Neurokinin-1 Receptor Antagonism Reduces Nonallergic Ocular Redness in a Rabbit Model.

Purpose: To evaluate the therapeutic efficacy of topical application of a neurokinin-1 receptor (NK1R) antagonist in a rabbit model of nonallergic ocular redness. Methods: Nonallergic ocular redness was induced in rabbits by a single, topical application of dapiparzole hydrochloride eye drops (0.5%, 1%, 2%, or 5%). The NK1R antagonist L-703,606 was topically applied to the eye at the same time of induction or 20 min after induction, and phosphate buffered saline (PBS) treatment served as the control. Superior bulbar conjunctival images were taken every 30 s for the first 2 min, followed by every 4 min for 8 min, and then every 10 min until 1 h. The severity of ocular redness was evaluated on the images using ImageJ-based ocular redness index (ORI) calculations. Results: The ORI scores were significantly increased after the application of 0.5%, 1%, 2%, or 5% dapiparzole at each time point evaluated, with the most severe redness induced by the 5% dapiprazole that led to a maximal mean increase in ORI score of 14 at 20 min post-induction and thus used for subsequent evaluation of therapeutic efficacy of NK1R antagonism. Topical L-703,606, when applied at the same time as dapiprazole induction, significantly suppressed the increase of ORI scores at all time points (∼40% decrease). Furthermore, when applied at 20 min after dapiprazole induction, L-703,606 rapidly and effectively suppressed the increase of ORI scores at 30, 40, 50, and 60 min (∼30% decrease). Conclusions: Topical blockade of NK1R effectively prevents and alleviates nonallergic ocular redness in a novel animal model.

Topical application of calcitonin gene-related peptide as a regenerative, antifibrotic, and immunomodulatory therapy for corneal injury.

Calcitonin gene-related peptide (CGRP) is a multifunctional neuropeptide abundantly expressed by corneal nerves. Using a murine model of corneal mechanical injury, we found CGRP levels in the cornea significantly reduced after injury. Topical application of CGRP as an eye drop accelerates corneal epithelial wound closure, reduces corneal opacification, and prevents corneal edema after injury in vivo. CGRP promotes corneal epithelial cell migration, proliferation, and the secretion of laminin. It reduces TGF-ß1 signaling and prevents TGF-ß1-mediated stromal fibroblast activation and tissue fibrosis. CGRP preserves corneal endothelial cell density, morphology, and pump function, thus reducing corneal edema. Lastly, CGRP reduces neutrophil infiltration, macrophage maturation, and the production of inflammatory cytokines in the cornea. Taken together, our results show that corneal nerve-derived CGRP plays a cytoprotective, pro-regenerative, anti-fibrotic, and anti-inflammatory role in corneal wound healing. In addition, our results highlight the critical role of sensory nerves in ocular surface homeostasis and injury repair.

Wearable strain sensor integrating mechanoluminescent fiber with a flexible printed circuit.

This paper reports an optical strain sensor that integrates a self-powered mechanoluminescent (ML) elastic fiber with a flexible circuit. The inclusion of an alumina nanoparticle as the additive results in seven-fold enhancement of ML intensity while maintaining flexibility of 120% strain. The sensor facilitates the detection of strain and stretching speed. It attains a sensitivity of 0.0022 lx/(1% strain) and a resolution of 0.2% strain, respectively. We have successfully applied it to detect bending motions of the finger, wrist, and elbow. This wearable strain sensor holds promise for diverse applications in wearable technology.

Lifestyle behaviours and associated factors among people with type 2 diabetes attending a diabetes clinic in Ningbo, China: A cross-sectional study.

