3D Sheet Research Articles

Hypoxia-responsive expression of vascular endothelial growth factor for induction of angiogenesis in artificial three-dimensional tissues

Constructing three-dimensional (3D) tissues is an important process to improve cellular functions in tissue engineering. When transplanting artificially constructed tissues, a poor vascular network restricts oxygen and nutrient supplies to the tissue cells, which leads to cell death and reduced rates of tissue engraftment. Therefore, it is necessary to develop a system that builds a vascular network within 3D tissues. Here, we developed a hypoxia-responsive gene expression system for production of an angiogenic factor, vascular endothelial growth factor (VEGF), to improve hypoxia and nutrition deficiencies inside artificial 3D tissues. We demonstrated that cells into which the hypoxia-responsive VEGF gene expression system had been introduced autonomously controlled VEGF expression in a hypoxic stress-dependent manner. Next, we confirmed that VEGF expression within a 3D cell sheet was induced in response to a hypoxic environment invitro. The genetically modified cell sheet was subcutaneously transplanted into mice to evaluate the feasibility of the hypoxia-responsive VEGF gene expression system invivo. The results suggest that the hypoxia-responsive VEGF gene expression system is promising to prepare artificial 3D tissues in regenerative medicine.

Small extracellular vesicles obtained from hypoxic mesenchymal stromal cells have unique characteristics that promote cerebral angiogenesis, brain remodeling and neurological recovery after focal cerebral ischemia in mice

Obtained from the right cell-type, mesenchymal stromal cell (MSC)-derived small extracellular vesicles (sEVs) promote stroke recovery. Within this process, microvascular remodeling plays a central role. Herein, we evaluated the effects of MSC-sEVs on the proliferation, migration, and tube formation of human cerebral microvascular endothelial cells (hCMEC/D3) in vitro and on post-ischemic angiogenesis, brain remodeling and neurological recovery after middle cerebral artery occlusion (MCAO) in mice. In vitro, sEVs obtained from hypoxic (1% O2), but not ‘normoxic’ (21% O2) MSCs dose-dependently promoted endothelial proliferation, migration, and tube formation and increased post-ischemic endothelial survival. sEVs from hypoxic MSCs regulated a distinct set of miRNAs in hCMEC/D3 cells previously linked to angiogenesis, three being upregulated (miR-126-3p, miR-140-5p, let-7c-5p) and three downregulated (miR-186-5p, miR-370-3p, miR-409-3p). LC/MS–MS revealed 52 proteins differentially abundant in sEVs from hypoxic and ‘normoxic’ MSCs. 19 proteins were enriched (among them proteins involved in extracellular matrix–receptor interaction, focal adhesion, leukocyte transendothelial migration, protein digestion, and absorption), and 33 proteins reduced (among them proteins associated with metabolic pathways, extracellular matrix–receptor interaction, focal adhesion, and actin cytoskeleton) in hypoxic MSC-sEVs. Post-MCAO, sEVs from hypoxic MSCs increased microvascular length and branching point density in previously ischemic tissue assessed by 3D light sheet microscopy over up to 56 days, reduced delayed neuronal degeneration and brain atrophy, and enhanced neurological recovery. sEV-induced angiogenesis in vivo depended on the presence of polymorphonuclear neutrophils. In neutrophil-depleted mice, MSC-sEVs did not influence microvascular remodeling. sEVs from hypoxic MSCs have distinct angiogenic properties. Hypoxic preconditioning enhances the restorative effects of MSC-sEVs.

Intravenous Delivery of Lung-Targeted Nanofibers for Pulmonary Hypertension in Mice.

Pulmonary hypertension is a highly morbid disease with no cure. Available treatments are limited by systemic adverse effects due to non-specific biodistribution. Self-assembled peptide amphiphile (PA) nanofibers are biocompatible nanomaterials that can be modified to recognize specific biological markers to provide targeted drug delivery and reduce off-target toxicity. Here, PA nanofibers that target the angiotensin I-converting enzyme and the receptor for advanced glycation end-products (RAGE) are developed, as both proteins are overexpressed in the lung with pulmonary hypertension. It is demonstrated that intravenous delivery of RAGE-targeted nanofibers containing the targeting epitope LVFFAED (LVFF) significantly accumulated within the lung in a chronic hypoxia-induced pulmonary hypertension mouse model. Using 3D light sheet fluorescence microscopy, it is shown that LVFF nanofiber localization is specific to the diseased pulmonary tissue with immunofluorescence analysis demonstrating colocalization of the targeted nanofiber to RAGE in the hypoxic lung. Furthermore, biodistribution studies show that significantly more LVFF nanofibers localized to the lung compared to major off-target organs. Targeted nanofibers are retained within the pulmonary tissue for 24 h after injection. Collectively, these data demonstrate the potential of a RAGE-targeted nanomaterial as a drug delivery platform to treat pulmonary hypertension.

