Facet-controlled growth and soft-chemical exfoliation of two-dimensional titanium dioxide nanosheets.

TiO2 remains one of the most popular materials used in catalysts, photovoltaics, coatings, and electronics due to its abundance, chemical stability, and excellent catalytic properties. The tailoring of the TiO2 structure into two-dimensional nanosheets prompted the successful isolation of graphene and MXenes. In this review, facet-controlled TiO2 and monolayer titanate are outlined, covering their synthesis route and formation mechanism. The reactive facet of TiO2 is usually controlled by a capping agent. In contrast, the monolayer titanate is achieved by ion-exchange and delamination of layered titanates. Each route leads to 2D structures with unique physical and chemical properties, which expands its utilisation into several niche applications. We elaborate the detailed outlook for the future use and research studies of facet-controlled TiO2 and monolayer titanates. Advantages and disadvantages of both structures are provided, along with suggested applications for each type of 2D TiO2 nanosheets.

CDR3 Variants of the TXB2 Shuttle with Increased TfR1 Association Rate and Enhanced Brain Penetration.

Since the delivery of biologic drugs to the brain is greatly hampered by the existence of the blood-brain barrier (BBB), brain shuttles are being developed to enhance therapeutic efficacy. As we have previously shown, efficient and selective brain delivery was achieved with TXB2, a cross-species reactive, anti-TfR1 VNAR antibody. To further explore the limits of brain penetration, we conducted restricted randomization of the CDR3 loop, followed by phage display to identify improved TXB2 variants. The variants were screened for brain penetration in mice using a 25 nmol/kg (1.875 mg/kg) dose and a single 18 h timepoint. A higher kinetic association rate to TfR1 correlated with improved brain penetration in vivo. The most potent variant, TXB4, showed a 3.6-fold improvement over TXB2, which had on average 14-fold higher brain levels when compared to an isotype control. Like TXB2, TXB4 retained brain specificity with parenchymal penetration and no accumulation in other organs. When fused with a neurotensin (NT) payload, it led to a rapid drop in body temperature upon transport across the BBB. We also showed that fusion of TXB4 to four therapeutic antibodies (anti-CD20, anti-EGFRvIII, anti-PD-L1 and anti-BACE1) improved their brain exposure between 14- to 30-fold. In summary, we enhanced the potency of parental TXB2 brain shuttle and gained a critical mechanistic understanding of brain delivery mediated by the VNAR anti-TfR1 antibody.

A Single Domain Shark Antibody Targeting the Transferrin Receptor 1 Delivers a TrkB Agonist Antibody to the Brain and Provides Full Neuroprotection in a Mouse Model of Parkinson's Disease.

Single domain shark antibodies that bind to the transferrin receptor 1 (TfR1) on brain endothelial cells have been used to shuttle antibodies and other cargos across the blood brain barrier (BBB) to the brain. For these studies the TXB4 brain shuttle was fused to a TrkB neurotrophin receptor agonist antibody. The TXB4-TrkB fusion retained potent agonist activity at its cognate receptor and after systemic administration showed a 12-fold increase in brain levels over the unmodified antibody. Only the TXB4-TrkB antibody fusion was detected within the brain and localized to TrkB positive cells in the cortex and tyrosine hydroxylase (TH) positive dopaminergic neurons in the substantia nigra pars compacta (SNc), where it was associated with activated ERK1/2 signaling. When tested in the 6-hydroxydopamine (6-OHDA) mouse model of Parkinson's disease (PD), TXB4-TrkB, but not the unmodified antibody, completely prevented the 6-OHDA induced death of TH positive neurons in the SNc. In conclusion, the fusion of the TXB4 brain shuttle allows a TrkB agonist antibody to reach neuroprotective concentrations in the brain parenchyma following systemic administration.

Selection of oxygen reduction catalysts for secondary tri-electrode zinc-air batteries.

Oxygen reduction reaction (ORR) electrocatalysts, which are highly efficient, low-cost, yet durable, are important for secondary Zn-air cell applications. ORR activities of single and mixed metal oxide and carbon electrocatalysts were studied using rotating disc electrode (RDE) measurements, Tafel slope and Koutecky-Levich plots. It was found that MnOx combined with XC-72R demonstrated high ORR activity and good stability-up to 100 mA cm-2. The performance of the selected ORR electrode and a previously optimised oxygen evolution reaction (OER) electrode was thereafter tested in a custom-built secondary Zn-air cell in a tri-electrode configuration, and the effects of current density, electrolyte molarity, temperature, and oxygen purity on the performance of the ORR and OER electrode were investigated. Finally, the durability of the secondary Zn-air system was assessed, demonstrating energy efficiencies of 58-61% at 20 mA cm-2 over 40 h in 4 M NaOH + 0.3 M ZnO at 333 K.