The burden of type 2 diabetes (T2DM) in China is significant and growing, and this is reflected in high rates of T2DM in the city of Ningbo, China. Consequent impacts on morbidity, mortality, healthcare expenditure, and health-related quality of life, make this a problem of the utmost importance to address. One way to improve T2DM outcomes is to address lifestyle behaviours that may affect prognosis and complications, such as physical activity levels, dietary habits, smoking status, and alcohol intake. A cross-sectional survey was undertaken to describe the prevalence of being physically active, having a healthy diet, currently smoking, and currently drinking alcohol among people living with T2DM attending a diabetes clinic in Ningbo, China. Regression analysis was used to determine the factors associated with these lifestyle behaviours. We found a high prevalence of a healthy diet (97.8%, 95% CI 96.5-98.7%). Prevalence of being physically active (83.4%, 95% CI 80.6-85.9%), smoking (21.6%, 95% CI 18.8-24.6%), and alcohol drinking (32.9%. 95% CI 29.6-36.2%) appeared in keeping with those of the general population. Marked associations were demonstrated between male sex and smoking (OR 41.1, 95% CI 16.2-139.0), and male sex and alcohol drinking (OR 4.00, 95% CI 2.62-6.20). Correlation between lifestyle factors was demonstrated including between alcohol drinking and smoking, and between physical activity and reduced smoking. General diabetes self-management education programmes that address multiple lifestyle risk factors simultaneously may be beneficial in this population. Specific interventions targeting smoking cessation and reduction in alcohol drinking may be of benefit to men living with T2DM attending a diabetes clinic in Ningbo.

Topical application of calcitonin gene-related peptide as a regenerative, antifibrotic, and immunomodulatory therapy for corneal injury.

Calcitonin gene-related peptide (CGRP) is a multifunctional neuropeptide abundantly expressed by corneal nerves. Using a murine model of corneal mechanical injury, we found CGRP levels in the cornea to be significantly reduced after injury. Topical application of CGRP as an eye drop three times daily accelerates corneal epithelial wound closure, reduces corneal opacification, and prevents corneal edema after injury in vivo. We then used a series of in vitro and in vivo techniques to investigate the mechanisms underlying CGRP's functions. CGRP promotes corneal epithelial cell migration, proliferation, and the secretion of laminin. It reduces TGF-ß1 signaling and prevents TGF-ß1-mediated stromal fibroblast activation and tissue fibrosis. CGRP reduces corneal endothelial cell apoptosis and death, preserves cell density and morphology, and promotes their pump function, thus reducing edema. Lastly, CGRP reduces neutrophil infiltration, macrophage maturation, and the production of inflammatory cytokines in the cornea. Taken together, our results show that corneal nerve-derived CGRP plays a cyto-protective, pro-regenerative, anti-fibrotic, and anti-inflammatory role in corneal wound healing. Given that current treatment options for corneal injury and opacity are scarce, CGRP has significant therapeutic potential in this area of unmet medical needs. In addition, our results highlight the critical role of sensory nerves in ocular surface homeostasis and injury repair.

Identification and Characterization of Two Novel Extracellular ß-Glucanases from Chaetomium globosum against Fusarium sporotrichioides.

Chaetomium globosum can inhibit the growth of fusarium by means of their extracellular proteins. Two novel ß-glucanases, designated Cgglu17A and Cgglu16B, were separated from the supernatant of C. globosum W7 and verified to have the ability to hydrolyze cell walls of Fusarium sporotrichioides MLS-19. Cgglu17A (397 amino acids) was classified as glycoside hydrolase family 17 while Cgglu16B belongs to the family16 (284 amino acids). Recombinant protein Cgglu17A was successfully expressed in Escherichia coli, and the enzymes were purified by affinity chromatography. Maximum activity of Cgglu17A appeared at the pH 5.5 and temperature 50 °C, but Cgglu16B shows the maximum activity at the pH 5.0 and temperature 50 °C. Most of heavy metal ions had inhibition effect on the two enzymes, but Cgglu17A and Cgglu16B were respectively activated by Ba2+ and Mn2+. Cgglu17A exhibited high substrate specificity, almost only catalyzing the cleavage of ß-1,3-glycosidic bond, in various polysaccharose, to liberate glucose. However, Cgglu16B showed high catalytic activities to both ß-1,3-glycosidic and ß-1,3-1,4-glycosidic bonds. Cgglu17A was an exo-glucanase, but Cgglu16B was an endo-glucanase based on hydrolytic properties assay. Both of two enzymes showed potential antifungal activity, and the synergistic effect was observed in the germination experiment of pathogenic fungus. In conclusion, Cgglu17A (exo-1,3-ß-glucanase) and Cgglu16B (endo-1,3(4)-ß-glucanase) were confirmed to play a key role in the process of C. globosum controlling fusarium and have potential application value on industry and agriculture for the first time.