Segmentor: a tool for manual refinement of 3D microscopy annotations

BackgroundRecent advances in tissue clearing techniques, combined with high-speed image acquisition through light sheet microscopy, enable rapid three-dimensional (3D) imaging of biological specimens, such as whole mouse brains, in a matter of hours. Quantitative analysis of such 3D images can help us understand how changes in brain structure lead to differences in behavior or cognition, but distinguishing densely packed features of interest, such as nuclei, from background can be challenging. Recent deep learning-based nuclear segmentation algorithms show great promise for automated segmentation, but require large numbers of accurate manually labeled nuclei as training data.ResultsWe present Segmentor, an open-source tool for reliable, efficient, and user-friendly manual annotation and refinement of objects (e.g., nuclei) within 3D light sheet microscopy images. Segmentor employs a hybrid 2D-3D approach for visualizing and segmenting objects and contains features for automatic region splitting, designed specifically for streamlining the process of 3D segmentation of nuclei. We show that editing simultaneously in 2D and 3D using Segmentor significantly decreases time spent on manual annotations without affecting accuracy as compared to editing the same set of images with only 2D capabilities.ConclusionsSegmentor is a tool for increased efficiency of manual annotation and refinement of 3D objects that can be used to train deep learning segmentation algorithms, and is available at https://www.nucleininja.org/ and https://github.com/RENCI/Segmentor.

3D cell sheet structure augments mesenchymal stem cell cytokine production

Mesenchymal stem cells (MSCs) secrete paracrine factors that play crucial roles during tissue regeneration. An increasing body of evidence suggests that this paracrine function is enhanced by MSC cultivation in three-dimensional (3D) tissue-like microenvironments. Toward this end, this study explored scaffold-free cell sheet technology as a new 3D platform. MSCs cultivated on temperature-responsive culture dishes to a confluent 2D monolayer were harvested by temperature reduction from 37 to 20 °C that induces a surface wettability transition from hydrophobic to hydrophilic. Release of culture-adherent tension induced spontaneous cell sheet contraction, reducing the diameter 2.4-fold, and increasing the thickness 8.0-fold to render a 3D tissue-like construct with a 36% increase in tissue volume. This 2D-to-3D transition reorganized MSC actin cytoskeleton from aligned to multidirectional, corresponding to a cell morphological change from elongated in 2D monolayers to rounded in 3D cell sheets. 3D culture increased MSC gene expression of cell interaction proteins, β-catenin, integrin β1, and connexin 43, and of pro-tissue regenerative cytokines, vascular endothelial growth factor (VEGF), hepatocyte growth factor (HGF), and interleukin-10 (IL-10), and increased VEGF secretion per MSC 2.1-fold relative to 2D cultures. Together, these findings demonstrate that MSC therapeutic potency can be enhanced by 3D cell sheet tissue structure.

Unbiased analysis of obesity related, fat depot specific changes of adipocyte volumes and numbers using light sheet fluorescence microscopy.

In translational obesity research, objective assessment of adipocyte sizes and numbers is essential to characterize histomorphological alterations linked to obesity, and to evaluate the efficacies of experimental medicinal or dietetic interventions. Design-based quantitative stereological techniques based on the analysis of 2D-histological sections provide unbiased estimates of relevant 3D-parameters of adipocyte morphology, but often involve complex and time-consuming tissue processing and analysis steps. Here we report the application of direct 3D light sheet fluorescence microscopy (LSFM) for effective and accurate analysis of adipocyte volumes and numbers in optically cleared adipose tissue samples from a porcine model of diet-induced obesity (DIO). Subcutaneous and visceral adipose tissue samples from DIO-minipigs and lean controls were systematically randomly sampled, optically cleared with 3DISCO (3-dimensional imaging of solvent cleared organs), stained with eosin, and subjected to LSFM for detection of adipocyte cell membrane autofluorescence. Individual adipocytes were unbiasedly sampled in digital 3D reconstructions of the adipose tissue samples, and their individual cell volumes were directly measured by automated digital image analysis. Adipocyte numbers and mean volumes obtained by LSFM analysis did not significantly differ from the corresponding values obtained by unbiased quantitative stereological analysis techniques performed on the same samples, thus proving the applicability of LSFM for efficient analysis of relevant morphological adipocyte parameters. The results of the present study demonstrate an adipose tissue depot specific plasticity of adipocyte growth responses to nutrient oversupply. This was characterized by an exclusively hypertrophic growth of visceral adipocytes, whereas adipocytes in subcutaneous fat tissue depots also displayed a marked (hyperplastic) increase in cell number. LSFM allows for accurate and efficient determination of relevant quantitative morphological adipocyte parameters. The applied stereological methods and LSFM protocols are described in detail and can serve as a guideline for unbiased quantitative morphological analyses of adipocytes in other studies and species.