Carbon Materials as Positive Electrodes in Bromine-Based Flow Batteries.

Bromine based redox flow batteries (RFBs) can provide sustainable energy storage due to the abundance of bromine. Such devices pair Br2 /Br- at the positive electrode with complementary redox couples at the negative electrode. Due to the highly corrosive nature of bromine, electrode materials need to be corrosion resistant and durable. The positive electrode requires good electrochemical activity and reversibility for the Br2 /Br- couple. Carbon materials enjoy the advantages of low cost, excellent electrical conductivity, chemical resistance, wide operational potential ranges, modifiable surface properties, and high surface area. Here carbon based materials for bromine electrodes are reviewed, with a focus on application in zinc-bromine, hydrogen-bromine, and polysulphide-bromine RFB systems, aiming to provide an overview of carbon materials to be used for design and development of bromine electrodes with improved performance. Aspects deserving further R&D are highlighted.

Single domain shark VNAR antibodies neutralize SARS-CoV-2 infection in vitro.

Single domain shark variable domain of new antigen receptor (VNAR) antibodies can offer a viable alternative to conventional Ig-based monoclonal antibodies in treating COVID-19 disease during the current pandemic. Here we report the identification of neutralizing single domain VNAR antibodies selected against the severe acute respiratory syndrome coronavirus 2 spike protein derived from the Wuhan variant using phage display. We identified 56 unique binding clones that exhibited high affinity and specificity to the spike protein. Of those, 10 showed an ability to block both the spike protein receptor binding domain from the Wuhan variant and the N501Y mutant from interacting with recombinant angiotensin-converting enzyme 2 (ACE2) receptor in vitro. In addition, three antibody clones retained in vitro blocking activity when the E484K spike protein mutant was used. The inhibitory property of the VNAR antibodies was further confirmed for all 10 antibody clones using ACE2 expressing cells with spike protein from the Wuhan variant. The viral neutralizing potential of the VNAR clones was also confirmed for the 10 antibodies tested using live Wuhan variant virus in in vitro cell infectivity assays. Single domain VNAR antibodies, due to their low complexity, small size, unique epitope recognition, and formatting flexibility, should be a useful adjunct to existing antibody approaches to treat COVID-19.

Blood-brain barrier transport using a high affinity, brain-selective VNAR antibody targeting transferrin receptor 1.

Transfer across the blood-brain barrier (BBB) remains a significant hurdle for the development of biopharmaceuticals with therapeutic effects within the central nervous system. We established a functional selection method to identify high affinity single domain antibodies to the transferrin receptor 1 (TfR1) with efficient biotherapeutic delivery across the BBB. A synthetic phage display library based on the variable domain of new antigen receptor (VNAR) was used for in vitro selection against recombinant human TfR1 ectodomain (rh-TfR1-ECD) followed by in vivo selection in mouse for brain parenchyma penetrating antibodies. TXB2 VNAR was identified as a high affinity, species cross-reactive VNAR antibody against TfR1-ECD that does not compete with transferrin or ferritin for receptor binding. IV dosing of TXB2 when fused to human Fc domain (TXB2-hFc) at 25 nmol/kg (1.875 mg/kg) in mice resulted in rapid binding to brain capillaries with subsequent transport into the brain parenchyma and specific uptake into TfR1-positive neurons. Likewise, IV dosing of TXB2-hFc fused with neurotensin (TXB2-hFc-NT) at 25 nmol/kg resulted in a rapid and reversible pharmacological response as measured by body temperature reduction. TXB2-hFc did not elicit any acute adverse reactions, bind, or deplete circulating reticulocytes or reduce BBB-expressed endogenous TfR1 in mice. There was no evidence of target-mediated clearance or accumulation in peripheral organs except lung. In conclusion, TXB2 is a high affinity, species cross-reactive, and brain-selective VNAR antibody to TfR1 that rapidly crosses the BBB and exhibits a favorable pharmacokinetic and safety profile and can be readily adapted to carry a wide variety of biotherapeutics from blood to brain.