Corrigendum: Therapeutic potential of topical administration of acriflavine against hypoxia-inducible factors for corneal fibrosis.

[This corrects the article DOI: 10.3389/fphar.2022.996635.].

Therapeutic potential of topical administration of acriflavine against hypoxia-inducible factors for corneal fibrosis.

Transdifferentiation of keratocytes into fibroblasts or further into myofibroblasts, which produced denser and more disorganized extracellular matrix, is the major cause of corneal fibrosis and scarring, leading to corneal blindness. TGF-ß1 is the critical cytokine for the myofibroblast's transdifferentiation and survival. Hypoxia Inducible Factor (HIF) was found to play an important role in promoting fibrosis in lung, kidney, and dermal tissues recently. Our preliminary study demonstrated that topical administration of the acriflavine (ACF), a drug inhibiting HIF dimerization, delayed corneal opacity and neovascularization after the alkali burn. To know whether ACF could prevent corneal fibrosis and improve corneal transparency, we created a mouse mechanical corneal injury model and found that topical administration of ACF significantly inhibited corneal fibrosis at day 14 post-injury. The reduction of myofibroblast marker α-SMA, and fibronectin, one of the disorganized extracellular matrix molecules, in the corneal stroma were confirmed by the examination of immunohistochemistry and real-time PCR. Furthermore, the ACF inhibited the expression of α-SMA and fibronectin in both TGF-ß1 stimulated or unstimulated fibroblasts in vitro. This effect was based on the inhibition of HIF signal pathways since the levels of the HIF-1α downstream genes including Slc2a1, Bnip3 and VEGFA were downregulated. To our knowledge, this is the first time to implicate that HIFs might be a new treatment target for controlling corneal fibrosis in mechanical corneal injuries.

Perfluorodecalin-based oxygenated emulsion as a topical treatment for chemical burn to the eye.

Chemical injuries to the eye are emergencies with limited acute treatment options other than prompt irrigation and can cause permanent vision loss. We developed a perfluorodecalin-based supersaturated oxygen emulsion (SSOE) to topically deliver high concentration of oxygen to the eye. SSOE is manufactured in hyperbaric conditions and stored in a ready-to-use canister. Upon dispensation, SSOE rapidly raises partial oxygen pressure 3 times over atmospheric level. SSOE is biocompatible with human corneal cells and safe on mouse eyes in vivo. A single topical application of SSOE to the eye after alkali injury significantly promotes corneal epithelial wound healing, decreases anterior chamber exudation, and reduces optical opacity and cataract formation in mice. SSOE treatment reduces intraocular hypoxia, cell death, leukocyte infiltration, production of inflammatory mediators, and hypoxia-inducible factor 1-alpha signaling, thus hastening recovery of normal tissue integrity during the wound healing process. Here, we show that SSOE is an effective topical therapeutic in the acute treatment of ocular chemical injuries.

Health-related quality of life of people with type 2 diabetes and its associated factors at a tertiary care clinic in Ningbo, China: A cross-sectional study.