Effect of captopril on post-infarction remodelling visualized by light sheet microscopy and echocardiography

Angiotensin converting enzyme inhibitors, among them captopril, improve survival following myocardial infarction (MI). The mechanisms of captopril action remain inadequately understood due to its diverse effects on multiple signalling pathways at different time periods following MI. Here we aimed to establish the role of captopril in late-stage post-MI remodelling. Left anterior descending artery (LAD) ligation or sham surgery was carried out in male C57BL/6J mice. Seven days post-surgery LAD ligated mice were allocated to daily vehicle or captopril treatment continued over four weeks. To provide comprehensive characterization of the changes in mouse heart following MI a 3D light sheet imaging method was established together with automated image analysis workflow. The combination of echocardiography and light sheet imaging enabled to assess cardiac function and the underlying morphological changes. We show that delayed captopril treatment does not affect infarct size but prevents left ventricle dilation and hypertrophy, resulting in improved ejection fraction. Quantification of lectin perfused blood vessels showed improved vascular density in the infarct border zone in captopril treated mice in comparison to vehicle dosed control mice. These results validate the applicability of combined echocardiographic and light sheet assessment of drug mode of action in preclinical cardiovascular research.

Rapid Multilevel Compartmentalization of Stable All-Aqueous Blastosomes by Interfacial Aqueous-Phase Separation.

Producing artificial multicellular structures to process multistep cascade reactions and mimic the fundamental aspects of living systems is an outstanding challenge. Highly biocompatible, artificial systems consisting of all-aqueous, compartmentalized multicellular systems have yet to be realized. Here, a rapid multilevel compartmentalization of an all-aqueous system where a 3D sheet of subcolloidosomes encloses a mother colloidosome by interfacial phase separation is demonstrated. These spatially organized multicellular structures are termed "blastosomes" since they are similar to blastula in appearance. The barrier to nanoparticle assembly at the water-water interface is overcome using oppositely charged polyelectrolytes that form a coacervate-nanoparticle-composite network. The conditions required to trigger interfacial phase separation and form blastosomes are quantified in a mapped state diagram. We show a versatile model for constructing artificial multicellular spheroids in all-aqueous systems. The rapid interfacial assembly of charged particles and polyelectrolytes can lock in nonequilibrium shapes of water, which also enables top-down technologies, such as 3D printing and microfluidics, to program flexible compartmentalized structures.

457-P: Quantification of Vascular Density by 3D Light Sheet Imaging in a Surgical Ligation of the Left Anterior Descending Artery (LAD) Model in Mouse

Introduction: Patients with diabetes have an increased risk of cardiovascular disease including myocardial infarction (MI). A major consequence of MI is left ventricular (LV) remodeling including compensatory hypertrophy without concomitant adaptation of the capillary vasculature. Targeting capillary density is thus a promising therapeutic strategy but methods for unbiased and direct quantification are lacking. In a surgical MI model, we used 3D light sheet imaging to visualize and quantify LV remodeling including capillary density. Methods: Surgical ligation of the left anterior descending artery (LAD) was performed in male C57BL/6 mice. Infarct localization and LV function were evaluated by echocardiography, and LV remodeling and capillary density quantified by 3D light sheet imaging. Results: Ejection fraction (EF) as measured by echocardiography was reduced in LAD-ligated mice with anterior wall MI compared to mice without MI (29.1±1.5 vs. 55.2±1.1 %, p<0.001), while internal LV volume (as assessed by 3D imaging) was increased (16.6±0.7 vs. 22.7±1.3 mm3, p<0.01) 10 days after LAD ligation. Furthermore, EF and LV volume correlated (R2: 0.59, p<0.001, slope -0.32). The capillary density in the infarct zone was reduced in MI versus no MI mice (10.5±1.00 vs. 23.5±2.5 % of total tissue volume, p<0.001). In a subsequent treatment study, EF was reduced by 43.2% in MI compared to no MI mice (p<0.001) 7 days after LAD ligation. The effects of 4 weeks of treatment with captopril on LV function, remodeling and capillary density was investigated by echocardiography and 3D light sheet imaging. Conclusions: The combination of echocardiography and 3D light sheet imaging offers a novel approach to visualize and quantify LV function, remodeling and capillary density in a mouse model of MI. This high-resolution 3D imaging technology thus allows for preclinical efficacy testing of novel therapeutics for heart disease including MI. Disclosure N.E. Zois: Employee; Self; Gubra. U. Roostalu: Employee; Self; Gubra. L. Thisted: Employee; Self; Gubra. P.J. Pedersen: Employee; Self; Gubra. K. Fosgerau: None. J. Jelsing: Board Member; Self; Gubra. Stock/Shareholder; Self; Gubra. N. Vrang: Board Member; Self; Gubra. Employee; Self; Gubra. Stock/Shareholder; Self; Gubra.