Experimental and computation assessment of thermomechanical effects during auxetic foam fabrication.

Auxetic foams continue to interest researchers owing to their unique and enhanced properties. Existing studies attest to the importance of fabrication mechanisms and parameters. However, disparity in thermo-mechanical parameters has left much debate as to which factors dominate fabrication output quality. This paper provides experimental, computational, and statistical insights into the mechanisms that enable auxetic foams to be produced, using key parameters reported within the literature: porosity; heating time; and volumetric compression ratio. To advance the considerations on manufacturing parameter dominance, both study design and scale have been optimised to enable statistical inferences to be drawn. Whilst being unusual for a manufacturing domain, such additional analysis provides more conclusive evidence of auxetic properties and highlights the supremacy of volumetric compression ratio in predicting Poisson's ratio outcomes in the manufacture process. Furthermore statistical results are exploited to formulate key recommendations for those wishing to maximise/optimise auxetic foam production.

Brain delivery of biologics using a cross-species reactive transferrin receptor 1 VNAR shuttle.

Transferrin receptor 1 (TfR1) mediated transcytosis is an attractive strategy to enhance brain uptake of protein drugs, but translation remains a challenge. Here, a single domain shark antibody VNAR fragment (TXB2) with similar affinity to murine and human TfR1 was used to shuttle protein cargo into the brain. TXB2 was fused to a human IgG1 Fc domain (hFc) or to the amyloid-ß (Aß) antibody bapineuzumab (Bapi). TXB2-hFc displayed 20-fold higher brain concentrations compared with a control VNAR-hFc at 18 hours post-injection in wt mice. At the same time point, brain concentrations of Bapi-TXB2 was threefold higher than Bapi. In transgenic mice overexpressing human Aß, the brain-to-blood concentration ratio increased with time due to interaction with intracerebral Aß deposits. The relatively stable threefold difference between Bapi-TXB2 and Bapi was observed for up to 6 days after injection. PET imaging and ex vivo autoradiography revealed more parenchymal distribution of Bapi-TXB2 compared with Bapi. In conclusion, the TXB2 VNAR shuttle markedly increased brain uptake of protein cargo and increased brain concentrations of the Aß binding antibody Bapi.

3D Hierarchically Structured CoS Nanosheets: Li+ Storage Mechanism and Application of the High-Performance Lithium-Ion Capacitors.

Lithium-ion capacitors possess excellent power and energy densities, and they can combine both of those advantages from supercapacitors and lithium-ion batteries, leading to novel generation hybrid devices for storing energy. This study synthesized one three-dimensional (3D) hierarchical structure, self-assembled from CoS nanosheets, according to a simple and efficient manner, and can be used as an anode for lithium ion capacitors. This CoS anode, based on a conversion-type Li+ storage mechanism dominated by diffusion control, showed a large reversible capacity, together with excellent stability for cycling. The CoS shows a discharge capacity ≈434 mA h/g at 0.1 A/g. The hybrid lithium-ion capacitor, which had the CoS anode as well as the biochar cathode, exhibits excellent electrochemical performance with ultrahigh energy and power densities of 125.2 Wh/kg and 6400 W/kg, respectively, and an extended cycling life of 81.75% retention after 40 000 cycles. The CoS with self-assembled 3D hierarchical structure in combination with a carbon cathode offers a versatile device for future applications in energy storage.

Voltammetric characterisation of diferrocenylborinic acid in organic solution and in aqueous media when immobilised into a titanate nanosheet film.

Diferrocenylborinic acid (Fc2BOH, 1) has been synthesized in good yield via an improved synthetic path. Characterisation by nuclear magnetic resonance (NMR), mass spectrometry (HRMS), infrared spectroscopy (FTIR), X-ray crystallography, and by electrochemical methods reveal two one-electron oxidation processes for the two electronically coupled ferrocenyl moieties. The oxidation of 1 dissolved in organic media is contrasted to the oxidation of 1 in aqueous environments (by incorporation of 1 into a lamellar film of 2D titanate nanosheets on a glassy carbon electrode). Data from cyclic voltammetry and from square wave voltammetry suggest that the bridging boron can bind to nucleophiles (hydroxide, fluoride) upon oxidation of the ferrocenyl groups. A multi-pathway ECE reaction scheme is proposed. Potential applications in sensing are discussed.