INTRODUCTION: The burden of type 2 diabetes (T2DM) in China is increasing, with potential impacts on the health-related quality of life (HRQoL) of those who develop the disease. Context-specific assessment of HRQoL and its associated factors informs the development of contextually appropriate interventions to improve HRQoL. This study aimed to determine the HRQoL and its associated factors in people with T2DM at a tertiary care clinic in Ningbo, China. METHODS: A cross-sectional survey was undertaken among 406 people with T2DM in 2020-21. The primary outcome was HRQoL measured using EQ VAS and EQ-5D index from the EQ-5D-3L questionnaire. Multivariable regression analysis was used to determine the factors associated with HRQoL scores. RESULTS: The mean (± standard deviation) EQ VAS score was 68.7 (13.8). Median (interquartile range) EQ-5D index was 1 (0.027). Prevalence of problems in HRQoL domains was as follows: pain/discomfort (15.7%), anxiety/depression (13.3%), mobility (5.4%), self-care (3.5%) and managing usual activities (5.2%). The ≥60 years age group had a mean EQ VAS score 8.7 points higher (95% CI 3.4, 13.9; p < .001) than the 18-39 years age group. Those with T2DM >10 years had a mean EQ VAS score 8.6 points lower than those with a duration <1 year (-12.8, -4.4; p = .001). A T2DM duration >10 years was associated with a reduction in the EQ-5D index of 0.029 (-0.041, -0.016; p < .001) compared with a duration <1 year. CONCLUSIONS: Depression/anxiety and pain/discomfort are important domains of reduced HRQoL for this population. A longer duration of T2DM is associated with reduced HRQoL scores, including both EQ VAS and EQ-5D index. Increasing age may be counterintuitively associated with an increase in EQ VAS score in this population, potentially reflecting a 'paradox of aging' process. Future work should focus on developing, evaluating and implementing interventions to improve HRQoL in T2DM, such as strategies to manage pain and mental health conditions.

Promotion of corneal angiogenesis by sensory neuron-derived calcitonin gene-related peptide.

The normal cornea has no blood vessels but has abundant innervation. There is emerging evidence that sensory nerves, originated from the trigeminal ganglion (TG) neurons, play a key role in corneal angiogenesis. In the current study, we examined the role of TG sensory neuron-derived calcitonin gene-related peptide (CGRP) in promoting corneal neovascularization (CNV). We found that CGRP was expressed in the TG and cultured TG neurons. In the cornea, minimal CGRP mRNA was detected and CGRP immunohistochemical staining was exclusively co-localized with corneal nerves, suggesting corneal nerves are likely the source of CGRP in the cornea. In response to intrastromal suture placement and neovascularization in the cornea, CGRP expression was increased in the TG. In addition, we showed that CGRP was potently pro-angiogenic, leading to vascular endothelial cell (VEC) proliferation, migration, and tube formation in vitro and corneal hemangiogenesis and lymphangiogenesis in vivo. In a co-culture system of TG neurons and VEC, blocking CGRP signaling in the conditioned media of TG neurons led to decreased VEC migration and tube formation. More importantly, subconjunctival injection of a CGRP antagonist CGRP8-37 reduced suture-induced corneal hemangiogenesis and lymphangiogenesis in vivo. Taken together, our data suggest that TG sensory neuron and corneal nerve-derived CGRP promotes corneal angiogenesis.

Directing osteoblastic cell migration on arrays of nanopillars and nanoholes with different aspect ratios.

To realize highly directional guidance for cell migration, both micro- and nano-scale topographies were studied to better understand and mimic the complex extracellular matrix environment. Polydimethylsiloxane-based platforms with micro- and nano-topographies were developed to systematically study their guidance effects on cell migration behaviors. Compared to microtopography such as flat surface or grating, nanotopographies such as nanoholes and nanopillars could promote the generation of filopodia and extension of long protrusions with increased migration speed for MC3T3-E1 cells. Although cells on the grating structures showed lower migration speed, more directional cell migration was achieved due to their anisotropic topography compared to nanohole or nanopillar arrays with isotropic structures. To further enhance the cell migration directionality, the nanotopographies were patterned in grating arrangements and the results showed that both nanoholes and nanopillars in grating arrangements introduced more directional cell migration compared to gratings. The effects of physical dimensions of the nanotopographies on cell migration were studied and the results showed that there was less cell elongation and less directional migration of the nanoholes in grating arrangements with increasing depth of nanoholes. However, the nanopillars in grating arrangements showed more cell elongation, more directional migration, and higher migration speed with increasing height of the nanopillars. Platforms with nanopillars in grating arrangements and large height could be used to control cell migration speed and directionality, which could potentially lead to cell sorting and screening.