Modelling macrosegregation modification in dc casting of aluminium alloys in sheet ingots accounting for inlet melt flow, equiaxed grain morphology and transport

Macrosegregation is a severe defect present in direct-chill (DC) cast aluminium ingots and billets. In the recent years, experimental studies were conducted to modify and to an extent optimize macrosegregation formation by modifying the inlet melt flow. Due to several limitations, the grain settling behavior and corresponding liquid flow pattern is difficult to analyze using experiments. Simulations on the other hand can provide this insight. However, conducting 2D sheet ingot simulations, as has been previously done, provides an incomplete description of flow pattern. To avoid this and as a first qualitative study, full scale 3D sheet ingot simulation results with two different inlets are presented in this paper. A simplified three-phase multiscale solidification model accounting for solidification shrinkage, natural convection and equiaxed grain growth and transport is used to conduct this study. We show that modification of inlet flow results in modification of grain settling and eventually leading to modification of macrosegregation. The impact of grain morphology is also additionally analyzed.

Surface modification and edge layer post curing of 3D sheet moulding compounds (SMC)

Incomplete curing of sheet moulding compounds (SMC), as well as the post-curing and outgassing during the industrial thermal coating process, are the two main reasons for the coating problems of SMC Class-A automotive parts. Furthermore, their surface properties as contact angle and surface roughness strongly depend on the processing parameters of thermal curing and coating as well as cleaning and pickling methods used. Consequently, cost and energy-intensive additional process steps are required in the automotive industry in order to reduce or avoid above mentioned problems during the industrial coating process of SMC-Class-A automotive parts. A cost-efficient robust procedure is required in order to overcome these disadvantages as well as to fulfil the requirements of the industrial coating process. Based on electron beam curing and surface functionalization by low energy electrons a novel pre-treatment procedure was developed and tested. For this purpose, two different compact electron emitters have been coupled to an industrial robot in order to validate this novel in-line pre-treatment procedure. Through this one-step treatment, post edge-layer curing and surface functionalization of the three-dimensional SMC-parts are achieved.

Scalable CVD synthesis of three-dimensional graphene from cast catalyst

Three-dimensional (3D) graphene has become an area of great interest due to its unique properties, and different synthesis routes and structures have been reported in the literature. However, the challenges of retaining high quality, scaling up and improving economic feasibility are apparent. Here we describe 3D graphene sheet (3DGS), which is a novel, electrically conductive and porous 3D graphene material that addresses some of these challenges. Due to the combination of polymer binders and a casting technique, scale up for this material is possible. The 3DGS reported in this work can be described as a seamless and freestanding assembly with low structural defects, electrical conductivity of 14.71 S/cm and reasonable mechanical integrity. This material exhibits an average density of 21.65 ± 1.49 kg/m3 and a mesoporous structure with a specific surface area of 16.5 m2/g. The Chemical Vapor Deposition (CVD) synthesis and the cast catalyst preparation method is simple and versatile in terms of tuning the material properties such as areal density and electrical conductivity. These and other properties of 3DGS enable its use in many applications, especially as binder-free, flexible electrodes and current collectors for energy storage devices and sensors.

