximum operating frequency exceeding 500 MHz. An inductance of 1.24 μH at 10 kHz has been achieved for a single microtube inductor, with corresponding areal and volumetric inductance densities of 3 μH/mm2 and 23 μH/mm3, respectively. The simulated intensity of the magnetic induction reaches tens of mtesla in fabricated devices at 10 MHz.

Reconfigurable hybrid nanoparticles made by decorating flexible polymer shells on rigid inorganic nanoparticle cores can provide a unique means to build stimuli-responsive functional materials. The polymer shell reconfiguration has been expected to depend on the local core shape details, but limited systematic investigations have been undertaken. Here, two literature methods are adapted to coat either thiol-terminated polystyrene (PS) or polystyrene-poly(acrylic acid) (PS-b-PAA) shells onto a series of anisotropic gold nanoparticles of shapes not studied previously, including octahedron, concave cube, and bipyramid. These core shapes are complex, rendering shell contours with nanoscale details (e.g., local surface curvature, shell thickness) that are imaged and analyzed quantitatively using the authors' customized analysis codes. It is found that the hybrid nanoparticles based on the chosen core shapes, when coated with the above two polymer shells, exhibit distinct shell segregations upon a variation in solvent polarity or temperature. It is demonstrated for the PS-b-PAA-coated hybrid nanoparticles, the shell segregation is maintained even after a further decoration of the shell periphery with gold seeds; these seeds can potentially facilitate subsequent deposition of other nanostructures to enrich structural and functional diversity. These synthesis, imaging, and analysis methods for the hybrid nanoparticles of anisotropically shaped cores can potentially aid in their predictive design for materials reconfigurable from the bottom up.

Background Akkermansia muciniphila is one of the most dominant bacteria that resides on the mucus layer of intestinal tract and plays key role in human health, however, little is known about its genomic content. Results Herein, we for the first time characterized the genomic architecture of A. muciniphila based on whole-genome sequencing, assembling, and annotating of 39 isolates derived from human and mouse feces. We revealed a flexible open pangenome of A. muciniphila currently consisting of 5644 unique proteins. Phylogenetic analysis identified three species-level A. muciniphila phylogroups exhibiting distinct metabolic and functional features. Based on the comprehensive genome catalogue, we reconstructed 106 newly A. muciniphila metagenome assembled genomes (MAGs) from available metagenomic datasets of human, mouse and pig gut microbiomes, revealing a transcontinental distribution of A. muciniphila phylogroups across mammalian gut microbiotas. Accurate quantitative analysis of A. muciniphila phylogroups in human subjects further demonstrated its strong correlation with body mass index and anti-diabetic drug usage. Furthermore, we found that, during their mammalian gut evolution history, A. muciniphila acquired extra genes, especially antibiotic resistance genes, from symbiotic microbes via recent lateral gene transfer. Conclusions The genome repertoire of A. muciniphila provided insights into population structure, evolutionary and functional specificity of this significant bacterium. Electronic supplementary material The online version of this article (10.1186/s12864-017-4195-3) contains supplementary material, which is available to authorized users.

Isolation, sequencing, assembly and gene prediction information of 39 A. muciniphila isolates and strain ATCC BAA-835. (XLSX 16 kb)