High-sensitivity magnetic sensor based on the evanescent scattering by a magnetorheological film.

We present a simple concept to implement a magnetic sensor that uses evanescent scattering by a suspended magnetorheological (MR) film above a planar waveguide. The soft MR film embedded with ferromagnetic particles is to induce scattering on the evanescent field of a planar waveguide at a proximity distance. This distance can be controlled precisely by a magnetic field. Consequently, the waveguide output power changes in response to the magnetic intensity. Two sensor prototypes of different film thicknesses were designed and tested showing a trade-off between the sensitivity and dynamic sensing range. A maximum sensitivity of ∼2.62dB/mT was obtained. Compared to optical micro-electromechanical systems, the presented sensors feature a simple design, easy fabrication, low cost, and the potential for large-scale production and miniaturization to be integrated into portable devices.

Efficacy of cyanoacrylate tissue adhesive in the management of corneal thinning and perforation due to microbial keratitis.

PURPOSE: Report the efficacy of cyanoacrylate tissue adhesive (CTA) application in the management of corneal thinning and perforations associated with microbial keratitis. METHODS: A retrospective review of consecutive patients who underwent CTA application for corneal thinning and perforation secondary to microbiologically proven infectious keratitis between 2001 and 2018 at a single center. We defined successful CTA application as an intact globe without tectonic surgical intervention. RESULTS: The cohort included 67 patients, and 37 presented with corneal perforation while 30 had corneal thinning. The perforation/thinning was central/paracentral in 43 eyes and peripheral in 23 eyes. The underlying infectious etiologies were monomicrobial in 42 cases (35 bacterial, 3 fungal, 2 viral, and 2 acanthamoeba cases) and polymicrobial in 25 cases (22 polybacterial cases and 3 cases with a combination of Gram positive bacteria and fungus). The median duration of glue retention was 29 days. The CTA success rate was 73%, 64%, and 44% at 10, 30, and 180 days, respectively. CTA application appears more successful in monomicrobial (vs. polymicrobial) and Gram positive bacterial (vs. Gram negative) keratitis but the differences are statistically non-significant. The location of perforation/thinning and the use of topical corticosteroid were not associated with CTA failure. CONCLUSION: CTA was moderately effective in restoring globe integrity in severe corneal thinning and perforation secondary to microbial keratitis in the short term. However the majority of patients require tectonic surgical intervention within 6 months. CTA application success is not significantly associated with the location of thinning/perforation or the use of topical corticosteroid.

3D nanoplasmonic biosensor for detection of filopodia in cells.

Filopodia are thin finger-like protrusions from cells and they are hard to detect using electrical, mechanical, or optical sensors because of their nanometer scale features. Besides, the signals from filopodia and the cell membrane are often mixed together which makes the detection of filopodia challenging. Here, a 3D nanoplasmonic biosensor with microposts is proposed to overcome these limitations. By using suitable chemical coating and physical dimensions, the signals from filopodia and the cell membrane were separated by having the microposts keep the cell membrane from making contact with the nanoplasmonic biosensor. The filopodia were detected by the 3D asymmetrical nanopillars with sharp Fano resonance. The sensitivity and figure of merit of the nanoplasmonic biosensor were 650 nm per refractive index unit and 28.3, respectively. A large peak shift of 6 nm was observed for the detection of MC3T3 osteoblastic cell filopodia at a concentration of 1300 cells per mm2. To the best of our knowledge, this is the first demonstration of filopodia detection using nanoplasmonic biosensors, where microposts were used to separate the cell membrane from filopodia and the 3D nanoplasmonic biosensors were used to monitor filopodia on the nanometer scale. These combined 3D micro- and nano-structures allow filopodia to be detected using different sensors without interference from the cell membrane.