MOF-Templated sword-like Co3O4@NiCo2O4 sheet arrays on carbon cloth as highly efficient Li–O2 battery cathode

Highly effective cathode materials are critical to improve existing Li–O2 batteries. In this paper, we report a free-standing Co3O4@NiCo2O4 sheet array cathode, which is prepared by in-situ growing an array of sword-like cobalt-based metal-organic framework (Co-MOF) sheets on a carbon cloth (CC) substrate, followed by impregnated with nickel nitrate solution and pyrolyzed in air flow. The Co3O4@NiCo2O4/CC cathode exhibits excellent ORR/OER bifunctional activity and high cathodic performance in a Li–O2 battery, achieving a specific capacity of 10645 mAh g−1 and a stability of 225 cycles. We suggest the high performance of our cathode can be ascribed to its well-defined 3D sheet array structure, which can facilitate O2 diffusion and electrolyte impregnation, provide sufficient space for the discharge products, and the synergistic effect between Co3O4 and NiCo2O4. This work provides an effective method for the rational design of electrode composition and structure.

A nano-Ge-coated 3D porous carbon fabricated by ionic liquid electrodeposition for application in lithium storage

In this work, we synthesized a new type of Ge coating for a 3D porous carbon on a Ni foam surface (3D-Void/Ge@C) using simple ionic liquid electrodeposition and annealing at low temperature. When the 3D-Void/Ge@C composite is used as a LIB anode, the 3D porous carbon sheet formed micro-nano voids as a highly efficient “bumper” to accommodate the large volume expansion of Ge. As a result, the as-prepared anode exhibited superior Li-storage capacity, delivered a first cycle discharge/charge specific capacity of 2019.9/1592.9 mA h g−1 at 0.1 mA g−1, and a discharge specific capacity that was more than 990 mA h g−1 after 100 cycles. With a high capacity and stable Li-storage performance, the well-designed composite may indicate a new strategy to promote further application of Ge-based anode materials in new high-performance LIBs in the future.

RPE tissue engineering based on human pluripotent stem cells for cell therapy

AbstractIn developed countries, retinal degenerative diseases affecting the Retinal Pigment Epithelium (RPE), including Age‐related Macular Degeneration and inherited retinal diseases such as Retinitis Pigmentosa (RP), are the predominant causes of human blindness. Despite the scientific advances achieved in the last years, there is no cure for the majority of patients. In this context, cell therapy based on human pluripotent stem cells is an attractive therapeutic alternative to replace dead or defective RPE cells. Different formulations were proposed: either as a cell suspension or as an engineered tissue. We will discuss the preclinical data obtained with these two strategies. In particular, we will present the preclinical development of our own RPE tissue therapy. This cell therapy consists in RPE cells derived from clinical grade human embryonic stem cells disposed on a biocompatible substrate allowing the formation of a 3D functional sheet, suitable for transplantation. Functionality and safety were evaluated in rodents and the surgical approach in non‐human primates. This therapy is currently evaluated in a phase I/II clinical trial targeting RP patients with mutations in RPE genes.

Hierarchical Co3O4 Nanofiber–Carbon Sheet Skeleton with Superior Na/Li‐Philic Property Enabling Highly Stable Alkali Metal Batteries

AbstractUncontrollable dendritic behavior and infinite volume expansion in alkali metal anode results in the severe safety hazards and short lifespan for high‐energy batteries. Constructing a stable host with superior Na/Li‐philic properties is a prerequisite for commercialization. Here, it is demonstrated that the small Gibbs free energy change in the reaction between metal oxide (Co3O4, SnO2, and CuO) and alkali metal is key for metal infusion. The as‐prepared hierarchical Co3O4 nanofiber–carbon sheet (CS) skeleton shows improved wettability toward molten Li/Na. The 3D carbon sheet serves as a primary framework, offering adequate lithium nucleation sites and sufficient electrolyte/electrode contact for fast charge transfer. The secondary framework of Co/Li2O nanofibers provides physical confinement of deposited Li and further redistributes the Li+ flux on each carbon fiber, which is verified by COMSOL Multiphysics simulations. Due to the uniform deposition behavior and near‐zero volume change, modified symmetrical Li/Li cells can operate under an ultrahigh current density of 20 mA cm−2 for more than 120 cycles. When paired with LiFePO4 cathodes, the Li/Co–CS cell shows low polarization and 88.4% capacity retention after 200 cycles under 2 C. Convincing improvement can also be observed in Na/Co–CS symmetrical cells applying NaClO4‐based electrolyte. These results illustrate a significant improvement in developing safe and stable alkali metal batteries.

Performance of convolutional neural networks for identification of bacteria in 3D microscopy datasets.