Polymer nanocomposites having a high filler content: synthesis, structures, properties, and applications.

The recent development of nanoscale fillers, such as carbon nanotubes, graphene, and nanocellulose, allows the functionality of polymer nanocomposites to be controlled and enhanced. However, conventional synthesis methods of polymer nanocomposites cannot maximise the reinforcement of these nanofillers at high filler content. Approaches for the synthesis of high content filler polymer nanocomposites are suggested to facilitate future applications. The fabrication methods address the design of the polymer nanocomposite architecture, which encompasses one, two, and three dimensional morphologies. Factors that hamper the reinforcement of nanostructures, such as alignment, dispersion of the filler and interfacial bonding between the filler and polymer, are outlined. Using suitable approaches, maximum potential reinforcement of nanoscale fillers can be anticipated without limitations in orientation, dispersion, and the integrity of the filler particle-matrix interface. High filler content polymer composites containing emerging materials such as 2D transition metal carbides, nitrides, and carbonitrides (MXenes) are expected in the future.

Extraction of hydrophobic analytes from organic solution into a titanate 2D-nanosheet host: Electroanalytical perspectives.

Titanate nanosheets (single layer, typically 200 nm lateral size) deposited from aqueous colloidal solution onto electrode surfaces form lamellar hosts that bind redox active molecular redox probes. Here, hydrophobic redox systems such as anthraquinone, 1-amino-anthraquinone, deca-methylferrocene, 5,10,15,20-tetraphenyl-21H,23H-porphine manganese (III) chloride (TPPMnCl), and α-tocopherol are shown to bind directly from cyclopentanone solution (and from other types of organic solvents) into the titanate nanosheet film. For anthraquinone derivatives, stable voltammetric responses are observed in aqueous media consistent with 2-electron 2-proton reduction, however, independent of the pH of the outside solution phase environments. For decamethylferrocene a gradual decay of the voltammetric response is observed, but for TPPMnCl a more stable voltammetric signal is seen when immersed in chloride containing (NaCl) electrolyte. α-Tocopherol exhibits chemically irreversible oxidation and is detected with 1 mM-20 mM linear range and approximately 10-3 M concentration limit of detection. All redox processes exhibit an increase in current with increasing titanate film thickness and with increasing external electrolyte concentration. This and other observations suggest that important factors are analyte concentration and mobility within the titanate host, as well as ion exchange between titanate nanosheets and the outside electrolyte phase to maintain electroneutrality during voltammetric experiments. The lamellar titanate (with embedded tetrabutyl-ammonium cations) behaves like a hydrophobic host (for hydrophobic redox systems) similar to hydrophobic organic microphase systems. Potential for analytical applications is discussed.

VNAR single-domain antibodies specific for BAFF inhibit B cell development by molecular mimicry.

B cell-activating factor (BAFF) plays a dominant role in the B cell homeostasis. However, excessive BAFF promotes the development of autoreactive B-cells and several antibodies have been developed to block its activity. Bispecific antibodies with added functionality represent the next wave of biologics that may be more effective in the treatment of complex autoimmune disease. The single variable domain from the immunoglobulin new antigen receptor (VNAR) is one of the smallest antibody recognition units that could be combined with monospecific antibodies to develop bispecific agents. We isolated a panel of BAFF-binding VNARs with low nM potency from a semi-synthetic phage display library and examined their functional activity. The anti-BAFF VNARs blocked the binding of BAFF to all three of its receptors (BR3, TACI and BCMA) and the presence of the conserved DXL receptor motif found in the CDR3 regions suggests molecular mimicry as the mechanism of antagonism. One clone was formatted as an Fc fusion for functional testing and it was found to inhibit both mouse and human BAFF with equal potency ex vivo in a splenocyte proliferation assay. In mice, subchronic administration reduced the number of immature and transitional intermediates B cells and mature B cell subsets. These results indicate that VNAR single domain antibodies function as selective B-cell inhibitors and offer an alternative molecular format for targeting B-cell disorders.

Diagnostic value of bronchoalveolar lavage in leukemic and bone marrow transplant patients: the impact of antimicrobial therapy.