Two-Dimensional Sandwich-Structured Mesoporous Mo2C/Carbon/Graphene Nanohybrids for Efficient Hydrogen Production Electrocatalysts.

The main challenge in water electrolysis, an appealing technique to alleviate future energy crisis, is the design of efficient electrocatalysts for hydrogen evolution reaction (HER). On the basis of an interface self-assembly approach, we synthesize mesoporous nitrogen-doped carbon/Mo2C/reduced graphene oxide nanohybrids (denoted as mNC-Mo2C@rGO), which represent a new type of two-dimensional Mo2C/carbon hybrid nanomaterials and possess a sandwichlike structure with well-defined mesopores. The method involves the co-self-assembly of spherical micelles formed from polystyrene- block-poly(ethylene oxide), pyrrole (Py) monomers, and molybdate ions (Mo7O246-) on GO surfaces in aqueous solution, followed by polymerization of Py and calcination of the nanocomposites at 900 °C under nitrogen atmosphere. The resultant mNC-Mo2C@rGO nanosheets possess high N contents, large specific surface areas (SSAs), and 4 nm Mo2C particles well-distributed in the mesoporous carbon matrix. The Mo2C content is controllable in the range of 18.4-42.4 wt % by adjusting the feed amount of Mo7O246-. In particular, mNC-Mo2C@rGO with an SSA of 344 m2/g and a Mo2C content of ca. 28 wt % exhibits the highest HER catalytic activity in 1 M KOH electrolyte, with a 95 mV overpotential at 10 mA/cm2, a Tafel slope of 49.8 mV/dec, and a long-term stability of 60 h at 20 mA/cm2. This study blazes a trail for the synthesis of new functional nanomaterials with potential applications as efficient HER electrocatalysts.

Highly sensitive detection of exosomes by 3D plasmonic photonic crystal biosensor.

In this study, two-dimensional (2D), quasi-three-dimensional (3D), and 3D plasmonic photonic crystal (PPC) nanostructures with point-defect cavities were developed and fabricated using direct and reversal nanoimprint lithography. As a result of the hybrid coupling of localized surface plasmon resonance and Fabry-Perot cavity modes, the quasi-3D plasmonic nanoholes showed higher electromagnetic field intensity and sensitivity than the 2D plasmonic nanoholes. Specifically, the sensitivity of the quasi-3D plasmonic nanoholes was 483 nm per refractive index unit (RIU), whereas that of the 2D plasmonic nanoholes was 276 nm RIU-1. In addition, by enhancing electromagnetic field intensity around corners and generating an additional subradiant dark mode, the symmetrical breakage of the quasi-3D plasmonic nanoholes further increased the sensitivity to 946 nm RIU-1. Among all the nanostructures developed in the study, the 3D PPC nanostructures with point-defect cavities showed the highest sensitivity up to 1376 nm RIU-1 and highest figure of merit of 11.6 as the result of the hybrid coupling of plasmonics and photonic crystal modes with multilayered plasmonic nanostructures. The spacing between the 3D PPC nanostructures was comparable with the average size of exosomes derived from fibroblast L cells, which allowed the exosomes to spread around the 3D PPC nanostructures with increased sensing area. This effect further enhanced the detection sensitivity with a large peak shift of 9 nm when using the 3D PPC biosensor to detect exosomes at the concentration of 1 × 104 particles per ml, and the peak shift increased to 102 nm as exosome concentration increased to 1 × 1011 particles per ml.

Label-free detection of live cancer cells and DNA hybridization using 3D multilayered plasmonic biosensor.