Three-dimensional microscopy is increasingly prevalent in biology due to the development of techniques such as multiphoton, spinning disk confocal, and light sheet fluorescence microscopies. These methods enable unprecedented studies of life at the microscale, but bring with them larger and more complex datasets. New image processing techniques are therefore called for to analyze the resulting images in an accurate and efficient manner. Convolutional neural networks are becoming the standard for classification of objects within images due to their accuracy and generalizability compared to traditional techniques. Their application to data derived from 3D imaging, however, is relatively new and has mostly been in areas of magnetic resonance imaging and computer tomography. It remains unclear, for images of discrete cells in variable backgrounds as are commonly encountered in fluorescence microscopy, whether convolutional neural networks provide sufficient performance to warrant their adoption, especially given the challenges of human comprehension of their classification criteria and their requirements of large training datasets. We therefore applied a 3D convolutional neural network to distinguish bacteria and non-bacterial objects in 3D light sheet fluorescence microscopy images of larval zebrafish intestines. We find that the neural network is as accurate as human experts, outperforms random forest and support vector machine classifiers, and generalizes well to a different bacterial species through the use of transfer learning. We also discuss network design considerations, and describe the dependence of accuracy on dataset size and data augmentation. We provide source code, labeled data, and descriptions of our analysis pipeline to facilitate adoption of convolutional neural network analysis for three-dimensional microscopy data.

A Rapid 3D Vision Inspection System for Sheet Metal Parts Based on Feature Extraction and Partial Point Clouds

3D vision inspection of sheet metal parts is usually a time-consuming task and hence not suitable for real-time measurement of 3D geometric features.To address this problem, this work presents an active binocular 3D vision inspection system for rapid measurement of features of sheet metal parts using 2D feature extraction and partial 3D point cloud. The inspectionsystem firstly extracts the feature to be measured from one 2D image, then identifies the homologous points describing the feature on the other 2D image with the assistance of structured light, andat lastselectively computes the 3D coordinates related to thefeature measurement to largely reduce computational complexity. The system is applied to a sheet metal parts punching production line to monitor a couple of critical dimensionsin real time. The experiment results indicate that it canacquireaperture center coordinate, radius, and aperture distances within 0.1 seconds and with an average error of less than 0.2mm. The proposed system shows the potentialfor being deployed on mass-production lines to realize rapid 3D measurementfor metal sheet parts.

Localization microscopy of single molecules enhanced by 3D imaging and light sheet illumination

Single-molecule super-resolution fluorescence microscopy has produced a revolution in the optical resolution available for study of the nanoscale details of cells and materials. The early work on two-dimensional imaging yielded images of samples that spanned only a small axial range on the order of ~500 nm. Much more useful information can be obtained in complex extended samples using three-dimensional (3D) single-molecule localization. Without 3D capability, visualization of structures extending in the axial direction can easily be missed or confused and the understanding of the science compromised. A variety of methods for obtaining 3D super-resolution images have been devised, each with their own strengths and weaknesses, ranging from point-spread-function engineering to steep axial illumination gradients. Imaging thicker samples, such as mammalian cells and tissue, in all three dimensions presents additional challenges due to increased background and large volumes to image. Light sheet illumination is a method that allows for selective irradiation of the image plane, and its inherent optical sectioning capability allows for imaging of biological samples with reduced background, photobleaching, and photodamage. Beyond these developments, there is a continuing need for better controllable fluorophores, additional novel optical system designs, and enhanced mathematical and statistical signal processing ideas to accurately extract the maximum information available from single emitters in the shortest possible time.

A novel boron and nitrogen co-doped three-dimensional porous graphene sheet framework as high performance Li-ion battery anode material

A boron and nitrogen co-doped 3D porous graphene sheet framework (BN-3DG) is prepared by simple heat treatment of borane tert-butylamine with cobalt ion-exchanged cationic resin. The material has a high specific surface area of 1347 m2 g−1 and is rich in macro, meso and microporous tertiary pore structures. XPS analysis shows that boron and nitrogen are successfully doped within the carbon structure. As a Li-ion battery anode, BN-3DG950 delivers high specific capacities of 1050 and 307 mA h g−1 after 200 cycles at 0.01 and 4 A g−1 respectively. Defects caused by boron and nitrogen co-doping increases the number of available Li-ion storage sites, and the unique interconnected pore structure of the 3D graphene sheet framework enables high cycling stability with rapid electron and Li-ion transport for high rate capability.