There is significant morbidity and mortality from pneumonia in leukemic and bone marrow transplant patients. We sought to explore the diagnostic yield of bronchoalveolar lavage (BAL) in these patients with new pulmonary infiltrates. A retrospective chart review of approximately 200 Non- human immunodeficiency virus (HIV) leukemic and Hematopoietic stem cell transplantation (HSCT) patients who underwent bronchoscopy at a single academic cancer center was performed. Antimicrobial use for less than 24 hours at the time of BAL was associated with a higher yield in this population (56.8% versus 32.8%, p<0.001). This supports performing bronchoscopy with BAL within 24 hours of antimicrobial therapy in leukemic and HSCT patients.

Transmission of Onchocerca volvulus by Simulium neavei in Mount Elgon focus of Eastern Uganda has been interrupted.

The study determined that Simulium neavei-transmitted onchocerciasis in Mount Elgon onchocerciasis focus had been interrupted. Annual mass treatment with ivermectin changed to two times per year along with vector elimination in 2007. Then, baseline microfilaria (mf) prevalence data of 1994 in five sentinel communities were compared with follow-up data in 2005 and 2011. Blood spots from 3,051 children obtained in 2009 were analyzed for Onchocerca volvulus immunoglobulin G4 antibodies. Fresh water crab host captures and blackflies collected indicated their infestation with larval stages of S. neavei and presence or absence of the vector, respectively. Mf rates dropped from 62.2% to 0.5%, and 1 (0.03%) of 3,051 children was positive for O. volvulus antibodies. Crab infestation dropped from 41.9% in 2007 to 0%, and S. neavei biting reduced to zero. Both remained zero for the next 3 years, confirming interruption of onchocerciasis transmission, and interventions were halted.

Hierarchical tube-in-tube structures prepared by electrophoretic deposition of nanostructured titanates into a TiO2 nanotube array.

Multiwalled nanotubular titanates have been incorporated inside the pores of a wide TiO2 nanotube array using electrophoretic deposition under vigorous stirring. The resulting hierarchical electrodes combine both benefits of open channels for rapid transport of ions and high specific surface area.

Transmission of Onchocerca volvulus continues in Nyagak-Bondo focus of northwestern Uganda after 18 years of a single dose of annual treatment with ivermectin.

The objective of the study was to determine whether annual ivermectin treatment in the Nyagak-Bondo onchocerciasis focus could safely be withdrawn. Baseline skin snip microfilariae (mf) and nodule prevalence data from six communities were compared with data collected in the 2011 follow-up in seven communities. Follow-up mf data in 607 adults and 145 children were compared with baseline (300 adults and 58 children). Flies collected in 2011 were dissected, and poolscreen analysis was applied to ascertain transmission. Nodule prevalence in adults dropped from 81.7% to 11.0% (P < 0.0001), and mf prevalence dropped from 97.0% to 23.2% (P < 0.0001). In children, mf prevalence decreased from 79.3% to 14.1% (P < 0.0001). Parous and infection rates of 401 flies that were dissected were 52.9% and 1.5%, respectively, whereas the infective rate on flies examination by polymerase chain reaction (PCR) was 1.92% and annual transmission potential was 26.9. Stopping ivermectin treatment may result in onchocerciasis recrudescence.

Comparison of fluorescence in situ hybridization (FISH) and dual-ISH (DISH) in the determination of HER2 status in breast cancer.

The determination of HER2 amplification is critical to selecting appropriate patients for HER2 targeted therapy in breast cancer. Dual in situ hybridization (DISH), an alternative to fluorescence in situ hybridization (FISH) and immunohistochemistry, is now available. To compare the FISH and DISH methods, we tested 251 samples enriched for common or difficult-to-assess HER2 anomalies. Seven samples failed DISH testing. There was a 64% (156/244) concordance between FISH and DISH by anomaly (κ = 0.58, 95% confidence interval, 0.51-0.65; P < .0001) and an 83% (203/244) concordance by amplification status (κ = 0.58; 95% confidence interval, 0.47-0.69; P < .0001). DISH resulted in lower estimates of HER2/ centromere 17 ratios than FISH, and many cases that were equivocal with FISH were normal with DISH. DISH did not detect any case with coamplification of HER2 and centromere 17. Using a cohort of difficult specimens, we observed less than 95% concordance between FISH and DISH. DISH may underestimate the HER2/chromosome 17 ratio, or FISH may overestimate this ratio.