Three-dimensional (3D) multilayered plasmonic nanostructures consisting of Au nanosquares on top of SU-8 nanopillars, Au asymmetrical nanostructures in the middle, and Au asymmetrical nanoholes at the bottom were fabricated through reversal nanoimprint technology. Compared with two-dimensional and quasi-3D plasmonic nanostructures, the 3D multilayered plasmonic nanostructures showed higher electromagnetic field intensity, longer plasmon decay length and larger plasmon sensing area, which are desirable for highly sensitive localized surface plasmonic resonance biosensors. The sensitivity and resonance peak wavelength of the 3D multilayered plasmonic nanostructures could be adjusted by varying the offset between the top and bottom SU-8 nanopillars from 31% to 56%, and the highest sensitivity of 382 and 442 nm/refractive index unit were observed for resonance peaks at 581 and 805 nm, respectively. Live lung cancer A549 cells with a low concentration of 5 × 103 cells ml-1 and a low sample volume of 2 µl could be detected by the 3D multilayered plasmonic nanostructures integrated in a microfluidic system. The 3D plasmonic biosensors also had the advantages of detecting DNA hybridization by capturing the complementary target DNA in the low concentration range of 10-14-10-7 M, and providing a large peak shift of 82 nm for capturing 10-7 M complementary target DNA without additional signal amplification.

Patterning Graphene Surfaces with Iron-Oxide-Embedded Mesoporous Polypyrrole and Derived N-Doped Carbon of Tunable Pore Size.

This study develops a novel strategy, based on block copolymer self-assembly in solution, for preparing two-dimensional (2D) graphene-based mesoporous nanohybrids with well-defined large pores of tunable sizes, by employing polystyrene-block-poly(ethylene oxide) (PS-b-PEO) spherical micelles as the pore-creating template. The resultant 2D nanohybrids possess a sandwich-like structure with Fe2 O3 nanoparticle-embedded mesoporous polypyrrole (PPy) monolayers grown on both sides of reduced graphene oxide (rGO) nanosheets (denoted as mPPy-Fe2 O3 @rGO). Serving as supercapacitor electrode materials, the 2D ternary nanohybrids exhibit controllable capacitive performance depending on the pore size, with high capacitance (up to 1006 F/g at 1 A/g), good rate performance (750 F/g at 20 A/g) and excellent cycling stability. Furthermore, the pyrolysis of mPPy-Fe2 O3 @rGO at 800 °C yields 2D sandwich-like mesoporous nitrogen-doped carbon/Fe3 O4 /rGO (mNC-Fe3 O4 @rGO). The mNC-Fe3 O4 @rGO nanohybrids with a mean pore size of 12 nm show excellent electrocatalytic activity as an oxygen reduction reaction (ORR) catalyst with a four-electron transfer nature, a high half-wave-potential of +0.84 V and a limiting current density of 5.7 mA/cm2 , which are well comparable with those of the best commercial Pt/C catalyst. This study takes advantage of block copolymer self-assembly for the synthesis of 2D multifunctional mesoporous nanohybrids, and helps to understand the control of their structures and electrochemical performance.

Growth of 2D Mesoporous Polyaniline with Controlled Pore Structures on Ultrathin MoS2 Nanosheets by Block Copolymer Self-Assembly in Solution.

The development of versatile strategies toward two-dimensional (2D) porous nanocomposites with tunable pore structures draws immense scientific attention in view of their attractive physiochemical properties and a wide range of promising applications. This paper describes a self-assembly approach for the directed growth of mesoporous polyaniline (PANi) with tunable pore structures and sizes on ultrathin freestanding MoS2 nanosheets in solution, which produces 2D mesoporous PANi/MoS2 nanocomposites. The strategy employs spherical and cylindrical micelles, which are formed by the controlled solution self-assembly of block copolymers, as the soft templates for the construction of well-defined spherical and cylindrical mesopores in the 2D PANi/MoS2 nanocomposites, respectively. With potential applications as supercapacitor electrode materials, the resultant 2D composites show excellent capacitive performance with a maximum capacitance of 500 F g-1 at a current density of 0.5 A g-1, good rate performance, as well as outstanding stability for charge-discharge cycling. Moreover, the 2D mesoporous nanocomposites offer an opportunity for the study on the influence of different pore structures on their capacitive performance, which helps to understand the pore structure-property relationship of 2D porous electrode materials and to achieve their electrochemical performance control.